1 /*
2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "memory/allocation.inline.hpp"
36 #include "memory/filemap.hpp"
37 #include "mutex_linux.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "os_share_linux.hpp"
40 #include "osContainer_linux.hpp"
41 #include "prims/jniFastGetField.hpp"
42 #include "prims/jvm.h"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/extendedPC.hpp"
46 #include "runtime/globals.hpp"
47 #include "runtime/interfaceSupport.hpp"
48 #include "runtime/init.hpp"
49 #include "runtime/java.hpp"
50 #include "runtime/javaCalls.hpp"
51 #include "runtime/mutexLocker.hpp"
52 #include "runtime/objectMonitor.hpp"
53 #include "runtime/orderAccess.inline.hpp"
54 #include "runtime/osThread.hpp"
55 #include "runtime/perfMemory.hpp"
56 #include "runtime/sharedRuntime.hpp"
57 #include "runtime/statSampler.hpp"
58 #include "runtime/stubRoutines.hpp"
59 #include "runtime/thread.inline.hpp"
60 #include "runtime/threadCritical.hpp"
61 #include "runtime/timer.hpp"
62 #include "services/attachListener.hpp"
63 #include "services/memTracker.hpp"
64 #include "services/runtimeService.hpp"
65 #include "utilities/decoder.hpp"
66 #include "utilities/defaultStream.hpp"
67 #include "utilities/events.hpp"
68 #include "utilities/elfFile.hpp"
69 #include "utilities/growableArray.hpp"
70 #include "utilities/vmError.hpp"
71
72 // put OS-includes here
73 # include <sys/types.h>
74 # include <sys/mman.h>
75 # include <sys/stat.h>
76 # include <sys/select.h>
77 # include <pthread.h>
78 # include <signal.h>
79 # include <errno.h>
80 # include <dlfcn.h>
81 # include <stdio.h>
82 # include <unistd.h>
83 # include <sys/resource.h>
84 # include <pthread.h>
85 # include <sys/stat.h>
86 # include <sys/time.h>
87 # include <sys/times.h>
88 # include <sys/utsname.h>
89 # include <sys/socket.h>
90 # include <sys/wait.h>
91 # include <pwd.h>
92 # include <poll.h>
93 # include <semaphore.h>
94 # include <fcntl.h>
95 # include <string.h>
96 # include <syscall.h>
97 # include <sys/sysinfo.h>
98 # include <gnu/libc-version.h>
99 # include <sys/ipc.h>
100 # include <sys/shm.h>
101 # include <link.h>
102 # include <stdint.h>
103 # include <inttypes.h>
104 # include <sys/ioctl.h>
105
106 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
107
108 #ifndef _GNU_SOURCE
109 #define _GNU_SOURCE
110 #include <sched.h>
111 #undef _GNU_SOURCE
112 #else
113 #include <sched.h>
114 #endif
115
116 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
117 // getrusage() is prepared to handle the associated failure.
118 #ifndef RUSAGE_THREAD
119 #define RUSAGE_THREAD (1) /* only the calling thread */
120 #endif
121
122 #define MAX_PATH (2 * K)
123
124 #define MAX_SECS 100000000
125
126 // for timer info max values which include all bits
127 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
128
129 #define LARGEPAGES_BIT (1 << 6)
130 ////////////////////////////////////////////////////////////////////////////////
131 // global variables
132 julong os::Linux::_physical_memory = 0;
133
134 address os::Linux::_initial_thread_stack_bottom = NULL;
135 uintptr_t os::Linux::_initial_thread_stack_size = 0;
136
137 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
138 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
139 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
140 Mutex* os::Linux::_createThread_lock = NULL;
141 pthread_t os::Linux::_main_thread;
142 int os::Linux::_page_size = -1;
143 const int os::Linux::_vm_default_page_size = (8 * K);
144 bool os::Linux::_is_floating_stack = false;
145 bool os::Linux::_is_NPTL = false;
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 const char * os::Linux::_glibc_version = NULL;
148 const char * os::Linux::_libpthread_version = NULL;
149 pthread_condattr_t os::Linux::_condattr[1];
150
151 static jlong initial_time_count=0;
152
153 static int clock_tics_per_sec = 100;
154
155 // For diagnostics to print a message once. see run_periodic_checks
156 static sigset_t check_signal_done;
157 static bool check_signals = true;
158
159 static pid_t _initial_pid = 0;
160
161 /* Signal number used to suspend/resume a thread */
162
163 /* do not use any signal number less than SIGSEGV, see 4355769 */
164 static int SR_signum = SIGUSR2;
165 sigset_t SR_sigset;
166
167 /* Used to protect dlsym() calls */
168 static pthread_mutex_t dl_mutex;
169
170 // Declarations
171 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
172
173 // utility functions
174
175 static int SR_initialize();
176
177 julong os::available_memory() {
178 return Linux::available_memory();
179 }
180
181 julong os::Linux::available_memory() {
182 // values in struct sysinfo are "unsigned long"
183 struct sysinfo si;
184 julong avail_mem;
185
186 if (OSContainer::is_containerized()) {
187 jlong mem_limit, mem_usage;
188 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
189 if (PrintContainerInfo) {
190 tty->print_cr("container memory limit %s: " JLONG_FORMAT ", using host value",
191 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
192 }
193 }
194
195 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
196 if (PrintContainerInfo) {
197 tty->print_cr("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
198 }
199 }
200
201 if (mem_limit > 0 && mem_usage > 0 ) {
202 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
203 if (PrintContainerInfo) {
204 tty->print_cr("available container memory: " JULONG_FORMAT, avail_mem);
205 }
206 return avail_mem;
207 }
208 }
209
210 sysinfo(&si);
211 avail_mem = (julong)si.freeram * si.mem_unit;
212 if (Verbose) {
213 tty->print_cr("available memory: " JULONG_FORMAT, avail_mem);
214 }
215 return avail_mem;
216 }
217
218 julong os::physical_memory() {
219 jlong phys_mem = 0;
220 if (OSContainer::is_containerized()) {
221 jlong mem_limit;
222 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
223 if (PrintContainerInfo) {
224 tty->print_cr("total container memory: " JLONG_FORMAT, mem_limit);
225 }
226 return mem_limit;
227 }
228
229 if (PrintContainerInfo) {
230 tty->print_cr("container memory limit %s: " JLONG_FORMAT ", using host value",
231 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
232 }
233 }
234
235 phys_mem = Linux::physical_memory();
236 if (Verbose) {
237 tty->print_cr("total system memory: " JLONG_FORMAT, phys_mem);
238 }
239 return phys_mem;
240 }
241
242 ////////////////////////////////////////////////////////////////////////////////
243 // environment support
244
245 bool os::getenv(const char* name, char* buf, int len) {
246 const char* val = ::getenv(name);
247 if (val != NULL && strlen(val) < (size_t)len) {
248 strcpy(buf, val);
249 return true;
250 }
251 if (len > 0) buf[0] = 0; // return a null string
252 return false;
253 }
254
255
256 // Return true if user is running as root.
257
258 bool os::have_special_privileges() {
259 static bool init = false;
260 static bool privileges = false;
261 if (!init) {
262 privileges = (getuid() != geteuid()) || (getgid() != getegid());
263 init = true;
264 }
265 return privileges;
266 }
267
268
269 #ifndef SYS_gettid
270 // i386: 224, ia64: 1105, amd64: 186, sparc 143
271 #ifdef __ia64__
272 #define SYS_gettid 1105
273 #else
274 #ifdef __i386__
275 #define SYS_gettid 224
276 #else
277 #ifdef __amd64__
278 #define SYS_gettid 186
279 #else
280 #ifdef __sparc__
281 #define SYS_gettid 143
282 #else
283 #error define gettid for the arch
284 #endif
285 #endif
286 #endif
287 #endif
288 #endif
289
290 // Cpu architecture string
291 static char cpu_arch[] = HOTSPOT_LIB_ARCH;
292
293 // pid_t gettid()
294 //
295 // Returns the kernel thread id of the currently running thread. Kernel
296 // thread id is used to access /proc.
297 //
298 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
299 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
300 //
301 pid_t os::Linux::gettid() {
302 int rslt = syscall(SYS_gettid);
303 if (rslt == -1) {
304 // old kernel, no NPTL support
305 return getpid();
306 } else {
307 return (pid_t)rslt;
308 }
309 }
310
311 // Most versions of linux have a bug where the number of processors are
312 // determined by looking at the /proc file system. In a chroot environment,
313 // the system call returns 1. This causes the VM to act as if it is
314 // a single processor and elide locking (see is_MP() call).
315 static bool unsafe_chroot_detected = false;
316 static const char *unstable_chroot_error = "/proc file system not found.\n"
317 "Java may be unstable running multithreaded in a chroot "
318 "environment on Linux when /proc filesystem is not mounted.";
319
320 void os::Linux::initialize_system_info() {
321 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
322 if (processor_count() == 1) {
323 pid_t pid = os::Linux::gettid();
324 char fname[32];
325 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
326 FILE *fp = fopen(fname, "r");
327 if (fp == NULL) {
328 unsafe_chroot_detected = true;
329 } else {
330 fclose(fp);
331 }
332 }
333 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
334 assert(processor_count() > 0, "linux error");
335 }
336
337 void os::init_system_properties_values() {
338 // The next steps are taken in the product version:
339 //
340 // Obtain the JAVA_HOME value from the location of libjvm.so.
341 // This library should be located at:
342 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
343 //
344 // If "/jre/lib/" appears at the right place in the path, then we
345 // assume libjvm.so is installed in a JDK and we use this path.
346 //
347 // Otherwise exit with message: "Could not create the Java virtual machine."
348 //
349 // The following extra steps are taken in the debugging version:
350 //
351 // If "/jre/lib/" does NOT appear at the right place in the path
352 // instead of exit check for $JAVA_HOME environment variable.
353 //
354 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
355 // then we append a fake suffix "hotspot/libjvm.so" to this path so
356 // it looks like libjvm.so is installed there
357 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
358 //
359 // Otherwise exit.
360 //
361 // Important note: if the location of libjvm.so changes this
362 // code needs to be changed accordingly.
363
364 // See ld(1):
365 // The linker uses the following search paths to locate required
366 // shared libraries:
367 // 1: ...
368 // ...
369 // 7: The default directories, normally /lib and /usr/lib.
370 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
371 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
372 #else
373 #define DEFAULT_LIBPATH "/lib:/usr/lib"
374 #endif
375
376 // Base path of extensions installed on the system.
377 #define SYS_EXT_DIR "/usr/java/packages"
378 #define EXTENSIONS_DIR "/lib/ext"
379 #define ENDORSED_DIR "/lib/endorsed"
380
381 // Buffer that fits several sprintfs.
382 // Note that the space for the colon and the trailing null are provided
383 // by the nulls included by the sizeof operator.
384 const size_t bufsize =
385 MAX3((size_t)MAXPATHLEN, // For dll_dir & friends.
386 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR), // extensions dir
387 (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir
388 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
389
390 // sysclasspath, java_home, dll_dir
391 {
392 char *pslash;
393 os::jvm_path(buf, bufsize);
394
395 // Found the full path to libjvm.so.
396 // Now cut the path to <java_home>/jre if we can.
397 *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
398 pslash = strrchr(buf, '/');
399 if (pslash != NULL) {
400 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
401 }
402 Arguments::set_dll_dir(buf);
403
404 if (pslash != NULL) {
405 pslash = strrchr(buf, '/');
406 if (pslash != NULL) {
407 *pslash = '\0'; // Get rid of /<arch>.
408 pslash = strrchr(buf, '/');
409 if (pslash != NULL) {
410 *pslash = '\0'; // Get rid of /lib.
411 }
412 }
413 }
414 Arguments::set_java_home(buf);
415 set_boot_path('/', ':');
416 }
417
418 // Where to look for native libraries.
419 //
420 // Note: Due to a legacy implementation, most of the library path
421 // is set in the launcher. This was to accomodate linking restrictions
422 // on legacy Linux implementations (which are no longer supported).
423 // Eventually, all the library path setting will be done here.
424 //
425 // However, to prevent the proliferation of improperly built native
426 // libraries, the new path component /usr/java/packages is added here.
427 // Eventually, all the library path setting will be done here.
428 {
429 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
430 // should always exist (until the legacy problem cited above is
431 // addressed).
432 const char *v = ::getenv("LD_LIBRARY_PATH");
433 const char *v_colon = ":";
434 if (v == NULL) { v = ""; v_colon = ""; }
435 // That's +1 for the colon and +1 for the trailing '\0'.
436 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
437 strlen(v) + 1 +
438 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
439 mtInternal);
440 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
441 Arguments::set_library_path(ld_library_path);
442 FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal);
443 }
444
445 // Extensions directories.
446 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
447 Arguments::set_ext_dirs(buf);
448
449 // Endorsed standards default directory.
450 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
451 Arguments::set_endorsed_dirs(buf);
452
453 FREE_C_HEAP_ARRAY(char, buf, mtInternal);
454
455 #undef DEFAULT_LIBPATH
456 #undef SYS_EXT_DIR
457 #undef EXTENSIONS_DIR
458 #undef ENDORSED_DIR
459 }
460
461 ////////////////////////////////////////////////////////////////////////////////
462 // breakpoint support
463
464 void os::breakpoint() {
465 BREAKPOINT;
466 }
467
468 extern "C" void breakpoint() {
469 // use debugger to set breakpoint here
470 }
471
472 ////////////////////////////////////////////////////////////////////////////////
473 // signal support
474
475 debug_only(static bool signal_sets_initialized = false);
476 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
477
478 bool os::Linux::is_sig_ignored(int sig) {
479 struct sigaction oact;
480 sigaction(sig, (struct sigaction*)NULL, &oact);
481 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
482 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
483 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
484 return true;
485 else
486 return false;
487 }
488
489 void os::Linux::signal_sets_init() {
490 // Should also have an assertion stating we are still single-threaded.
491 assert(!signal_sets_initialized, "Already initialized");
492 // Fill in signals that are necessarily unblocked for all threads in
493 // the VM. Currently, we unblock the following signals:
494 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
495 // by -Xrs (=ReduceSignalUsage));
496 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
497 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
498 // the dispositions or masks wrt these signals.
499 // Programs embedding the VM that want to use the above signals for their
500 // own purposes must, at this time, use the "-Xrs" option to prevent
501 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
502 // (See bug 4345157, and other related bugs).
503 // In reality, though, unblocking these signals is really a nop, since
504 // these signals are not blocked by default.
505 sigemptyset(&unblocked_sigs);
506 sigemptyset(&allowdebug_blocked_sigs);
507 sigaddset(&unblocked_sigs, SIGILL);
508 sigaddset(&unblocked_sigs, SIGSEGV);
509 sigaddset(&unblocked_sigs, SIGBUS);
510 sigaddset(&unblocked_sigs, SIGFPE);
511 #if defined(PPC64)
512 sigaddset(&unblocked_sigs, SIGTRAP);
513 #endif
514 sigaddset(&unblocked_sigs, SR_signum);
515
516 if (!ReduceSignalUsage) {
517 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
518 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
519 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
520 }
521 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
522 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
523 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
524 }
525 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
526 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
527 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
528 }
529 }
530 // Fill in signals that are blocked by all but the VM thread.
531 sigemptyset(&vm_sigs);
532 if (!ReduceSignalUsage)
533 sigaddset(&vm_sigs, BREAK_SIGNAL);
534 debug_only(signal_sets_initialized = true);
535
536 }
537
538 // These are signals that are unblocked while a thread is running Java.
539 // (For some reason, they get blocked by default.)
540 sigset_t* os::Linux::unblocked_signals() {
541 assert(signal_sets_initialized, "Not initialized");
542 return &unblocked_sigs;
543 }
544
545 // These are the signals that are blocked while a (non-VM) thread is
546 // running Java. Only the VM thread handles these signals.
547 sigset_t* os::Linux::vm_signals() {
548 assert(signal_sets_initialized, "Not initialized");
549 return &vm_sigs;
550 }
551
552 // These are signals that are blocked during cond_wait to allow debugger in
553 sigset_t* os::Linux::allowdebug_blocked_signals() {
554 assert(signal_sets_initialized, "Not initialized");
555 return &allowdebug_blocked_sigs;
556 }
557
558 void os::Linux::hotspot_sigmask(Thread* thread) {
559
560 //Save caller's signal mask before setting VM signal mask
561 sigset_t caller_sigmask;
562 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
563
564 OSThread* osthread = thread->osthread();
565 osthread->set_caller_sigmask(caller_sigmask);
566
567 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
568
569 if (!ReduceSignalUsage) {
570 if (thread->is_VM_thread()) {
571 // Only the VM thread handles BREAK_SIGNAL ...
572 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
573 } else {
574 // ... all other threads block BREAK_SIGNAL
575 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
576 }
577 }
578 }
579
580 //////////////////////////////////////////////////////////////////////////////
581 // detecting pthread library
582
583 void os::Linux::libpthread_init() {
584 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
585 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
586 // generic name for earlier versions.
587 // Define macros here so we can build HotSpot on old systems.
588 # ifndef _CS_GNU_LIBC_VERSION
589 # define _CS_GNU_LIBC_VERSION 2
590 # endif
591 # ifndef _CS_GNU_LIBPTHREAD_VERSION
592 # define _CS_GNU_LIBPTHREAD_VERSION 3
593 # endif
594
595 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
596 if (n > 0) {
597 char *str = (char *)malloc(n, mtInternal);
598 confstr(_CS_GNU_LIBC_VERSION, str, n);
599 os::Linux::set_glibc_version(str);
600 } else {
601 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
602 static char _gnu_libc_version[32];
603 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
604 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
605 os::Linux::set_glibc_version(_gnu_libc_version);
606 }
607
608 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
609 if (n > 0) {
610 char *str = (char *)malloc(n, mtInternal);
611 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
612 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
613 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
614 // is the case. LinuxThreads has a hard limit on max number of threads.
615 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
616 // On the other hand, NPTL does not have such a limit, sysconf()
617 // will return -1 and errno is not changed. Check if it is really NPTL.
618 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
619 strstr(str, "NPTL") &&
620 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
621 free(str);
622 os::Linux::set_libpthread_version("linuxthreads");
623 } else {
624 os::Linux::set_libpthread_version(str);
625 }
626 } else {
627 // glibc before 2.3.2 only has LinuxThreads.
628 os::Linux::set_libpthread_version("linuxthreads");
629 }
630
631 if (strstr(libpthread_version(), "NPTL")) {
632 os::Linux::set_is_NPTL();
633 } else {
634 os::Linux::set_is_LinuxThreads();
635 }
636
637 // LinuxThreads have two flavors: floating-stack mode, which allows variable
638 // stack size; and fixed-stack mode. NPTL is always floating-stack.
639 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
640 os::Linux::set_is_floating_stack();
641 }
642 }
643
644 /////////////////////////////////////////////////////////////////////////////
645 // thread stack
646
647 // Force Linux kernel to expand current thread stack. If "bottom" is close
648 // to the stack guard, caller should block all signals.
649 //
650 // MAP_GROWSDOWN:
651 // A special mmap() flag that is used to implement thread stacks. It tells
652 // kernel that the memory region should extend downwards when needed. This
653 // allows early versions of LinuxThreads to only mmap the first few pages
654 // when creating a new thread. Linux kernel will automatically expand thread
655 // stack as needed (on page faults).
656 //
657 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
658 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
659 // region, it's hard to tell if the fault is due to a legitimate stack
660 // access or because of reading/writing non-exist memory (e.g. buffer
661 // overrun). As a rule, if the fault happens below current stack pointer,
662 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
663 // application (see Linux kernel fault.c).
664 //
665 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
666 // stack overflow detection.
667 //
668 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
669 // not use this flag. However, the stack of initial thread is not created
670 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
671 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
672 // and then attach the thread to JVM.
673 //
674 // To get around the problem and allow stack banging on Linux, we need to
675 // manually expand thread stack after receiving the SIGSEGV.
676 //
677 // There are two ways to expand thread stack to address "bottom", we used
678 // both of them in JVM before 1.5:
679 // 1. adjust stack pointer first so that it is below "bottom", and then
680 // touch "bottom"
681 // 2. mmap() the page in question
682 //
683 // Now alternate signal stack is gone, it's harder to use 2. For instance,
684 // if current sp is already near the lower end of page 101, and we need to
685 // call mmap() to map page 100, it is possible that part of the mmap() frame
686 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
687 // That will destroy the mmap() frame and cause VM to crash.
688 //
689 // The following code works by adjusting sp first, then accessing the "bottom"
690 // page to force a page fault. Linux kernel will then automatically expand the
691 // stack mapping.
692 //
693 // _expand_stack_to() assumes its frame size is less than page size, which
694 // should always be true if the function is not inlined.
695
696 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
697 #define NOINLINE
698 #else
699 #define NOINLINE __attribute__ ((noinline))
700 #endif
701
702 static void _expand_stack_to(address bottom) NOINLINE;
703
704 static void _expand_stack_to(address bottom) {
705 address sp;
706 size_t size;
707 volatile char *p;
708
709 // Adjust bottom to point to the largest address within the same page, it
710 // gives us a one-page buffer if alloca() allocates slightly more memory.
711 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
712 bottom += os::Linux::page_size() - 1;
713
714 // sp might be slightly above current stack pointer; if that's the case, we
715 // will alloca() a little more space than necessary, which is OK. Don't use
716 // os::current_stack_pointer(), as its result can be slightly below current
717 // stack pointer, causing us to not alloca enough to reach "bottom".
718 sp = (address)&sp;
719
720 if (sp > bottom) {
721 size = sp - bottom;
722 p = (volatile char *)alloca(size);
723 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
724 p[0] = '\0';
725 }
726 }
727
728 void os::Linux::expand_stack_to(address bottom) {
729 _expand_stack_to(bottom);
730 }
731
732 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
733 assert(t!=NULL, "just checking");
734 assert(t->osthread()->expanding_stack(), "expand should be set");
735 assert(t->stack_base() != NULL, "stack_base was not initialized");
736
737 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
738 sigset_t mask_all, old_sigset;
739 sigfillset(&mask_all);
740 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
741 _expand_stack_to(addr);
742 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
743 return true;
744 }
745 return false;
746 }
747
748 //////////////////////////////////////////////////////////////////////////////
749 // create new thread
750
751 static address highest_vm_reserved_address();
752
753 // check if it's safe to start a new thread
754 static bool _thread_safety_check(Thread* thread) {
755 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
756 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
757 // Heap is mmap'ed at lower end of memory space. Thread stacks are
758 // allocated (MAP_FIXED) from high address space. Every thread stack
759 // occupies a fixed size slot (usually 2Mbytes, but user can change
760 // it to other values if they rebuild LinuxThreads).
761 //
762 // Problem with MAP_FIXED is that mmap() can still succeed even part of
763 // the memory region has already been mmap'ed. That means if we have too
764 // many threads and/or very large heap, eventually thread stack will
765 // collide with heap.
766 //
767 // Here we try to prevent heap/stack collision by comparing current
768 // stack bottom with the highest address that has been mmap'ed by JVM
769 // plus a safety margin for memory maps created by native code.
770 //
771 // This feature can be disabled by setting ThreadSafetyMargin to 0
772 //
773 if (ThreadSafetyMargin > 0) {
774 address stack_bottom = os::current_stack_base() - os::current_stack_size();
775
776 // not safe if our stack extends below the safety margin
777 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
778 } else {
779 return true;
780 }
781 } else {
782 // Floating stack LinuxThreads or NPTL:
783 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
784 // there's not enough space left, pthread_create() will fail. If we come
785 // here, that means enough space has been reserved for stack.
786 return true;
787 }
788 }
789
790 // Thread start routine for all newly created threads
791 static void *java_start(Thread *thread) {
792 // Try to randomize the cache line index of hot stack frames.
793 // This helps when threads of the same stack traces evict each other's
794 // cache lines. The threads can be either from the same JVM instance, or
795 // from different JVM instances. The benefit is especially true for
796 // processors with hyperthreading technology.
797 static int counter = 0;
798 int pid = os::current_process_id();
799 alloca(((pid ^ counter++) & 7) * 128);
800
801 ThreadLocalStorage::set_thread(thread);
802
803 OSThread* osthread = thread->osthread();
804 Monitor* sync = osthread->startThread_lock();
805
806 // non floating stack LinuxThreads needs extra check, see above
807 if (!_thread_safety_check(thread)) {
808 // notify parent thread
809 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
810 osthread->set_state(ZOMBIE);
811 sync->notify_all();
812 return NULL;
813 }
814
815 // thread_id is kernel thread id (similar to Solaris LWP id)
816 osthread->set_thread_id(os::Linux::gettid());
817
818 if (UseNUMA) {
819 int lgrp_id = os::numa_get_group_id();
820 if (lgrp_id != -1) {
821 thread->set_lgrp_id(lgrp_id);
822 }
823 }
824 // initialize signal mask for this thread
825 os::Linux::hotspot_sigmask(thread);
826
827 // initialize floating point control register
828 os::Linux::init_thread_fpu_state();
829
830 // handshaking with parent thread
831 {
832 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
833
834 // notify parent thread
835 osthread->set_state(INITIALIZED);
836 sync->notify_all();
837
838 // wait until os::start_thread()
839 while (osthread->get_state() == INITIALIZED) {
840 sync->wait(Mutex::_no_safepoint_check_flag);
841 }
842 }
843
844 // call one more level start routine
845 thread->run();
846
847 return 0;
848 }
849
850 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
851 assert(thread->osthread() == NULL, "caller responsible");
852
853 // Allocate the OSThread object
854 OSThread* osthread = new OSThread(NULL, NULL);
855 if (osthread == NULL) {
856 return false;
857 }
858
859 // set the correct thread state
860 osthread->set_thread_type(thr_type);
861
862 // Initial state is ALLOCATED but not INITIALIZED
863 osthread->set_state(ALLOCATED);
864
865 thread->set_osthread(osthread);
866
867 // init thread attributes
868 pthread_attr_t attr;
869 pthread_attr_init(&attr);
870 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
871
872 // stack size
873 if (os::Linux::supports_variable_stack_size()) {
874 // calculate stack size if it's not specified by caller
875 if (stack_size == 0) {
876 stack_size = os::Linux::default_stack_size(thr_type);
877
878 switch (thr_type) {
879 case os::java_thread:
880 // Java threads use ThreadStackSize which default value can be
881 // changed with the flag -Xss
882 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
883 stack_size = JavaThread::stack_size_at_create();
884 break;
885 case os::compiler_thread:
886 if (CompilerThreadStackSize > 0) {
887 stack_size = (size_t)(CompilerThreadStackSize * K);
888 break;
889 } // else fall through:
890 // use VMThreadStackSize if CompilerThreadStackSize is not defined
891 case os::vm_thread:
892 case os::pgc_thread:
893 case os::cgc_thread:
894 case os::watcher_thread:
895 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
896 break;
897 }
898 }
899
900 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
901 pthread_attr_setstacksize(&attr, stack_size);
902 } else {
903 // let pthread_create() pick the default value.
904 }
905
906 // glibc guard page
907 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
908
909 ThreadState state;
910
911 {
912 // Serialize thread creation if we are running with fixed stack LinuxThreads
913 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
914 if (lock) {
915 os::Linux::createThread_lock()->lock_without_safepoint_check();
916 }
917
918 pthread_t tid;
919 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
920
921 pthread_attr_destroy(&attr);
922
923 if (ret != 0) {
924 if (PrintMiscellaneous && (Verbose || WizardMode)) {
925 perror("pthread_create()");
926 }
927 // Need to clean up stuff we've allocated so far
928 thread->set_osthread(NULL);
929 delete osthread;
930 if (lock) os::Linux::createThread_lock()->unlock();
931 return false;
932 }
933
934 // Store pthread info into the OSThread
935 osthread->set_pthread_id(tid);
936
937 // Wait until child thread is either initialized or aborted
938 {
939 Monitor* sync_with_child = osthread->startThread_lock();
940 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
941 while ((state = osthread->get_state()) == ALLOCATED) {
942 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
943 }
944 }
945
946 if (lock) {
947 os::Linux::createThread_lock()->unlock();
948 }
949 }
950
951 // Aborted due to thread limit being reached
952 if (state == ZOMBIE) {
953 thread->set_osthread(NULL);
954 delete osthread;
955 return false;
956 }
957
958 // The thread is returned suspended (in state INITIALIZED),
959 // and is started higher up in the call chain
960 assert(state == INITIALIZED, "race condition");
961 return true;
962 }
963
964 /////////////////////////////////////////////////////////////////////////////
965 // attach existing thread
966
967 // bootstrap the main thread
968 bool os::create_main_thread(JavaThread* thread) {
969 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
970 return create_attached_thread(thread);
971 }
972
973 bool os::create_attached_thread(JavaThread* thread) {
974 #ifdef ASSERT
975 thread->verify_not_published();
976 #endif
977
978 // Allocate the OSThread object
979 OSThread* osthread = new OSThread(NULL, NULL);
980
981 if (osthread == NULL) {
982 return false;
983 }
984
985 // Store pthread info into the OSThread
986 osthread->set_thread_id(os::Linux::gettid());
987 osthread->set_pthread_id(::pthread_self());
988
989 // initialize floating point control register
990 os::Linux::init_thread_fpu_state();
991
992 // Initial thread state is RUNNABLE
993 osthread->set_state(RUNNABLE);
994
995 thread->set_osthread(osthread);
996
997 if (UseNUMA) {
998 int lgrp_id = os::numa_get_group_id();
999 if (lgrp_id != -1) {
1000 thread->set_lgrp_id(lgrp_id);
1001 }
1002 }
1003
1004 if (os::is_primordial_thread()) {
1005 // If current thread is primordial thread, its stack is mapped on demand,
1006 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1007 // the entire stack region to avoid SEGV in stack banging.
1008 // It is also useful to get around the heap-stack-gap problem on SuSE
1009 // kernel (see 4821821 for details). We first expand stack to the top
1010 // of yellow zone, then enable stack yellow zone (order is significant,
1011 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1012 // is no gap between the last two virtual memory regions.
1013
1014 JavaThread *jt = (JavaThread *)thread;
1015 address addr = jt->stack_yellow_zone_base();
1016 assert(addr != NULL, "initialization problem?");
1017 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1018
1019 osthread->set_expanding_stack();
1020 os::Linux::manually_expand_stack(jt, addr);
1021 osthread->clear_expanding_stack();
1022 }
1023
1024 // initialize signal mask for this thread
1025 // and save the caller's signal mask
1026 os::Linux::hotspot_sigmask(thread);
1027
1028 return true;
1029 }
1030
1031 void os::pd_start_thread(Thread* thread) {
1032 OSThread * osthread = thread->osthread();
1033 assert(osthread->get_state() != INITIALIZED, "just checking");
1034 Monitor* sync_with_child = osthread->startThread_lock();
1035 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1036 sync_with_child->notify();
1037 }
1038
1039 // Free Linux resources related to the OSThread
1040 void os::free_thread(OSThread* osthread) {
1041 assert(osthread != NULL, "osthread not set");
1042
1043 if (Thread::current()->osthread() == osthread) {
1044 // Restore caller's signal mask
1045 sigset_t sigmask = osthread->caller_sigmask();
1046 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1047 }
1048
1049 delete osthread;
1050 }
1051
1052 //////////////////////////////////////////////////////////////////////////////
1053 // thread local storage
1054
1055 // Restore the thread pointer if the destructor is called. This is in case
1056 // someone from JNI code sets up a destructor with pthread_key_create to run
1057 // detachCurrentThread on thread death. Unless we restore the thread pointer we
1058 // will hang or crash. When detachCurrentThread is called the key will be set
1059 // to null and we will not be called again. If detachCurrentThread is never
1060 // called we could loop forever depending on the pthread implementation.
1061 static void restore_thread_pointer(void* p) {
1062 Thread* thread = (Thread*) p;
1063 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread);
1064 }
1065
1066 int os::allocate_thread_local_storage() {
1067 pthread_key_t key;
1068 int rslt = pthread_key_create(&key, restore_thread_pointer);
1069 assert(rslt == 0, "cannot allocate thread local storage");
1070 return (int)key;
1071 }
1072
1073 // Note: This is currently not used by VM, as we don't destroy TLS key
1074 // on VM exit.
1075 void os::free_thread_local_storage(int index) {
1076 int rslt = pthread_key_delete((pthread_key_t)index);
1077 assert(rslt == 0, "invalid index");
1078 }
1079
1080 void os::thread_local_storage_at_put(int index, void* value) {
1081 int rslt = pthread_setspecific((pthread_key_t)index, value);
1082 assert(rslt == 0, "pthread_setspecific failed");
1083 }
1084
1085 extern "C" Thread* get_thread() {
1086 return ThreadLocalStorage::thread();
1087 }
1088
1089 //////////////////////////////////////////////////////////////////////////////
1090 // primordial thread
1091
1092 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1093 bool os::is_primordial_thread(void) {
1094 char dummy;
1095 // If called before init complete, thread stack bottom will be null.
1096 // Can be called if fatal error occurs before initialization.
1097 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1098 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1099 os::Linux::initial_thread_stack_size() != 0,
1100 "os::init did not locate primordial thread's stack region");
1101 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1102 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1103 os::Linux::initial_thread_stack_size()) {
1104 return true;
1105 } else {
1106 return false;
1107 }
1108 }
1109
1110 // Find the virtual memory area that contains addr
1111 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1112 FILE *fp = fopen("/proc/self/maps", "r");
1113 if (fp) {
1114 address low, high;
1115 while (!feof(fp)) {
1116 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1117 if (low <= addr && addr < high) {
1118 if (vma_low) *vma_low = low;
1119 if (vma_high) *vma_high = high;
1120 fclose (fp);
1121 return true;
1122 }
1123 }
1124 for (;;) {
1125 int ch = fgetc(fp);
1126 if (ch == EOF || ch == (int)'\n') break;
1127 }
1128 }
1129 fclose(fp);
1130 }
1131 return false;
1132 }
1133
1134 // Locate primordial thread stack. This special handling of primordial thread stack
1135 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1136 // bogus value for the primordial process thread. While the launcher has created
1137 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1138 // JNI invocation API from a primordial thread.
1139 void os::Linux::capture_initial_stack(size_t max_size) {
1140
1141 // max_size is either 0 (which means accept OS default for thread stacks) or
1142 // a user-specified value known to be at least the minimum needed. If we
1143 // are actually on the primordial thread we can make it appear that we have a
1144 // smaller max_size stack by inserting the guard pages at that location. But we
1145 // cannot do anything to emulate a larger stack than what has been provided by
1146 // the OS or threading library. In fact if we try to use a stack greater than
1147 // what is set by rlimit then we will crash the hosting process.
1148
1149 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1150 // If this is "unlimited" then it will be a huge value.
1151 struct rlimit rlim;
1152 getrlimit(RLIMIT_STACK, &rlim);
1153 size_t stack_size = rlim.rlim_cur;
1154
1155 // 6308388: a bug in ld.so will relocate its own .data section to the
1156 // lower end of primordial stack; reduce ulimit -s value a little bit
1157 // so we won't install guard page on ld.so's data section.
1158 // But ensure we don't underflow the stack size - allow 1 page spare
1159 if (stack_size >= (size_t)(3 * page_size())) {
1160 stack_size -= 2 * page_size();
1161 }
1162
1163 // Try to figure out where the stack base (top) is. This is harder.
1164 //
1165 // When an application is started, glibc saves the initial stack pointer in
1166 // a global variable "__libc_stack_end", which is then used by system
1167 // libraries. __libc_stack_end should be pretty close to stack top. The
1168 // variable is available since the very early days. However, because it is
1169 // a private interface, it could disappear in the future.
1170 //
1171 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1172 // to __libc_stack_end, it is very close to stack top, but isn't the real
1173 // stack top. Note that /proc may not exist if VM is running as a chroot
1174 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1175 // /proc/<pid>/stat could change in the future (though unlikely).
1176 //
1177 // We try __libc_stack_end first. If that doesn't work, look for
1178 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1179 // as a hint, which should work well in most cases.
1180
1181 uintptr_t stack_start;
1182
1183 // try __libc_stack_end first
1184 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1185 if (p && *p) {
1186 stack_start = *p;
1187 } else {
1188 // see if we can get the start_stack field from /proc/self/stat
1189 FILE *fp;
1190 int pid;
1191 char state;
1192 int ppid;
1193 int pgrp;
1194 int session;
1195 int nr;
1196 int tpgrp;
1197 unsigned long flags;
1198 unsigned long minflt;
1199 unsigned long cminflt;
1200 unsigned long majflt;
1201 unsigned long cmajflt;
1202 unsigned long utime;
1203 unsigned long stime;
1204 long cutime;
1205 long cstime;
1206 long prio;
1207 long nice;
1208 long junk;
1209 long it_real;
1210 uintptr_t start;
1211 uintptr_t vsize;
1212 intptr_t rss;
1213 uintptr_t rsslim;
1214 uintptr_t scodes;
1215 uintptr_t ecode;
1216 int i;
1217
1218 // Figure what the primordial thread stack base is. Code is inspired
1219 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1220 // followed by command name surrounded by parentheses, state, etc.
1221 char stat[2048];
1222 int statlen;
1223
1224 fp = fopen("/proc/self/stat", "r");
1225 if (fp) {
1226 statlen = fread(stat, 1, 2047, fp);
1227 stat[statlen] = '\0';
1228 fclose(fp);
1229
1230 // Skip pid and the command string. Note that we could be dealing with
1231 // weird command names, e.g. user could decide to rename java launcher
1232 // to "java 1.4.2 :)", then the stat file would look like
1233 // 1234 (java 1.4.2 :)) R ... ...
1234 // We don't really need to know the command string, just find the last
1235 // occurrence of ")" and then start parsing from there. See bug 4726580.
1236 char * s = strrchr(stat, ')');
1237
1238 i = 0;
1239 if (s) {
1240 // Skip blank chars
1241 do s++; while (isspace(*s));
1242
1243 #define _UFM UINTX_FORMAT
1244 #define _DFM INTX_FORMAT
1245
1246 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1247 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */
1248 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
1249 &state, /* 3 %c */
1250 &ppid, /* 4 %d */
1251 &pgrp, /* 5 %d */
1252 &session, /* 6 %d */
1253 &nr, /* 7 %d */
1254 &tpgrp, /* 8 %d */
1255 &flags, /* 9 %lu */
1256 &minflt, /* 10 %lu */
1257 &cminflt, /* 11 %lu */
1258 &majflt, /* 12 %lu */
1259 &cmajflt, /* 13 %lu */
1260 &utime, /* 14 %lu */
1261 &stime, /* 15 %lu */
1262 &cutime, /* 16 %ld */
1263 &cstime, /* 17 %ld */
1264 &prio, /* 18 %ld */
1265 &nice, /* 19 %ld */
1266 &junk, /* 20 %ld */
1267 &it_real, /* 21 %ld */
1268 &start, /* 22 UINTX_FORMAT */
1269 &vsize, /* 23 UINTX_FORMAT */
1270 &rss, /* 24 INTX_FORMAT */
1271 &rsslim, /* 25 UINTX_FORMAT */
1272 &scodes, /* 26 UINTX_FORMAT */
1273 &ecode, /* 27 UINTX_FORMAT */
1274 &stack_start); /* 28 UINTX_FORMAT */
1275 }
1276
1277 #undef _UFM
1278 #undef _DFM
1279
1280 if (i != 28 - 2) {
1281 assert(false, "Bad conversion from /proc/self/stat");
1282 // product mode - assume we are the primordial thread, good luck in the
1283 // embedded case.
1284 warning("Can't detect primordial thread stack location - bad conversion");
1285 stack_start = (uintptr_t) &rlim;
1286 }
1287 } else {
1288 // For some reason we can't open /proc/self/stat (for example, running on
1289 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1290 // most cases, so don't abort:
1291 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1292 stack_start = (uintptr_t) &rlim;
1293 }
1294 }
1295
1296 // Now we have a pointer (stack_start) very close to the stack top, the
1297 // next thing to do is to figure out the exact location of stack top. We
1298 // can find out the virtual memory area that contains stack_start by
1299 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1300 // and its upper limit is the real stack top. (again, this would fail if
1301 // running inside chroot, because /proc may not exist.)
1302
1303 uintptr_t stack_top;
1304 address low, high;
1305 if (find_vma((address)stack_start, &low, &high)) {
1306 // success, "high" is the true stack top. (ignore "low", because initial
1307 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1308 stack_top = (uintptr_t)high;
1309 } else {
1310 // failed, likely because /proc/self/maps does not exist
1311 warning("Can't detect primordial thread stack location - find_vma failed");
1312 // best effort: stack_start is normally within a few pages below the real
1313 // stack top, use it as stack top, and reduce stack size so we won't put
1314 // guard page outside stack.
1315 stack_top = stack_start;
1316 stack_size -= 16 * page_size();
1317 }
1318
1319 // stack_top could be partially down the page so align it
1320 stack_top = align_size_up(stack_top, page_size());
1321
1322 // Allowed stack value is minimum of max_size and what we derived from rlimit
1323 if (max_size > 0) {
1324 _initial_thread_stack_size = MIN2(max_size, stack_size);
1325 } else {
1326 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1327 // clamp it at 8MB as we do on Solaris
1328 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1329 }
1330
1331 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1332 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1333 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1334 }
1335
1336 ////////////////////////////////////////////////////////////////////////////////
1337 // time support
1338
1339 // Time since start-up in seconds to a fine granularity.
1340 // Used by VMSelfDestructTimer and the MemProfiler.
1341 double os::elapsedTime() {
1342
1343 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1344 }
1345
1346 jlong os::elapsed_counter() {
1347 return javaTimeNanos() - initial_time_count;
1348 }
1349
1350 jlong os::elapsed_frequency() {
1351 return NANOSECS_PER_SEC; // nanosecond resolution
1352 }
1353
1354 bool os::supports_vtime() { return true; }
1355 bool os::enable_vtime() { return false; }
1356 bool os::vtime_enabled() { return false; }
1357
1358 double os::elapsedVTime() {
1359 struct rusage usage;
1360 int retval = getrusage(RUSAGE_THREAD, &usage);
1361 if (retval == 0) {
1362 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
1363 } else {
1364 // better than nothing, but not much
1365 return elapsedTime();
1366 }
1367 }
1368
1369 jlong os::javaTimeMillis() {
1370 timeval time;
1371 int status = gettimeofday(&time, NULL);
1372 assert(status != -1, "linux error");
1373 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1374 }
1375
1376 #ifndef CLOCK_MONOTONIC
1377 #define CLOCK_MONOTONIC (1)
1378 #endif
1379
1380 void os::Linux::clock_init() {
1381 // we do dlopen's in this particular order due to bug in linux
1382 // dynamical loader (see 6348968) leading to crash on exit
1383 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1384 if (handle == NULL) {
1385 handle = dlopen("librt.so", RTLD_LAZY);
1386 }
1387
1388 if (handle) {
1389 int (*clock_getres_func)(clockid_t, struct timespec*) =
1390 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1391 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1392 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1393 if (clock_getres_func && clock_gettime_func) {
1394 // See if monotonic clock is supported by the kernel. Note that some
1395 // early implementations simply return kernel jiffies (updated every
1396 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1397 // for nano time (though the monotonic property is still nice to have).
1398 // It's fixed in newer kernels, however clock_getres() still returns
1399 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1400 // resolution for now. Hopefully as people move to new kernels, this
1401 // won't be a problem.
1402 struct timespec res;
1403 struct timespec tp;
1404 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1405 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1406 // yes, monotonic clock is supported
1407 _clock_gettime = clock_gettime_func;
1408 return;
1409 } else {
1410 // close librt if there is no monotonic clock
1411 dlclose(handle);
1412 }
1413 }
1414 }
1415 warning("No monotonic clock was available - timed services may " \
1416 "be adversely affected if the time-of-day clock changes");
1417 }
1418
1419 #ifndef SYS_clock_getres
1420
1421 #if defined(IA32) || defined(AMD64)
1422 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1423 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1424 #else
1425 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1426 #define sys_clock_getres(x,y) -1
1427 #endif
1428
1429 #else
1430 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1431 #endif
1432
1433 void os::Linux::fast_thread_clock_init() {
1434 if (!UseLinuxPosixThreadCPUClocks) {
1435 return;
1436 }
1437 clockid_t clockid;
1438 struct timespec tp;
1439 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1440 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1441
1442 // Switch to using fast clocks for thread cpu time if
1443 // the sys_clock_getres() returns 0 error code.
1444 // Note, that some kernels may support the current thread
1445 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1446 // returned by the pthread_getcpuclockid().
1447 // If the fast Posix clocks are supported then the sys_clock_getres()
1448 // must return at least tp.tv_sec == 0 which means a resolution
1449 // better than 1 sec. This is extra check for reliability.
1450
1451 if(pthread_getcpuclockid_func &&
1452 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1453 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1454
1455 _supports_fast_thread_cpu_time = true;
1456 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1457 }
1458 }
1459
1460 jlong os::javaTimeNanos() {
1461 if (Linux::supports_monotonic_clock()) {
1462 struct timespec tp;
1463 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1464 assert(status == 0, "gettime error");
1465 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1466 return result;
1467 } else {
1468 timeval time;
1469 int status = gettimeofday(&time, NULL);
1470 assert(status != -1, "linux error");
1471 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1472 return 1000 * usecs;
1473 }
1474 }
1475
1476 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1477 if (Linux::supports_monotonic_clock()) {
1478 info_ptr->max_value = ALL_64_BITS;
1479
1480 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1481 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1482 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1483 } else {
1484 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1485 info_ptr->max_value = ALL_64_BITS;
1486
1487 // gettimeofday is a real time clock so it skips
1488 info_ptr->may_skip_backward = true;
1489 info_ptr->may_skip_forward = true;
1490 }
1491
1492 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1493 }
1494
1495 // Return the real, user, and system times in seconds from an
1496 // arbitrary fixed point in the past.
1497 bool os::getTimesSecs(double* process_real_time,
1498 double* process_user_time,
1499 double* process_system_time) {
1500 struct tms ticks;
1501 clock_t real_ticks = times(&ticks);
1502
1503 if (real_ticks == (clock_t) (-1)) {
1504 return false;
1505 } else {
1506 double ticks_per_second = (double) clock_tics_per_sec;
1507 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1508 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1509 *process_real_time = ((double) real_ticks) / ticks_per_second;
1510
1511 return true;
1512 }
1513 }
1514
1515
1516 char * os::local_time_string(char *buf, size_t buflen) {
1517 struct tm t;
1518 time_t long_time;
1519 time(&long_time);
1520 localtime_r(&long_time, &t);
1521 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1522 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1523 t.tm_hour, t.tm_min, t.tm_sec);
1524 return buf;
1525 }
1526
1527 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1528 return localtime_r(clock, res);
1529 }
1530
1531 ////////////////////////////////////////////////////////////////////////////////
1532 // runtime exit support
1533
1534 // Note: os::shutdown() might be called very early during initialization, or
1535 // called from signal handler. Before adding something to os::shutdown(), make
1536 // sure it is async-safe and can handle partially initialized VM.
1537 void os::shutdown() {
1538
1539 // allow PerfMemory to attempt cleanup of any persistent resources
1540 perfMemory_exit();
1541
1542 // needs to remove object in file system
1543 AttachListener::abort();
1544
1545 // flush buffered output, finish log files
1546 ostream_abort();
1547
1548 // Check for abort hook
1549 abort_hook_t abort_hook = Arguments::abort_hook();
1550 if (abort_hook != NULL) {
1551 abort_hook();
1552 }
1553
1554 }
1555
1556 // Note: os::abort() might be called very early during initialization, or
1557 // called from signal handler. Before adding something to os::abort(), make
1558 // sure it is async-safe and can handle partially initialized VM.
1559 void os::abort(bool dump_core) {
1560 os::shutdown();
1561 if (dump_core) {
1562 #ifndef PRODUCT
1563 fdStream out(defaultStream::output_fd());
1564 out.print_raw("Current thread is ");
1565 char buf[16];
1566 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1567 out.print_raw_cr(buf);
1568 out.print_raw_cr("Dumping core ...");
1569 #endif
1570 ::abort(); // dump core
1571 }
1572
1573 ::exit(1);
1574 }
1575
1576 // Die immediately, no exit hook, no abort hook, no cleanup.
1577 void os::die() {
1578 // _exit() on LinuxThreads only kills current thread
1579 ::abort();
1580 }
1581
1582
1583 // This method is a copy of JDK's sysGetLastErrorString
1584 // from src/solaris/hpi/src/system_md.c
1585
1586 size_t os::lasterror(char *buf, size_t len) {
1587
1588 if (errno == 0) return 0;
1589
1590 const char *s = ::strerror(errno);
1591 size_t n = ::strlen(s);
1592 if (n >= len) {
1593 n = len - 1;
1594 }
1595 ::strncpy(buf, s, n);
1596 buf[n] = '\0';
1597 return n;
1598 }
1599
1600 intx os::current_thread_id() { return (intx)pthread_self(); }
1601 int os::current_process_id() {
1602
1603 // Under the old linux thread library, linux gives each thread
1604 // its own process id. Because of this each thread will return
1605 // a different pid if this method were to return the result
1606 // of getpid(2). Linux provides no api that returns the pid
1607 // of the launcher thread for the vm. This implementation
1608 // returns a unique pid, the pid of the launcher thread
1609 // that starts the vm 'process'.
1610
1611 // Under the NPTL, getpid() returns the same pid as the
1612 // launcher thread rather than a unique pid per thread.
1613 // Use gettid() if you want the old pre NPTL behaviour.
1614
1615 // if you are looking for the result of a call to getpid() that
1616 // returns a unique pid for the calling thread, then look at the
1617 // OSThread::thread_id() method in osThread_linux.hpp file
1618
1619 return (int)(_initial_pid ? _initial_pid : getpid());
1620 }
1621
1622 // DLL functions
1623
1624 const char* os::dll_file_extension() { return ".so"; }
1625
1626 // This must be hard coded because it's the system's temporary
1627 // directory not the java application's temp directory, ala java.io.tmpdir.
1628 const char* os::get_temp_directory() { return "/tmp"; }
1629
1630 static bool file_exists(const char* filename) {
1631 struct stat statbuf;
1632 if (filename == NULL || strlen(filename) == 0) {
1633 return false;
1634 }
1635 return os::stat(filename, &statbuf) == 0;
1636 }
1637
1638 bool os::dll_build_name(char* buffer, size_t buflen,
1639 const char* pname, const char* fname) {
1640 bool retval = false;
1641 // Copied from libhpi
1642 const size_t pnamelen = pname ? strlen(pname) : 0;
1643
1644 // Return error on buffer overflow.
1645 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1646 return retval;
1647 }
1648
1649 if (pnamelen == 0) {
1650 snprintf(buffer, buflen, "lib%s.so", fname);
1651 retval = true;
1652 } else if (strchr(pname, *os::path_separator()) != NULL) {
1653 int n;
1654 char** pelements = split_path(pname, &n);
1655 if (pelements == NULL) {
1656 return false;
1657 }
1658 for (int i = 0 ; i < n ; i++) {
1659 // Really shouldn't be NULL, but check can't hurt
1660 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1661 continue; // skip the empty path values
1662 }
1663 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1664 if (file_exists(buffer)) {
1665 retval = true;
1666 break;
1667 }
1668 }
1669 // release the storage
1670 for (int i = 0 ; i < n ; i++) {
1671 if (pelements[i] != NULL) {
1672 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1673 }
1674 }
1675 if (pelements != NULL) {
1676 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1677 }
1678 } else {
1679 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1680 retval = true;
1681 }
1682 return retval;
1683 }
1684
1685 // check if addr is inside libjvm.so
1686 bool os::address_is_in_vm(address addr) {
1687 static address libjvm_base_addr;
1688 Dl_info dlinfo;
1689
1690 if (libjvm_base_addr == NULL) {
1691 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1692 libjvm_base_addr = (address)dlinfo.dli_fbase;
1693 }
1694 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1695 }
1696
1697 if (dladdr((void *)addr, &dlinfo) != 0) {
1698 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1699 }
1700
1701 return false;
1702 }
1703
1704 bool os::dll_address_to_function_name(address addr, char *buf,
1705 int buflen, int *offset) {
1706 // buf is not optional, but offset is optional
1707 assert(buf != NULL, "sanity check");
1708
1709 Dl_info dlinfo;
1710
1711 if (dladdr((void*)addr, &dlinfo) != 0) {
1712 // see if we have a matching symbol
1713 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1714 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1715 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1716 }
1717 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1718 return true;
1719 }
1720 // no matching symbol so try for just file info
1721 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1722 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1723 buf, buflen, offset, dlinfo.dli_fname)) {
1724 return true;
1725 }
1726 }
1727 }
1728
1729 buf[0] = '\0';
1730 if (offset != NULL) *offset = -1;
1731 return false;
1732 }
1733
1734 struct _address_to_library_name {
1735 address addr; // input : memory address
1736 size_t buflen; // size of fname
1737 char* fname; // output: library name
1738 address base; // library base addr
1739 };
1740
1741 static int address_to_library_name_callback(struct dl_phdr_info *info,
1742 size_t size, void *data) {
1743 int i;
1744 bool found = false;
1745 address libbase = NULL;
1746 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1747
1748 // iterate through all loadable segments
1749 for (i = 0; i < info->dlpi_phnum; i++) {
1750 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1751 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1752 // base address of a library is the lowest address of its loaded
1753 // segments.
1754 if (libbase == NULL || libbase > segbase) {
1755 libbase = segbase;
1756 }
1757 // see if 'addr' is within current segment
1758 if (segbase <= d->addr &&
1759 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1760 found = true;
1761 }
1762 }
1763 }
1764
1765 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1766 // so dll_address_to_library_name() can fall through to use dladdr() which
1767 // can figure out executable name from argv[0].
1768 if (found && info->dlpi_name && info->dlpi_name[0]) {
1769 d->base = libbase;
1770 if (d->fname) {
1771 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1772 }
1773 return 1;
1774 }
1775 return 0;
1776 }
1777
1778 bool os::dll_address_to_library_name(address addr, char* buf,
1779 int buflen, int* offset) {
1780 // buf is not optional, but offset is optional
1781 assert(buf != NULL, "sanity check");
1782
1783 Dl_info dlinfo;
1784 struct _address_to_library_name data;
1785
1786 // There is a bug in old glibc dladdr() implementation that it could resolve
1787 // to wrong library name if the .so file has a base address != NULL. Here
1788 // we iterate through the program headers of all loaded libraries to find
1789 // out which library 'addr' really belongs to. This workaround can be
1790 // removed once the minimum requirement for glibc is moved to 2.3.x.
1791 data.addr = addr;
1792 data.fname = buf;
1793 data.buflen = buflen;
1794 data.base = NULL;
1795 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1796
1797 if (rslt) {
1798 // buf already contains library name
1799 if (offset) *offset = addr - data.base;
1800 return true;
1801 }
1802 if (dladdr((void*)addr, &dlinfo) != 0) {
1803 if (dlinfo.dli_fname != NULL) {
1804 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1805 }
1806 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1807 *offset = addr - (address)dlinfo.dli_fbase;
1808 }
1809 return true;
1810 }
1811
1812 buf[0] = '\0';
1813 if (offset) *offset = -1;
1814 return false;
1815 }
1816
1817 // Loads .dll/.so and
1818 // in case of error it checks if .dll/.so was built for the
1819 // same architecture as Hotspot is running on
1820
1821
1822 // Remember the stack's state. The Linux dynamic linker will change
1823 // the stack to 'executable' at most once, so we must safepoint only once.
1824 bool os::Linux::_stack_is_executable = false;
1825
1826 // VM operation that loads a library. This is necessary if stack protection
1827 // of the Java stacks can be lost during loading the library. If we
1828 // do not stop the Java threads, they can stack overflow before the stacks
1829 // are protected again.
1830 class VM_LinuxDllLoad: public VM_Operation {
1831 private:
1832 const char *_filename;
1833 char *_ebuf;
1834 int _ebuflen;
1835 void *_lib;
1836 public:
1837 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1838 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1839 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1840 void doit() {
1841 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1842 os::Linux::_stack_is_executable = true;
1843 }
1844 void* loaded_library() { return _lib; }
1845 };
1846
1847 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1848 {
1849 void * result = NULL;
1850 bool load_attempted = false;
1851
1852 // Check whether the library to load might change execution rights
1853 // of the stack. If they are changed, the protection of the stack
1854 // guard pages will be lost. We need a safepoint to fix this.
1855 //
1856 // See Linux man page execstack(8) for more info.
1857 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1858 ElfFile ef(filename);
1859 if (!ef.specifies_noexecstack()) {
1860 if (!is_init_completed()) {
1861 os::Linux::_stack_is_executable = true;
1862 // This is OK - No Java threads have been created yet, and hence no
1863 // stack guard pages to fix.
1864 //
1865 // This should happen only when you are building JDK7 using a very
1866 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1867 //
1868 // Dynamic loader will make all stacks executable after
1869 // this function returns, and will not do that again.
1870 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1871 } else {
1872 warning("You have loaded library %s which might have disabled stack guard. "
1873 "The VM will try to fix the stack guard now.\n"
1874 "It's highly recommended that you fix the library with "
1875 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1876 filename);
1877
1878 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1879 JavaThread *jt = JavaThread::current();
1880 if (jt->thread_state() != _thread_in_native) {
1881 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1882 // that requires ExecStack. Cannot enter safe point. Let's give up.
1883 warning("Unable to fix stack guard. Giving up.");
1884 } else {
1885 if (!LoadExecStackDllInVMThread) {
1886 // This is for the case where the DLL has an static
1887 // constructor function that executes JNI code. We cannot
1888 // load such DLLs in the VMThread.
1889 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1890 }
1891
1892 ThreadInVMfromNative tiv(jt);
1893 debug_only(VMNativeEntryWrapper vew;)
1894
1895 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1896 VMThread::execute(&op);
1897 if (LoadExecStackDllInVMThread) {
1898 result = op.loaded_library();
1899 }
1900 load_attempted = true;
1901 }
1902 }
1903 }
1904 }
1905
1906 if (!load_attempted) {
1907 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1908 }
1909
1910 if (result != NULL) {
1911 // Successful loading
1912 return result;
1913 }
1914
1915 Elf32_Ehdr elf_head;
1916 int diag_msg_max_length=ebuflen-strlen(ebuf);
1917 char* diag_msg_buf=ebuf+strlen(ebuf);
1918
1919 if (diag_msg_max_length==0) {
1920 // No more space in ebuf for additional diagnostics message
1921 return NULL;
1922 }
1923
1924
1925 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1926
1927 if (file_descriptor < 0) {
1928 // Can't open library, report dlerror() message
1929 return NULL;
1930 }
1931
1932 bool failed_to_read_elf_head=
1933 (sizeof(elf_head)!=
1934 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1935
1936 ::close(file_descriptor);
1937 if (failed_to_read_elf_head) {
1938 // file i/o error - report dlerror() msg
1939 return NULL;
1940 }
1941
1942 typedef struct {
1943 Elf32_Half code; // Actual value as defined in elf.h
1944 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1945 char elf_class; // 32 or 64 bit
1946 char endianess; // MSB or LSB
1947 char* name; // String representation
1948 } arch_t;
1949
1950 #ifndef EM_486
1951 #define EM_486 6 /* Intel 80486 */
1952 #endif
1953
1954 static const arch_t arch_array[]={
1955 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1956 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1957 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1958 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1959 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1960 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1961 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1962 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1963 #if defined(VM_LITTLE_ENDIAN)
1964 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1965 #else
1966 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1967 #endif
1968 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1969 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1970 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1971 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1972 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1973 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1974 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1975 };
1976
1977 #if (defined IA32)
1978 static Elf32_Half running_arch_code=EM_386;
1979 #elif (defined AMD64)
1980 static Elf32_Half running_arch_code=EM_X86_64;
1981 #elif (defined IA64)
1982 static Elf32_Half running_arch_code=EM_IA_64;
1983 #elif (defined __sparc) && (defined _LP64)
1984 static Elf32_Half running_arch_code=EM_SPARCV9;
1985 #elif (defined __sparc) && (!defined _LP64)
1986 static Elf32_Half running_arch_code=EM_SPARC;
1987 #elif (defined __powerpc64__)
1988 static Elf32_Half running_arch_code=EM_PPC64;
1989 #elif (defined __powerpc__)
1990 static Elf32_Half running_arch_code=EM_PPC;
1991 #elif (defined ARM)
1992 static Elf32_Half running_arch_code=EM_ARM;
1993 #elif (defined S390)
1994 static Elf32_Half running_arch_code=EM_S390;
1995 #elif (defined ALPHA)
1996 static Elf32_Half running_arch_code=EM_ALPHA;
1997 #elif (defined MIPSEL)
1998 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1999 #elif (defined PARISC)
2000 static Elf32_Half running_arch_code=EM_PARISC;
2001 #elif (defined MIPS)
2002 static Elf32_Half running_arch_code=EM_MIPS;
2003 #elif (defined M68K)
2004 static Elf32_Half running_arch_code=EM_68K;
2005 #else
2006 #error Method os::dll_load requires that one of following is defined:\
2007 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
2008 #endif
2009
2010 // Identify compatability class for VM's architecture and library's architecture
2011 // Obtain string descriptions for architectures
2012
2013 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
2014 int running_arch_index=-1;
2015
2016 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
2017 if (running_arch_code == arch_array[i].code) {
2018 running_arch_index = i;
2019 }
2020 if (lib_arch.code == arch_array[i].code) {
2021 lib_arch.compat_class = arch_array[i].compat_class;
2022 lib_arch.name = arch_array[i].name;
2023 }
2024 }
2025
2026 assert(running_arch_index != -1,
2027 "Didn't find running architecture code (running_arch_code) in arch_array");
2028 if (running_arch_index == -1) {
2029 // Even though running architecture detection failed
2030 // we may still continue with reporting dlerror() message
2031 return NULL;
2032 }
2033
2034 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
2035 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
2036 return NULL;
2037 }
2038
2039 #ifndef S390
2040 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
2041 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
2042 return NULL;
2043 }
2044 #endif // !S390
2045
2046 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
2047 if ( lib_arch.name!=NULL ) {
2048 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2049 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
2050 lib_arch.name, arch_array[running_arch_index].name);
2051 } else {
2052 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2053 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
2054 lib_arch.code,
2055 arch_array[running_arch_index].name);
2056 }
2057 }
2058
2059 return NULL;
2060 }
2061
2062 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) {
2063 void * result = ::dlopen(filename, RTLD_LAZY);
2064 if (result == NULL) {
2065 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
2066 ebuf[ebuflen-1] = '\0';
2067 }
2068 return result;
2069 }
2070
2071 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) {
2072 void * result = NULL;
2073 if (LoadExecStackDllInVMThread) {
2074 result = dlopen_helper(filename, ebuf, ebuflen);
2075 }
2076
2077 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2078 // library that requires an executable stack, or which does not have this
2079 // stack attribute set, dlopen changes the stack attribute to executable. The
2080 // read protection of the guard pages gets lost.
2081 //
2082 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2083 // may have been queued at the same time.
2084
2085 if (!_stack_is_executable) {
2086 JavaThread *jt = Threads::first();
2087
2088 while (jt) {
2089 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2090 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions
2091 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(),
2092 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) {
2093 warning("Attempt to reguard stack yellow zone failed.");
2094 }
2095 }
2096 jt = jt->next();
2097 }
2098 }
2099
2100 return result;
2101 }
2102
2103 /*
2104 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
2105 * chances are you might want to run the generated bits against glibc-2.0
2106 * libdl.so, so always use locking for any version of glibc.
2107 */
2108 void* os::dll_lookup(void* handle, const char* name) {
2109 pthread_mutex_lock(&dl_mutex);
2110 void* res = dlsym(handle, name);
2111 pthread_mutex_unlock(&dl_mutex);
2112 return res;
2113 }
2114
2115 void* os::get_default_process_handle() {
2116 return (void*)::dlopen(NULL, RTLD_LAZY);
2117 }
2118
2119 static bool _print_ascii_file(const char* filename, outputStream* st) {
2120 int fd = ::open(filename, O_RDONLY);
2121 if (fd == -1) {
2122 return false;
2123 }
2124
2125 char buf[32];
2126 int bytes;
2127 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2128 st->print_raw(buf, bytes);
2129 }
2130
2131 ::close(fd);
2132
2133 return true;
2134 }
2135
2136 void os::print_dll_info(outputStream *st) {
2137 st->print_cr("Dynamic libraries:");
2138
2139 char fname[32];
2140 pid_t pid = os::Linux::gettid();
2141
2142 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2143
2144 if (!_print_ascii_file(fname, st)) {
2145 st->print("Can not get library information for pid = %d\n", pid);
2146 }
2147 }
2148
2149 void os::print_os_info_brief(outputStream* st) {
2150 os::Linux::print_distro_info(st);
2151
2152 os::Posix::print_uname_info(st);
2153
2154 os::Linux::print_libversion_info(st);
2155
2156 }
2157
2158 void os::print_os_info(outputStream* st) {
2159 st->print("OS:");
2160
2161 os::Linux::print_distro_info(st);
2162
2163 os::Posix::print_uname_info(st);
2164
2165 // Print warning if unsafe chroot environment detected
2166 if (unsafe_chroot_detected) {
2167 st->print("WARNING!! ");
2168 st->print_cr("%s", unstable_chroot_error);
2169 }
2170
2171 os::Linux::print_libversion_info(st);
2172
2173 os::Posix::print_rlimit_info(st);
2174
2175 os::Posix::print_load_average(st);
2176
2177 os::Linux::print_full_memory_info(st);
2178
2179 os::Linux::print_container_info(st);
2180 }
2181
2182 // Try to identify popular distros.
2183 // Most Linux distributions have a /etc/XXX-release file, which contains
2184 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2185 // file that also contains the OS version string. Some have more than one
2186 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2187 // /etc/redhat-release.), so the order is important.
2188 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2189 // their own specific XXX-release file as well as a redhat-release file.
2190 // Because of this the XXX-release file needs to be searched for before the
2191 // redhat-release file.
2192 // Since Red Hat has a lsb-release file that is not very descriptive the
2193 // search for redhat-release needs to be before lsb-release.
2194 // Since the lsb-release file is the new standard it needs to be searched
2195 // before the older style release files.
2196 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2197 // next to last resort. The os-release file is a new standard that contains
2198 // distribution information and the system-release file seems to be an old
2199 // standard that has been replaced by the lsb-release and os-release files.
2200 // Searching for the debian_version file is the last resort. It contains
2201 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2202 // "Debian " is printed before the contents of the debian_version file.
2203 void os::Linux::print_distro_info(outputStream* st) {
2204 if (!_print_ascii_file("/etc/oracle-release", st) &&
2205 !_print_ascii_file("/etc/mandriva-release", st) &&
2206 !_print_ascii_file("/etc/mandrake-release", st) &&
2207 !_print_ascii_file("/etc/sun-release", st) &&
2208 !_print_ascii_file("/etc/redhat-release", st) &&
2209 !_print_ascii_file("/etc/lsb-release", st) &&
2210 !_print_ascii_file("/etc/SuSE-release", st) &&
2211 !_print_ascii_file("/etc/turbolinux-release", st) &&
2212 !_print_ascii_file("/etc/gentoo-release", st) &&
2213 !_print_ascii_file("/etc/ltib-release", st) &&
2214 !_print_ascii_file("/etc/angstrom-version", st) &&
2215 !_print_ascii_file("/etc/system-release", st) &&
2216 !_print_ascii_file("/etc/os-release", st)) {
2217
2218 if (file_exists("/etc/debian_version")) {
2219 st->print("Debian ");
2220 _print_ascii_file("/etc/debian_version", st);
2221 } else {
2222 st->print("Linux");
2223 }
2224 }
2225 st->cr();
2226 }
2227
2228 void os::Linux::print_libversion_info(outputStream* st) {
2229 // libc, pthread
2230 st->print("libc:");
2231 st->print("%s ", os::Linux::glibc_version());
2232 st->print("%s ", os::Linux::libpthread_version());
2233 if (os::Linux::is_LinuxThreads()) {
2234 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2235 }
2236 st->cr();
2237 }
2238
2239 void os::Linux::print_full_memory_info(outputStream* st) {
2240 st->print("\n/proc/meminfo:\n");
2241 _print_ascii_file("/proc/meminfo", st);
2242 st->cr();
2243 }
2244
2245 void os::Linux::print_container_info(outputStream* st) {
2246 if (!OSContainer::is_containerized()) {
2247 return;
2248 }
2249
2250 st->print("container (cgroup) information:\n");
2251
2252 const char *p_ct = OSContainer::container_type();
2253 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "failed");
2254
2255 char *p = OSContainer::cpu_cpuset_cpus();
2256 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "failed");
2257 free(p);
2258
2259 p = OSContainer::cpu_cpuset_memory_nodes();
2260 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "failed");
2261 free(p);
2262
2263 int i = OSContainer::active_processor_count();
2264 if (i > 0) {
2265 st->print("active_processor_count: %d\n", i);
2266 } else {
2267 st->print("active_processor_count: failed\n");
2268 }
2269
2270 i = OSContainer::cpu_quota();
2271 st->print("cpu_quota: %d\n", i);
2272
2273 i = OSContainer::cpu_period();
2274 st->print("cpu_period: %d\n", i);
2275
2276 i = OSContainer::cpu_shares();
2277 st->print("cpu_shares: %d\n", i);
2278
2279 jlong j = OSContainer::memory_limit_in_bytes();
2280 st->print("memory_limit_in_bytes: " JLONG_FORMAT "\n", j);
2281
2282 j = OSContainer::memory_and_swap_limit_in_bytes();
2283 st->print("memory_and_swap_limit_in_bytes: " JLONG_FORMAT "\n", j);
2284
2285 j = OSContainer::memory_soft_limit_in_bytes();
2286 st->print("memory_soft_limit_in_bytes: " JLONG_FORMAT "\n", j);
2287
2288 j = OSContainer::OSContainer::memory_usage_in_bytes();
2289 st->print("memory_usage_in_bytes: " JLONG_FORMAT "\n", j);
2290
2291 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2292 st->print("memory_max_usage_in_bytes: " JLONG_FORMAT "\n", j);
2293 st->cr();
2294 }
2295
2296 void os::print_memory_info(outputStream* st) {
2297
2298 st->print("Memory:");
2299 st->print(" %dk page", os::vm_page_size()>>10);
2300
2301 // values in struct sysinfo are "unsigned long"
2302 struct sysinfo si;
2303 sysinfo(&si);
2304
2305 st->print(", physical " UINT64_FORMAT "k",
2306 os::physical_memory() >> 10);
2307 st->print("(" UINT64_FORMAT "k free)",
2308 os::available_memory() >> 10);
2309 st->print(", swap " UINT64_FORMAT "k",
2310 ((jlong)si.totalswap * si.mem_unit) >> 10);
2311 st->print("(" UINT64_FORMAT "k free)",
2312 ((jlong)si.freeswap * si.mem_unit) >> 10);
2313 st->cr();
2314 }
2315
2316 void os::pd_print_cpu_info(outputStream* st) {
2317 st->print("\n/proc/cpuinfo:\n");
2318 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2319 st->print(" <Not Available>");
2320 }
2321 st->cr();
2322 }
2323
2324 void os::print_siginfo(outputStream* st, void* siginfo) {
2325 const siginfo_t* si = (const siginfo_t*)siginfo;
2326
2327 os::Posix::print_siginfo_brief(st, si);
2328 #if INCLUDE_CDS
2329 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2330 UseSharedSpaces) {
2331 FileMapInfo* mapinfo = FileMapInfo::current_info();
2332 if (mapinfo->is_in_shared_space(si->si_addr)) {
2333 st->print("\n\nError accessing class data sharing archive." \
2334 " Mapped file inaccessible during execution, " \
2335 " possible disk/network problem.");
2336 }
2337 }
2338 #endif
2339 st->cr();
2340 }
2341
2342
2343 static void print_signal_handler(outputStream* st, int sig,
2344 char* buf, size_t buflen);
2345
2346 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2347 st->print_cr("Signal Handlers:");
2348 print_signal_handler(st, SIGSEGV, buf, buflen);
2349 print_signal_handler(st, SIGBUS , buf, buflen);
2350 print_signal_handler(st, SIGFPE , buf, buflen);
2351 print_signal_handler(st, SIGPIPE, buf, buflen);
2352 print_signal_handler(st, SIGXFSZ, buf, buflen);
2353 print_signal_handler(st, SIGILL , buf, buflen);
2354 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2355 print_signal_handler(st, SR_signum, buf, buflen);
2356 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2357 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2358 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2359 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2360 #if defined(PPC64)
2361 print_signal_handler(st, SIGTRAP, buf, buflen);
2362 #endif
2363 }
2364
2365 static char saved_jvm_path[MAXPATHLEN] = {0};
2366
2367 // Find the full path to the current module, libjvm.so
2368 void os::jvm_path(char *buf, jint buflen) {
2369 // Error checking.
2370 if (buflen < MAXPATHLEN) {
2371 assert(false, "must use a large-enough buffer");
2372 buf[0] = '\0';
2373 return;
2374 }
2375 // Lazy resolve the path to current module.
2376 if (saved_jvm_path[0] != 0) {
2377 strcpy(buf, saved_jvm_path);
2378 return;
2379 }
2380
2381 char dli_fname[MAXPATHLEN];
2382 bool ret = dll_address_to_library_name(
2383 CAST_FROM_FN_PTR(address, os::jvm_path),
2384 dli_fname, sizeof(dli_fname), NULL);
2385 assert(ret, "cannot locate libjvm");
2386 char *rp = NULL;
2387 if (ret && dli_fname[0] != '\0') {
2388 rp = realpath(dli_fname, buf);
2389 }
2390 if (rp == NULL)
2391 return;
2392
2393 if (Arguments::created_by_gamma_launcher()) {
2394 // Support for the gamma launcher. Typical value for buf is
2395 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2396 // the right place in the string, then assume we are installed in a JDK and
2397 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2398 // up the path so it looks like libjvm.so is installed there (append a
2399 // fake suffix hotspot/libjvm.so).
2400 const char *p = buf + strlen(buf) - 1;
2401 for (int count = 0; p > buf && count < 5; ++count) {
2402 for (--p; p > buf && *p != '/'; --p)
2403 /* empty */ ;
2404 }
2405
2406 if (strncmp(p, "/jre/lib/", 9) != 0) {
2407 // Look for JAVA_HOME in the environment.
2408 char* java_home_var = ::getenv("JAVA_HOME");
2409 if (java_home_var != NULL && java_home_var[0] != 0) {
2410 char* jrelib_p;
2411 int len;
2412
2413 // Check the current module name "libjvm.so".
2414 p = strrchr(buf, '/');
2415 assert(strstr(p, "/libjvm") == p, "invalid library name");
2416
2417 rp = realpath(java_home_var, buf);
2418 if (rp == NULL)
2419 return;
2420
2421 // determine if this is a legacy image or modules image
2422 // modules image doesn't have "jre" subdirectory
2423 len = strlen(buf);
2424 assert(len < buflen, "Ran out of buffer room");
2425 jrelib_p = buf + len;
2426 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2427 if (0 != access(buf, F_OK)) {
2428 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2429 }
2430
2431 if (0 == access(buf, F_OK)) {
2432 // Use current module name "libjvm.so"
2433 len = strlen(buf);
2434 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2435 } else {
2436 // Go back to path of .so
2437 rp = realpath(dli_fname, buf);
2438 if (rp == NULL)
2439 return;
2440 }
2441 }
2442 }
2443 }
2444
2445 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2446 }
2447
2448 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2449 // no prefix required, not even "_"
2450 }
2451
2452 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2453 // no suffix required
2454 }
2455
2456 ////////////////////////////////////////////////////////////////////////////////
2457 // sun.misc.Signal support
2458
2459 static volatile jint sigint_count = 0;
2460
2461 static void
2462 UserHandler(int sig, void *siginfo, void *context) {
2463 // 4511530 - sem_post is serialized and handled by the manager thread. When
2464 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2465 // don't want to flood the manager thread with sem_post requests.
2466 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2467 return;
2468
2469 // Ctrl-C is pressed during error reporting, likely because the error
2470 // handler fails to abort. Let VM die immediately.
2471 if (sig == SIGINT && is_error_reported()) {
2472 os::die();
2473 }
2474
2475 os::signal_notify(sig);
2476 }
2477
2478 void* os::user_handler() {
2479 return CAST_FROM_FN_PTR(void*, UserHandler);
2480 }
2481
2482 class Semaphore : public StackObj {
2483 public:
2484 Semaphore();
2485 ~Semaphore();
2486 void signal();
2487 void wait();
2488 bool trywait();
2489 bool timedwait(unsigned int sec, int nsec);
2490 private:
2491 sem_t _semaphore;
2492 };
2493
2494 Semaphore::Semaphore() {
2495 sem_init(&_semaphore, 0, 0);
2496 }
2497
2498 Semaphore::~Semaphore() {
2499 sem_destroy(&_semaphore);
2500 }
2501
2502 void Semaphore::signal() {
2503 sem_post(&_semaphore);
2504 }
2505
2506 void Semaphore::wait() {
2507 sem_wait(&_semaphore);
2508 }
2509
2510 bool Semaphore::trywait() {
2511 return sem_trywait(&_semaphore) == 0;
2512 }
2513
2514 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2515
2516 struct timespec ts;
2517 // Semaphore's are always associated with CLOCK_REALTIME
2518 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2519 // see unpackTime for discussion on overflow checking
2520 if (sec >= MAX_SECS) {
2521 ts.tv_sec += MAX_SECS;
2522 ts.tv_nsec = 0;
2523 } else {
2524 ts.tv_sec += sec;
2525 ts.tv_nsec += nsec;
2526 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2527 ts.tv_nsec -= NANOSECS_PER_SEC;
2528 ++ts.tv_sec; // note: this must be <= max_secs
2529 }
2530 }
2531
2532 while (1) {
2533 int result = sem_timedwait(&_semaphore, &ts);
2534 if (result == 0) {
2535 return true;
2536 } else if (errno == EINTR) {
2537 continue;
2538 } else if (errno == ETIMEDOUT) {
2539 return false;
2540 } else {
2541 return false;
2542 }
2543 }
2544 }
2545
2546 extern "C" {
2547 typedef void (*sa_handler_t)(int);
2548 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2549 }
2550
2551 void* os::signal(int signal_number, void* handler) {
2552 struct sigaction sigAct, oldSigAct;
2553
2554 sigfillset(&(sigAct.sa_mask));
2555 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2556 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2557
2558 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2559 // -1 means registration failed
2560 return (void *)-1;
2561 }
2562
2563 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2564 }
2565
2566 void os::signal_raise(int signal_number) {
2567 ::raise(signal_number);
2568 }
2569
2570 /*
2571 * The following code is moved from os.cpp for making this
2572 * code platform specific, which it is by its very nature.
2573 */
2574
2575 // Will be modified when max signal is changed to be dynamic
2576 int os::sigexitnum_pd() {
2577 return NSIG;
2578 }
2579
2580 // a counter for each possible signal value
2581 static volatile jint pending_signals[NSIG+1] = { 0 };
2582
2583 // Linux(POSIX) specific hand shaking semaphore.
2584 static sem_t sig_sem;
2585 static Semaphore sr_semaphore;
2586
2587 void os::signal_init_pd() {
2588 // Initialize signal structures
2589 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2590
2591 // Initialize signal semaphore
2592 ::sem_init(&sig_sem, 0, 0);
2593 }
2594
2595 void os::signal_notify(int sig) {
2596 Atomic::inc(&pending_signals[sig]);
2597 ::sem_post(&sig_sem);
2598 }
2599
2600 static int check_pending_signals(bool wait) {
2601 Atomic::store(0, &sigint_count);
2602 for (;;) {
2603 for (int i = 0; i < NSIG + 1; i++) {
2604 jint n = pending_signals[i];
2605 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2606 return i;
2607 }
2608 }
2609 if (!wait) {
2610 return -1;
2611 }
2612 JavaThread *thread = JavaThread::current();
2613 ThreadBlockInVM tbivm(thread);
2614
2615 bool threadIsSuspended;
2616 do {
2617 thread->set_suspend_equivalent();
2618 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2619 ::sem_wait(&sig_sem);
2620
2621 // were we externally suspended while we were waiting?
2622 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2623 if (threadIsSuspended) {
2624 //
2625 // The semaphore has been incremented, but while we were waiting
2626 // another thread suspended us. We don't want to continue running
2627 // while suspended because that would surprise the thread that
2628 // suspended us.
2629 //
2630 ::sem_post(&sig_sem);
2631
2632 thread->java_suspend_self();
2633 }
2634 } while (threadIsSuspended);
2635 }
2636 }
2637
2638 int os::signal_lookup() {
2639 return check_pending_signals(false);
2640 }
2641
2642 int os::signal_wait() {
2643 return check_pending_signals(true);
2644 }
2645
2646 ////////////////////////////////////////////////////////////////////////////////
2647 // Virtual Memory
2648
2649 int os::vm_page_size() {
2650 // Seems redundant as all get out
2651 assert(os::Linux::page_size() != -1, "must call os::init");
2652 return os::Linux::page_size();
2653 }
2654
2655 // Solaris allocates memory by pages.
2656 int os::vm_allocation_granularity() {
2657 assert(os::Linux::page_size() != -1, "must call os::init");
2658 return os::Linux::page_size();
2659 }
2660
2661 // Rationale behind this function:
2662 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2663 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2664 // samples for JITted code. Here we create private executable mapping over the code cache
2665 // and then we can use standard (well, almost, as mapping can change) way to provide
2666 // info for the reporting script by storing timestamp and location of symbol
2667 void linux_wrap_code(char* base, size_t size) {
2668 static volatile jint cnt = 0;
2669
2670 if (!UseOprofile) {
2671 return;
2672 }
2673
2674 char buf[PATH_MAX+1];
2675 int num = Atomic::add(1, &cnt);
2676
2677 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2678 os::get_temp_directory(), os::current_process_id(), num);
2679 unlink(buf);
2680
2681 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2682
2683 if (fd != -1) {
2684 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2685 if (rv != (off_t)-1) {
2686 if (::write(fd, "", 1) == 1) {
2687 mmap(base, size,
2688 PROT_READ|PROT_WRITE|PROT_EXEC,
2689 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2690 }
2691 }
2692 ::close(fd);
2693 unlink(buf);
2694 }
2695 }
2696
2697 static bool recoverable_mmap_error(int err) {
2698 // See if the error is one we can let the caller handle. This
2699 // list of errno values comes from JBS-6843484. I can't find a
2700 // Linux man page that documents this specific set of errno
2701 // values so while this list currently matches Solaris, it may
2702 // change as we gain experience with this failure mode.
2703 switch (err) {
2704 case EBADF:
2705 case EINVAL:
2706 case ENOTSUP:
2707 // let the caller deal with these errors
2708 return true;
2709
2710 default:
2711 // Any remaining errors on this OS can cause our reserved mapping
2712 // to be lost. That can cause confusion where different data
2713 // structures think they have the same memory mapped. The worst
2714 // scenario is if both the VM and a library think they have the
2715 // same memory mapped.
2716 return false;
2717 }
2718 }
2719
2720 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2721 int err) {
2722 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2723 ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2724 strerror(err), err);
2725 }
2726
2727 static void warn_fail_commit_memory(char* addr, size_t size,
2728 size_t alignment_hint, bool exec,
2729 int err) {
2730 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2731 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size,
2732 alignment_hint, exec, strerror(err), err);
2733 }
2734
2735 // NOTE: Linux kernel does not really reserve the pages for us.
2736 // All it does is to check if there are enough free pages
2737 // left at the time of mmap(). This could be a potential
2738 // problem.
2739 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2740 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2741 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2742 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2743 if (res != (uintptr_t) MAP_FAILED) {
2744 if (UseNUMAInterleaving) {
2745 numa_make_global(addr, size);
2746 }
2747 return 0;
2748 }
2749
2750 int err = errno; // save errno from mmap() call above
2751
2752 if (!recoverable_mmap_error(err)) {
2753 warn_fail_commit_memory(addr, size, exec, err);
2754 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2755 }
2756
2757 return err;
2758 }
2759
2760 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2761 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2762 }
2763
2764 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2765 const char* mesg) {
2766 assert(mesg != NULL, "mesg must be specified");
2767 int err = os::Linux::commit_memory_impl(addr, size, exec);
2768 if (err != 0) {
2769 // the caller wants all commit errors to exit with the specified mesg:
2770 warn_fail_commit_memory(addr, size, exec, err);
2771 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2772 }
2773 }
2774
2775 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2776 #ifndef MAP_HUGETLB
2777 #define MAP_HUGETLB 0x40000
2778 #endif
2779
2780 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2781 #ifndef MADV_HUGEPAGE
2782 #define MADV_HUGEPAGE 14
2783 #endif
2784
2785 int os::Linux::commit_memory_impl(char* addr, size_t size,
2786 size_t alignment_hint, bool exec) {
2787 int err = os::Linux::commit_memory_impl(addr, size, exec);
2788 if (err == 0) {
2789 realign_memory(addr, size, alignment_hint);
2790 }
2791 return err;
2792 }
2793
2794 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2795 bool exec) {
2796 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2797 }
2798
2799 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2800 size_t alignment_hint, bool exec,
2801 const char* mesg) {
2802 assert(mesg != NULL, "mesg must be specified");
2803 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2804 if (err != 0) {
2805 // the caller wants all commit errors to exit with the specified mesg:
2806 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2807 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2808 }
2809 }
2810
2811 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2812 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2813 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2814 // be supported or the memory may already be backed by huge pages.
2815 ::madvise(addr, bytes, MADV_HUGEPAGE);
2816 }
2817 }
2818
2819 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2820 // This method works by doing an mmap over an existing mmaping and effectively discarding
2821 // the existing pages. However it won't work for SHM-based large pages that cannot be
2822 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2823 // small pages on top of the SHM segment. This method always works for small pages, so we
2824 // allow that in any case.
2825 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2826 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2827 }
2828 }
2829
2830 void os::numa_make_global(char *addr, size_t bytes) {
2831 Linux::numa_interleave_memory(addr, bytes);
2832 }
2833
2834 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2835 // bind policy to MPOL_PREFERRED for the current thread.
2836 #define USE_MPOL_PREFERRED 0
2837
2838 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2839 // To make NUMA and large pages more robust when both enabled, we need to ease
2840 // the requirements on where the memory should be allocated. MPOL_BIND is the
2841 // default policy and it will force memory to be allocated on the specified
2842 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2843 // the specified node, but will not force it. Using this policy will prevent
2844 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2845 // free large pages.
2846 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2847 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2848 }
2849
2850 bool os::numa_topology_changed() { return false; }
2851
2852 size_t os::numa_get_groups_num() {
2853 // Return just the number of nodes in which it's possible to allocate memory
2854 // (in numa terminology, configured nodes).
2855 return Linux::numa_num_configured_nodes();
2856 }
2857
2858 int os::numa_get_group_id() {
2859 int cpu_id = Linux::sched_getcpu();
2860 if (cpu_id != -1) {
2861 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2862 if (lgrp_id != -1) {
2863 return lgrp_id;
2864 }
2865 }
2866 return 0;
2867 }
2868
2869 int os::Linux::get_existing_num_nodes() {
2870 size_t node;
2871 size_t highest_node_number = Linux::numa_max_node();
2872 int num_nodes = 0;
2873
2874 // Get the total number of nodes in the system including nodes without memory.
2875 for (node = 0; node <= highest_node_number; node++) {
2876 if (isnode_in_existing_nodes(node)) {
2877 num_nodes++;
2878 }
2879 }
2880 return num_nodes;
2881 }
2882
2883 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2884 size_t highest_node_number = Linux::numa_max_node();
2885 size_t i = 0;
2886
2887 // Map all node ids in which is possible to allocate memory. Also nodes are
2888 // not always consecutively available, i.e. available from 0 to the highest
2889 // node number.
2890 for (size_t node = 0; node <= highest_node_number; node++) {
2891 if (Linux::isnode_in_configured_nodes(node)) {
2892 ids[i++] = node;
2893 }
2894 }
2895 return i;
2896 }
2897
2898 bool os::get_page_info(char *start, page_info* info) {
2899 return false;
2900 }
2901
2902 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2903 return end;
2904 }
2905
2906
2907 int os::Linux::sched_getcpu_syscall(void) {
2908 unsigned int cpu = 0;
2909 int retval = -1;
2910
2911 #if defined(IA32)
2912 # ifndef SYS_getcpu
2913 # define SYS_getcpu 318
2914 # endif
2915 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2916 #elif defined(AMD64)
2917 // Unfortunately we have to bring all these macros here from vsyscall.h
2918 // to be able to compile on old linuxes.
2919 # define __NR_vgetcpu 2
2920 # define VSYSCALL_START (-10UL << 20)
2921 # define VSYSCALL_SIZE 1024
2922 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2923 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2924 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2925 retval = vgetcpu(&cpu, NULL, NULL);
2926 #endif
2927
2928 return (retval == -1) ? retval : cpu;
2929 }
2930
2931 // Something to do with the numa-aware allocator needs these symbols
2932 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2933 extern "C" JNIEXPORT void numa_error(char *where) { }
2934 extern "C" JNIEXPORT int fork1() { return fork(); }
2935
2936 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
2937 // load symbol from base version instead.
2938 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2939 void *f = dlvsym(handle, name, "libnuma_1.1");
2940 if (f == NULL) {
2941 f = dlsym(handle, name);
2942 }
2943 return f;
2944 }
2945
2946 // Handle request to load libnuma symbol version 1.2 (API v2) only.
2947 // Return NULL if the symbol is not defined in this particular version.
2948 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
2949 return dlvsym(handle, name, "libnuma_1.2");
2950 }
2951
2952 bool os::Linux::libnuma_init() {
2953 // sched_getcpu() should be in libc.
2954 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2955 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2956
2957 // If it's not, try a direct syscall.
2958 if (sched_getcpu() == -1)
2959 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2960
2961 if (sched_getcpu() != -1) { // Does it work?
2962 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2963 if (handle != NULL) {
2964 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2965 libnuma_dlsym(handle, "numa_node_to_cpus")));
2966 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2967 libnuma_dlsym(handle, "numa_max_node")));
2968 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
2969 libnuma_dlsym(handle, "numa_num_configured_nodes")));
2970 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2971 libnuma_dlsym(handle, "numa_available")));
2972 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2973 libnuma_dlsym(handle, "numa_tonode_memory")));
2974 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2975 libnuma_dlsym(handle, "numa_interleave_memory")));
2976 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
2977 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
2978 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2979 libnuma_dlsym(handle, "numa_set_bind_policy")));
2980 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
2981 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
2982 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
2983 libnuma_dlsym(handle, "numa_distance")));
2984
2985 if (numa_available() != -1) {
2986 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2987 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
2988 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
2989 // Create an index -> node mapping, since nodes are not always consecutive
2990 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2991 rebuild_nindex_to_node_map();
2992 // Create a cpu -> node mapping
2993 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2994 rebuild_cpu_to_node_map();
2995 return true;
2996 }
2997 }
2998 }
2999 return false;
3000 }
3001
3002 void os::Linux::rebuild_nindex_to_node_map() {
3003 int highest_node_number = Linux::numa_max_node();
3004
3005 nindex_to_node()->clear();
3006 for (int node = 0; node <= highest_node_number; node++) {
3007 if (Linux::isnode_in_existing_nodes(node)) {
3008 nindex_to_node()->append(node);
3009 }
3010 }
3011 }
3012
3013 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3014 // The table is later used in get_node_by_cpu().
3015 void os::Linux::rebuild_cpu_to_node_map() {
3016 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3017 // in libnuma (possible values are starting from 16,
3018 // and continuing up with every other power of 2, but less
3019 // than the maximum number of CPUs supported by kernel), and
3020 // is a subject to change (in libnuma version 2 the requirements
3021 // are more reasonable) we'll just hardcode the number they use
3022 // in the library.
3023 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3024
3025 size_t cpu_num = processor_count();
3026 size_t cpu_map_size = NCPUS / BitsPerCLong;
3027 size_t cpu_map_valid_size =
3028 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3029
3030 cpu_to_node()->clear();
3031 cpu_to_node()->at_grow(cpu_num - 1);
3032
3033 size_t node_num = get_existing_num_nodes();
3034
3035 int distance = 0;
3036 int closest_distance = INT_MAX;
3037 int closest_node = 0;
3038 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3039 for (size_t i = 0; i < node_num; i++) {
3040 // Check if node is configured (not a memory-less node). If it is not, find
3041 // the closest configured node.
3042 if (!isnode_in_configured_nodes(nindex_to_node()->at(i))) {
3043 closest_distance = INT_MAX;
3044 // Check distance from all remaining nodes in the system. Ignore distance
3045 // from itself and from another non-configured node.
3046 for (size_t m = 0; m < node_num; m++) {
3047 if (m != i && isnode_in_configured_nodes(nindex_to_node()->at(m))) {
3048 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3049 // If a closest node is found, update. There is always at least one
3050 // configured node in the system so there is always at least one node
3051 // close.
3052 if (distance != 0 && distance < closest_distance) {
3053 closest_distance = distance;
3054 closest_node = nindex_to_node()->at(m);
3055 }
3056 }
3057 }
3058 } else {
3059 // Current node is already a configured node.
3060 closest_node = nindex_to_node()->at(i);
3061 }
3062
3063 // Get cpus from the original node and map them to the closest node. If node
3064 // is a configured node (not a memory-less node), then original node and
3065 // closest node are the same.
3066 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3067 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3068 if (cpu_map[j] != 0) {
3069 for (size_t k = 0; k < BitsPerCLong; k++) {
3070 if (cpu_map[j] & (1UL << k)) {
3071 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3072 }
3073 }
3074 }
3075 }
3076 }
3077 }
3078 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
3079 }
3080
3081 int os::Linux::get_node_by_cpu(int cpu_id) {
3082 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3083 return cpu_to_node()->at(cpu_id);
3084 }
3085 return -1;
3086 }
3087
3088 GrowableArray<int>* os::Linux::_cpu_to_node;
3089 GrowableArray<int>* os::Linux::_nindex_to_node;
3090 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3091 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3092 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3093 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3094 os::Linux::numa_available_func_t os::Linux::_numa_available;
3095 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3096 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3097 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3098 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3099 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3100 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3101 unsigned long* os::Linux::_numa_all_nodes;
3102 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3103 struct bitmask* os::Linux::_numa_nodes_ptr;
3104
3105 bool os::pd_uncommit_memory(char* addr, size_t size) {
3106 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3107 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3108 return res != (uintptr_t) MAP_FAILED;
3109 }
3110
3111 static
3112 address get_stack_commited_bottom(address bottom, size_t size) {
3113 address nbot = bottom;
3114 address ntop = bottom + size;
3115
3116 size_t page_sz = os::vm_page_size();
3117 unsigned pages = size / page_sz;
3118
3119 unsigned char vec[1];
3120 unsigned imin = 1, imax = pages + 1, imid;
3121 int mincore_return_value = 0;
3122
3123 assert(imin <= imax, "Unexpected page size");
3124
3125 while (imin < imax) {
3126 imid = (imax + imin) / 2;
3127 nbot = ntop - (imid * page_sz);
3128
3129 // Use a trick with mincore to check whether the page is mapped or not.
3130 // mincore sets vec to 1 if page resides in memory and to 0 if page
3131 // is swapped output but if page we are asking for is unmapped
3132 // it returns -1,ENOMEM
3133 mincore_return_value = mincore(nbot, page_sz, vec);
3134
3135 if (mincore_return_value == -1) {
3136 // Page is not mapped go up
3137 // to find first mapped page
3138 if (errno != EAGAIN) {
3139 assert(errno == ENOMEM, "Unexpected mincore errno");
3140 imax = imid;
3141 }
3142 } else {
3143 // Page is mapped go down
3144 // to find first not mapped page
3145 imin = imid + 1;
3146 }
3147 }
3148
3149 nbot = nbot + page_sz;
3150
3151 // Adjust stack bottom one page up if last checked page is not mapped
3152 if (mincore_return_value == -1) {
3153 nbot = nbot + page_sz;
3154 }
3155
3156 return nbot;
3157 }
3158
3159
3160 // Linux uses a growable mapping for the stack, and if the mapping for
3161 // the stack guard pages is not removed when we detach a thread the
3162 // stack cannot grow beyond the pages where the stack guard was
3163 // mapped. If at some point later in the process the stack expands to
3164 // that point, the Linux kernel cannot expand the stack any further
3165 // because the guard pages are in the way, and a segfault occurs.
3166 //
3167 // However, it's essential not to split the stack region by unmapping
3168 // a region (leaving a hole) that's already part of the stack mapping,
3169 // so if the stack mapping has already grown beyond the guard pages at
3170 // the time we create them, we have to truncate the stack mapping.
3171 // So, we need to know the extent of the stack mapping when
3172 // create_stack_guard_pages() is called.
3173
3174 // We only need this for stacks that are growable: at the time of
3175 // writing thread stacks don't use growable mappings (i.e. those
3176 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3177 // only applies to the main thread.
3178
3179 // If the (growable) stack mapping already extends beyond the point
3180 // where we're going to put our guard pages, truncate the mapping at
3181 // that point by munmap()ping it. This ensures that when we later
3182 // munmap() the guard pages we don't leave a hole in the stack
3183 // mapping. This only affects the main/primordial thread
3184
3185 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3186
3187 if (os::is_primordial_thread()) {
3188 // As we manually grow stack up to bottom inside create_attached_thread(),
3189 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3190 // we don't need to do anything special.
3191 // Check it first, before calling heavy function.
3192 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3193 unsigned char vec[1];
3194
3195 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3196 // Fallback to slow path on all errors, including EAGAIN
3197 stack_extent = (uintptr_t) get_stack_commited_bottom(
3198 os::Linux::initial_thread_stack_bottom(),
3199 (size_t)addr - stack_extent);
3200 }
3201
3202 if (stack_extent < (uintptr_t)addr) {
3203 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3204 }
3205 }
3206
3207 return os::commit_memory(addr, size, !ExecMem);
3208 }
3209
3210 // If this is a growable mapping, remove the guard pages entirely by
3211 // munmap()ping them. If not, just call uncommit_memory(). This only
3212 // affects the main/primordial thread, but guard against future OS changes.
3213 // It's safe to always unmap guard pages for primordial thread because we
3214 // always place it right after end of the mapped region.
3215
3216 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3217 uintptr_t stack_extent, stack_base;
3218
3219 if (os::is_primordial_thread()) {
3220 return ::munmap(addr, size) == 0;
3221 }
3222
3223 return os::uncommit_memory(addr, size);
3224 }
3225
3226 static address _highest_vm_reserved_address = NULL;
3227
3228 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3229 // at 'requested_addr'. If there are existing memory mappings at the same
3230 // location, however, they will be overwritten. If 'fixed' is false,
3231 // 'requested_addr' is only treated as a hint, the return value may or
3232 // may not start from the requested address. Unlike Linux mmap(), this
3233 // function returns NULL to indicate failure.
3234 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3235 char * addr;
3236 int flags;
3237
3238 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3239 if (fixed) {
3240 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3241 flags |= MAP_FIXED;
3242 }
3243
3244 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3245 // touch an uncommitted page. Otherwise, the read/write might
3246 // succeed if we have enough swap space to back the physical page.
3247 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3248 flags, -1, 0);
3249
3250 if (addr != MAP_FAILED) {
3251 // anon_mmap() should only get called during VM initialization,
3252 // don't need lock (actually we can skip locking even it can be called
3253 // from multiple threads, because _highest_vm_reserved_address is just a
3254 // hint about the upper limit of non-stack memory regions.)
3255 if ((address)addr + bytes > _highest_vm_reserved_address) {
3256 _highest_vm_reserved_address = (address)addr + bytes;
3257 }
3258 }
3259
3260 return addr == MAP_FAILED ? NULL : addr;
3261 }
3262
3263 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3264 // (req_addr != NULL) or with a given alignment.
3265 // - bytes shall be a multiple of alignment.
3266 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3267 // - alignment sets the alignment at which memory shall be allocated.
3268 // It must be a multiple of allocation granularity.
3269 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3270 // req_addr or NULL.
3271 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3272
3273 size_t extra_size = bytes;
3274 if (req_addr == NULL && alignment > 0) {
3275 extra_size += alignment;
3276 }
3277
3278 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3279 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3280 -1, 0);
3281 if (start == MAP_FAILED) {
3282 start = NULL;
3283 } else {
3284 if (req_addr != NULL) {
3285 if (start != req_addr) {
3286 ::munmap(start, extra_size);
3287 start = NULL;
3288 }
3289 } else {
3290 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3291 char* const end_aligned = start_aligned + bytes;
3292 char* const end = start + extra_size;
3293 if (start_aligned > start) {
3294 ::munmap(start, start_aligned - start);
3295 }
3296 if (end_aligned < end) {
3297 ::munmap(end_aligned, end - end_aligned);
3298 }
3299 start = start_aligned;
3300 }
3301 }
3302 return start;
3303 }
3304
3305 // Don't update _highest_vm_reserved_address, because there might be memory
3306 // regions above addr + size. If so, releasing a memory region only creates
3307 // a hole in the address space, it doesn't help prevent heap-stack collision.
3308 //
3309 static int anon_munmap(char * addr, size_t size) {
3310 return ::munmap(addr, size) == 0;
3311 }
3312
3313 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3314 size_t alignment_hint) {
3315 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3316 }
3317
3318 bool os::pd_release_memory(char* addr, size_t size) {
3319 return anon_munmap(addr, size);
3320 }
3321
3322 static address highest_vm_reserved_address() {
3323 return _highest_vm_reserved_address;
3324 }
3325
3326 static bool linux_mprotect(char* addr, size_t size, int prot) {
3327 // Linux wants the mprotect address argument to be page aligned.
3328 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3329
3330 // According to SUSv3, mprotect() should only be used with mappings
3331 // established by mmap(), and mmap() always maps whole pages. Unaligned
3332 // 'addr' likely indicates problem in the VM (e.g. trying to change
3333 // protection of malloc'ed or statically allocated memory). Check the
3334 // caller if you hit this assert.
3335 assert(addr == bottom, "sanity check");
3336
3337 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3338 return ::mprotect(bottom, size, prot) == 0;
3339 }
3340
3341 // Set protections specified
3342 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3343 bool is_committed) {
3344 unsigned int p = 0;
3345 switch (prot) {
3346 case MEM_PROT_NONE: p = PROT_NONE; break;
3347 case MEM_PROT_READ: p = PROT_READ; break;
3348 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3349 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3350 default:
3351 ShouldNotReachHere();
3352 }
3353 // is_committed is unused.
3354 return linux_mprotect(addr, bytes, p);
3355 }
3356
3357 bool os::guard_memory(char* addr, size_t size) {
3358 return linux_mprotect(addr, size, PROT_NONE);
3359 }
3360
3361 bool os::unguard_memory(char* addr, size_t size) {
3362 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3363 }
3364
3365 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
3366 bool result = false;
3367 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3368 MAP_ANONYMOUS|MAP_PRIVATE,
3369 -1, 0);
3370 if (p != MAP_FAILED) {
3371 void *aligned_p = align_ptr_up(p, page_size);
3372
3373 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3374
3375 munmap(p, page_size * 2);
3376 }
3377
3378 if (warn && !result) {
3379 warning("TransparentHugePages is not supported by the operating system.");
3380 }
3381
3382 return result;
3383 }
3384
3385 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3386 bool result = false;
3387 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3388 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3389 -1, 0);
3390
3391 if (p != MAP_FAILED) {
3392 // We don't know if this really is a huge page or not.
3393 FILE *fp = fopen("/proc/self/maps", "r");
3394 if (fp) {
3395 while (!feof(fp)) {
3396 char chars[257];
3397 long x = 0;
3398 if (fgets(chars, sizeof(chars), fp)) {
3399 if (sscanf(chars, "%lx-%*x", &x) == 1
3400 && x == (long)p) {
3401 if (strstr (chars, "hugepage")) {
3402 result = true;
3403 break;
3404 }
3405 }
3406 }
3407 }
3408 fclose(fp);
3409 }
3410 munmap(p, page_size);
3411 }
3412
3413 if (warn && !result) {
3414 warning("HugeTLBFS is not supported by the operating system.");
3415 }
3416
3417 return result;
3418 }
3419
3420 /*
3421 * Set the coredump_filter bits to include largepages in core dump (bit 6)
3422 *
3423 * From the coredump_filter documentation:
3424 *
3425 * - (bit 0) anonymous private memory
3426 * - (bit 1) anonymous shared memory
3427 * - (bit 2) file-backed private memory
3428 * - (bit 3) file-backed shared memory
3429 * - (bit 4) ELF header pages in file-backed private memory areas (it is
3430 * effective only if the bit 2 is cleared)
3431 * - (bit 5) hugetlb private memory
3432 * - (bit 6) hugetlb shared memory
3433 */
3434 static void set_coredump_filter(void) {
3435 FILE *f;
3436 long cdm;
3437
3438 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3439 return;
3440 }
3441
3442 if (fscanf(f, "%lx", &cdm) != 1) {
3443 fclose(f);
3444 return;
3445 }
3446
3447 rewind(f);
3448
3449 if ((cdm & LARGEPAGES_BIT) == 0) {
3450 cdm |= LARGEPAGES_BIT;
3451 fprintf(f, "%#lx", cdm);
3452 }
3453
3454 fclose(f);
3455 }
3456
3457 // Large page support
3458
3459 static size_t _large_page_size = 0;
3460
3461 size_t os::Linux::find_large_page_size() {
3462 size_t large_page_size = 0;
3463
3464 // large_page_size on Linux is used to round up heap size. x86 uses either
3465 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3466 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3467 // page as large as 256M.
3468 //
3469 // Here we try to figure out page size by parsing /proc/meminfo and looking
3470 // for a line with the following format:
3471 // Hugepagesize: 2048 kB
3472 //
3473 // If we can't determine the value (e.g. /proc is not mounted, or the text
3474 // format has been changed), we'll use the largest page size supported by
3475 // the processor.
3476
3477 #ifndef ZERO
3478 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3479 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3480 #endif // ZERO
3481
3482 FILE *fp = fopen("/proc/meminfo", "r");
3483 if (fp) {
3484 while (!feof(fp)) {
3485 int x = 0;
3486 char buf[16];
3487 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3488 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3489 large_page_size = x * K;
3490 break;
3491 }
3492 } else {
3493 // skip to next line
3494 for (;;) {
3495 int ch = fgetc(fp);
3496 if (ch == EOF || ch == (int)'\n') break;
3497 }
3498 }
3499 }
3500 fclose(fp);
3501 }
3502
3503 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3504 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3505 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3506 proper_unit_for_byte_size(large_page_size));
3507 }
3508
3509 return large_page_size;
3510 }
3511
3512 size_t os::Linux::setup_large_page_size() {
3513 _large_page_size = Linux::find_large_page_size();
3514 const size_t default_page_size = (size_t)Linux::page_size();
3515 if (_large_page_size > default_page_size) {
3516 _page_sizes[0] = _large_page_size;
3517 _page_sizes[1] = default_page_size;
3518 _page_sizes[2] = 0;
3519 }
3520
3521 return _large_page_size;
3522 }
3523
3524 bool os::Linux::setup_large_page_type(size_t page_size) {
3525 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3526 FLAG_IS_DEFAULT(UseSHM) &&
3527 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3528
3529 // The type of large pages has not been specified by the user.
3530
3531 // Try UseHugeTLBFS and then UseSHM.
3532 UseHugeTLBFS = UseSHM = true;
3533
3534 // Don't try UseTransparentHugePages since there are known
3535 // performance issues with it turned on. This might change in the future.
3536 UseTransparentHugePages = false;
3537 }
3538
3539 if (UseTransparentHugePages) {
3540 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3541 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3542 UseHugeTLBFS = false;
3543 UseSHM = false;
3544 return true;
3545 }
3546 UseTransparentHugePages = false;
3547 }
3548
3549 if (UseHugeTLBFS) {
3550 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3551 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3552 UseSHM = false;
3553 return true;
3554 }
3555 UseHugeTLBFS = false;
3556 }
3557
3558 return UseSHM;
3559 }
3560
3561 void os::large_page_init() {
3562 if (!UseLargePages &&
3563 !UseTransparentHugePages &&
3564 !UseHugeTLBFS &&
3565 !UseSHM) {
3566 // Not using large pages.
3567 return;
3568 }
3569
3570 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3571 // The user explicitly turned off large pages.
3572 // Ignore the rest of the large pages flags.
3573 UseTransparentHugePages = false;
3574 UseHugeTLBFS = false;
3575 UseSHM = false;
3576 return;
3577 }
3578
3579 size_t large_page_size = Linux::setup_large_page_size();
3580 UseLargePages = Linux::setup_large_page_type(large_page_size);
3581
3582 set_coredump_filter();
3583 }
3584
3585 #ifndef SHM_HUGETLB
3586 #define SHM_HUGETLB 04000
3587 #endif
3588
3589 #define shm_warning_format(format, ...) \
3590 do { \
3591 if (UseLargePages && \
3592 (!FLAG_IS_DEFAULT(UseLargePages) || \
3593 !FLAG_IS_DEFAULT(UseSHM) || \
3594 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3595 warning(format, __VA_ARGS__); \
3596 } \
3597 } while (0)
3598
3599 #define shm_warning(str) shm_warning_format("%s", str)
3600
3601 #define shm_warning_with_errno(str) \
3602 do { \
3603 int err = errno; \
3604 shm_warning_format(str " (error = %d)", err); \
3605 } while (0)
3606
3607 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3608 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3609
3610 if (!is_size_aligned(alignment, SHMLBA)) {
3611 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3612 return NULL;
3613 }
3614
3615 // To ensure that we get 'alignment' aligned memory from shmat,
3616 // we pre-reserve aligned virtual memory and then attach to that.
3617
3618 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3619 if (pre_reserved_addr == NULL) {
3620 // Couldn't pre-reserve aligned memory.
3621 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3622 return NULL;
3623 }
3624
3625 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3626 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3627
3628 if ((intptr_t)addr == -1) {
3629 int err = errno;
3630 shm_warning_with_errno("Failed to attach shared memory.");
3631
3632 assert(err != EACCES, "Unexpected error");
3633 assert(err != EIDRM, "Unexpected error");
3634 assert(err != EINVAL, "Unexpected error");
3635
3636 // Since we don't know if the kernel unmapped the pre-reserved memory area
3637 // we can't unmap it, since that would potentially unmap memory that was
3638 // mapped from other threads.
3639 return NULL;
3640 }
3641
3642 return addr;
3643 }
3644
3645 static char* shmat_at_address(int shmid, char* req_addr) {
3646 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3647 assert(false, "Requested address needs to be SHMLBA aligned");
3648 return NULL;
3649 }
3650
3651 char* addr = (char*)shmat(shmid, req_addr, 0);
3652
3653 if ((intptr_t)addr == -1) {
3654 shm_warning_with_errno("Failed to attach shared memory.");
3655 return NULL;
3656 }
3657
3658 return addr;
3659 }
3660
3661 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3662 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3663 if (req_addr != NULL) {
3664 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3665 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3666 return shmat_at_address(shmid, req_addr);
3667 }
3668
3669 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3670 // return large page size aligned memory addresses when req_addr == NULL.
3671 // However, if the alignment is larger than the large page size, we have
3672 // to manually ensure that the memory returned is 'alignment' aligned.
3673 if (alignment > os::large_page_size()) {
3674 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3675 return shmat_with_alignment(shmid, bytes, alignment);
3676 } else {
3677 return shmat_at_address(shmid, NULL);
3678 }
3679 }
3680
3681 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3682 // "exec" is passed in but not used. Creating the shared image for
3683 // the code cache doesn't have an SHM_X executable permission to check.
3684 assert(UseLargePages && UseSHM, "only for SHM large pages");
3685 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3686 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3687
3688 if (!is_size_aligned(bytes, os::large_page_size())) {
3689 return NULL; // Fallback to small pages.
3690 }
3691
3692 // Create a large shared memory region to attach to based on size.
3693 // Currently, size is the total size of the heap.
3694 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3695 if (shmid == -1) {
3696 // Possible reasons for shmget failure:
3697 // 1. shmmax is too small for Java heap.
3698 // > check shmmax value: cat /proc/sys/kernel/shmmax
3699 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3700 // 2. not enough large page memory.
3701 // > check available large pages: cat /proc/meminfo
3702 // > increase amount of large pages:
3703 // echo new_value > /proc/sys/vm/nr_hugepages
3704 // Note 1: different Linux may use different name for this property,
3705 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3706 // Note 2: it's possible there's enough physical memory available but
3707 // they are so fragmented after a long run that they can't
3708 // coalesce into large pages. Try to reserve large pages when
3709 // the system is still "fresh".
3710 shm_warning_with_errno("Failed to reserve shared memory.");
3711 return NULL;
3712 }
3713
3714 // Attach to the region.
3715 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3716
3717 // Remove shmid. If shmat() is successful, the actual shared memory segment
3718 // will be deleted when it's detached by shmdt() or when the process
3719 // terminates. If shmat() is not successful this will remove the shared
3720 // segment immediately.
3721 shmctl(shmid, IPC_RMID, NULL);
3722
3723 return addr;
3724 }
3725
3726 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
3727 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3728
3729 bool warn_on_failure = UseLargePages &&
3730 (!FLAG_IS_DEFAULT(UseLargePages) ||
3731 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3732 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3733
3734 if (warn_on_failure) {
3735 char msg[128];
3736 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3737 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3738 warning("%s", msg);
3739 }
3740 }
3741
3742 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
3743 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3744 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3745 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3746
3747 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3748 char* addr = (char*)::mmap(req_addr, bytes, prot,
3749 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3750 -1, 0);
3751
3752 if (addr == MAP_FAILED) {
3753 warn_on_large_pages_failure(req_addr, bytes, errno);
3754 return NULL;
3755 }
3756
3757 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3758
3759 return addr;
3760 }
3761
3762 // Reserve memory using mmap(MAP_HUGETLB).
3763 // - bytes shall be a multiple of alignment.
3764 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3765 // - alignment sets the alignment at which memory shall be allocated.
3766 // It must be a multiple of allocation granularity.
3767 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3768 // req_addr or NULL.
3769 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3770 size_t large_page_size = os::large_page_size();
3771 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3772
3773 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3774 assert(is_size_aligned(bytes, alignment), "Must be");
3775
3776 // First reserve - but not commit - the address range in small pages.
3777 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3778
3779 if (start == NULL) {
3780 return NULL;
3781 }
3782
3783 assert(is_ptr_aligned(start, alignment), "Must be");
3784
3785 char* end = start + bytes;
3786
3787 // Find the regions of the allocated chunk that can be promoted to large pages.
3788 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3789 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3790
3791 size_t lp_bytes = lp_end - lp_start;
3792
3793 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3794
3795 if (lp_bytes == 0) {
3796 // The mapped region doesn't even span the start and the end of a large page.
3797 // Fall back to allocate a non-special area.
3798 ::munmap(start, end - start);
3799 return NULL;
3800 }
3801
3802 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3803
3804 void* result;
3805
3806 // Commit small-paged leading area.
3807 if (start != lp_start) {
3808 result = ::mmap(start, lp_start - start, prot,
3809 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3810 -1, 0);
3811 if (result == MAP_FAILED) {
3812 ::munmap(lp_start, end - lp_start);
3813 return NULL;
3814 }
3815 }
3816
3817 // Commit large-paged area.
3818 result = ::mmap(lp_start, lp_bytes, prot,
3819 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3820 -1, 0);
3821 if (result == MAP_FAILED) {
3822 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3823 // If the mmap above fails, the large pages region will be unmapped and we
3824 // have regions before and after with small pages. Release these regions.
3825 //
3826 // | mapped | unmapped | mapped |
3827 // ^ ^ ^ ^
3828 // start lp_start lp_end end
3829 //
3830 ::munmap(start, lp_start - start);
3831 ::munmap(lp_end, end - lp_end);
3832 return NULL;
3833 }
3834
3835 // Commit small-paged trailing area.
3836 if (lp_end != end) {
3837 result = ::mmap(lp_end, end - lp_end, prot,
3838 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3839 -1, 0);
3840 if (result == MAP_FAILED) {
3841 ::munmap(start, lp_end - start);
3842 return NULL;
3843 }
3844 }
3845
3846 return start;
3847 }
3848
3849 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3850 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3851 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3852 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3853 assert(is_power_of_2(os::large_page_size()), "Must be");
3854 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3855
3856 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3857 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3858 } else {
3859 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3860 }
3861 }
3862
3863 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3864 assert(UseLargePages, "only for large pages");
3865
3866 char* addr;
3867 if (UseSHM) {
3868 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3869 } else {
3870 assert(UseHugeTLBFS, "must be");
3871 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3872 }
3873
3874 if (addr != NULL) {
3875 if (UseNUMAInterleaving) {
3876 numa_make_global(addr, bytes);
3877 }
3878
3879 // The memory is committed
3880 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3881 }
3882
3883 return addr;
3884 }
3885
3886 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3887 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3888 return shmdt(base) == 0;
3889 }
3890
3891 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3892 return pd_release_memory(base, bytes);
3893 }
3894
3895 bool os::release_memory_special(char* base, size_t bytes) {
3896 bool res;
3897 if (MemTracker::tracking_level() > NMT_minimal) {
3898 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3899 res = os::Linux::release_memory_special_impl(base, bytes);
3900 if (res) {
3901 tkr.record((address)base, bytes);
3902 }
3903
3904 } else {
3905 res = os::Linux::release_memory_special_impl(base, bytes);
3906 }
3907 return res;
3908 }
3909
3910 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3911 assert(UseLargePages, "only for large pages");
3912 bool res;
3913
3914 if (UseSHM) {
3915 res = os::Linux::release_memory_special_shm(base, bytes);
3916 } else {
3917 assert(UseHugeTLBFS, "must be");
3918 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3919 }
3920 return res;
3921 }
3922
3923 size_t os::large_page_size() {
3924 return _large_page_size;
3925 }
3926
3927 // With SysV SHM the entire memory region must be allocated as shared
3928 // memory.
3929 // HugeTLBFS allows application to commit large page memory on demand.
3930 // However, when committing memory with HugeTLBFS fails, the region
3931 // that was supposed to be committed will lose the old reservation
3932 // and allow other threads to steal that memory region. Because of this
3933 // behavior we can't commit HugeTLBFS memory.
3934 bool os::can_commit_large_page_memory() {
3935 return UseTransparentHugePages;
3936 }
3937
3938 bool os::can_execute_large_page_memory() {
3939 return UseTransparentHugePages || UseHugeTLBFS;
3940 }
3941
3942 // Reserve memory at an arbitrary address, only if that area is
3943 // available (and not reserved for something else).
3944
3945 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3946 const int max_tries = 10;
3947 char* base[max_tries];
3948 size_t size[max_tries];
3949 const size_t gap = 0x000000;
3950
3951 // Assert only that the size is a multiple of the page size, since
3952 // that's all that mmap requires, and since that's all we really know
3953 // about at this low abstraction level. If we need higher alignment,
3954 // we can either pass an alignment to this method or verify alignment
3955 // in one of the methods further up the call chain. See bug 5044738.
3956 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3957
3958 // Repeatedly allocate blocks until the block is allocated at the
3959 // right spot. Give up after max_tries. Note that reserve_memory() will
3960 // automatically update _highest_vm_reserved_address if the call is
3961 // successful. The variable tracks the highest memory address every reserved
3962 // by JVM. It is used to detect heap-stack collision if running with
3963 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3964 // space than needed, it could confuse the collision detecting code. To
3965 // solve the problem, save current _highest_vm_reserved_address and
3966 // calculate the correct value before return.
3967 address old_highest = _highest_vm_reserved_address;
3968
3969 // Linux mmap allows caller to pass an address as hint; give it a try first,
3970 // if kernel honors the hint then we can return immediately.
3971 char * addr = anon_mmap(requested_addr, bytes, false);
3972 if (addr == requested_addr) {
3973 return requested_addr;
3974 }
3975
3976 if (addr != NULL) {
3977 // mmap() is successful but it fails to reserve at the requested address
3978 anon_munmap(addr, bytes);
3979 }
3980
3981 int i;
3982 for (i = 0; i < max_tries; ++i) {
3983 base[i] = reserve_memory(bytes);
3984
3985 if (base[i] != NULL) {
3986 // Is this the block we wanted?
3987 if (base[i] == requested_addr) {
3988 size[i] = bytes;
3989 break;
3990 }
3991
3992 // Does this overlap the block we wanted? Give back the overlapped
3993 // parts and try again.
3994
3995 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3996 if (top_overlap >= 0 && top_overlap < bytes) {
3997 unmap_memory(base[i], top_overlap);
3998 base[i] += top_overlap;
3999 size[i] = bytes - top_overlap;
4000 } else {
4001 size_t bottom_overlap = base[i] + bytes - requested_addr;
4002 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
4003 unmap_memory(requested_addr, bottom_overlap);
4004 size[i] = bytes - bottom_overlap;
4005 } else {
4006 size[i] = bytes;
4007 }
4008 }
4009 }
4010 }
4011
4012 // Give back the unused reserved pieces.
4013
4014 for (int j = 0; j < i; ++j) {
4015 if (base[j] != NULL) {
4016 unmap_memory(base[j], size[j]);
4017 }
4018 }
4019
4020 if (i < max_tries) {
4021 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
4022 return requested_addr;
4023 } else {
4024 _highest_vm_reserved_address = old_highest;
4025 return NULL;
4026 }
4027 }
4028
4029 size_t os::read(int fd, void *buf, unsigned int nBytes) {
4030 return ::read(fd, buf, nBytes);
4031 }
4032
4033 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
4034 // Solaris uses poll(), linux uses park().
4035 // Poll() is likely a better choice, assuming that Thread.interrupt()
4036 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
4037 // SIGSEGV, see 4355769.
4038
4039 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
4040 assert(thread == Thread::current(), "thread consistency check");
4041
4042 ParkEvent * const slp = thread->_SleepEvent ;
4043 slp->reset() ;
4044 OrderAccess::fence() ;
4045
4046 if (interruptible) {
4047 jlong prevtime = javaTimeNanos();
4048
4049 for (;;) {
4050 if (os::is_interrupted(thread, true)) {
4051 return OS_INTRPT;
4052 }
4053
4054 jlong newtime = javaTimeNanos();
4055
4056 if (newtime - prevtime < 0) {
4057 // time moving backwards, should only happen if no monotonic clock
4058 // not a guarantee() because JVM should not abort on kernel/glibc bugs
4059 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
4060 } else {
4061 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
4062 }
4063
4064 if(millis <= 0) {
4065 return OS_OK;
4066 }
4067
4068 prevtime = newtime;
4069
4070 {
4071 assert(thread->is_Java_thread(), "sanity check");
4072 JavaThread *jt = (JavaThread *) thread;
4073 ThreadBlockInVM tbivm(jt);
4074 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
4075
4076 jt->set_suspend_equivalent();
4077 // cleared by handle_special_suspend_equivalent_condition() or
4078 // java_suspend_self() via check_and_wait_while_suspended()
4079
4080 slp->park(millis);
4081
4082 // were we externally suspended while we were waiting?
4083 jt->check_and_wait_while_suspended();
4084 }
4085 }
4086 } else {
4087 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4088 jlong prevtime = javaTimeNanos();
4089
4090 for (;;) {
4091 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
4092 // the 1st iteration ...
4093 jlong newtime = javaTimeNanos();
4094
4095 if (newtime - prevtime < 0) {
4096 // time moving backwards, should only happen if no monotonic clock
4097 // not a guarantee() because JVM should not abort on kernel/glibc bugs
4098 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
4099 } else {
4100 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
4101 }
4102
4103 if(millis <= 0) break ;
4104
4105 prevtime = newtime;
4106 slp->park(millis);
4107 }
4108 return OS_OK ;
4109 }
4110 }
4111
4112 //
4113 // Short sleep, direct OS call.
4114 //
4115 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
4116 // sched_yield(2) will actually give up the CPU:
4117 //
4118 // * Alone on this pariticular CPU, keeps running.
4119 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
4120 // (pre 2.6.39).
4121 //
4122 // So calling this with 0 is an alternative.
4123 //
4124 void os::naked_short_sleep(jlong ms) {
4125 struct timespec req;
4126
4127 assert(ms < 1000, "Un-interruptable sleep, short time use only");
4128 req.tv_sec = 0;
4129 if (ms > 0) {
4130 req.tv_nsec = (ms % 1000) * 1000000;
4131 }
4132 else {
4133 req.tv_nsec = 1;
4134 }
4135
4136 nanosleep(&req, NULL);
4137
4138 return;
4139 }
4140
4141 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4142 void os::infinite_sleep() {
4143 while (true) { // sleep forever ...
4144 ::sleep(100); // ... 100 seconds at a time
4145 }
4146 }
4147
4148 // Used to convert frequent JVM_Yield() to nops
4149 bool os::dont_yield() {
4150 return DontYieldALot;
4151 }
4152
4153 void os::yield() {
4154 sched_yield();
4155 }
4156
4157 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
4158
4159 void os::yield_all(int attempts) {
4160 // Yields to all threads, including threads with lower priorities
4161 // Threads on Linux are all with same priority. The Solaris style
4162 // os::yield_all() with nanosleep(1ms) is not necessary.
4163 sched_yield();
4164 }
4165
4166 // Called from the tight loops to possibly influence time-sharing heuristics
4167 void os::loop_breaker(int attempts) {
4168 os::yield_all(attempts);
4169 }
4170
4171 ////////////////////////////////////////////////////////////////////////////////
4172 // thread priority support
4173
4174 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4175 // only supports dynamic priority, static priority must be zero. For real-time
4176 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4177 // However, for large multi-threaded applications, SCHED_RR is not only slower
4178 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4179 // of 5 runs - Sep 2005).
4180 //
4181 // The following code actually changes the niceness of kernel-thread/LWP. It
4182 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4183 // not the entire user process, and user level threads are 1:1 mapped to kernel
4184 // threads. It has always been the case, but could change in the future. For
4185 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4186 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
4187
4188 int os::java_to_os_priority[CriticalPriority + 1] = {
4189 19, // 0 Entry should never be used
4190
4191 4, // 1 MinPriority
4192 3, // 2
4193 2, // 3
4194
4195 1, // 4
4196 0, // 5 NormPriority
4197 -1, // 6
4198
4199 -2, // 7
4200 -3, // 8
4201 -4, // 9 NearMaxPriority
4202
4203 -5, // 10 MaxPriority
4204
4205 -5 // 11 CriticalPriority
4206 };
4207
4208 static int prio_init() {
4209 if (ThreadPriorityPolicy == 1) {
4210 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
4211 // if effective uid is not root. Perhaps, a more elegant way of doing
4212 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
4213 if (geteuid() != 0) {
4214 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
4215 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
4216 }
4217 ThreadPriorityPolicy = 0;
4218 }
4219 }
4220 if (UseCriticalJavaThreadPriority) {
4221 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4222 }
4223 return 0;
4224 }
4225
4226 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4227 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
4228
4229 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4230 return (ret == 0) ? OS_OK : OS_ERR;
4231 }
4232
4233 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
4234 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
4235 *priority_ptr = java_to_os_priority[NormPriority];
4236 return OS_OK;
4237 }
4238
4239 errno = 0;
4240 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4241 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4242 }
4243
4244 // Hint to the underlying OS that a task switch would not be good.
4245 // Void return because it's a hint and can fail.
4246 void os::hint_no_preempt() {}
4247
4248 ////////////////////////////////////////////////////////////////////////////////
4249 // suspend/resume support
4250
4251 // the low-level signal-based suspend/resume support is a remnant from the
4252 // old VM-suspension that used to be for java-suspension, safepoints etc,
4253 // within hotspot. Now there is a single use-case for this:
4254 // - calling get_thread_pc() on the VMThread by the flat-profiler task
4255 // that runs in the watcher thread.
4256 // The remaining code is greatly simplified from the more general suspension
4257 // code that used to be used.
4258 //
4259 // The protocol is quite simple:
4260 // - suspend:
4261 // - sends a signal to the target thread
4262 // - polls the suspend state of the osthread using a yield loop
4263 // - target thread signal handler (SR_handler) sets suspend state
4264 // and blocks in sigsuspend until continued
4265 // - resume:
4266 // - sets target osthread state to continue
4267 // - sends signal to end the sigsuspend loop in the SR_handler
4268 //
4269 // Note that the SR_lock plays no role in this suspend/resume protocol.
4270 //
4271
4272 static void resume_clear_context(OSThread *osthread) {
4273 osthread->set_ucontext(NULL);
4274 osthread->set_siginfo(NULL);
4275 }
4276
4277 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
4278 osthread->set_ucontext(context);
4279 osthread->set_siginfo(siginfo);
4280 }
4281
4282 //
4283 // Handler function invoked when a thread's execution is suspended or
4284 // resumed. We have to be careful that only async-safe functions are
4285 // called here (Note: most pthread functions are not async safe and
4286 // should be avoided.)
4287 //
4288 // Note: sigwait() is a more natural fit than sigsuspend() from an
4289 // interface point of view, but sigwait() prevents the signal hander
4290 // from being run. libpthread would get very confused by not having
4291 // its signal handlers run and prevents sigwait()'s use with the
4292 // mutex granting granting signal.
4293 //
4294 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4295 //
4296 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4297 // Save and restore errno to avoid confusing native code with EINTR
4298 // after sigsuspend.
4299 int old_errno = errno;
4300
4301 Thread* thread = Thread::current();
4302 OSThread* osthread = thread->osthread();
4303 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4304
4305 os::SuspendResume::State current = osthread->sr.state();
4306 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4307 suspend_save_context(osthread, siginfo, context);
4308
4309 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4310 os::SuspendResume::State state = osthread->sr.suspended();
4311 if (state == os::SuspendResume::SR_SUSPENDED) {
4312 sigset_t suspend_set; // signals for sigsuspend()
4313
4314 // get current set of blocked signals and unblock resume signal
4315 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4316 sigdelset(&suspend_set, SR_signum);
4317
4318 sr_semaphore.signal();
4319 // wait here until we are resumed
4320 while (1) {
4321 sigsuspend(&suspend_set);
4322
4323 os::SuspendResume::State result = osthread->sr.running();
4324 if (result == os::SuspendResume::SR_RUNNING) {
4325 sr_semaphore.signal();
4326 break;
4327 }
4328 }
4329
4330 } else if (state == os::SuspendResume::SR_RUNNING) {
4331 // request was cancelled, continue
4332 } else {
4333 ShouldNotReachHere();
4334 }
4335
4336 resume_clear_context(osthread);
4337 } else if (current == os::SuspendResume::SR_RUNNING) {
4338 // request was cancelled, continue
4339 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4340 // ignore
4341 } else {
4342 // ignore
4343 }
4344
4345 errno = old_errno;
4346 }
4347
4348
4349 static int SR_initialize() {
4350 struct sigaction act;
4351 char *s;
4352 /* Get signal number to use for suspend/resume */
4353 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4354 int sig = ::strtol(s, 0, 10);
4355 if (sig > 0 || sig < _NSIG) {
4356 SR_signum = sig;
4357 }
4358 }
4359
4360 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4361 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4362
4363 sigemptyset(&SR_sigset);
4364 sigaddset(&SR_sigset, SR_signum);
4365
4366 /* Set up signal handler for suspend/resume */
4367 act.sa_flags = SA_RESTART|SA_SIGINFO;
4368 act.sa_handler = (void (*)(int)) SR_handler;
4369
4370 // SR_signum is blocked by default.
4371 // 4528190 - We also need to block pthread restart signal (32 on all
4372 // supported Linux platforms). Note that LinuxThreads need to block
4373 // this signal for all threads to work properly. So we don't have
4374 // to use hard-coded signal number when setting up the mask.
4375 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4376
4377 if (sigaction(SR_signum, &act, 0) == -1) {
4378 return -1;
4379 }
4380
4381 // Save signal flag
4382 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4383 return 0;
4384 }
4385
4386 static int sr_notify(OSThread* osthread) {
4387 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4388 assert_status(status == 0, status, "pthread_kill");
4389 return status;
4390 }
4391
4392 // "Randomly" selected value for how long we want to spin
4393 // before bailing out on suspending a thread, also how often
4394 // we send a signal to a thread we want to resume
4395 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4396 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4397
4398 // returns true on success and false on error - really an error is fatal
4399 // but this seems the normal response to library errors
4400 static bool do_suspend(OSThread* osthread) {
4401 assert(osthread->sr.is_running(), "thread should be running");
4402 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4403
4404 // mark as suspended and send signal
4405 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4406 // failed to switch, state wasn't running?
4407 ShouldNotReachHere();
4408 return false;
4409 }
4410
4411 if (sr_notify(osthread) != 0) {
4412 ShouldNotReachHere();
4413 }
4414
4415 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4416 while (true) {
4417 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4418 break;
4419 } else {
4420 // timeout
4421 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4422 if (cancelled == os::SuspendResume::SR_RUNNING) {
4423 return false;
4424 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4425 // make sure that we consume the signal on the semaphore as well
4426 sr_semaphore.wait();
4427 break;
4428 } else {
4429 ShouldNotReachHere();
4430 return false;
4431 }
4432 }
4433 }
4434
4435 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4436 return true;
4437 }
4438
4439 static void do_resume(OSThread* osthread) {
4440 assert(osthread->sr.is_suspended(), "thread should be suspended");
4441 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4442
4443 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4444 // failed to switch to WAKEUP_REQUEST
4445 ShouldNotReachHere();
4446 return;
4447 }
4448
4449 while (true) {
4450 if (sr_notify(osthread) == 0) {
4451 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4452 if (osthread->sr.is_running()) {
4453 return;
4454 }
4455 }
4456 } else {
4457 ShouldNotReachHere();
4458 }
4459 }
4460
4461 guarantee(osthread->sr.is_running(), "Must be running!");
4462 }
4463
4464 ////////////////////////////////////////////////////////////////////////////////
4465 // interrupt support
4466
4467 void os::interrupt(Thread* thread) {
4468 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4469 "possibility of dangling Thread pointer");
4470
4471 OSThread* osthread = thread->osthread();
4472
4473 if (!osthread->interrupted()) {
4474 osthread->set_interrupted(true);
4475 // More than one thread can get here with the same value of osthread,
4476 // resulting in multiple notifications. We do, however, want the store
4477 // to interrupted() to be visible to other threads before we execute unpark().
4478 OrderAccess::fence();
4479 ParkEvent * const slp = thread->_SleepEvent ;
4480 if (slp != NULL) slp->unpark() ;
4481 }
4482
4483 // For JSR166. Unpark even if interrupt status already was set
4484 if (thread->is_Java_thread())
4485 ((JavaThread*)thread)->parker()->unpark();
4486
4487 ParkEvent * ev = thread->_ParkEvent ;
4488 if (ev != NULL) ev->unpark() ;
4489
4490 }
4491
4492 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
4493 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4494 "possibility of dangling Thread pointer");
4495
4496 OSThread* osthread = thread->osthread();
4497
4498 bool interrupted = osthread->interrupted();
4499
4500 if (interrupted && clear_interrupted) {
4501 osthread->set_interrupted(false);
4502 // consider thread->_SleepEvent->reset() ... optional optimization
4503 }
4504
4505 return interrupted;
4506 }
4507
4508 ///////////////////////////////////////////////////////////////////////////////////
4509 // signal handling (except suspend/resume)
4510
4511 // This routine may be used by user applications as a "hook" to catch signals.
4512 // The user-defined signal handler must pass unrecognized signals to this
4513 // routine, and if it returns true (non-zero), then the signal handler must
4514 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4515 // routine will never retun false (zero), but instead will execute a VM panic
4516 // routine kill the process.
4517 //
4518 // If this routine returns false, it is OK to call it again. This allows
4519 // the user-defined signal handler to perform checks either before or after
4520 // the VM performs its own checks. Naturally, the user code would be making
4521 // a serious error if it tried to handle an exception (such as a null check
4522 // or breakpoint) that the VM was generating for its own correct operation.
4523 //
4524 // This routine may recognize any of the following kinds of signals:
4525 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4526 // It should be consulted by handlers for any of those signals.
4527 //
4528 // The caller of this routine must pass in the three arguments supplied
4529 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4530 // field of the structure passed to sigaction(). This routine assumes that
4531 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4532 //
4533 // Note that the VM will print warnings if it detects conflicting signal
4534 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4535 //
4536 extern "C" JNIEXPORT int
4537 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
4538 void* ucontext, int abort_if_unrecognized);
4539
4540 void signalHandler(int sig, siginfo_t* info, void* uc) {
4541 assert(info != NULL && uc != NULL, "it must be old kernel");
4542 int orig_errno = errno; // Preserve errno value over signal handler.
4543 JVM_handle_linux_signal(sig, info, uc, true);
4544 errno = orig_errno;
4545 }
4546
4547
4548 // This boolean allows users to forward their own non-matching signals
4549 // to JVM_handle_linux_signal, harmlessly.
4550 bool os::Linux::signal_handlers_are_installed = false;
4551
4552 // For signal-chaining
4553 struct sigaction os::Linux::sigact[MAXSIGNUM];
4554 unsigned int os::Linux::sigs = 0;
4555 bool os::Linux::libjsig_is_loaded = false;
4556 typedef struct sigaction *(*get_signal_t)(int);
4557 get_signal_t os::Linux::get_signal_action = NULL;
4558
4559 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4560 struct sigaction *actp = NULL;
4561
4562 if (libjsig_is_loaded) {
4563 // Retrieve the old signal handler from libjsig
4564 actp = (*get_signal_action)(sig);
4565 }
4566 if (actp == NULL) {
4567 // Retrieve the preinstalled signal handler from jvm
4568 actp = get_preinstalled_handler(sig);
4569 }
4570
4571 return actp;
4572 }
4573
4574 static bool call_chained_handler(struct sigaction *actp, int sig,
4575 siginfo_t *siginfo, void *context) {
4576 // Call the old signal handler
4577 if (actp->sa_handler == SIG_DFL) {
4578 // It's more reasonable to let jvm treat it as an unexpected exception
4579 // instead of taking the default action.
4580 return false;
4581 } else if (actp->sa_handler != SIG_IGN) {
4582 if ((actp->sa_flags & SA_NODEFER) == 0) {
4583 // automaticlly block the signal
4584 sigaddset(&(actp->sa_mask), sig);
4585 }
4586
4587 sa_handler_t hand = NULL;
4588 sa_sigaction_t sa = NULL;
4589 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4590 // retrieve the chained handler
4591 if (siginfo_flag_set) {
4592 sa = actp->sa_sigaction;
4593 } else {
4594 hand = actp->sa_handler;
4595 }
4596
4597 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4598 actp->sa_handler = SIG_DFL;
4599 }
4600
4601 // try to honor the signal mask
4602 sigset_t oset;
4603 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4604
4605 // call into the chained handler
4606 if (siginfo_flag_set) {
4607 (*sa)(sig, siginfo, context);
4608 } else {
4609 (*hand)(sig);
4610 }
4611
4612 // restore the signal mask
4613 pthread_sigmask(SIG_SETMASK, &oset, 0);
4614 }
4615 // Tell jvm's signal handler the signal is taken care of.
4616 return true;
4617 }
4618
4619 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4620 bool chained = false;
4621 // signal-chaining
4622 if (UseSignalChaining) {
4623 struct sigaction *actp = get_chained_signal_action(sig);
4624 if (actp != NULL) {
4625 chained = call_chained_handler(actp, sig, siginfo, context);
4626 }
4627 }
4628 return chained;
4629 }
4630
4631 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4632 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
4633 return &sigact[sig];
4634 }
4635 return NULL;
4636 }
4637
4638 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4639 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4640 sigact[sig] = oldAct;
4641 sigs |= (unsigned int)1 << sig;
4642 }
4643
4644 // for diagnostic
4645 int os::Linux::sigflags[MAXSIGNUM];
4646
4647 int os::Linux::get_our_sigflags(int sig) {
4648 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4649 return sigflags[sig];
4650 }
4651
4652 void os::Linux::set_our_sigflags(int sig, int flags) {
4653 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4654 sigflags[sig] = flags;
4655 }
4656
4657 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4658 // Check for overwrite.
4659 struct sigaction oldAct;
4660 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4661
4662 void* oldhand = oldAct.sa_sigaction
4663 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4664 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4665 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4666 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4667 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4668 if (AllowUserSignalHandlers || !set_installed) {
4669 // Do not overwrite; user takes responsibility to forward to us.
4670 return;
4671 } else if (UseSignalChaining) {
4672 // save the old handler in jvm
4673 save_preinstalled_handler(sig, oldAct);
4674 // libjsig also interposes the sigaction() call below and saves the
4675 // old sigaction on it own.
4676 } else {
4677 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
4678 "%#lx for signal %d.", (long)oldhand, sig));
4679 }
4680 }
4681
4682 struct sigaction sigAct;
4683 sigfillset(&(sigAct.sa_mask));
4684 sigAct.sa_handler = SIG_DFL;
4685 if (!set_installed) {
4686 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4687 } else {
4688 sigAct.sa_sigaction = signalHandler;
4689 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4690 }
4691 // Save flags, which are set by ours
4692 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4693 sigflags[sig] = sigAct.sa_flags;
4694
4695 int ret = sigaction(sig, &sigAct, &oldAct);
4696 assert(ret == 0, "check");
4697
4698 void* oldhand2 = oldAct.sa_sigaction
4699 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4700 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4701 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4702 }
4703
4704 // install signal handlers for signals that HotSpot needs to
4705 // handle in order to support Java-level exception handling.
4706
4707 void os::Linux::install_signal_handlers() {
4708 if (!signal_handlers_are_installed) {
4709 signal_handlers_are_installed = true;
4710
4711 // signal-chaining
4712 typedef void (*signal_setting_t)();
4713 signal_setting_t begin_signal_setting = NULL;
4714 signal_setting_t end_signal_setting = NULL;
4715 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4716 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4717 if (begin_signal_setting != NULL) {
4718 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4719 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4720 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4721 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4722 libjsig_is_loaded = true;
4723 assert(UseSignalChaining, "should enable signal-chaining");
4724 }
4725 if (libjsig_is_loaded) {
4726 // Tell libjsig jvm is setting signal handlers
4727 (*begin_signal_setting)();
4728 }
4729
4730 set_signal_handler(SIGSEGV, true);
4731 set_signal_handler(SIGPIPE, true);
4732 set_signal_handler(SIGBUS, true);
4733 set_signal_handler(SIGILL, true);
4734 set_signal_handler(SIGFPE, true);
4735 #if defined(PPC64)
4736 set_signal_handler(SIGTRAP, true);
4737 #endif
4738 set_signal_handler(SIGXFSZ, true);
4739
4740 if (libjsig_is_loaded) {
4741 // Tell libjsig jvm finishes setting signal handlers
4742 (*end_signal_setting)();
4743 }
4744
4745 // We don't activate signal checker if libjsig is in place, we trust ourselves
4746 // and if UserSignalHandler is installed all bets are off.
4747 // Log that signal checking is off only if -verbose:jni is specified.
4748 if (CheckJNICalls) {
4749 if (libjsig_is_loaded) {
4750 if (PrintJNIResolving) {
4751 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4752 }
4753 check_signals = false;
4754 }
4755 if (AllowUserSignalHandlers) {
4756 if (PrintJNIResolving) {
4757 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4758 }
4759 check_signals = false;
4760 }
4761 }
4762 }
4763 }
4764
4765 // This is the fastest way to get thread cpu time on Linux.
4766 // Returns cpu time (user+sys) for any thread, not only for current.
4767 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4768 // It might work on 2.6.10+ with a special kernel/glibc patch.
4769 // For reference, please, see IEEE Std 1003.1-2004:
4770 // http://www.unix.org/single_unix_specification
4771
4772 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4773 struct timespec tp;
4774 int rc = os::Linux::clock_gettime(clockid, &tp);
4775 assert(rc == 0, "clock_gettime is expected to return 0 code");
4776
4777 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4778 }
4779
4780 /////
4781 // glibc on Linux platform uses non-documented flag
4782 // to indicate, that some special sort of signal
4783 // trampoline is used.
4784 // We will never set this flag, and we should
4785 // ignore this flag in our diagnostic
4786 #ifdef SIGNIFICANT_SIGNAL_MASK
4787 #undef SIGNIFICANT_SIGNAL_MASK
4788 #endif
4789 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4790
4791 static const char* get_signal_handler_name(address handler,
4792 char* buf, int buflen) {
4793 int offset = 0;
4794 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4795 if (found) {
4796 // skip directory names
4797 const char *p1, *p2;
4798 p1 = buf;
4799 size_t len = strlen(os::file_separator());
4800 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4801 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4802 } else {
4803 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4804 }
4805 return buf;
4806 }
4807
4808 static void print_signal_handler(outputStream* st, int sig,
4809 char* buf, size_t buflen) {
4810 struct sigaction sa;
4811
4812 sigaction(sig, NULL, &sa);
4813
4814 // See comment for SIGNIFICANT_SIGNAL_MASK define
4815 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4816
4817 st->print("%s: ", os::exception_name(sig, buf, buflen));
4818
4819 address handler = (sa.sa_flags & SA_SIGINFO)
4820 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4821 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4822
4823 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4824 st->print("SIG_DFL");
4825 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4826 st->print("SIG_IGN");
4827 } else {
4828 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4829 }
4830
4831 st->print(", sa_mask[0]=");
4832 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4833
4834 address rh = VMError::get_resetted_sighandler(sig);
4835 // May be, handler was resetted by VMError?
4836 if(rh != NULL) {
4837 handler = rh;
4838 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4839 }
4840
4841 st->print(", sa_flags=");
4842 os::Posix::print_sa_flags(st, sa.sa_flags);
4843
4844 // Check: is it our handler?
4845 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4846 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4847 // It is our signal handler
4848 // check for flags, reset system-used one!
4849 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4850 st->print(
4851 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4852 os::Linux::get_our_sigflags(sig));
4853 }
4854 }
4855 st->cr();
4856 }
4857
4858
4859 #define DO_SIGNAL_CHECK(sig) \
4860 if (!sigismember(&check_signal_done, sig)) \
4861 os::Linux::check_signal_handler(sig)
4862
4863 // This method is a periodic task to check for misbehaving JNI applications
4864 // under CheckJNI, we can add any periodic checks here
4865
4866 void os::run_periodic_checks() {
4867
4868 if (check_signals == false) return;
4869
4870 // SEGV and BUS if overridden could potentially prevent
4871 // generation of hs*.log in the event of a crash, debugging
4872 // such a case can be very challenging, so we absolutely
4873 // check the following for a good measure:
4874 DO_SIGNAL_CHECK(SIGSEGV);
4875 DO_SIGNAL_CHECK(SIGILL);
4876 DO_SIGNAL_CHECK(SIGFPE);
4877 DO_SIGNAL_CHECK(SIGBUS);
4878 DO_SIGNAL_CHECK(SIGPIPE);
4879 DO_SIGNAL_CHECK(SIGXFSZ);
4880 #if defined(PPC64)
4881 DO_SIGNAL_CHECK(SIGTRAP);
4882 #endif
4883
4884 // ReduceSignalUsage allows the user to override these handlers
4885 // see comments at the very top and jvm_solaris.h
4886 if (!ReduceSignalUsage) {
4887 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4888 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4889 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4890 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4891 }
4892
4893 DO_SIGNAL_CHECK(SR_signum);
4894 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4895 }
4896
4897 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4898
4899 static os_sigaction_t os_sigaction = NULL;
4900
4901 void os::Linux::check_signal_handler(int sig) {
4902 char buf[O_BUFLEN];
4903 address jvmHandler = NULL;
4904
4905
4906 struct sigaction act;
4907 if (os_sigaction == NULL) {
4908 // only trust the default sigaction, in case it has been interposed
4909 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4910 if (os_sigaction == NULL) return;
4911 }
4912
4913 os_sigaction(sig, (struct sigaction*)NULL, &act);
4914
4915
4916 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4917
4918 address thisHandler = (act.sa_flags & SA_SIGINFO)
4919 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4920 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4921
4922
4923 switch(sig) {
4924 case SIGSEGV:
4925 case SIGBUS:
4926 case SIGFPE:
4927 case SIGPIPE:
4928 case SIGILL:
4929 case SIGXFSZ:
4930 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4931 break;
4932
4933 case SHUTDOWN1_SIGNAL:
4934 case SHUTDOWN2_SIGNAL:
4935 case SHUTDOWN3_SIGNAL:
4936 case BREAK_SIGNAL:
4937 jvmHandler = (address)user_handler();
4938 break;
4939
4940 case INTERRUPT_SIGNAL:
4941 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4942 break;
4943
4944 default:
4945 if (sig == SR_signum) {
4946 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4947 } else {
4948 return;
4949 }
4950 break;
4951 }
4952
4953 if (thisHandler != jvmHandler) {
4954 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4955 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4956 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4957 // No need to check this sig any longer
4958 sigaddset(&check_signal_done, sig);
4959 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4960 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4961 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4962 exception_name(sig, buf, O_BUFLEN));
4963 }
4964 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4965 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4966 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4967 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4968 // No need to check this sig any longer
4969 sigaddset(&check_signal_done, sig);
4970 }
4971
4972 // Dump all the signal
4973 if (sigismember(&check_signal_done, sig)) {
4974 print_signal_handlers(tty, buf, O_BUFLEN);
4975 }
4976 }
4977
4978 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4979
4980 extern bool signal_name(int signo, char* buf, size_t len);
4981
4982 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4983 if (0 < exception_code && exception_code <= SIGRTMAX) {
4984 // signal
4985 if (!signal_name(exception_code, buf, size)) {
4986 jio_snprintf(buf, size, "SIG%d", exception_code);
4987 }
4988 return buf;
4989 } else {
4990 return NULL;
4991 }
4992 }
4993
4994 // this is called _before_ most of the global arguments have been parsed
4995 void os::init(void) {
4996 char dummy; /* used to get a guess on initial stack address */
4997
4998 // With LinuxThreads the JavaMain thread pid (primordial thread)
4999 // is different than the pid of the java launcher thread.
5000 // So, on Linux, the launcher thread pid is passed to the VM
5001 // via the sun.java.launcher.pid property.
5002 // Use this property instead of getpid() if it was correctly passed.
5003 // See bug 6351349.
5004 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
5005
5006 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
5007
5008 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5009
5010 init_random(1234567);
5011
5012 ThreadCritical::initialize();
5013
5014 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5015 if (Linux::page_size() == -1) {
5016 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
5017 strerror(errno)));
5018 }
5019 init_page_sizes((size_t) Linux::page_size());
5020
5021 Linux::initialize_system_info();
5022
5023 // _main_thread points to the thread that created/loaded the JVM.
5024 Linux::_main_thread = pthread_self();
5025
5026 Linux::clock_init();
5027 initial_time_count = javaTimeNanos();
5028
5029 // pthread_condattr initialization for monotonic clock
5030 int status;
5031 pthread_condattr_t* _condattr = os::Linux::condAttr();
5032 if ((status = pthread_condattr_init(_condattr)) != 0) {
5033 fatal(err_msg("pthread_condattr_init: %s", strerror(status)));
5034 }
5035 // Only set the clock if CLOCK_MONOTONIC is available
5036 if (Linux::supports_monotonic_clock()) {
5037 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
5038 if (status == EINVAL) {
5039 warning("Unable to use monotonic clock with relative timed-waits" \
5040 " - changes to the time-of-day clock may have adverse affects");
5041 } else {
5042 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status)));
5043 }
5044 }
5045 }
5046 // else it defaults to CLOCK_REALTIME
5047
5048 pthread_mutex_init(&dl_mutex, NULL);
5049
5050 // If the pagesize of the VM is greater than 8K determine the appropriate
5051 // number of initial guard pages. The user can change this with the
5052 // command line arguments, if needed.
5053 if (vm_page_size() > (int)Linux::vm_default_page_size()) {
5054 StackYellowPages = 1;
5055 StackRedPages = 1;
5056 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size();
5057 }
5058
5059 // retrieve entry point for pthread_setname_np
5060 Linux::_pthread_setname_np =
5061 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5062
5063 }
5064
5065 // To install functions for atexit system call
5066 extern "C" {
5067 static void perfMemory_exit_helper() {
5068 perfMemory_exit();
5069 }
5070 }
5071
5072 void os::pd_init_container_support() {
5073 OSContainer::init();
5074 }
5075
5076 // this is called _after_ the global arguments have been parsed
5077 jint os::init_2(void)
5078 {
5079 Linux::fast_thread_clock_init();
5080
5081 // Allocate a single page and mark it as readable for safepoint polling
5082 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
5083 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
5084
5085 os::set_polling_page( polling_page );
5086
5087 #ifndef PRODUCT
5088 if(Verbose && PrintMiscellaneous)
5089 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
5090 #endif
5091
5092 if (!UseMembar) {
5093 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
5094 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
5095 os::set_memory_serialize_page( mem_serialize_page );
5096
5097 #ifndef PRODUCT
5098 if(Verbose && PrintMiscellaneous)
5099 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
5100 #endif
5101 }
5102
5103 // initialize suspend/resume support - must do this before signal_sets_init()
5104 if (SR_initialize() != 0) {
5105 perror("SR_initialize failed");
5106 return JNI_ERR;
5107 }
5108
5109 Linux::signal_sets_init();
5110 Linux::install_signal_handlers();
5111
5112 // Check minimum allowable stack size for thread creation and to initialize
5113 // the java system classes, including StackOverflowError - depends on page
5114 // size. Add a page for compiler2 recursion in main thread.
5115 // Add in 2*BytesPerWord times page size to account for VM stack during
5116 // class initialization depending on 32 or 64 bit VM.
5117 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
5118 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() +
5119 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
5120
5121 size_t threadStackSizeInBytes = ThreadStackSize * K;
5122 if (threadStackSizeInBytes != 0 &&
5123 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
5124 tty->print_cr("\nThe stack size specified is too small, "
5125 "Specify at least %dk",
5126 os::Linux::min_stack_allowed/ K);
5127 return JNI_ERR;
5128 }
5129
5130 // Make the stack size a multiple of the page size so that
5131 // the yellow/red zones can be guarded.
5132 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
5133 vm_page_size()));
5134
5135 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5136
5137 #if defined(IA32)
5138 workaround_expand_exec_shield_cs_limit();
5139 #endif
5140
5141 Linux::libpthread_init();
5142 if (PrintMiscellaneous && (Verbose || WizardMode)) {
5143 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
5144 Linux::glibc_version(), Linux::libpthread_version(),
5145 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
5146 }
5147
5148 if (UseNUMA) {
5149 if (!Linux::libnuma_init()) {
5150 UseNUMA = false;
5151 } else {
5152 if ((Linux::numa_max_node() < 1)) {
5153 // There's only one node(they start from 0), disable NUMA.
5154 UseNUMA = false;
5155 }
5156 }
5157 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5158 // we can make the adaptive lgrp chunk resizing work. If the user specified
5159 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
5160 // disable adaptive resizing.
5161 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5162 if (FLAG_IS_DEFAULT(UseNUMA)) {
5163 UseNUMA = false;
5164 } else {
5165 if (FLAG_IS_DEFAULT(UseLargePages) &&
5166 FLAG_IS_DEFAULT(UseSHM) &&
5167 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
5168 UseLargePages = false;
5169 } else {
5170 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
5171 UseAdaptiveSizePolicy = false;
5172 UseAdaptiveNUMAChunkSizing = false;
5173 }
5174 }
5175 }
5176 if (!UseNUMA && ForceNUMA) {
5177 UseNUMA = true;
5178 }
5179 }
5180
5181 if (MaxFDLimit) {
5182 // set the number of file descriptors to max. print out error
5183 // if getrlimit/setrlimit fails but continue regardless.
5184 struct rlimit nbr_files;
5185 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5186 if (status != 0) {
5187 if (PrintMiscellaneous && (Verbose || WizardMode))
5188 perror("os::init_2 getrlimit failed");
5189 } else {
5190 nbr_files.rlim_cur = nbr_files.rlim_max;
5191 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5192 if (status != 0) {
5193 if (PrintMiscellaneous && (Verbose || WizardMode))
5194 perror("os::init_2 setrlimit failed");
5195 }
5196 }
5197 }
5198
5199 // Initialize lock used to serialize thread creation (see os::create_thread)
5200 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
5201
5202 // at-exit methods are called in the reverse order of their registration.
5203 // atexit functions are called on return from main or as a result of a
5204 // call to exit(3C). There can be only 32 of these functions registered
5205 // and atexit() does not set errno.
5206
5207 if (PerfAllowAtExitRegistration) {
5208 // only register atexit functions if PerfAllowAtExitRegistration is set.
5209 // atexit functions can be delayed until process exit time, which
5210 // can be problematic for embedded VM situations. Embedded VMs should
5211 // call DestroyJavaVM() to assure that VM resources are released.
5212
5213 // note: perfMemory_exit_helper atexit function may be removed in
5214 // the future if the appropriate cleanup code can be added to the
5215 // VM_Exit VMOperation's doit method.
5216 if (atexit(perfMemory_exit_helper) != 0) {
5217 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5218 }
5219 }
5220
5221 // initialize thread priority policy
5222 prio_init();
5223
5224 return JNI_OK;
5225 }
5226
5227 // Mark the polling page as unreadable
5228 void os::make_polling_page_unreadable(void) {
5229 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
5230 fatal("Could not disable polling page");
5231 };
5232
5233 // Mark the polling page as readable
5234 void os::make_polling_page_readable(void) {
5235 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
5236 fatal("Could not enable polling page");
5237 }
5238 };
5239
5240 static int os_cpu_count(const cpu_set_t* cpus) {
5241 int count = 0;
5242 // only look up to the number of configured processors
5243 for (int i = 0; i < os::processor_count(); i++) {
5244 if (CPU_ISSET(i, cpus)) {
5245 count++;
5246 }
5247 }
5248 return count;
5249 }
5250
5251 // Get the current number of available processors for this process.
5252 // This value can change at any time during a process's lifetime.
5253 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5254 // If anything goes wrong we fallback to returning the number of online
5255 // processors - which can be greater than the number available to the process.
5256 int os::Linux::active_processor_count() {
5257 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5258 int cpus_size = sizeof(cpu_set_t);
5259 int cpu_count = 0;
5260
5261 // pid 0 means the current thread - which we have to assume represents the process
5262 if (sched_getaffinity(0, cpus_size, &cpus) == 0) {
5263 cpu_count = os_cpu_count(&cpus);
5264 if (PrintActiveCpus) {
5265 tty->print_cr("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5266 }
5267 }
5268 else {
5269 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5270 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5271 "which may exceed available processors", strerror(errno), cpu_count);
5272 }
5273
5274 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5275 return cpu_count;
5276 }
5277
5278 // Determine the active processor count from one of
5279 // three different sources:
5280 //
5281 // 1. User option -XX:ActiveProcessorCount
5282 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5283 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5284 //
5285 // Option 1, if specified, will always override.
5286 // If the cgroup subsystem is active and configured, we
5287 // will return the min of the cgroup and option 2 results.
5288 // This is required since tools, such as numactl, that
5289 // alter cpu affinity do not update cgroup subsystem
5290 // cpuset configuration files.
5291 int os::active_processor_count() {
5292 // User has overridden the number of active processors
5293 if (ActiveProcessorCount > 0) {
5294 if (PrintActiveCpus) {
5295 tty->print_cr("active_processor_count: "
5296 "active processor count set by user : %d",
5297 ActiveProcessorCount);
5298 }
5299 return ActiveProcessorCount;
5300 }
5301
5302 int active_cpus;
5303 if (OSContainer::is_containerized()) {
5304 active_cpus = OSContainer::active_processor_count();
5305 if (PrintActiveCpus) {
5306 tty->print_cr("active_processor_count: determined by OSContainer: %d",
5307 active_cpus);
5308 }
5309 } else {
5310 active_cpus = os::Linux::active_processor_count();
5311 }
5312
5313 return active_cpus;
5314 }
5315
5316 void os::set_native_thread_name(const char *name) {
5317 if (Linux::_pthread_setname_np) {
5318 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5319 snprintf(buf, sizeof(buf), "%s", name);
5320 buf[sizeof(buf) - 1] = '\0';
5321 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5322 // ERANGE should not happen; all other errors should just be ignored.
5323 assert(rc != ERANGE, "pthread_setname_np failed");
5324 }
5325 }
5326
5327 bool os::distribute_processes(uint length, uint* distribution) {
5328 // Not yet implemented.
5329 return false;
5330 }
5331
5332 bool os::bind_to_processor(uint processor_id) {
5333 // Not yet implemented.
5334 return false;
5335 }
5336
5337 ///
5338
5339 void os::SuspendedThreadTask::internal_do_task() {
5340 if (do_suspend(_thread->osthread())) {
5341 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5342 do_task(context);
5343 do_resume(_thread->osthread());
5344 }
5345 }
5346
5347 class PcFetcher : public os::SuspendedThreadTask {
5348 public:
5349 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5350 ExtendedPC result();
5351 protected:
5352 void do_task(const os::SuspendedThreadTaskContext& context);
5353 private:
5354 ExtendedPC _epc;
5355 };
5356
5357 ExtendedPC PcFetcher::result() {
5358 guarantee(is_done(), "task is not done yet.");
5359 return _epc;
5360 }
5361
5362 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5363 Thread* thread = context.thread();
5364 OSThread* osthread = thread->osthread();
5365 if (osthread->ucontext() != NULL) {
5366 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext());
5367 } else {
5368 // NULL context is unexpected, double-check this is the VMThread
5369 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5370 }
5371 }
5372
5373 // Suspends the target using the signal mechanism and then grabs the PC before
5374 // resuming the target. Used by the flat-profiler only
5375 ExtendedPC os::get_thread_pc(Thread* thread) {
5376 // Make sure that it is called by the watcher for the VMThread
5377 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5378 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5379
5380 PcFetcher fetcher(thread);
5381 fetcher.run();
5382 return fetcher.result();
5383 }
5384
5385 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
5386 {
5387 if (is_NPTL()) {
5388 return pthread_cond_timedwait(_cond, _mutex, _abstime);
5389 } else {
5390 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
5391 // word back to default 64bit precision if condvar is signaled. Java
5392 // wants 53bit precision. Save and restore current value.
5393 int fpu = get_fpu_control_word();
5394 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
5395 set_fpu_control_word(fpu);
5396 return status;
5397 }
5398 }
5399
5400 ////////////////////////////////////////////////////////////////////////////////
5401 // debug support
5402
5403 bool os::find(address addr, outputStream* st) {
5404 Dl_info dlinfo;
5405 memset(&dlinfo, 0, sizeof(dlinfo));
5406 if (dladdr(addr, &dlinfo) != 0) {
5407 st->print(PTR_FORMAT ": ", addr);
5408 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5409 st->print("%s+%#x", dlinfo.dli_sname,
5410 addr - (intptr_t)dlinfo.dli_saddr);
5411 } else if (dlinfo.dli_fbase != NULL) {
5412 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
5413 } else {
5414 st->print("<absolute address>");
5415 }
5416 if (dlinfo.dli_fname != NULL) {
5417 st->print(" in %s", dlinfo.dli_fname);
5418 }
5419 if (dlinfo.dli_fbase != NULL) {
5420 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
5421 }
5422 st->cr();
5423
5424 if (Verbose) {
5425 // decode some bytes around the PC
5426 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5427 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5428 address lowest = (address) dlinfo.dli_sname;
5429 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5430 if (begin < lowest) begin = lowest;
5431 Dl_info dlinfo2;
5432 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5433 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
5434 end = (address) dlinfo2.dli_saddr;
5435 Disassembler::decode(begin, end, st);
5436 }
5437 return true;
5438 }
5439 return false;
5440 }
5441
5442 ////////////////////////////////////////////////////////////////////////////////
5443 // misc
5444
5445 // This does not do anything on Linux. This is basically a hook for being
5446 // able to use structured exception handling (thread-local exception filters)
5447 // on, e.g., Win32.
5448 void
5449 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
5450 JavaCallArguments* args, Thread* thread) {
5451 f(value, method, args, thread);
5452 }
5453
5454 void os::print_statistics() {
5455 }
5456
5457 int os::message_box(const char* title, const char* message) {
5458 int i;
5459 fdStream err(defaultStream::error_fd());
5460 for (i = 0; i < 78; i++) err.print_raw("=");
5461 err.cr();
5462 err.print_raw_cr(title);
5463 for (i = 0; i < 78; i++) err.print_raw("-");
5464 err.cr();
5465 err.print_raw_cr(message);
5466 for (i = 0; i < 78; i++) err.print_raw("=");
5467 err.cr();
5468
5469 char buf[16];
5470 // Prevent process from exiting upon "read error" without consuming all CPU
5471 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5472
5473 return buf[0] == 'y' || buf[0] == 'Y';
5474 }
5475
5476 int os::stat(const char *path, struct stat *sbuf) {
5477 char pathbuf[MAX_PATH];
5478 if (strlen(path) > MAX_PATH - 1) {
5479 errno = ENAMETOOLONG;
5480 return -1;
5481 }
5482 os::native_path(strcpy(pathbuf, path));
5483 return ::stat(pathbuf, sbuf);
5484 }
5485
5486 bool os::check_heap(bool force) {
5487 return true;
5488 }
5489
5490 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
5491 return ::vsnprintf(buf, count, format, args);
5492 }
5493
5494 // Is a (classpath) directory empty?
5495 bool os::dir_is_empty(const char* path) {
5496 DIR *dir = NULL;
5497 struct dirent *ptr;
5498
5499 dir = opendir(path);
5500 if (dir == NULL) return true;
5501
5502 /* Scan the directory */
5503 bool result = true;
5504 while (result && (ptr = readdir(dir)) != NULL) {
5505 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5506 result = false;
5507 }
5508 }
5509 closedir(dir);
5510 return result;
5511 }
5512
5513 // This code originates from JDK's sysOpen and open64_w
5514 // from src/solaris/hpi/src/system_md.c
5515
5516 #ifndef O_DELETE
5517 #define O_DELETE 0x10000
5518 #endif
5519
5520 // Open a file. Unlink the file immediately after open returns
5521 // if the specified oflag has the O_DELETE flag set.
5522 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
5523
5524 int os::open(const char *path, int oflag, int mode) {
5525
5526 if (strlen(path) > MAX_PATH - 1) {
5527 errno = ENAMETOOLONG;
5528 return -1;
5529 }
5530 int fd;
5531 int o_delete = (oflag & O_DELETE);
5532 oflag = oflag & ~O_DELETE;
5533
5534 fd = ::open64(path, oflag, mode);
5535 if (fd == -1) return -1;
5536
5537 //If the open succeeded, the file might still be a directory
5538 {
5539 struct stat64 buf64;
5540 int ret = ::fstat64(fd, &buf64);
5541 int st_mode = buf64.st_mode;
5542
5543 if (ret != -1) {
5544 if ((st_mode & S_IFMT) == S_IFDIR) {
5545 errno = EISDIR;
5546 ::close(fd);
5547 return -1;
5548 }
5549 } else {
5550 ::close(fd);
5551 return -1;
5552 }
5553 }
5554
5555 /*
5556 * All file descriptors that are opened in the JVM and not
5557 * specifically destined for a subprocess should have the
5558 * close-on-exec flag set. If we don't set it, then careless 3rd
5559 * party native code might fork and exec without closing all
5560 * appropriate file descriptors (e.g. as we do in closeDescriptors in
5561 * UNIXProcess.c), and this in turn might:
5562 *
5563 * - cause end-of-file to fail to be detected on some file
5564 * descriptors, resulting in mysterious hangs, or
5565 *
5566 * - might cause an fopen in the subprocess to fail on a system
5567 * suffering from bug 1085341.
5568 *
5569 * (Yes, the default setting of the close-on-exec flag is a Unix
5570 * design flaw)
5571 *
5572 * See:
5573 * 1085341: 32-bit stdio routines should support file descriptors >255
5574 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5575 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5576 */
5577 #ifdef FD_CLOEXEC
5578 {
5579 int flags = ::fcntl(fd, F_GETFD);
5580 if (flags != -1)
5581 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5582 }
5583 #endif
5584
5585 if (o_delete != 0) {
5586 ::unlink(path);
5587 }
5588 return fd;
5589 }
5590
5591
5592 // create binary file, rewriting existing file if required
5593 int os::create_binary_file(const char* path, bool rewrite_existing) {
5594 int oflags = O_WRONLY | O_CREAT;
5595 if (!rewrite_existing) {
5596 oflags |= O_EXCL;
5597 }
5598 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5599 }
5600
5601 // return current position of file pointer
5602 jlong os::current_file_offset(int fd) {
5603 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5604 }
5605
5606 // move file pointer to the specified offset
5607 jlong os::seek_to_file_offset(int fd, jlong offset) {
5608 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5609 }
5610
5611 // This code originates from JDK's sysAvailable
5612 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5613
5614 int os::available(int fd, jlong *bytes) {
5615 jlong cur, end;
5616 int mode;
5617 struct stat64 buf64;
5618
5619 if (::fstat64(fd, &buf64) >= 0) {
5620 mode = buf64.st_mode;
5621 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5622 /*
5623 * XXX: is the following call interruptible? If so, this might
5624 * need to go through the INTERRUPT_IO() wrapper as for other
5625 * blocking, interruptible calls in this file.
5626 */
5627 int n;
5628 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5629 *bytes = n;
5630 return 1;
5631 }
5632 }
5633 }
5634 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5635 return 0;
5636 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5637 return 0;
5638 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5639 return 0;
5640 }
5641 *bytes = end - cur;
5642 return 1;
5643 }
5644
5645 int os::socket_available(int fd, jint *pbytes) {
5646 // Linux doc says EINTR not returned, unlike Solaris
5647 int ret = ::ioctl(fd, FIONREAD, pbytes);
5648
5649 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
5650 // is expected to return 0 on failure and 1 on success to the jdk.
5651 return (ret < 0) ? 0 : 1;
5652 }
5653
5654 // Map a block of memory.
5655 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5656 char *addr, size_t bytes, bool read_only,
5657 bool allow_exec) {
5658 int prot;
5659 int flags = MAP_PRIVATE;
5660
5661 if (read_only) {
5662 prot = PROT_READ;
5663 } else {
5664 prot = PROT_READ | PROT_WRITE;
5665 }
5666
5667 if (allow_exec) {
5668 prot |= PROT_EXEC;
5669 }
5670
5671 if (addr != NULL) {
5672 flags |= MAP_FIXED;
5673 }
5674
5675 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5676 fd, file_offset);
5677 if (mapped_address == MAP_FAILED) {
5678 return NULL;
5679 }
5680 return mapped_address;
5681 }
5682
5683
5684 // Remap a block of memory.
5685 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5686 char *addr, size_t bytes, bool read_only,
5687 bool allow_exec) {
5688 // same as map_memory() on this OS
5689 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5690 allow_exec);
5691 }
5692
5693
5694 // Unmap a block of memory.
5695 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5696 return munmap(addr, bytes) == 0;
5697 }
5698
5699 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5700
5701 static clockid_t thread_cpu_clockid(Thread* thread) {
5702 pthread_t tid = thread->osthread()->pthread_id();
5703 clockid_t clockid;
5704
5705 // Get thread clockid
5706 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5707 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5708 return clockid;
5709 }
5710
5711 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5712 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5713 // of a thread.
5714 //
5715 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5716 // the fast estimate available on the platform.
5717
5718 jlong os::current_thread_cpu_time() {
5719 if (os::Linux::supports_fast_thread_cpu_time()) {
5720 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5721 } else {
5722 // return user + sys since the cost is the same
5723 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5724 }
5725 }
5726
5727 jlong os::thread_cpu_time(Thread* thread) {
5728 // consistent with what current_thread_cpu_time() returns
5729 if (os::Linux::supports_fast_thread_cpu_time()) {
5730 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5731 } else {
5732 return slow_thread_cpu_time(thread, true /* user + sys */);
5733 }
5734 }
5735
5736 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5737 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5738 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5739 } else {
5740 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5741 }
5742 }
5743
5744 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5745 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5746 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5747 } else {
5748 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5749 }
5750 }
5751
5752 //
5753 // -1 on error.
5754 //
5755
5756 PRAGMA_DIAG_PUSH
5757 PRAGMA_FORMAT_NONLITERAL_IGNORED
5758 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5759 static bool proc_task_unchecked = true;
5760 static const char *proc_stat_path = "/proc/%d/stat";
5761 pid_t tid = thread->osthread()->thread_id();
5762 char *s;
5763 char stat[2048];
5764 int statlen;
5765 char proc_name[64];
5766 int count;
5767 long sys_time, user_time;
5768 char cdummy;
5769 int idummy;
5770 long ldummy;
5771 FILE *fp;
5772
5773 // The /proc/<tid>/stat aggregates per-process usage on
5774 // new Linux kernels 2.6+ where NPTL is supported.
5775 // The /proc/self/task/<tid>/stat still has the per-thread usage.
5776 // See bug 6328462.
5777 // There possibly can be cases where there is no directory
5778 // /proc/self/task, so we check its availability.
5779 if (proc_task_unchecked && os::Linux::is_NPTL()) {
5780 // This is executed only once
5781 proc_task_unchecked = false;
5782 fp = fopen("/proc/self/task", "r");
5783 if (fp != NULL) {
5784 proc_stat_path = "/proc/self/task/%d/stat";
5785 fclose(fp);
5786 }
5787 }
5788
5789 sprintf(proc_name, proc_stat_path, tid);
5790 fp = fopen(proc_name, "r");
5791 if ( fp == NULL ) return -1;
5792 statlen = fread(stat, 1, 2047, fp);
5793 stat[statlen] = '\0';
5794 fclose(fp);
5795
5796 // Skip pid and the command string. Note that we could be dealing with
5797 // weird command names, e.g. user could decide to rename java launcher
5798 // to "java 1.4.2 :)", then the stat file would look like
5799 // 1234 (java 1.4.2 :)) R ... ...
5800 // We don't really need to know the command string, just find the last
5801 // occurrence of ")" and then start parsing from there. See bug 4726580.
5802 s = strrchr(stat, ')');
5803 if (s == NULL ) return -1;
5804
5805 // Skip blank chars
5806 do s++; while (isspace(*s));
5807
5808 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5809 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5810 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5811 &user_time, &sys_time);
5812 if ( count != 13 ) return -1;
5813 if (user_sys_cpu_time) {
5814 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5815 } else {
5816 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5817 }
5818 }
5819 PRAGMA_DIAG_POP
5820
5821 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5822 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5823 info_ptr->may_skip_backward = false; // elapsed time not wall time
5824 info_ptr->may_skip_forward = false; // elapsed time not wall time
5825 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5826 }
5827
5828 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5829 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5830 info_ptr->may_skip_backward = false; // elapsed time not wall time
5831 info_ptr->may_skip_forward = false; // elapsed time not wall time
5832 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5833 }
5834
5835 bool os::is_thread_cpu_time_supported() {
5836 return true;
5837 }
5838
5839 // System loadavg support. Returns -1 if load average cannot be obtained.
5840 // Linux doesn't yet have a (official) notion of processor sets,
5841 // so just return the system wide load average.
5842 int os::loadavg(double loadavg[], int nelem) {
5843 return ::getloadavg(loadavg, nelem);
5844 }
5845
5846 void os::pause() {
5847 char filename[MAX_PATH];
5848 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5849 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
5850 } else {
5851 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5852 }
5853
5854 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5855 if (fd != -1) {
5856 struct stat buf;
5857 ::close(fd);
5858 while (::stat(filename, &buf) == 0) {
5859 (void)::poll(NULL, 0, 100);
5860 }
5861 } else {
5862 jio_fprintf(stderr,
5863 "Could not open pause file '%s', continuing immediately.\n", filename);
5864 }
5865 }
5866
5867
5868 // Refer to the comments in os_solaris.cpp park-unpark.
5869 //
5870 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5871 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5872 // For specifics regarding the bug see GLIBC BUGID 261237 :
5873 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5874 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5875 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5876 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5877 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5878 // and monitorenter when we're using 1-0 locking. All those operations may result in
5879 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5880 // of libpthread avoids the problem, but isn't practical.
5881 //
5882 // Possible remedies:
5883 //
5884 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5885 // This is palliative and probabilistic, however. If the thread is preempted
5886 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5887 // than the minimum period may have passed, and the abstime may be stale (in the
5888 // past) resultin in a hang. Using this technique reduces the odds of a hang
5889 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5890 //
5891 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5892 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5893 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5894 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5895 // thread.
5896 //
5897 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5898 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5899 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5900 // This also works well. In fact it avoids kernel-level scalability impediments
5901 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5902 // timers in a graceful fashion.
5903 //
5904 // 4. When the abstime value is in the past it appears that control returns
5905 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5906 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5907 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5908 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5909 // It may be possible to avoid reinitialization by checking the return
5910 // value from pthread_cond_timedwait(). In addition to reinitializing the
5911 // condvar we must establish the invariant that cond_signal() is only called
5912 // within critical sections protected by the adjunct mutex. This prevents
5913 // cond_signal() from "seeing" a condvar that's in the midst of being
5914 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5915 // desirable signal-after-unlock optimization that avoids futile context switching.
5916 //
5917 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5918 // structure when a condvar is used or initialized. cond_destroy() would
5919 // release the helper structure. Our reinitialize-after-timedwait fix
5920 // put excessive stress on malloc/free and locks protecting the c-heap.
5921 //
5922 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5923 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5924 // and only enabling the work-around for vulnerable environments.
5925
5926 // utility to compute the abstime argument to timedwait:
5927 // millis is the relative timeout time
5928 // abstime will be the absolute timeout time
5929 // TODO: replace compute_abstime() with unpackTime()
5930
5931 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5932 if (millis < 0) millis = 0;
5933
5934 jlong seconds = millis / 1000;
5935 millis %= 1000;
5936 if (seconds > 50000000) { // see man cond_timedwait(3T)
5937 seconds = 50000000;
5938 }
5939
5940 if (os::Linux::supports_monotonic_clock()) {
5941 struct timespec now;
5942 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5943 assert_status(status == 0, status, "clock_gettime");
5944 abstime->tv_sec = now.tv_sec + seconds;
5945 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5946 if (nanos >= NANOSECS_PER_SEC) {
5947 abstime->tv_sec += 1;
5948 nanos -= NANOSECS_PER_SEC;
5949 }
5950 abstime->tv_nsec = nanos;
5951 } else {
5952 struct timeval now;
5953 int status = gettimeofday(&now, NULL);
5954 assert(status == 0, "gettimeofday");
5955 abstime->tv_sec = now.tv_sec + seconds;
5956 long usec = now.tv_usec + millis * 1000;
5957 if (usec >= 1000000) {
5958 abstime->tv_sec += 1;
5959 usec -= 1000000;
5960 }
5961 abstime->tv_nsec = usec * 1000;
5962 }
5963 return abstime;
5964 }
5965
5966
5967 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5968 // Conceptually TryPark() should be equivalent to park(0).
5969
5970 int os::PlatformEvent::TryPark() {
5971 for (;;) {
5972 const int v = _Event ;
5973 guarantee ((v == 0) || (v == 1), "invariant") ;
5974 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5975 }
5976 }
5977
5978 void os::PlatformEvent::park() { // AKA "down()"
5979 // Invariant: Only the thread associated with the Event/PlatformEvent
5980 // may call park().
5981 // TODO: assert that _Assoc != NULL or _Assoc == Self
5982 int v ;
5983 for (;;) {
5984 v = _Event ;
5985 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5986 }
5987 guarantee (v >= 0, "invariant") ;
5988 if (v == 0) {
5989 // Do this the hard way by blocking ...
5990 int status = pthread_mutex_lock(_mutex);
5991 assert_status(status == 0, status, "mutex_lock");
5992 guarantee (_nParked == 0, "invariant") ;
5993 ++ _nParked ;
5994 while (_Event < 0) {
5995 status = pthread_cond_wait(_cond, _mutex);
5996 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5997 // Treat this the same as if the wait was interrupted
5998 if (status == ETIME) { status = EINTR; }
5999 assert_status(status == 0 || status == EINTR, status, "cond_wait");
6000 }
6001 -- _nParked ;
6002
6003 _Event = 0 ;
6004 status = pthread_mutex_unlock(_mutex);
6005 assert_status(status == 0, status, "mutex_unlock");
6006 // Paranoia to ensure our locked and lock-free paths interact
6007 // correctly with each other.
6008 OrderAccess::fence();
6009 }
6010 guarantee (_Event >= 0, "invariant") ;
6011 }
6012
6013 int os::PlatformEvent::park(jlong millis) {
6014 guarantee (_nParked == 0, "invariant") ;
6015
6016 int v ;
6017 for (;;) {
6018 v = _Event ;
6019 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
6020 }
6021 guarantee (v >= 0, "invariant") ;
6022 if (v != 0) return OS_OK ;
6023
6024 // We do this the hard way, by blocking the thread.
6025 // Consider enforcing a minimum timeout value.
6026 struct timespec abst;
6027 compute_abstime(&abst, millis);
6028
6029 int ret = OS_TIMEOUT;
6030 int status = pthread_mutex_lock(_mutex);
6031 assert_status(status == 0, status, "mutex_lock");
6032 guarantee (_nParked == 0, "invariant") ;
6033 ++_nParked ;
6034
6035 // Object.wait(timo) will return because of
6036 // (a) notification
6037 // (b) timeout
6038 // (c) thread.interrupt
6039 //
6040 // Thread.interrupt and object.notify{All} both call Event::set.
6041 // That is, we treat thread.interrupt as a special case of notification.
6042 // The underlying Solaris implementation, cond_timedwait, admits
6043 // spurious/premature wakeups, but the JLS/JVM spec prevents the
6044 // JVM from making those visible to Java code. As such, we must
6045 // filter out spurious wakeups. We assume all ETIME returns are valid.
6046 //
6047 // TODO: properly differentiate simultaneous notify+interrupt.
6048 // In that case, we should propagate the notify to another waiter.
6049
6050 while (_Event < 0) {
6051 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
6052 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
6053 pthread_cond_destroy (_cond);
6054 pthread_cond_init (_cond, os::Linux::condAttr()) ;
6055 }
6056 assert_status(status == 0 || status == EINTR ||
6057 status == ETIME || status == ETIMEDOUT,
6058 status, "cond_timedwait");
6059 if (!FilterSpuriousWakeups) break ; // previous semantics
6060 if (status == ETIME || status == ETIMEDOUT) break ;
6061 // We consume and ignore EINTR and spurious wakeups.
6062 }
6063 --_nParked ;
6064 if (_Event >= 0) {
6065 ret = OS_OK;
6066 }
6067 _Event = 0 ;
6068 status = pthread_mutex_unlock(_mutex);
6069 assert_status(status == 0, status, "mutex_unlock");
6070 assert (_nParked == 0, "invariant") ;
6071 // Paranoia to ensure our locked and lock-free paths interact
6072 // correctly with each other.
6073 OrderAccess::fence();
6074 return ret;
6075 }
6076
6077 void os::PlatformEvent::unpark() {
6078 // Transitions for _Event:
6079 // 0 :=> 1
6080 // 1 :=> 1
6081 // -1 :=> either 0 or 1; must signal target thread
6082 // That is, we can safely transition _Event from -1 to either
6083 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back
6084 // unpark() calls.
6085 // See also: "Semaphores in Plan 9" by Mullender & Cox
6086 //
6087 // Note: Forcing a transition from "-1" to "1" on an unpark() means
6088 // that it will take two back-to-back park() calls for the owning
6089 // thread to block. This has the benefit of forcing a spurious return
6090 // from the first park() call after an unpark() call which will help
6091 // shake out uses of park() and unpark() without condition variables.
6092
6093 if (Atomic::xchg(1, &_Event) >= 0) return;
6094
6095 // Wait for the thread associated with the event to vacate
6096 int status = pthread_mutex_lock(_mutex);
6097 assert_status(status == 0, status, "mutex_lock");
6098 int AnyWaiters = _nParked;
6099 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
6100 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
6101 AnyWaiters = 0;
6102 pthread_cond_signal(_cond);
6103 }
6104 status = pthread_mutex_unlock(_mutex);
6105 assert_status(status == 0, status, "mutex_unlock");
6106 if (AnyWaiters != 0) {
6107 status = pthread_cond_signal(_cond);
6108 assert_status(status == 0, status, "cond_signal");
6109 }
6110
6111 // Note that we signal() _after dropping the lock for "immortal" Events.
6112 // This is safe and avoids a common class of futile wakeups. In rare
6113 // circumstances this can cause a thread to return prematurely from
6114 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
6115 // simply re-test the condition and re-park itself.
6116 }
6117
6118
6119 // JSR166
6120 // -------------------------------------------------------
6121
6122 /*
6123 * The solaris and linux implementations of park/unpark are fairly
6124 * conservative for now, but can be improved. They currently use a
6125 * mutex/condvar pair, plus a a count.
6126 * Park decrements count if > 0, else does a condvar wait. Unpark
6127 * sets count to 1 and signals condvar. Only one thread ever waits
6128 * on the condvar. Contention seen when trying to park implies that someone
6129 * is unparking you, so don't wait. And spurious returns are fine, so there
6130 * is no need to track notifications.
6131 */
6132
6133 /*
6134 * This code is common to linux and solaris and will be moved to a
6135 * common place in dolphin.
6136 *
6137 * The passed in time value is either a relative time in nanoseconds
6138 * or an absolute time in milliseconds. Either way it has to be unpacked
6139 * into suitable seconds and nanoseconds components and stored in the
6140 * given timespec structure.
6141 * Given time is a 64-bit value and the time_t used in the timespec is only
6142 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
6143 * overflow if times way in the future are given. Further on Solaris versions
6144 * prior to 10 there is a restriction (see cond_timedwait) that the specified
6145 * number of seconds, in abstime, is less than current_time + 100,000,000.
6146 * As it will be 28 years before "now + 100000000" will overflow we can
6147 * ignore overflow and just impose a hard-limit on seconds using the value
6148 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
6149 * years from "now".
6150 */
6151
6152 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
6153 assert (time > 0, "convertTime");
6154 time_t max_secs = 0;
6155
6156 if (!os::Linux::supports_monotonic_clock() || isAbsolute) {
6157 struct timeval now;
6158 int status = gettimeofday(&now, NULL);
6159 assert(status == 0, "gettimeofday");
6160
6161 max_secs = now.tv_sec + MAX_SECS;
6162
6163 if (isAbsolute) {
6164 jlong secs = time / 1000;
6165 if (secs > max_secs) {
6166 absTime->tv_sec = max_secs;
6167 } else {
6168 absTime->tv_sec = secs;
6169 }
6170 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
6171 } else {
6172 jlong secs = time / NANOSECS_PER_SEC;
6173 if (secs >= MAX_SECS) {
6174 absTime->tv_sec = max_secs;
6175 absTime->tv_nsec = 0;
6176 } else {
6177 absTime->tv_sec = now.tv_sec + secs;
6178 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
6179 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
6180 absTime->tv_nsec -= NANOSECS_PER_SEC;
6181 ++absTime->tv_sec; // note: this must be <= max_secs
6182 }
6183 }
6184 }
6185 } else {
6186 // must be relative using monotonic clock
6187 struct timespec now;
6188 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
6189 assert_status(status == 0, status, "clock_gettime");
6190 max_secs = now.tv_sec + MAX_SECS;
6191 jlong secs = time / NANOSECS_PER_SEC;
6192 if (secs >= MAX_SECS) {
6193 absTime->tv_sec = max_secs;
6194 absTime->tv_nsec = 0;
6195 } else {
6196 absTime->tv_sec = now.tv_sec + secs;
6197 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
6198 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
6199 absTime->tv_nsec -= NANOSECS_PER_SEC;
6200 ++absTime->tv_sec; // note: this must be <= max_secs
6201 }
6202 }
6203 }
6204 assert(absTime->tv_sec >= 0, "tv_sec < 0");
6205 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
6206 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
6207 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
6208 }
6209
6210 void Parker::park(bool isAbsolute, jlong time) {
6211 // Ideally we'd do something useful while spinning, such
6212 // as calling unpackTime().
6213
6214 // Optional fast-path check:
6215 // Return immediately if a permit is available.
6216 // We depend on Atomic::xchg() having full barrier semantics
6217 // since we are doing a lock-free update to _counter.
6218 if (Atomic::xchg(0, &_counter) > 0) return;
6219
6220 Thread* thread = Thread::current();
6221 assert(thread->is_Java_thread(), "Must be JavaThread");
6222 JavaThread *jt = (JavaThread *)thread;
6223
6224 // Optional optimization -- avoid state transitions if there's an interrupt pending.
6225 // Check interrupt before trying to wait
6226 if (Thread::is_interrupted(thread, false)) {
6227 return;
6228 }
6229
6230 // Next, demultiplex/decode time arguments
6231 timespec absTime;
6232 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
6233 return;
6234 }
6235 if (time > 0) {
6236 unpackTime(&absTime, isAbsolute, time);
6237 }
6238
6239
6240 // Enter safepoint region
6241 // Beware of deadlocks such as 6317397.
6242 // The per-thread Parker:: mutex is a classic leaf-lock.
6243 // In particular a thread must never block on the Threads_lock while
6244 // holding the Parker:: mutex. If safepoints are pending both the
6245 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
6246 ThreadBlockInVM tbivm(jt);
6247
6248 // Don't wait if cannot get lock since interference arises from
6249 // unblocking. Also. check interrupt before trying wait
6250 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
6251 return;
6252 }
6253
6254 int status ;
6255 if (_counter > 0) { // no wait needed
6256 _counter = 0;
6257 status = pthread_mutex_unlock(_mutex);
6258 assert (status == 0, "invariant") ;
6259 // Paranoia to ensure our locked and lock-free paths interact
6260 // correctly with each other and Java-level accesses.
6261 OrderAccess::fence();
6262 return;
6263 }
6264
6265 #ifdef ASSERT
6266 // Don't catch signals while blocked; let the running threads have the signals.
6267 // (This allows a debugger to break into the running thread.)
6268 sigset_t oldsigs;
6269 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
6270 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
6271 #endif
6272
6273 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
6274 jt->set_suspend_equivalent();
6275 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
6276
6277 assert(_cur_index == -1, "invariant");
6278 if (time == 0) {
6279 _cur_index = REL_INDEX; // arbitrary choice when not timed
6280 status = pthread_cond_wait (&_cond[_cur_index], _mutex) ;
6281 } else {
6282 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
6283 status = os::Linux::safe_cond_timedwait (&_cond[_cur_index], _mutex, &absTime) ;
6284 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
6285 pthread_cond_destroy (&_cond[_cur_index]) ;
6286 pthread_cond_init (&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr());
6287 }
6288 }
6289 _cur_index = -1;
6290 assert_status(status == 0 || status == EINTR ||
6291 status == ETIME || status == ETIMEDOUT,
6292 status, "cond_timedwait");
6293
6294 #ifdef ASSERT
6295 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
6296 #endif
6297
6298 _counter = 0 ;
6299 status = pthread_mutex_unlock(_mutex) ;
6300 assert_status(status == 0, status, "invariant") ;
6301 // Paranoia to ensure our locked and lock-free paths interact
6302 // correctly with each other and Java-level accesses.
6303 OrderAccess::fence();
6304
6305 // If externally suspended while waiting, re-suspend
6306 if (jt->handle_special_suspend_equivalent_condition()) {
6307 jt->java_suspend_self();
6308 }
6309 }
6310
6311 void Parker::unpark() {
6312 int s, status ;
6313 status = pthread_mutex_lock(_mutex);
6314 assert (status == 0, "invariant") ;
6315 s = _counter;
6316 _counter = 1;
6317 if (s < 1) {
6318 // thread might be parked
6319 if (_cur_index != -1) {
6320 // thread is definitely parked
6321 if (WorkAroundNPTLTimedWaitHang) {
6322 status = pthread_cond_signal (&_cond[_cur_index]);
6323 assert (status == 0, "invariant");
6324 status = pthread_mutex_unlock(_mutex);
6325 assert (status == 0, "invariant");
6326 } else {
6327 // must capture correct index before unlocking
6328 int index = _cur_index;
6329 status = pthread_mutex_unlock(_mutex);
6330 assert (status == 0, "invariant");
6331 status = pthread_cond_signal (&_cond[index]);
6332 assert (status == 0, "invariant");
6333 }
6334 } else {
6335 pthread_mutex_unlock(_mutex);
6336 assert (status == 0, "invariant") ;
6337 }
6338 } else {
6339 pthread_mutex_unlock(_mutex);
6340 assert (status == 0, "invariant") ;
6341 }
6342 }
6343
6344
6345 extern char** environ;
6346
6347 // Run the specified command in a separate process. Return its exit value,
6348 // or -1 on failure (e.g. can't fork a new process).
6349 // Unlike system(), this function can be called from signal handler. It
6350 // doesn't block SIGINT et al.
6351 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
6352 const char * argv[4] = {"sh", "-c", cmd, NULL};
6353
6354 pid_t pid ;
6355
6356 if (use_vfork_if_available) {
6357 pid = vfork();
6358 } else {
6359 pid = fork();
6360 }
6361
6362 if (pid < 0) {
6363 // fork failed
6364 return -1;
6365
6366 } else if (pid == 0) {
6367 // child process
6368
6369 execve("/bin/sh", (char* const*)argv, environ);
6370
6371 // execve failed
6372 _exit(-1);
6373
6374 } else {
6375 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
6376 // care about the actual exit code, for now.
6377
6378 int status;
6379
6380 // Wait for the child process to exit. This returns immediately if
6381 // the child has already exited. */
6382 while (waitpid(pid, &status, 0) < 0) {
6383 switch (errno) {
6384 case ECHILD: return 0;
6385 case EINTR: break;
6386 default: return -1;
6387 }
6388 }
6389
6390 if (WIFEXITED(status)) {
6391 // The child exited normally; get its exit code.
6392 return WEXITSTATUS(status);
6393 } else if (WIFSIGNALED(status)) {
6394 // The child exited because of a signal
6395 // The best value to return is 0x80 + signal number,
6396 // because that is what all Unix shells do, and because
6397 // it allows callers to distinguish between process exit and
6398 // process death by signal.
6399 return 0x80 + WTERMSIG(status);
6400 } else {
6401 // Unknown exit code; pass it through
6402 return status;
6403 }
6404 }
6405 }
6406
6407 // is_headless_jre()
6408 //
6409 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
6410 // in order to report if we are running in a headless jre
6411 //
6412 // Since JDK8 xawt/libmawt.so was moved into the same directory
6413 // as libawt.so, and renamed libawt_xawt.so
6414 //
6415 bool os::is_headless_jre() {
6416 struct stat statbuf;
6417 char buf[MAXPATHLEN];
6418 char libmawtpath[MAXPATHLEN];
6419 const char *xawtstr = "/xawt/libmawt.so";
6420 const char *new_xawtstr = "/libawt_xawt.so";
6421 char *p;
6422
6423 // Get path to libjvm.so
6424 os::jvm_path(buf, sizeof(buf));
6425
6426 // Get rid of libjvm.so
6427 p = strrchr(buf, '/');
6428 if (p == NULL) return false;
6429 else *p = '\0';
6430
6431 // Get rid of client or server
6432 p = strrchr(buf, '/');
6433 if (p == NULL) return false;
6434 else *p = '\0';
6435
6436 // check xawt/libmawt.so
6437 strcpy(libmawtpath, buf);
6438 strcat(libmawtpath, xawtstr);
6439 if (::stat(libmawtpath, &statbuf) == 0) return false;
6440
6441 // check libawt_xawt.so
6442 strcpy(libmawtpath, buf);
6443 strcat(libmawtpath, new_xawtstr);
6444 if (::stat(libmawtpath, &statbuf) == 0) return false;
6445
6446 return true;
6447 }
6448
6449 // Get the default path to the core file
6450 // Returns the length of the string
6451 int os::get_core_path(char* buffer, size_t bufferSize) {
6452 const char* p = get_current_directory(buffer, bufferSize);
6453
6454 if (p == NULL) {
6455 assert(p != NULL, "failed to get current directory");
6456 return 0;
6457 }
6458
6459 return strlen(buffer);
6460 }
6461
6462 /////////////// Unit tests ///////////////
6463
6464 #ifndef PRODUCT
6465
6466 #define test_log(...) \
6467 do {\
6468 if (VerboseInternalVMTests) { \
6469 tty->print_cr(__VA_ARGS__); \
6470 tty->flush(); \
6471 }\
6472 } while (false)
6473
6474 class TestReserveMemorySpecial : AllStatic {
6475 public:
6476 static void small_page_write(void* addr, size_t size) {
6477 size_t page_size = os::vm_page_size();
6478
6479 char* end = (char*)addr + size;
6480 for (char* p = (char*)addr; p < end; p += page_size) {
6481 *p = 1;
6482 }
6483 }
6484
6485 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6486 if (!UseHugeTLBFS) {
6487 return;
6488 }
6489
6490 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6491
6492 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6493
6494 if (addr != NULL) {
6495 small_page_write(addr, size);
6496
6497 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6498 }
6499 }
6500
6501 static void test_reserve_memory_special_huge_tlbfs_only() {
6502 if (!UseHugeTLBFS) {
6503 return;
6504 }
6505
6506 size_t lp = os::large_page_size();
6507
6508 for (size_t size = lp; size <= lp * 10; size += lp) {
6509 test_reserve_memory_special_huge_tlbfs_only(size);
6510 }
6511 }
6512
6513 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6514 size_t lp = os::large_page_size();
6515 size_t ag = os::vm_allocation_granularity();
6516
6517 // sizes to test
6518 const size_t sizes[] = {
6519 lp, lp + ag, lp + lp / 2, lp * 2,
6520 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6521 lp * 10, lp * 10 + lp / 2
6522 };
6523 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6524
6525 // For each size/alignment combination, we test three scenarios:
6526 // 1) with req_addr == NULL
6527 // 2) with a non-null req_addr at which we expect to successfully allocate
6528 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6529 // expect the allocation to either fail or to ignore req_addr
6530
6531 // Pre-allocate two areas; they shall be as large as the largest allocation
6532 // and aligned to the largest alignment we will be testing.
6533 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6534 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6535 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6536 -1, 0);
6537 assert(mapping1 != MAP_FAILED, "should work");
6538
6539 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6540 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6541 -1, 0);
6542 assert(mapping2 != MAP_FAILED, "should work");
6543
6544 // Unmap the first mapping, but leave the second mapping intact: the first
6545 // mapping will serve as a value for a "good" req_addr (case 2). The second
6546 // mapping, still intact, as "bad" req_addr (case 3).
6547 ::munmap(mapping1, mapping_size);
6548
6549 // Case 1
6550 test_log("%s, req_addr NULL:", __FUNCTION__);
6551 test_log("size align result");
6552
6553 for (int i = 0; i < num_sizes; i++) {
6554 const size_t size = sizes[i];
6555 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6556 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6557 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6558 size, alignment, p, (p != NULL ? "" : "(failed)"));
6559 if (p != NULL) {
6560 assert(is_ptr_aligned(p, alignment), "must be");
6561 small_page_write(p, size);
6562 os::Linux::release_memory_special_huge_tlbfs(p, size);
6563 }
6564 }
6565 }
6566
6567 // Case 2
6568 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6569 test_log("size align req_addr result");
6570
6571 for (int i = 0; i < num_sizes; i++) {
6572 const size_t size = sizes[i];
6573 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6574 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
6575 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6576 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6577 size, alignment, req_addr, p,
6578 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6579 if (p != NULL) {
6580 assert(p == req_addr, "must be");
6581 small_page_write(p, size);
6582 os::Linux::release_memory_special_huge_tlbfs(p, size);
6583 }
6584 }
6585 }
6586
6587 // Case 3
6588 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6589 test_log("size align req_addr result");
6590
6591 for (int i = 0; i < num_sizes; i++) {
6592 const size_t size = sizes[i];
6593 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6594 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6595 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6596 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6597 size, alignment, req_addr, p,
6598 ((p != NULL ? "" : "(failed)")));
6599 // as the area around req_addr contains already existing mappings, the API should always
6600 // return NULL (as per contract, it cannot return another address)
6601 assert(p == NULL, "must be");
6602 }
6603 }
6604
6605 ::munmap(mapping2, mapping_size);
6606
6607 }
6608
6609 static void test_reserve_memory_special_huge_tlbfs() {
6610 if (!UseHugeTLBFS) {
6611 return;
6612 }
6613
6614 test_reserve_memory_special_huge_tlbfs_only();
6615 test_reserve_memory_special_huge_tlbfs_mixed();
6616 }
6617
6618 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6619 if (!UseSHM) {
6620 return;
6621 }
6622
6623 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6624
6625 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6626
6627 if (addr != NULL) {
6628 assert(is_ptr_aligned(addr, alignment), "Check");
6629 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6630
6631 small_page_write(addr, size);
6632
6633 os::Linux::release_memory_special_shm(addr, size);
6634 }
6635 }
6636
6637 static void test_reserve_memory_special_shm() {
6638 size_t lp = os::large_page_size();
6639 size_t ag = os::vm_allocation_granularity();
6640
6641 for (size_t size = ag; size < lp * 3; size += ag) {
6642 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6643 test_reserve_memory_special_shm(size, alignment);
6644 }
6645 }
6646 }
6647
6648 static void test() {
6649 test_reserve_memory_special_huge_tlbfs();
6650 test_reserve_memory_special_shm();
6651 }
6652 };
6653
6654 void TestReserveMemorySpecial_test() {
6655 TestReserveMemorySpecial::test();
6656 }
6657
6658 #endif