1 /*
2 * Copyright (c) 1999, 2014, 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 "prims/jniFastGetField.hpp"
41 #include "prims/jvm.h"
42 #include "prims/jvm_misc.hpp"
43 #include "runtime/arguments.hpp"
44 #include "runtime/extendedPC.hpp"
45 #include "runtime/globals.hpp"
46 #include "runtime/interfaceSupport.hpp"
47 #include "runtime/init.hpp"
48 #include "runtime/java.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "runtime/objectMonitor.hpp"
52 #include "runtime/osThread.hpp"
53 #include "runtime/perfMemory.hpp"
54 #include "runtime/sharedRuntime.hpp"
55 #include "runtime/statSampler.hpp"
56 #include "runtime/stubRoutines.hpp"
57 #include "runtime/thread.inline.hpp"
58 #include "runtime/threadCritical.hpp"
59 #include "runtime/timer.hpp"
60 #include "services/attachListener.hpp"
61 #include "services/memTracker.hpp"
62 #include "services/runtimeService.hpp"
63 #include "utilities/decoder.hpp"
64 #include "utilities/defaultStream.hpp"
65 #include "utilities/events.hpp"
66 #include "utilities/elfFile.hpp"
67 #include "utilities/growableArray.hpp"
68 #include "utilities/vmError.hpp"
69
70 // put OS-includes here
71 # include <sys/types.h>
72 # include <sys/mman.h>
73 # include <sys/stat.h>
74 # include <sys/select.h>
75 # include <pthread.h>
76 # include <signal.h>
77 # include <errno.h>
78 # include <dlfcn.h>
79 # include <stdio.h>
80 # include <unistd.h>
81 # include <sys/resource.h>
82 # include <pthread.h>
83 # include <sys/stat.h>
84 # include <sys/time.h>
85 # include <sys/times.h>
86 # include <sys/utsname.h>
87 # include <sys/socket.h>
88 # include <sys/wait.h>
89 # include <pwd.h>
90 # include <poll.h>
91 # include <semaphore.h>
92 # include <fcntl.h>
93 # include <string.h>
94 # include <syscall.h>
95 # include <sys/sysinfo.h>
96 # include <gnu/libc-version.h>
97 # include <sys/ipc.h>
98 # include <sys/shm.h>
99 # include <link.h>
100 # include <stdint.h>
101 # include <inttypes.h>
102 # include <sys/ioctl.h>
103
104 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
105 // getrusage() is prepared to handle the associated failure.
106 #ifndef RUSAGE_THREAD
107 #define RUSAGE_THREAD (1) /* only the calling thread */
108 #endif
109
110 #define MAX_PATH (2 * K)
111
112 // for timer info max values which include all bits
113 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
114
115 #define LARGEPAGES_BIT (1 << 6)
116 ////////////////////////////////////////////////////////////////////////////////
117 // global variables
118 julong os::Linux::_physical_memory = 0;
119
120 address os::Linux::_initial_thread_stack_bottom = NULL;
121 uintptr_t os::Linux::_initial_thread_stack_size = 0;
122
123 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
124 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
125 Mutex* os::Linux::_createThread_lock = NULL;
126 pthread_t os::Linux::_main_thread;
127 int os::Linux::_page_size = -1;
128 const int os::Linux::_vm_default_page_size = (8 * K);
129 bool os::Linux::_is_floating_stack = false;
130 bool os::Linux::_is_NPTL = false;
131 bool os::Linux::_supports_fast_thread_cpu_time = false;
132 const char * os::Linux::_glibc_version = NULL;
133 const char * os::Linux::_libpthread_version = NULL;
134 pthread_condattr_t os::Linux::_condattr[1];
135
136 static jlong initial_time_count=0;
137
138 static int clock_tics_per_sec = 100;
139
140 // For diagnostics to print a message once. see run_periodic_checks
141 static sigset_t check_signal_done;
142 static bool check_signals = true;
143
144 static pid_t _initial_pid = 0;
145
146 /* Signal number used to suspend/resume a thread */
147
148 /* do not use any signal number less than SIGSEGV, see 4355769 */
149 static int SR_signum = SIGUSR2;
150 sigset_t SR_sigset;
151
152 /* Used to protect dlsym() calls */
153 static pthread_mutex_t dl_mutex;
154
155 // Declarations
156 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
157 static void absoluteRealTimeForRelativeTime(timespec* absTime, jlong relTime);
158
159 #ifdef JAVASE_EMBEDDED
160 class MemNotifyThread: public Thread {
161 friend class VMStructs;
162 public:
163 virtual void run();
164
165 private:
166 static MemNotifyThread* _memnotify_thread;
167 int _fd;
168
169 public:
170
171 // Constructor
172 MemNotifyThread(int fd);
173
174 // Tester
175 bool is_memnotify_thread() const { return true; }
176
177 // Printing
178 char* name() const { return (char*)"Linux MemNotify Thread"; }
179
180 // Returns the single instance of the MemNotifyThread
181 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
182
183 // Create and start the single instance of MemNotifyThread
184 static void start();
185 };
186 #endif // JAVASE_EMBEDDED
187
188 // utility functions
189
190 static int SR_initialize();
191
192 julong os::available_memory() {
193 return Linux::available_memory();
194 }
195
196 julong os::Linux::available_memory() {
197 // values in struct sysinfo are "unsigned long"
198 struct sysinfo si;
199 sysinfo(&si);
200
201 return (julong)si.freeram * si.mem_unit;
202 }
203
204 julong os::physical_memory() {
205 return Linux::physical_memory();
206 }
207
208 ////////////////////////////////////////////////////////////////////////////////
209 // environment support
210
211 bool os::getenv(const char* name, char* buf, int len) {
212 const char* val = ::getenv(name);
213 if (val != NULL && strlen(val) < (size_t)len) {
214 strcpy(buf, val);
215 return true;
216 }
217 if (len > 0) buf[0] = 0; // return a null string
218 return false;
219 }
220
221
222 // Return true if user is running as root.
223
224 bool os::have_special_privileges() {
225 static bool init = false;
226 static bool privileges = false;
227 if (!init) {
228 privileges = (getuid() != geteuid()) || (getgid() != getegid());
229 init = true;
230 }
231 return privileges;
232 }
233
234
235 #ifndef SYS_gettid
236 // i386: 224, ia64: 1105, amd64: 186, sparc 143
237 #ifdef __ia64__
238 #define SYS_gettid 1105
239 #elif __i386__
240 #define SYS_gettid 224
241 #elif __amd64__
242 #define SYS_gettid 186
243 #elif __sparc__
244 #define SYS_gettid 143
245 #else
246 #error define gettid for the arch
247 #endif
248 #endif
249
250 // Cpu architecture string
251 #if defined(ZERO)
252 static char cpu_arch[] = ZERO_LIBARCH;
253 #elif defined(IA64)
254 static char cpu_arch[] = "ia64";
255 #elif defined(IA32)
256 static char cpu_arch[] = "i386";
257 #elif defined(AMD64)
258 static char cpu_arch[] = "amd64";
259 #elif defined(ARM)
260 static char cpu_arch[] = "arm";
261 #elif defined(PPC32)
262 static char cpu_arch[] = "ppc";
263 #elif defined(PPC64)
264 static char cpu_arch[] = "ppc64";
265 #elif defined(SPARC)
266 # ifdef _LP64
267 static char cpu_arch[] = "sparcv9";
268 # else
269 static char cpu_arch[] = "sparc";
270 # endif
271 #else
272 #error Add appropriate cpu_arch setting
273 #endif
274
275
276 // pid_t gettid()
277 //
278 // Returns the kernel thread id of the currently running thread. Kernel
279 // thread id is used to access /proc.
280 //
281 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
282 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
283 //
284 pid_t os::Linux::gettid() {
285 int rslt = syscall(SYS_gettid);
286 if (rslt == -1) {
287 // old kernel, no NPTL support
288 return getpid();
289 } else {
290 return (pid_t)rslt;
291 }
292 }
293
294 // Most versions of linux have a bug where the number of processors are
295 // determined by looking at the /proc file system. In a chroot environment,
296 // the system call returns 1. This causes the VM to act as if it is
297 // a single processor and elide locking (see is_MP() call).
298 static bool unsafe_chroot_detected = false;
299 static const char *unstable_chroot_error = "/proc file system not found.\n"
300 "Java may be unstable running multithreaded in a chroot "
301 "environment on Linux when /proc filesystem is not mounted.";
302
303 void os::Linux::initialize_system_info() {
304 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
305 if (processor_count() == 1) {
306 pid_t pid = os::Linux::gettid();
307 char fname[32];
308 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
309 FILE *fp = fopen(fname, "r");
310 if (fp == NULL) {
311 unsafe_chroot_detected = true;
312 } else {
313 fclose(fp);
314 }
315 }
316 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
317 assert(processor_count() > 0, "linux error");
318 }
319
320 void os::init_system_properties_values() {
321 // char arch[12];
322 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
323
324 // The next steps are taken in the product version:
325 //
326 // Obtain the JAVA_HOME value from the location of libjvm.so.
327 // This library should be located at:
328 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
329 //
330 // If "/jre/lib/" appears at the right place in the path, then we
331 // assume libjvm.so is installed in a JDK and we use this path.
332 //
333 // Otherwise exit with message: "Could not create the Java virtual machine."
334 //
335 // The following extra steps are taken in the debugging version:
336 //
337 // If "/jre/lib/" does NOT appear at the right place in the path
338 // instead of exit check for $JAVA_HOME environment variable.
339 //
340 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
341 // then we append a fake suffix "hotspot/libjvm.so" to this path so
342 // it looks like libjvm.so is installed there
343 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
344 //
345 // Otherwise exit.
346 //
347 // Important note: if the location of libjvm.so changes this
348 // code needs to be changed accordingly.
349
350 // The next few definitions allow the code to be verbatim:
351 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal)
352 #define getenv(n) ::getenv(n)
353
354 /*
355 * See ld(1):
356 * The linker uses the following search paths to locate required
357 * shared libraries:
358 * 1: ...
359 * ...
360 * 7: The default directories, normally /lib and /usr/lib.
361 */
362 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
363 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
364 #else
365 #define DEFAULT_LIBPATH "/lib:/usr/lib"
366 #endif
367
368 #define EXTENSIONS_DIR "/lib/ext"
369 #define ENDORSED_DIR "/lib/endorsed"
370 #define REG_DIR "/usr/java/packages"
371
372 {
373 /* sysclasspath, java_home, dll_dir */
374 {
375 char *home_path;
376 char *dll_path;
377 char *pslash;
378 char buf[MAXPATHLEN];
379 os::jvm_path(buf, sizeof(buf));
380
381 // Found the full path to libjvm.so.
382 // Now cut the path to <java_home>/jre if we can.
383 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
384 pslash = strrchr(buf, '/');
385 if (pslash != NULL)
386 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
387 dll_path = malloc(strlen(buf) + 1);
388 if (dll_path == NULL)
389 return;
390 strcpy(dll_path, buf);
391 Arguments::set_dll_dir(dll_path);
392
393 if (pslash != NULL) {
394 pslash = strrchr(buf, '/');
395 if (pslash != NULL) {
396 *pslash = '\0'; /* get rid of /<arch> */
397 pslash = strrchr(buf, '/');
398 if (pslash != NULL)
399 *pslash = '\0'; /* get rid of /lib */
400 }
401 }
402
403 home_path = malloc(strlen(buf) + 1);
404 if (home_path == NULL)
405 return;
406 strcpy(home_path, buf);
407 Arguments::set_java_home(home_path);
408
409 if (!set_boot_path('/', ':'))
410 return;
411 }
412
413 /*
414 * Where to look for native libraries
415 *
416 * Note: Due to a legacy implementation, most of the library path
417 * is set in the launcher. This was to accomodate linking restrictions
418 * on legacy Linux implementations (which are no longer supported).
419 * Eventually, all the library path setting will be done here.
420 *
421 * However, to prevent the proliferation of improperly built native
422 * libraries, the new path component /usr/java/packages is added here.
423 * Eventually, all the library path setting will be done here.
424 */
425 {
426 char *ld_library_path;
427
428 /*
429 * Construct the invariant part of ld_library_path. Note that the
430 * space for the colon and the trailing null are provided by the
431 * nulls included by the sizeof operator (so actually we allocate
432 * a byte more than necessary).
433 */
434 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
435 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
436 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
437
438 /*
439 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
440 * should always exist (until the legacy problem cited above is
441 * addressed).
442 */
443 char *v = getenv("LD_LIBRARY_PATH");
444 if (v != NULL) {
445 char *t = ld_library_path;
446 /* That's +1 for the colon and +1 for the trailing '\0' */
447 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
448 sprintf(ld_library_path, "%s:%s", v, t);
449 }
450 Arguments::set_library_path(ld_library_path);
451 }
452
453 /*
454 * Extensions directories.
455 *
456 * Note that the space for the colon and the trailing null are provided
457 * by the nulls included by the sizeof operator (so actually one byte more
458 * than necessary is allocated).
459 */
460 {
461 char *buf = malloc(strlen(Arguments::get_java_home()) +
462 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
463 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
464 Arguments::get_java_home());
465 Arguments::set_ext_dirs(buf);
466 }
467
468 /* Endorsed standards default directory. */
469 {
470 char * buf;
471 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
472 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
473 Arguments::set_endorsed_dirs(buf);
474 }
475 }
476
477 #undef malloc
478 #undef getenv
479 #undef EXTENSIONS_DIR
480 #undef ENDORSED_DIR
481
482 // Done
483 return;
484 }
485
486 ////////////////////////////////////////////////////////////////////////////////
487 // breakpoint support
488
489 void os::breakpoint() {
490 BREAKPOINT;
491 }
492
493 extern "C" void breakpoint() {
494 // use debugger to set breakpoint here
495 }
496
497 ////////////////////////////////////////////////////////////////////////////////
498 // signal support
499
500 debug_only(static bool signal_sets_initialized = false);
501 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
502
503 bool os::Linux::is_sig_ignored(int sig) {
504 struct sigaction oact;
505 sigaction(sig, (struct sigaction*)NULL, &oact);
506 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
507 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
508 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
509 return true;
510 else
511 return false;
512 }
513
514 void os::Linux::signal_sets_init() {
515 // Should also have an assertion stating we are still single-threaded.
516 assert(!signal_sets_initialized, "Already initialized");
517 // Fill in signals that are necessarily unblocked for all threads in
518 // the VM. Currently, we unblock the following signals:
519 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
520 // by -Xrs (=ReduceSignalUsage));
521 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
522 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
523 // the dispositions or masks wrt these signals.
524 // Programs embedding the VM that want to use the above signals for their
525 // own purposes must, at this time, use the "-Xrs" option to prevent
526 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
527 // (See bug 4345157, and other related bugs).
528 // In reality, though, unblocking these signals is really a nop, since
529 // these signals are not blocked by default.
530 sigemptyset(&unblocked_sigs);
531 sigemptyset(&allowdebug_blocked_sigs);
532 sigaddset(&unblocked_sigs, SIGILL);
533 sigaddset(&unblocked_sigs, SIGSEGV);
534 sigaddset(&unblocked_sigs, SIGBUS);
535 sigaddset(&unblocked_sigs, SIGFPE);
536 #if defined(PPC64)
537 sigaddset(&unblocked_sigs, SIGTRAP);
538 #endif
539 sigaddset(&unblocked_sigs, SR_signum);
540
541 if (!ReduceSignalUsage) {
542 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
543 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
544 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
545 }
546 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
547 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
548 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
549 }
550 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
551 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
552 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
553 }
554 }
555 // Fill in signals that are blocked by all but the VM thread.
556 sigemptyset(&vm_sigs);
557 if (!ReduceSignalUsage)
558 sigaddset(&vm_sigs, BREAK_SIGNAL);
559 debug_only(signal_sets_initialized = true);
560
561 }
562
563 // These are signals that are unblocked while a thread is running Java.
564 // (For some reason, they get blocked by default.)
565 sigset_t* os::Linux::unblocked_signals() {
566 assert(signal_sets_initialized, "Not initialized");
567 return &unblocked_sigs;
568 }
569
570 // These are the signals that are blocked while a (non-VM) thread is
571 // running Java. Only the VM thread handles these signals.
572 sigset_t* os::Linux::vm_signals() {
573 assert(signal_sets_initialized, "Not initialized");
574 return &vm_sigs;
575 }
576
577 // These are signals that are blocked during cond_wait to allow debugger in
578 sigset_t* os::Linux::allowdebug_blocked_signals() {
579 assert(signal_sets_initialized, "Not initialized");
580 return &allowdebug_blocked_sigs;
581 }
582
583 void os::Linux::hotspot_sigmask(Thread* thread) {
584
585 //Save caller's signal mask before setting VM signal mask
586 sigset_t caller_sigmask;
587 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
588
589 OSThread* osthread = thread->osthread();
590 osthread->set_caller_sigmask(caller_sigmask);
591
592 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
593
594 if (!ReduceSignalUsage) {
595 if (thread->is_VM_thread()) {
596 // Only the VM thread handles BREAK_SIGNAL ...
597 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
598 } else {
599 // ... all other threads block BREAK_SIGNAL
600 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
601 }
602 }
603 }
604
605 //////////////////////////////////////////////////////////////////////////////
606 // detecting pthread library
607
608 void os::Linux::libpthread_init() {
609 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
610 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
611 // generic name for earlier versions.
612 // Define macros here so we can build HotSpot on old systems.
613 # ifndef _CS_GNU_LIBC_VERSION
614 # define _CS_GNU_LIBC_VERSION 2
615 # endif
616 # ifndef _CS_GNU_LIBPTHREAD_VERSION
617 # define _CS_GNU_LIBPTHREAD_VERSION 3
618 # endif
619
620 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
621 if (n > 0) {
622 char *str = (char *)malloc(n, mtInternal);
623 confstr(_CS_GNU_LIBC_VERSION, str, n);
624 os::Linux::set_glibc_version(str);
625 } else {
626 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
627 static char _gnu_libc_version[32];
628 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
629 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
630 os::Linux::set_glibc_version(_gnu_libc_version);
631 }
632
633 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
634 if (n > 0) {
635 char *str = (char *)malloc(n, mtInternal);
636 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
637 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
638 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
639 // is the case. LinuxThreads has a hard limit on max number of threads.
640 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
641 // On the other hand, NPTL does not have such a limit, sysconf()
642 // will return -1 and errno is not changed. Check if it is really NPTL.
643 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
644 strstr(str, "NPTL") &&
645 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
646 free(str);
647 os::Linux::set_libpthread_version("linuxthreads");
648 } else {
649 os::Linux::set_libpthread_version(str);
650 }
651 } else {
652 // glibc before 2.3.2 only has LinuxThreads.
653 os::Linux::set_libpthread_version("linuxthreads");
654 }
655
656 if (strstr(libpthread_version(), "NPTL")) {
657 os::Linux::set_is_NPTL();
658 } else {
659 os::Linux::set_is_LinuxThreads();
660 }
661
662 // LinuxThreads have two flavors: floating-stack mode, which allows variable
663 // stack size; and fixed-stack mode. NPTL is always floating-stack.
664 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
665 os::Linux::set_is_floating_stack();
666 }
667 }
668
669 /////////////////////////////////////////////////////////////////////////////
670 // thread stack
671
672 // Force Linux kernel to expand current thread stack. If "bottom" is close
673 // to the stack guard, caller should block all signals.
674 //
675 // MAP_GROWSDOWN:
676 // A special mmap() flag that is used to implement thread stacks. It tells
677 // kernel that the memory region should extend downwards when needed. This
678 // allows early versions of LinuxThreads to only mmap the first few pages
679 // when creating a new thread. Linux kernel will automatically expand thread
680 // stack as needed (on page faults).
681 //
682 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
683 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
684 // region, it's hard to tell if the fault is due to a legitimate stack
685 // access or because of reading/writing non-exist memory (e.g. buffer
686 // overrun). As a rule, if the fault happens below current stack pointer,
687 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
688 // application (see Linux kernel fault.c).
689 //
690 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
691 // stack overflow detection.
692 //
693 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
694 // not use this flag. However, the stack of initial thread is not created
695 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
696 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
697 // and then attach the thread to JVM.
698 //
699 // To get around the problem and allow stack banging on Linux, we need to
700 // manually expand thread stack after receiving the SIGSEGV.
701 //
702 // There are two ways to expand thread stack to address "bottom", we used
703 // both of them in JVM before 1.5:
704 // 1. adjust stack pointer first so that it is below "bottom", and then
705 // touch "bottom"
706 // 2. mmap() the page in question
707 //
708 // Now alternate signal stack is gone, it's harder to use 2. For instance,
709 // if current sp is already near the lower end of page 101, and we need to
710 // call mmap() to map page 100, it is possible that part of the mmap() frame
711 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
712 // That will destroy the mmap() frame and cause VM to crash.
713 //
714 // The following code works by adjusting sp first, then accessing the "bottom"
715 // page to force a page fault. Linux kernel will then automatically expand the
716 // stack mapping.
717 //
718 // _expand_stack_to() assumes its frame size is less than page size, which
719 // should always be true if the function is not inlined.
720
721 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
722 #define NOINLINE
723 #else
724 #define NOINLINE __attribute__ ((noinline))
725 #endif
726
727 static void _expand_stack_to(address bottom) NOINLINE;
728
729 static void _expand_stack_to(address bottom) {
730 address sp;
731 size_t size;
732 volatile char *p;
733
734 // Adjust bottom to point to the largest address within the same page, it
735 // gives us a one-page buffer if alloca() allocates slightly more memory.
736 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
737 bottom += os::Linux::page_size() - 1;
738
739 // sp might be slightly above current stack pointer; if that's the case, we
740 // will alloca() a little more space than necessary, which is OK. Don't use
741 // os::current_stack_pointer(), as its result can be slightly below current
742 // stack pointer, causing us to not alloca enough to reach "bottom".
743 sp = (address)&sp;
744
745 if (sp > bottom) {
746 size = sp - bottom;
747 p = (volatile char *)alloca(size);
748 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
749 p[0] = '\0';
750 }
751 }
752
753 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
754 assert(t!=NULL, "just checking");
755 assert(t->osthread()->expanding_stack(), "expand should be set");
756 assert(t->stack_base() != NULL, "stack_base was not initialized");
757
758 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
759 sigset_t mask_all, old_sigset;
760 sigfillset(&mask_all);
761 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
762 _expand_stack_to(addr);
763 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
764 return true;
765 }
766 return false;
767 }
768
769 //////////////////////////////////////////////////////////////////////////////
770 // create new thread
771
772 static address highest_vm_reserved_address();
773
774 // check if it's safe to start a new thread
775 static bool _thread_safety_check(Thread* thread) {
776 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
777 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
778 // Heap is mmap'ed at lower end of memory space. Thread stacks are
779 // allocated (MAP_FIXED) from high address space. Every thread stack
780 // occupies a fixed size slot (usually 2Mbytes, but user can change
781 // it to other values if they rebuild LinuxThreads).
782 //
783 // Problem with MAP_FIXED is that mmap() can still succeed even part of
784 // the memory region has already been mmap'ed. That means if we have too
785 // many threads and/or very large heap, eventually thread stack will
786 // collide with heap.
787 //
788 // Here we try to prevent heap/stack collision by comparing current
789 // stack bottom with the highest address that has been mmap'ed by JVM
790 // plus a safety margin for memory maps created by native code.
791 //
792 // This feature can be disabled by setting ThreadSafetyMargin to 0
793 //
794 if (ThreadSafetyMargin > 0) {
795 address stack_bottom = os::current_stack_base() - os::current_stack_size();
796
797 // not safe if our stack extends below the safety margin
798 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
799 } else {
800 return true;
801 }
802 } else {
803 // Floating stack LinuxThreads or NPTL:
804 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
805 // there's not enough space left, pthread_create() will fail. If we come
806 // here, that means enough space has been reserved for stack.
807 return true;
808 }
809 }
810
811 // Thread start routine for all newly created threads
812 static void *java_start(Thread *thread) {
813 // Try to randomize the cache line index of hot stack frames.
814 // This helps when threads of the same stack traces evict each other's
815 // cache lines. The threads can be either from the same JVM instance, or
816 // from different JVM instances. The benefit is especially true for
817 // processors with hyperthreading technology.
818 static int counter = 0;
819 int pid = os::current_process_id();
820 alloca(((pid ^ counter++) & 7) * 128);
821
822 ThreadLocalStorage::set_thread(thread);
823
824 OSThread* osthread = thread->osthread();
825 Monitor* sync = osthread->startThread_lock();
826
827 // non floating stack LinuxThreads needs extra check, see above
828 if (!_thread_safety_check(thread)) {
829 // notify parent thread
830 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
831 osthread->set_state(ZOMBIE);
832 sync->notify_all();
833 return NULL;
834 }
835
836 // thread_id is kernel thread id (similar to Solaris LWP id)
837 osthread->set_thread_id(os::Linux::gettid());
838
839 if (UseNUMA) {
840 int lgrp_id = os::numa_get_group_id();
841 if (lgrp_id != -1) {
842 thread->set_lgrp_id(lgrp_id);
843 }
844 }
845 // initialize signal mask for this thread
846 os::Linux::hotspot_sigmask(thread);
847
848 // initialize floating point control register
849 os::Linux::init_thread_fpu_state();
850
851 // handshaking with parent thread
852 {
853 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
854
855 // notify parent thread
856 osthread->set_state(INITIALIZED);
857 sync->notify_all();
858
859 // wait until os::start_thread()
860 while (osthread->get_state() == INITIALIZED) {
861 sync->wait(Mutex::_no_safepoint_check_flag);
862 }
863 }
864
865 // call one more level start routine
866 thread->run();
867
868 return 0;
869 }
870
871 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
872 assert(thread->osthread() == NULL, "caller responsible");
873
874 // Allocate the OSThread object
875 OSThread* osthread = new OSThread(NULL, NULL);
876 if (osthread == NULL) {
877 return false;
878 }
879
880 // set the correct thread state
881 osthread->set_thread_type(thr_type);
882
883 // Initial state is ALLOCATED but not INITIALIZED
884 osthread->set_state(ALLOCATED);
885
886 thread->set_osthread(osthread);
887
888 // init thread attributes
889 pthread_attr_t attr;
890 pthread_attr_init(&attr);
891 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
892
893 // stack size
894 if (os::Linux::supports_variable_stack_size()) {
895 // calculate stack size if it's not specified by caller
896 if (stack_size == 0) {
897 stack_size = os::Linux::default_stack_size(thr_type);
898
899 switch (thr_type) {
900 case os::java_thread:
901 // Java threads use ThreadStackSize which default value can be
902 // changed with the flag -Xss
903 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
904 stack_size = JavaThread::stack_size_at_create();
905 break;
906 case os::compiler_thread:
907 if (CompilerThreadStackSize > 0) {
908 stack_size = (size_t)(CompilerThreadStackSize * K);
909 break;
910 } // else fall through:
911 // use VMThreadStackSize if CompilerThreadStackSize is not defined
912 case os::vm_thread:
913 case os::pgc_thread:
914 case os::cgc_thread:
915 case os::watcher_thread:
916 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
917 break;
918 }
919 }
920
921 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
922 pthread_attr_setstacksize(&attr, stack_size);
923 } else {
924 // let pthread_create() pick the default value.
925 }
926
927 // glibc guard page
928 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
929
930 ThreadState state;
931
932 {
933 // Serialize thread creation if we are running with fixed stack LinuxThreads
934 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
935 if (lock) {
936 os::Linux::createThread_lock()->lock_without_safepoint_check();
937 }
938
939 pthread_t tid;
940 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
941
942 pthread_attr_destroy(&attr);
943
944 if (ret != 0) {
945 if (PrintMiscellaneous && (Verbose || WizardMode)) {
946 perror("pthread_create()");
947 }
948 // Need to clean up stuff we've allocated so far
949 thread->set_osthread(NULL);
950 delete osthread;
951 if (lock) os::Linux::createThread_lock()->unlock();
952 return false;
953 }
954
955 // Store pthread info into the OSThread
956 osthread->set_pthread_id(tid);
957
958 // Wait until child thread is either initialized or aborted
959 {
960 Monitor* sync_with_child = osthread->startThread_lock();
961 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
962 while ((state = osthread->get_state()) == ALLOCATED) {
963 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
964 }
965 }
966
967 if (lock) {
968 os::Linux::createThread_lock()->unlock();
969 }
970 }
971
972 // Aborted due to thread limit being reached
973 if (state == ZOMBIE) {
974 thread->set_osthread(NULL);
975 delete osthread;
976 return false;
977 }
978
979 // The thread is returned suspended (in state INITIALIZED),
980 // and is started higher up in the call chain
981 assert(state == INITIALIZED, "race condition");
982 return true;
983 }
984
985 /////////////////////////////////////////////////////////////////////////////
986 // attach existing thread
987
988 // bootstrap the main thread
989 bool os::create_main_thread(JavaThread* thread) {
990 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
991 return create_attached_thread(thread);
992 }
993
994 bool os::create_attached_thread(JavaThread* thread) {
995 #ifdef ASSERT
996 thread->verify_not_published();
997 #endif
998
999 // Allocate the OSThread object
1000 OSThread* osthread = new OSThread(NULL, NULL);
1001
1002 if (osthread == NULL) {
1003 return false;
1004 }
1005
1006 // Store pthread info into the OSThread
1007 osthread->set_thread_id(os::Linux::gettid());
1008 osthread->set_pthread_id(::pthread_self());
1009
1010 // initialize floating point control register
1011 os::Linux::init_thread_fpu_state();
1012
1013 // Initial thread state is RUNNABLE
1014 osthread->set_state(RUNNABLE);
1015
1016 thread->set_osthread(osthread);
1017
1018 if (UseNUMA) {
1019 int lgrp_id = os::numa_get_group_id();
1020 if (lgrp_id != -1) {
1021 thread->set_lgrp_id(lgrp_id);
1022 }
1023 }
1024
1025 if (os::Linux::is_initial_thread()) {
1026 // If current thread is initial thread, its stack is mapped on demand,
1027 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1028 // the entire stack region to avoid SEGV in stack banging.
1029 // It is also useful to get around the heap-stack-gap problem on SuSE
1030 // kernel (see 4821821 for details). We first expand stack to the top
1031 // of yellow zone, then enable stack yellow zone (order is significant,
1032 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1033 // is no gap between the last two virtual memory regions.
1034
1035 JavaThread *jt = (JavaThread *)thread;
1036 address addr = jt->stack_yellow_zone_base();
1037 assert(addr != NULL, "initialization problem?");
1038 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1039
1040 osthread->set_expanding_stack();
1041 os::Linux::manually_expand_stack(jt, addr);
1042 osthread->clear_expanding_stack();
1043 }
1044
1045 // initialize signal mask for this thread
1046 // and save the caller's signal mask
1047 os::Linux::hotspot_sigmask(thread);
1048
1049 return true;
1050 }
1051
1052 void os::pd_start_thread(Thread* thread) {
1053 OSThread * osthread = thread->osthread();
1054 assert(osthread->get_state() != INITIALIZED, "just checking");
1055 Monitor* sync_with_child = osthread->startThread_lock();
1056 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1057 sync_with_child->notify();
1058 }
1059
1060 // Free Linux resources related to the OSThread
1061 void os::free_thread(OSThread* osthread) {
1062 assert(osthread != NULL, "osthread not set");
1063
1064 if (Thread::current()->osthread() == osthread) {
1065 // Restore caller's signal mask
1066 sigset_t sigmask = osthread->caller_sigmask();
1067 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1068 }
1069
1070 delete osthread;
1071 }
1072
1073 //////////////////////////////////////////////////////////////////////////////
1074 // thread local storage
1075
1076 int os::allocate_thread_local_storage() {
1077 pthread_key_t key;
1078 int rslt = pthread_key_create(&key, NULL);
1079 assert(rslt == 0, "cannot allocate thread local storage");
1080 return (int)key;
1081 }
1082
1083 // Note: This is currently not used by VM, as we don't destroy TLS key
1084 // on VM exit.
1085 void os::free_thread_local_storage(int index) {
1086 int rslt = pthread_key_delete((pthread_key_t)index);
1087 assert(rslt == 0, "invalid index");
1088 }
1089
1090 void os::thread_local_storage_at_put(int index, void* value) {
1091 int rslt = pthread_setspecific((pthread_key_t)index, value);
1092 assert(rslt == 0, "pthread_setspecific failed");
1093 }
1094
1095 extern "C" Thread* get_thread() {
1096 return ThreadLocalStorage::thread();
1097 }
1098
1099 //////////////////////////////////////////////////////////////////////////////
1100 // initial thread
1101
1102 // Check if current thread is the initial thread, similar to Solaris thr_main.
1103 bool os::Linux::is_initial_thread(void) {
1104 char dummy;
1105 // If called before init complete, thread stack bottom will be null.
1106 // Can be called if fatal error occurs before initialization.
1107 if (initial_thread_stack_bottom() == NULL) return false;
1108 assert(initial_thread_stack_bottom() != NULL &&
1109 initial_thread_stack_size() != 0,
1110 "os::init did not locate initial thread's stack region");
1111 if ((address)&dummy >= initial_thread_stack_bottom() &&
1112 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1113 return true;
1114 else return false;
1115 }
1116
1117 // Find the virtual memory area that contains addr
1118 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1119 FILE *fp = fopen("/proc/self/maps", "r");
1120 if (fp) {
1121 address low, high;
1122 while (!feof(fp)) {
1123 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1124 if (low <= addr && addr < high) {
1125 if (vma_low) *vma_low = low;
1126 if (vma_high) *vma_high = high;
1127 fclose (fp);
1128 return true;
1129 }
1130 }
1131 for (;;) {
1132 int ch = fgetc(fp);
1133 if (ch == EOF || ch == (int)'\n') break;
1134 }
1135 }
1136 fclose(fp);
1137 }
1138 return false;
1139 }
1140
1141 // Locate initial thread stack. This special handling of initial thread stack
1142 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1143 // bogus value for initial thread.
1144 void os::Linux::capture_initial_stack(size_t max_size) {
1145 // stack size is the easy part, get it from RLIMIT_STACK
1146 size_t stack_size;
1147 struct rlimit rlim;
1148 getrlimit(RLIMIT_STACK, &rlim);
1149 stack_size = rlim.rlim_cur;
1150
1151 // 6308388: a bug in ld.so will relocate its own .data section to the
1152 // lower end of primordial stack; reduce ulimit -s value a little bit
1153 // so we won't install guard page on ld.so's data section.
1154 stack_size -= 2 * page_size();
1155
1156 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1157 // 7.1, in both cases we will get 2G in return value.
1158 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1159 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1160 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1161 // in case other parts in glibc still assumes 2M max stack size.
1162 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1163 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1164 if (stack_size > 2 * K * K IA64_ONLY(*2))
1165 stack_size = 2 * K * K IA64_ONLY(*2);
1166 // Try to figure out where the stack base (top) is. This is harder.
1167 //
1168 // When an application is started, glibc saves the initial stack pointer in
1169 // a global variable "__libc_stack_end", which is then used by system
1170 // libraries. __libc_stack_end should be pretty close to stack top. The
1171 // variable is available since the very early days. However, because it is
1172 // a private interface, it could disappear in the future.
1173 //
1174 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1175 // to __libc_stack_end, it is very close to stack top, but isn't the real
1176 // stack top. Note that /proc may not exist if VM is running as a chroot
1177 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1178 // /proc/<pid>/stat could change in the future (though unlikely).
1179 //
1180 // We try __libc_stack_end first. If that doesn't work, look for
1181 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1182 // as a hint, which should work well in most cases.
1183
1184 uintptr_t stack_start;
1185
1186 // try __libc_stack_end first
1187 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1188 if (p && *p) {
1189 stack_start = *p;
1190 } else {
1191 // see if we can get the start_stack field from /proc/self/stat
1192 FILE *fp;
1193 int pid;
1194 char state;
1195 int ppid;
1196 int pgrp;
1197 int session;
1198 int nr;
1199 int tpgrp;
1200 unsigned long flags;
1201 unsigned long minflt;
1202 unsigned long cminflt;
1203 unsigned long majflt;
1204 unsigned long cmajflt;
1205 unsigned long utime;
1206 unsigned long stime;
1207 long cutime;
1208 long cstime;
1209 long prio;
1210 long nice;
1211 long junk;
1212 long it_real;
1213 uintptr_t start;
1214 uintptr_t vsize;
1215 intptr_t rss;
1216 uintptr_t rsslim;
1217 uintptr_t scodes;
1218 uintptr_t ecode;
1219 int i;
1220
1221 // Figure what the primordial thread stack base is. Code is inspired
1222 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1223 // followed by command name surrounded by parentheses, state, etc.
1224 char stat[2048];
1225 int statlen;
1226
1227 fp = fopen("/proc/self/stat", "r");
1228 if (fp) {
1229 statlen = fread(stat, 1, 2047, fp);
1230 stat[statlen] = '\0';
1231 fclose(fp);
1232
1233 // Skip pid and the command string. Note that we could be dealing with
1234 // weird command names, e.g. user could decide to rename java launcher
1235 // to "java 1.4.2 :)", then the stat file would look like
1236 // 1234 (java 1.4.2 :)) R ... ...
1237 // We don't really need to know the command string, just find the last
1238 // occurrence of ")" and then start parsing from there. See bug 4726580.
1239 char * s = strrchr(stat, ')');
1240
1241 i = 0;
1242 if (s) {
1243 // Skip blank chars
1244 do s++; while (isspace(*s));
1245
1246 #define _UFM UINTX_FORMAT
1247 #define _DFM INTX_FORMAT
1248
1249 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1250 /* 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 */
1251 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,
1252 &state, /* 3 %c */
1253 &ppid, /* 4 %d */
1254 &pgrp, /* 5 %d */
1255 &session, /* 6 %d */
1256 &nr, /* 7 %d */
1257 &tpgrp, /* 8 %d */
1258 &flags, /* 9 %lu */
1259 &minflt, /* 10 %lu */
1260 &cminflt, /* 11 %lu */
1261 &majflt, /* 12 %lu */
1262 &cmajflt, /* 13 %lu */
1263 &utime, /* 14 %lu */
1264 &stime, /* 15 %lu */
1265 &cutime, /* 16 %ld */
1266 &cstime, /* 17 %ld */
1267 &prio, /* 18 %ld */
1268 &nice, /* 19 %ld */
1269 &junk, /* 20 %ld */
1270 &it_real, /* 21 %ld */
1271 &start, /* 22 UINTX_FORMAT */
1272 &vsize, /* 23 UINTX_FORMAT */
1273 &rss, /* 24 INTX_FORMAT */
1274 &rsslim, /* 25 UINTX_FORMAT */
1275 &scodes, /* 26 UINTX_FORMAT */
1276 &ecode, /* 27 UINTX_FORMAT */
1277 &stack_start); /* 28 UINTX_FORMAT */
1278 }
1279
1280 #undef _UFM
1281 #undef _DFM
1282
1283 if (i != 28 - 2) {
1284 assert(false, "Bad conversion from /proc/self/stat");
1285 // product mode - assume we are the initial thread, good luck in the
1286 // embedded case.
1287 warning("Can't detect initial thread stack location - bad conversion");
1288 stack_start = (uintptr_t) &rlim;
1289 }
1290 } else {
1291 // For some reason we can't open /proc/self/stat (for example, running on
1292 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1293 // most cases, so don't abort:
1294 warning("Can't detect initial thread stack location - no /proc/self/stat");
1295 stack_start = (uintptr_t) &rlim;
1296 }
1297 }
1298
1299 // Now we have a pointer (stack_start) very close to the stack top, the
1300 // next thing to do is to figure out the exact location of stack top. We
1301 // can find out the virtual memory area that contains stack_start by
1302 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1303 // and its upper limit is the real stack top. (again, this would fail if
1304 // running inside chroot, because /proc may not exist.)
1305
1306 uintptr_t stack_top;
1307 address low, high;
1308 if (find_vma((address)stack_start, &low, &high)) {
1309 // success, "high" is the true stack top. (ignore "low", because initial
1310 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1311 stack_top = (uintptr_t)high;
1312 } else {
1313 // failed, likely because /proc/self/maps does not exist
1314 warning("Can't detect initial thread stack location - find_vma failed");
1315 // best effort: stack_start is normally within a few pages below the real
1316 // stack top, use it as stack top, and reduce stack size so we won't put
1317 // guard page outside stack.
1318 stack_top = stack_start;
1319 stack_size -= 16 * page_size();
1320 }
1321
1322 // stack_top could be partially down the page so align it
1323 stack_top = align_size_up(stack_top, page_size());
1324
1325 if (max_size && stack_size > max_size) {
1326 _initial_thread_stack_size = max_size;
1327 } else {
1328 _initial_thread_stack_size = stack_size;
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 }
1334
1335 ////////////////////////////////////////////////////////////////////////////////
1336 // time support
1337
1338 // Time since start-up in seconds to a fine granularity.
1339 // Used by VMSelfDestructTimer and the MemProfiler.
1340 double os::elapsedTime() {
1341
1342 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1343 }
1344
1345 jlong os::elapsed_counter() {
1346 return javaTimeNanos() - initial_time_count;
1347 }
1348
1349 jlong os::elapsed_frequency() {
1350 return NANOSECS_PER_SEC; // nanosecond resolution
1351 }
1352
1353 bool os::supports_vtime() { return true; }
1354 bool os::enable_vtime() { return false; }
1355 bool os::vtime_enabled() { return false; }
1356
1357 double os::elapsedVTime() {
1358 struct rusage usage;
1359 int retval = getrusage(RUSAGE_THREAD, &usage);
1360 if (retval == 0) {
1361 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);
1362 } else {
1363 // better than nothing, but not much
1364 return elapsedTime();
1365 }
1366 }
1367
1368 jlong os::javaTimeMillis() {
1369 timeval time;
1370 int status = gettimeofday(&time, NULL);
1371 assert(status != -1, "linux error");
1372 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1373 }
1374
1375 #ifndef CLOCK_MONOTONIC
1376 #define CLOCK_MONOTONIC (1)
1377 #endif
1378
1379 void os::Linux::clock_init() {
1380 // we do dlopen's in this particular order due to bug in linux
1381 // dynamical loader (see 6348968) leading to crash on exit
1382 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1383 if (handle == NULL) {
1384 handle = dlopen("librt.so", RTLD_LAZY);
1385 }
1386
1387 if (handle) {
1388 int (*clock_getres_func)(clockid_t, struct timespec*) =
1389 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1390 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1391 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1392 if (clock_getres_func && clock_gettime_func) {
1393 // See if monotonic clock is supported by the kernel. Note that some
1394 // early implementations simply return kernel jiffies (updated every
1395 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1396 // for nano time (though the monotonic property is still nice to have).
1397 // It's fixed in newer kernels, however clock_getres() still returns
1398 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1399 // resolution for now. Hopefully as people move to new kernels, this
1400 // won't be a problem.
1401 struct timespec res;
1402 struct timespec tp;
1403 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1404 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1405 // yes, monotonic clock is supported
1406 _clock_gettime = clock_gettime_func;
1407 return;
1408 } else {
1409 // close librt if there is no monotonic clock
1410 dlclose(handle);
1411 }
1412 }
1413 }
1414 warning("No monotonic clock was available - timed services may " \
1415 "be adversely affected if the time-of-day clock changes");
1416 }
1417
1418 #ifndef SYS_clock_getres
1419
1420 #if defined(IA32) || defined(AMD64)
1421 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1422 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1423 #else
1424 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1425 #define sys_clock_getres(x,y) -1
1426 #endif
1427
1428 #else
1429 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1430 #endif
1431
1432 void os::Linux::fast_thread_clock_init() {
1433 if (!UseLinuxPosixThreadCPUClocks) {
1434 return;
1435 }
1436 clockid_t clockid;
1437 struct timespec tp;
1438 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1439 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1440
1441 // Switch to using fast clocks for thread cpu time if
1442 // the sys_clock_getres() returns 0 error code.
1443 // Note, that some kernels may support the current thread
1444 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1445 // returned by the pthread_getcpuclockid().
1446 // If the fast Posix clocks are supported then the sys_clock_getres()
1447 // must return at least tp.tv_sec == 0 which means a resolution
1448 // better than 1 sec. This is extra check for reliability.
1449
1450 if(pthread_getcpuclockid_func &&
1451 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1452 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1453
1454 _supports_fast_thread_cpu_time = true;
1455 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1456 }
1457 }
1458
1459 jlong os::javaTimeNanos() {
1460 if (os::supports_monotonic_clock()) {
1461 struct timespec tp;
1462 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1463 assert(status == 0, "gettime error");
1464 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1465 return result;
1466 } else {
1467 timeval time;
1468 int status = gettimeofday(&time, NULL);
1469 assert(status != -1, "linux error");
1470 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1471 return 1000 * usecs;
1472 }
1473 }
1474
1475 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1476 if (os::supports_monotonic_clock()) {
1477 info_ptr->max_value = ALL_64_BITS;
1478
1479 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1480 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1481 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1482 } else {
1483 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1484 info_ptr->max_value = ALL_64_BITS;
1485
1486 // gettimeofday is a real time clock so it skips
1487 info_ptr->may_skip_backward = true;
1488 info_ptr->may_skip_forward = true;
1489 }
1490
1491 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1492 }
1493
1494 // Return the real, user, and system times in seconds from an
1495 // arbitrary fixed point in the past.
1496 bool os::getTimesSecs(double* process_real_time,
1497 double* process_user_time,
1498 double* process_system_time) {
1499 struct tms ticks;
1500 clock_t real_ticks = times(&ticks);
1501
1502 if (real_ticks == (clock_t) (-1)) {
1503 return false;
1504 } else {
1505 double ticks_per_second = (double) clock_tics_per_sec;
1506 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1507 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1508 *process_real_time = ((double) real_ticks) / ticks_per_second;
1509
1510 return true;
1511 }
1512 }
1513
1514
1515 char * os::local_time_string(char *buf, size_t buflen) {
1516 struct tm t;
1517 time_t long_time;
1518 time(&long_time);
1519 localtime_r(&long_time, &t);
1520 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1521 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1522 t.tm_hour, t.tm_min, t.tm_sec);
1523 return buf;
1524 }
1525
1526 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1527 return localtime_r(clock, res);
1528 }
1529
1530 ////////////////////////////////////////////////////////////////////////////////
1531 // runtime exit support
1532
1533 // Note: os::shutdown() might be called very early during initialization, or
1534 // called from signal handler. Before adding something to os::shutdown(), make
1535 // sure it is async-safe and can handle partially initialized VM.
1536 void os::shutdown() {
1537
1538 // allow PerfMemory to attempt cleanup of any persistent resources
1539 perfMemory_exit();
1540
1541 // needs to remove object in file system
1542 AttachListener::abort();
1543
1544 // flush buffered output, finish log files
1545 ostream_abort();
1546
1547 // Check for abort hook
1548 abort_hook_t abort_hook = Arguments::abort_hook();
1549 if (abort_hook != NULL) {
1550 abort_hook();
1551 }
1552
1553 }
1554
1555 // Note: os::abort() might be called very early during initialization, or
1556 // called from signal handler. Before adding something to os::abort(), make
1557 // sure it is async-safe and can handle partially initialized VM.
1558 void os::abort(bool dump_core) {
1559 os::shutdown();
1560 if (dump_core) {
1561 #ifndef PRODUCT
1562 fdStream out(defaultStream::output_fd());
1563 out.print_raw("Current thread is ");
1564 char buf[16];
1565 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1566 out.print_raw_cr(buf);
1567 out.print_raw_cr("Dumping core ...");
1568 #endif
1569 ::abort(); // dump core
1570 }
1571
1572 ::exit(1);
1573 }
1574
1575 // Die immediately, no exit hook, no abort hook, no cleanup.
1576 void os::die() {
1577 // _exit() on LinuxThreads only kills current thread
1578 ::abort();
1579 }
1580
1581 // unused on linux for now.
1582 void os::set_error_file(const char *logfile) {}
1583
1584
1585 // This method is a copy of JDK's sysGetLastErrorString
1586 // from src/solaris/hpi/src/system_md.c
1587
1588 size_t os::lasterror(char *buf, size_t len) {
1589
1590 if (errno == 0) return 0;
1591
1592 const char *s = ::strerror(errno);
1593 size_t n = ::strlen(s);
1594 if (n >= len) {
1595 n = len - 1;
1596 }
1597 ::strncpy(buf, s, n);
1598 buf[n] = '\0';
1599 return n;
1600 }
1601
1602 intx os::current_thread_id() { return (intx)pthread_self(); }
1603 int os::current_process_id() {
1604
1605 // Under the old linux thread library, linux gives each thread
1606 // its own process id. Because of this each thread will return
1607 // a different pid if this method were to return the result
1608 // of getpid(2). Linux provides no api that returns the pid
1609 // of the launcher thread for the vm. This implementation
1610 // returns a unique pid, the pid of the launcher thread
1611 // that starts the vm 'process'.
1612
1613 // Under the NPTL, getpid() returns the same pid as the
1614 // launcher thread rather than a unique pid per thread.
1615 // Use gettid() if you want the old pre NPTL behaviour.
1616
1617 // if you are looking for the result of a call to getpid() that
1618 // returns a unique pid for the calling thread, then look at the
1619 // OSThread::thread_id() method in osThread_linux.hpp file
1620
1621 return (int)(_initial_pid ? _initial_pid : getpid());
1622 }
1623
1624 // DLL functions
1625
1626 const char* os::dll_file_extension() { return ".so"; }
1627
1628 // This must be hard coded because it's the system's temporary
1629 // directory not the java application's temp directory, ala java.io.tmpdir.
1630 const char* os::get_temp_directory() { return "/tmp"; }
1631
1632 static bool file_exists(const char* filename) {
1633 struct stat statbuf;
1634 if (filename == NULL || strlen(filename) == 0) {
1635 return false;
1636 }
1637 return os::stat(filename, &statbuf) == 0;
1638 }
1639
1640 bool os::dll_build_name(char* buffer, size_t buflen,
1641 const char* pname, const char* fname) {
1642 bool retval = false;
1643 // Copied from libhpi
1644 const size_t pnamelen = pname ? strlen(pname) : 0;
1645
1646 // Return error on buffer overflow.
1647 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1648 return retval;
1649 }
1650
1651 if (pnamelen == 0) {
1652 snprintf(buffer, buflen, "lib%s.so", fname);
1653 retval = true;
1654 } else if (strchr(pname, *os::path_separator()) != NULL) {
1655 int n;
1656 char** pelements = split_path(pname, &n);
1657 if (pelements == NULL) {
1658 return false;
1659 }
1660 for (int i = 0 ; i < n ; i++) {
1661 // Really shouldn't be NULL, but check can't hurt
1662 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1663 continue; // skip the empty path values
1664 }
1665 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1666 if (file_exists(buffer)) {
1667 retval = true;
1668 break;
1669 }
1670 }
1671 // release the storage
1672 for (int i = 0 ; i < n ; i++) {
1673 if (pelements[i] != NULL) {
1674 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1675 }
1676 }
1677 if (pelements != NULL) {
1678 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1679 }
1680 } else {
1681 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1682 retval = true;
1683 }
1684 return retval;
1685 }
1686
1687 // check if addr is inside libjvm.so
1688 bool os::address_is_in_vm(address addr) {
1689 static address libjvm_base_addr;
1690 Dl_info dlinfo;
1691
1692 if (libjvm_base_addr == NULL) {
1693 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1694 libjvm_base_addr = (address)dlinfo.dli_fbase;
1695 }
1696 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1697 }
1698
1699 if (dladdr((void *)addr, &dlinfo) != 0) {
1700 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1701 }
1702
1703 return false;
1704 }
1705
1706 bool os::dll_address_to_function_name(address addr, char *buf,
1707 int buflen, int *offset) {
1708 // buf is not optional, but offset is optional
1709 assert(buf != NULL, "sanity check");
1710
1711 Dl_info dlinfo;
1712
1713 if (dladdr((void*)addr, &dlinfo) != 0) {
1714 // see if we have a matching symbol
1715 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1716 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1717 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1718 }
1719 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1720 return true;
1721 }
1722 // no matching symbol so try for just file info
1723 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1724 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1725 buf, buflen, offset, dlinfo.dli_fname)) {
1726 return true;
1727 }
1728 }
1729 }
1730
1731 buf[0] = '\0';
1732 if (offset != NULL) *offset = -1;
1733 return false;
1734 }
1735
1736 struct _address_to_library_name {
1737 address addr; // input : memory address
1738 size_t buflen; // size of fname
1739 char* fname; // output: library name
1740 address base; // library base addr
1741 };
1742
1743 static int address_to_library_name_callback(struct dl_phdr_info *info,
1744 size_t size, void *data) {
1745 int i;
1746 bool found = false;
1747 address libbase = NULL;
1748 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1749
1750 // iterate through all loadable segments
1751 for (i = 0; i < info->dlpi_phnum; i++) {
1752 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1753 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1754 // base address of a library is the lowest address of its loaded
1755 // segments.
1756 if (libbase == NULL || libbase > segbase) {
1757 libbase = segbase;
1758 }
1759 // see if 'addr' is within current segment
1760 if (segbase <= d->addr &&
1761 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1762 found = true;
1763 }
1764 }
1765 }
1766
1767 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1768 // so dll_address_to_library_name() can fall through to use dladdr() which
1769 // can figure out executable name from argv[0].
1770 if (found && info->dlpi_name && info->dlpi_name[0]) {
1771 d->base = libbase;
1772 if (d->fname) {
1773 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1774 }
1775 return 1;
1776 }
1777 return 0;
1778 }
1779
1780 bool os::dll_address_to_library_name(address addr, char* buf,
1781 int buflen, int* offset) {
1782 // buf is not optional, but offset is optional
1783 assert(buf != NULL, "sanity check");
1784
1785 Dl_info dlinfo;
1786 struct _address_to_library_name data;
1787
1788 // There is a bug in old glibc dladdr() implementation that it could resolve
1789 // to wrong library name if the .so file has a base address != NULL. Here
1790 // we iterate through the program headers of all loaded libraries to find
1791 // out which library 'addr' really belongs to. This workaround can be
1792 // removed once the minimum requirement for glibc is moved to 2.3.x.
1793 data.addr = addr;
1794 data.fname = buf;
1795 data.buflen = buflen;
1796 data.base = NULL;
1797 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1798
1799 if (rslt) {
1800 // buf already contains library name
1801 if (offset) *offset = addr - data.base;
1802 return true;
1803 }
1804 if (dladdr((void*)addr, &dlinfo) != 0) {
1805 if (dlinfo.dli_fname != NULL) {
1806 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1807 }
1808 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1809 *offset = addr - (address)dlinfo.dli_fbase;
1810 }
1811 return true;
1812 }
1813
1814 buf[0] = '\0';
1815 if (offset) *offset = -1;
1816 return false;
1817 }
1818
1819 // Loads .dll/.so and
1820 // in case of error it checks if .dll/.so was built for the
1821 // same architecture as Hotspot is running on
1822
1823
1824 // Remember the stack's state. The Linux dynamic linker will change
1825 // the stack to 'executable' at most once, so we must safepoint only once.
1826 bool os::Linux::_stack_is_executable = false;
1827
1828 // VM operation that loads a library. This is necessary if stack protection
1829 // of the Java stacks can be lost during loading the library. If we
1830 // do not stop the Java threads, they can stack overflow before the stacks
1831 // are protected again.
1832 class VM_LinuxDllLoad: public VM_Operation {
1833 private:
1834 const char *_filename;
1835 char *_ebuf;
1836 int _ebuflen;
1837 void *_lib;
1838 public:
1839 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1840 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1841 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1842 void doit() {
1843 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1844 os::Linux::_stack_is_executable = true;
1845 }
1846 void* loaded_library() { return _lib; }
1847 };
1848
1849 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1850 {
1851 void * result = NULL;
1852 bool load_attempted = false;
1853
1854 // Check whether the library to load might change execution rights
1855 // of the stack. If they are changed, the protection of the stack
1856 // guard pages will be lost. We need a safepoint to fix this.
1857 //
1858 // See Linux man page execstack(8) for more info.
1859 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1860 ElfFile ef(filename);
1861 if (!ef.specifies_noexecstack()) {
1862 if (!is_init_completed()) {
1863 os::Linux::_stack_is_executable = true;
1864 // This is OK - No Java threads have been created yet, and hence no
1865 // stack guard pages to fix.
1866 //
1867 // This should happen only when you are building JDK7 using a very
1868 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1869 //
1870 // Dynamic loader will make all stacks executable after
1871 // this function returns, and will not do that again.
1872 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1873 } else {
1874 warning("You have loaded library %s which might have disabled stack guard. "
1875 "The VM will try to fix the stack guard now.\n"
1876 "It's highly recommended that you fix the library with "
1877 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1878 filename);
1879
1880 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1881 JavaThread *jt = JavaThread::current();
1882 if (jt->thread_state() != _thread_in_native) {
1883 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1884 // that requires ExecStack. Cannot enter safe point. Let's give up.
1885 warning("Unable to fix stack guard. Giving up.");
1886 } else {
1887 if (!LoadExecStackDllInVMThread) {
1888 // This is for the case where the DLL has an static
1889 // constructor function that executes JNI code. We cannot
1890 // load such DLLs in the VMThread.
1891 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1892 }
1893
1894 ThreadInVMfromNative tiv(jt);
1895 debug_only(VMNativeEntryWrapper vew;)
1896
1897 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1898 VMThread::execute(&op);
1899 if (LoadExecStackDllInVMThread) {
1900 result = op.loaded_library();
1901 }
1902 load_attempted = true;
1903 }
1904 }
1905 }
1906 }
1907
1908 if (!load_attempted) {
1909 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1910 }
1911
1912 if (result != NULL) {
1913 // Successful loading
1914 return result;
1915 }
1916
1917 Elf32_Ehdr elf_head;
1918 int diag_msg_max_length=ebuflen-strlen(ebuf);
1919 char* diag_msg_buf=ebuf+strlen(ebuf);
1920
1921 if (diag_msg_max_length==0) {
1922 // No more space in ebuf for additional diagnostics message
1923 return NULL;
1924 }
1925
1926
1927 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1928
1929 if (file_descriptor < 0) {
1930 // Can't open library, report dlerror() message
1931 return NULL;
1932 }
1933
1934 bool failed_to_read_elf_head=
1935 (sizeof(elf_head)!=
1936 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1937
1938 ::close(file_descriptor);
1939 if (failed_to_read_elf_head) {
1940 // file i/o error - report dlerror() msg
1941 return NULL;
1942 }
1943
1944 typedef struct {
1945 Elf32_Half code; // Actual value as defined in elf.h
1946 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1947 char elf_class; // 32 or 64 bit
1948 char endianess; // MSB or LSB
1949 char* name; // String representation
1950 } arch_t;
1951
1952 #ifndef EM_486
1953 #define EM_486 6 /* Intel 80486 */
1954 #endif
1955
1956 static const arch_t arch_array[]={
1957 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1958 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1959 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1960 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1961 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1962 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1963 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1964 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1965 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1966 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1967 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1968 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1969 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1970 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1971 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1972 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1973 };
1974
1975 #if (defined IA32)
1976 static Elf32_Half running_arch_code=EM_386;
1977 #elif (defined AMD64)
1978 static Elf32_Half running_arch_code=EM_X86_64;
1979 #elif (defined IA64)
1980 static Elf32_Half running_arch_code=EM_IA_64;
1981 #elif (defined __sparc) && (defined _LP64)
1982 static Elf32_Half running_arch_code=EM_SPARCV9;
1983 #elif (defined __sparc) && (!defined _LP64)
1984 static Elf32_Half running_arch_code=EM_SPARC;
1985 #elif (defined __powerpc64__)
1986 static Elf32_Half running_arch_code=EM_PPC64;
1987 #elif (defined __powerpc__)
1988 static Elf32_Half running_arch_code=EM_PPC;
1989 #elif (defined ARM)
1990 static Elf32_Half running_arch_code=EM_ARM;
1991 #elif (defined S390)
1992 static Elf32_Half running_arch_code=EM_S390;
1993 #elif (defined ALPHA)
1994 static Elf32_Half running_arch_code=EM_ALPHA;
1995 #elif (defined MIPSEL)
1996 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1997 #elif (defined PARISC)
1998 static Elf32_Half running_arch_code=EM_PARISC;
1999 #elif (defined MIPS)
2000 static Elf32_Half running_arch_code=EM_MIPS;
2001 #elif (defined M68K)
2002 static Elf32_Half running_arch_code=EM_68K;
2003 #else
2004 #error Method os::dll_load requires that one of following is defined:\
2005 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
2006 #endif
2007
2008 // Identify compatability class for VM's architecture and library's architecture
2009 // Obtain string descriptions for architectures
2010
2011 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
2012 int running_arch_index=-1;
2013
2014 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
2015 if (running_arch_code == arch_array[i].code) {
2016 running_arch_index = i;
2017 }
2018 if (lib_arch.code == arch_array[i].code) {
2019 lib_arch.compat_class = arch_array[i].compat_class;
2020 lib_arch.name = arch_array[i].name;
2021 }
2022 }
2023
2024 assert(running_arch_index != -1,
2025 "Didn't find running architecture code (running_arch_code) in arch_array");
2026 if (running_arch_index == -1) {
2027 // Even though running architecture detection failed
2028 // we may still continue with reporting dlerror() message
2029 return NULL;
2030 }
2031
2032 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
2033 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
2034 return NULL;
2035 }
2036
2037 #ifndef S390
2038 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
2039 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
2040 return NULL;
2041 }
2042 #endif // !S390
2043
2044 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
2045 if ( lib_arch.name!=NULL ) {
2046 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2047 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
2048 lib_arch.name, arch_array[running_arch_index].name);
2049 } else {
2050 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2051 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
2052 lib_arch.code,
2053 arch_array[running_arch_index].name);
2054 }
2055 }
2056
2057 return NULL;
2058 }
2059
2060 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) {
2061 void * result = ::dlopen(filename, RTLD_LAZY);
2062 if (result == NULL) {
2063 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
2064 ebuf[ebuflen-1] = '\0';
2065 }
2066 return result;
2067 }
2068
2069 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) {
2070 void * result = NULL;
2071 if (LoadExecStackDllInVMThread) {
2072 result = dlopen_helper(filename, ebuf, ebuflen);
2073 }
2074
2075 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2076 // library that requires an executable stack, or which does not have this
2077 // stack attribute set, dlopen changes the stack attribute to executable. The
2078 // read protection of the guard pages gets lost.
2079 //
2080 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2081 // may have been queued at the same time.
2082
2083 if (!_stack_is_executable) {
2084 JavaThread *jt = Threads::first();
2085
2086 while (jt) {
2087 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2088 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions
2089 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(),
2090 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) {
2091 warning("Attempt to reguard stack yellow zone failed.");
2092 }
2093 }
2094 jt = jt->next();
2095 }
2096 }
2097
2098 return result;
2099 }
2100
2101 /*
2102 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
2103 * chances are you might want to run the generated bits against glibc-2.0
2104 * libdl.so, so always use locking for any version of glibc.
2105 */
2106 void* os::dll_lookup(void* handle, const char* name) {
2107 pthread_mutex_lock(&dl_mutex);
2108 void* res = dlsym(handle, name);
2109 pthread_mutex_unlock(&dl_mutex);
2110 return res;
2111 }
2112
2113 void* os::get_default_process_handle() {
2114 return (void*)::dlopen(NULL, RTLD_LAZY);
2115 }
2116
2117 static bool _print_ascii_file(const char* filename, outputStream* st) {
2118 int fd = ::open(filename, O_RDONLY);
2119 if (fd == -1) {
2120 return false;
2121 }
2122
2123 char buf[32];
2124 int bytes;
2125 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2126 st->print_raw(buf, bytes);
2127 }
2128
2129 ::close(fd);
2130
2131 return true;
2132 }
2133
2134 void os::print_dll_info(outputStream *st) {
2135 st->print_cr("Dynamic libraries:");
2136
2137 char fname[32];
2138 pid_t pid = os::Linux::gettid();
2139
2140 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2141
2142 if (!_print_ascii_file(fname, st)) {
2143 st->print("Can not get library information for pid = %d\n", pid);
2144 }
2145 }
2146
2147 void os::print_os_info_brief(outputStream* st) {
2148 os::Linux::print_distro_info(st);
2149
2150 os::Posix::print_uname_info(st);
2151
2152 os::Linux::print_libversion_info(st);
2153
2154 }
2155
2156 void os::print_os_info(outputStream* st) {
2157 st->print("OS:");
2158
2159 os::Linux::print_distro_info(st);
2160
2161 os::Posix::print_uname_info(st);
2162
2163 // Print warning if unsafe chroot environment detected
2164 if (unsafe_chroot_detected) {
2165 st->print("WARNING!! ");
2166 st->print_cr(unstable_chroot_error);
2167 }
2168
2169 os::Linux::print_libversion_info(st);
2170
2171 os::Posix::print_rlimit_info(st);
2172
2173 os::Posix::print_load_average(st);
2174
2175 os::Linux::print_full_memory_info(st);
2176 }
2177
2178 // Try to identify popular distros.
2179 // Most Linux distributions have a /etc/XXX-release file, which contains
2180 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2181 // file that also contains the OS version string. Some have more than one
2182 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2183 // /etc/redhat-release.), so the order is important.
2184 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2185 // their own specific XXX-release file as well as a redhat-release file.
2186 // Because of this the XXX-release file needs to be searched for before the
2187 // redhat-release file.
2188 // Since Red Hat has a lsb-release file that is not very descriptive the
2189 // search for redhat-release needs to be before lsb-release.
2190 // Since the lsb-release file is the new standard it needs to be searched
2191 // before the older style release files.
2192 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2193 // next to last resort. The os-release file is a new standard that contains
2194 // distribution information and the system-release file seems to be an old
2195 // standard that has been replaced by the lsb-release and os-release files.
2196 // Searching for the debian_version file is the last resort. It contains
2197 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2198 // "Debian " is printed before the contents of the debian_version file.
2199 void os::Linux::print_distro_info(outputStream* st) {
2200 if (!_print_ascii_file("/etc/oracle-release", st) &&
2201 !_print_ascii_file("/etc/mandriva-release", st) &&
2202 !_print_ascii_file("/etc/mandrake-release", st) &&
2203 !_print_ascii_file("/etc/sun-release", st) &&
2204 !_print_ascii_file("/etc/redhat-release", st) &&
2205 !_print_ascii_file("/etc/lsb-release", st) &&
2206 !_print_ascii_file("/etc/SuSE-release", st) &&
2207 !_print_ascii_file("/etc/turbolinux-release", st) &&
2208 !_print_ascii_file("/etc/gentoo-release", st) &&
2209 !_print_ascii_file("/etc/ltib-release", st) &&
2210 !_print_ascii_file("/etc/angstrom-version", st) &&
2211 !_print_ascii_file("/etc/system-release", st) &&
2212 !_print_ascii_file("/etc/os-release", st)) {
2213
2214 if (file_exists("/etc/debian_version")) {
2215 st->print("Debian ");
2216 _print_ascii_file("/etc/debian_version", st);
2217 } else {
2218 st->print("Linux");
2219 }
2220 }
2221 st->cr();
2222 }
2223
2224 void os::Linux::print_libversion_info(outputStream* st) {
2225 // libc, pthread
2226 st->print("libc:");
2227 st->print(os::Linux::glibc_version()); st->print(" ");
2228 st->print(os::Linux::libpthread_version()); st->print(" ");
2229 if (os::Linux::is_LinuxThreads()) {
2230 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2231 }
2232 st->cr();
2233 }
2234
2235 void os::Linux::print_full_memory_info(outputStream* st) {
2236 st->print("\n/proc/meminfo:\n");
2237 _print_ascii_file("/proc/meminfo", st);
2238 st->cr();
2239 }
2240
2241 void os::print_memory_info(outputStream* st) {
2242
2243 st->print("Memory:");
2244 st->print(" %dk page", os::vm_page_size()>>10);
2245
2246 // values in struct sysinfo are "unsigned long"
2247 struct sysinfo si;
2248 sysinfo(&si);
2249
2250 st->print(", physical " UINT64_FORMAT "k",
2251 os::physical_memory() >> 10);
2252 st->print("(" UINT64_FORMAT "k free)",
2253 os::available_memory() >> 10);
2254 st->print(", swap " UINT64_FORMAT "k",
2255 ((jlong)si.totalswap * si.mem_unit) >> 10);
2256 st->print("(" UINT64_FORMAT "k free)",
2257 ((jlong)si.freeswap * si.mem_unit) >> 10);
2258 st->cr();
2259 }
2260
2261 void os::pd_print_cpu_info(outputStream* st) {
2262 st->print("\n/proc/cpuinfo:\n");
2263 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2264 st->print(" <Not Available>");
2265 }
2266 st->cr();
2267 }
2268
2269 void os::print_siginfo(outputStream* st, void* siginfo) {
2270 const siginfo_t* si = (const siginfo_t*)siginfo;
2271
2272 os::Posix::print_siginfo_brief(st, si);
2273
2274 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2275 UseSharedSpaces) {
2276 FileMapInfo* mapinfo = FileMapInfo::current_info();
2277 if (mapinfo->is_in_shared_space(si->si_addr)) {
2278 st->print("\n\nError accessing class data sharing archive." \
2279 " Mapped file inaccessible during execution, " \
2280 " possible disk/network problem.");
2281 }
2282 }
2283 st->cr();
2284 }
2285
2286
2287 static void print_signal_handler(outputStream* st, int sig,
2288 char* buf, size_t buflen);
2289
2290 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2291 st->print_cr("Signal Handlers:");
2292 print_signal_handler(st, SIGSEGV, buf, buflen);
2293 print_signal_handler(st, SIGBUS , buf, buflen);
2294 print_signal_handler(st, SIGFPE , buf, buflen);
2295 print_signal_handler(st, SIGPIPE, buf, buflen);
2296 print_signal_handler(st, SIGXFSZ, buf, buflen);
2297 print_signal_handler(st, SIGILL , buf, buflen);
2298 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2299 print_signal_handler(st, SR_signum, buf, buflen);
2300 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2301 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2302 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2303 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2304 #if defined(PPC64)
2305 print_signal_handler(st, SIGTRAP, buf, buflen);
2306 #endif
2307 }
2308
2309 static char saved_jvm_path[MAXPATHLEN] = {0};
2310
2311 // Find the full path to the current module, libjvm.so
2312 void os::jvm_path(char *buf, jint buflen) {
2313 // Error checking.
2314 if (buflen < MAXPATHLEN) {
2315 assert(false, "must use a large-enough buffer");
2316 buf[0] = '\0';
2317 return;
2318 }
2319 // Lazy resolve the path to current module.
2320 if (saved_jvm_path[0] != 0) {
2321 strcpy(buf, saved_jvm_path);
2322 return;
2323 }
2324
2325 char dli_fname[MAXPATHLEN];
2326 bool ret = dll_address_to_library_name(
2327 CAST_FROM_FN_PTR(address, os::jvm_path),
2328 dli_fname, sizeof(dli_fname), NULL);
2329 assert(ret, "cannot locate libjvm");
2330 char *rp = NULL;
2331 if (ret && dli_fname[0] != '\0') {
2332 rp = realpath(dli_fname, buf);
2333 }
2334 if (rp == NULL)
2335 return;
2336
2337 if (Arguments::sun_java_launcher_is_altjvm()) {
2338 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2339 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so".
2340 // If "/jre/lib/" appears at the right place in the string, then
2341 // assume we are installed in a JDK and we're done. Otherwise, check
2342 // for a JAVA_HOME environment variable and fix up the path so it
2343 // looks like libjvm.so is installed there (append a fake suffix
2344 // hotspot/libjvm.so).
2345 const char *p = buf + strlen(buf) - 1;
2346 for (int count = 0; p > buf && count < 5; ++count) {
2347 for (--p; p > buf && *p != '/'; --p)
2348 /* empty */ ;
2349 }
2350
2351 if (strncmp(p, "/jre/lib/", 9) != 0) {
2352 // Look for JAVA_HOME in the environment.
2353 char* java_home_var = ::getenv("JAVA_HOME");
2354 if (java_home_var != NULL && java_home_var[0] != 0) {
2355 char* jrelib_p;
2356 int len;
2357
2358 // Check the current module name "libjvm.so".
2359 p = strrchr(buf, '/');
2360 assert(strstr(p, "/libjvm") == p, "invalid library name");
2361
2362 rp = realpath(java_home_var, buf);
2363 if (rp == NULL)
2364 return;
2365
2366 // determine if this is a legacy image or modules image
2367 // modules image doesn't have "jre" subdirectory
2368 len = strlen(buf);
2369 jrelib_p = buf + len;
2370 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2371 if (0 != access(buf, F_OK)) {
2372 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2373 }
2374
2375 if (0 == access(buf, F_OK)) {
2376 // Use current module name "libjvm.so"
2377 len = strlen(buf);
2378 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2379 } else {
2380 // Go back to path of .so
2381 rp = realpath(dli_fname, buf);
2382 if (rp == NULL)
2383 return;
2384 }
2385 }
2386 }
2387 }
2388
2389 strcpy(saved_jvm_path, buf);
2390 }
2391
2392 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2393 // no prefix required, not even "_"
2394 }
2395
2396 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2397 // no suffix required
2398 }
2399
2400 ////////////////////////////////////////////////////////////////////////////////
2401 // sun.misc.Signal support
2402
2403 static volatile jint sigint_count = 0;
2404
2405 static void
2406 UserHandler(int sig, void *siginfo, void *context) {
2407 // 4511530 - sem_post is serialized and handled by the manager thread. When
2408 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2409 // don't want to flood the manager thread with sem_post requests.
2410 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2411 return;
2412
2413 // Ctrl-C is pressed during error reporting, likely because the error
2414 // handler fails to abort. Let VM die immediately.
2415 if (sig == SIGINT && is_error_reported()) {
2416 os::die();
2417 }
2418
2419 os::signal_notify(sig);
2420 }
2421
2422 void* os::user_handler() {
2423 return CAST_FROM_FN_PTR(void*, UserHandler);
2424 }
2425
2426 class Semaphore : public StackObj {
2427 public:
2428 Semaphore();
2429 ~Semaphore();
2430 void signal();
2431 void wait();
2432 bool trywait();
2433 bool timedwait(unsigned int sec, int nsec);
2434 private:
2435 sem_t _semaphore;
2436 };
2437
2438 Semaphore::Semaphore() {
2439 sem_init(&_semaphore, 0, 0);
2440 }
2441
2442 Semaphore::~Semaphore() {
2443 sem_destroy(&_semaphore);
2444 }
2445
2446 void Semaphore::signal() {
2447 sem_post(&_semaphore);
2448 }
2449
2450 void Semaphore::wait() {
2451 sem_wait(&_semaphore);
2452 }
2453
2454 bool Semaphore::trywait() {
2455 return sem_trywait(&_semaphore) == 0;
2456 }
2457
2458 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2459 struct timespec ts;
2460 // Semaphore's are always associated with CLOCK_REALTIME
2461 absoluteRealTimeForRelativeTime(&ts, (sec * NANOSECS_PER_SEC) + nsec);
2462
2463 while (1) {
2464 int result = sem_timedwait(&_semaphore, &ts);
2465 if (result == 0) {
2466 return true;
2467 } else if (errno == EINTR) {
2468 continue;
2469 } else if (errno == ETIMEDOUT) {
2470 return false;
2471 } else {
2472 return false;
2473 }
2474 }
2475 }
2476
2477 extern "C" {
2478 typedef void (*sa_handler_t)(int);
2479 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2480 }
2481
2482 void* os::signal(int signal_number, void* handler) {
2483 struct sigaction sigAct, oldSigAct;
2484
2485 sigfillset(&(sigAct.sa_mask));
2486 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2487 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2488
2489 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2490 // -1 means registration failed
2491 return (void *)-1;
2492 }
2493
2494 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2495 }
2496
2497 void os::signal_raise(int signal_number) {
2498 ::raise(signal_number);
2499 }
2500
2501 /*
2502 * The following code is moved from os.cpp for making this
2503 * code platform specific, which it is by its very nature.
2504 */
2505
2506 // Will be modified when max signal is changed to be dynamic
2507 int os::sigexitnum_pd() {
2508 return NSIG;
2509 }
2510
2511 // a counter for each possible signal value
2512 static volatile jint pending_signals[NSIG+1] = { 0 };
2513
2514 // Linux(POSIX) specific hand shaking semaphore.
2515 static sem_t sig_sem;
2516 static Semaphore sr_semaphore;
2517
2518 void os::signal_init_pd() {
2519 // Initialize signal structures
2520 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2521
2522 // Initialize signal semaphore
2523 ::sem_init(&sig_sem, 0, 0);
2524 }
2525
2526 void os::signal_notify(int sig) {
2527 Atomic::inc(&pending_signals[sig]);
2528 ::sem_post(&sig_sem);
2529 }
2530
2531 static int check_pending_signals(bool wait) {
2532 Atomic::store(0, &sigint_count);
2533 for (;;) {
2534 for (int i = 0; i < NSIG + 1; i++) {
2535 jint n = pending_signals[i];
2536 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2537 return i;
2538 }
2539 }
2540 if (!wait) {
2541 return -1;
2542 }
2543 JavaThread *thread = JavaThread::current();
2544 ThreadBlockInVM tbivm(thread);
2545
2546 bool threadIsSuspended;
2547 do {
2548 thread->set_suspend_equivalent();
2549 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2550 ::sem_wait(&sig_sem);
2551
2552 // were we externally suspended while we were waiting?
2553 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2554 if (threadIsSuspended) {
2555 //
2556 // The semaphore has been incremented, but while we were waiting
2557 // another thread suspended us. We don't want to continue running
2558 // while suspended because that would surprise the thread that
2559 // suspended us.
2560 //
2561 ::sem_post(&sig_sem);
2562
2563 thread->java_suspend_self();
2564 }
2565 } while (threadIsSuspended);
2566 }
2567 }
2568
2569 int os::signal_lookup() {
2570 return check_pending_signals(false);
2571 }
2572
2573 int os::signal_wait() {
2574 return check_pending_signals(true);
2575 }
2576
2577 ////////////////////////////////////////////////////////////////////////////////
2578 // Virtual Memory
2579
2580 int os::vm_page_size() {
2581 // Seems redundant as all get out
2582 assert(os::Linux::page_size() != -1, "must call os::init");
2583 return os::Linux::page_size();
2584 }
2585
2586 // Solaris allocates memory by pages.
2587 int os::vm_allocation_granularity() {
2588 assert(os::Linux::page_size() != -1, "must call os::init");
2589 return os::Linux::page_size();
2590 }
2591
2592 // Rationale behind this function:
2593 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2594 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2595 // samples for JITted code. Here we create private executable mapping over the code cache
2596 // and then we can use standard (well, almost, as mapping can change) way to provide
2597 // info for the reporting script by storing timestamp and location of symbol
2598 void linux_wrap_code(char* base, size_t size) {
2599 static volatile jint cnt = 0;
2600
2601 if (!UseOprofile) {
2602 return;
2603 }
2604
2605 char buf[PATH_MAX+1];
2606 int num = Atomic::add(1, &cnt);
2607
2608 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2609 os::get_temp_directory(), os::current_process_id(), num);
2610 unlink(buf);
2611
2612 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2613
2614 if (fd != -1) {
2615 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2616 if (rv != (off_t)-1) {
2617 if (::write(fd, "", 1) == 1) {
2618 mmap(base, size,
2619 PROT_READ|PROT_WRITE|PROT_EXEC,
2620 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2621 }
2622 }
2623 ::close(fd);
2624 unlink(buf);
2625 }
2626 }
2627
2628 static bool recoverable_mmap_error(int err) {
2629 // See if the error is one we can let the caller handle. This
2630 // list of errno values comes from JBS-6843484. I can't find a
2631 // Linux man page that documents this specific set of errno
2632 // values so while this list currently matches Solaris, it may
2633 // change as we gain experience with this failure mode.
2634 switch (err) {
2635 case EBADF:
2636 case EINVAL:
2637 case ENOTSUP:
2638 // let the caller deal with these errors
2639 return true;
2640
2641 default:
2642 // Any remaining errors on this OS can cause our reserved mapping
2643 // to be lost. That can cause confusion where different data
2644 // structures think they have the same memory mapped. The worst
2645 // scenario is if both the VM and a library think they have the
2646 // same memory mapped.
2647 return false;
2648 }
2649 }
2650
2651 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2652 int err) {
2653 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2654 ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2655 strerror(err), err);
2656 }
2657
2658 static void warn_fail_commit_memory(char* addr, size_t size,
2659 size_t alignment_hint, bool exec,
2660 int err) {
2661 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2662 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size,
2663 alignment_hint, exec, strerror(err), err);
2664 }
2665
2666 // NOTE: Linux kernel does not really reserve the pages for us.
2667 // All it does is to check if there are enough free pages
2668 // left at the time of mmap(). This could be a potential
2669 // problem.
2670 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2671 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2672 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2673 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2674 if (res != (uintptr_t) MAP_FAILED) {
2675 if (UseNUMAInterleaving) {
2676 numa_make_global(addr, size);
2677 }
2678 return 0;
2679 }
2680
2681 int err = errno; // save errno from mmap() call above
2682
2683 if (!recoverable_mmap_error(err)) {
2684 warn_fail_commit_memory(addr, size, exec, err);
2685 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2686 }
2687
2688 return err;
2689 }
2690
2691 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2692 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2693 }
2694
2695 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2696 const char* mesg) {
2697 assert(mesg != NULL, "mesg must be specified");
2698 int err = os::Linux::commit_memory_impl(addr, size, exec);
2699 if (err != 0) {
2700 // the caller wants all commit errors to exit with the specified mesg:
2701 warn_fail_commit_memory(addr, size, exec, err);
2702 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2703 }
2704 }
2705
2706 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2707 #ifndef MAP_HUGETLB
2708 #define MAP_HUGETLB 0x40000
2709 #endif
2710
2711 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2712 #ifndef MADV_HUGEPAGE
2713 #define MADV_HUGEPAGE 14
2714 #endif
2715
2716 int os::Linux::commit_memory_impl(char* addr, size_t size,
2717 size_t alignment_hint, bool exec) {
2718 int err = os::Linux::commit_memory_impl(addr, size, exec);
2719 if (err == 0) {
2720 realign_memory(addr, size, alignment_hint);
2721 }
2722 return err;
2723 }
2724
2725 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2726 bool exec) {
2727 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2728 }
2729
2730 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2731 size_t alignment_hint, bool exec,
2732 const char* mesg) {
2733 assert(mesg != NULL, "mesg must be specified");
2734 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2735 if (err != 0) {
2736 // the caller wants all commit errors to exit with the specified mesg:
2737 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2738 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2739 }
2740 }
2741
2742 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2743 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2744 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2745 // be supported or the memory may already be backed by huge pages.
2746 ::madvise(addr, bytes, MADV_HUGEPAGE);
2747 }
2748 }
2749
2750 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2751 // This method works by doing an mmap over an existing mmaping and effectively discarding
2752 // the existing pages. However it won't work for SHM-based large pages that cannot be
2753 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2754 // small pages on top of the SHM segment. This method always works for small pages, so we
2755 // allow that in any case.
2756 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2757 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2758 }
2759 }
2760
2761 void os::numa_make_global(char *addr, size_t bytes) {
2762 Linux::numa_interleave_memory(addr, bytes);
2763 }
2764
2765 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2766 // bind policy to MPOL_PREFERRED for the current thread.
2767 #define USE_MPOL_PREFERRED 0
2768
2769 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2770 // To make NUMA and large pages more robust when both enabled, we need to ease
2771 // the requirements on where the memory should be allocated. MPOL_BIND is the
2772 // default policy and it will force memory to be allocated on the specified
2773 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2774 // the specified node, but will not force it. Using this policy will prevent
2775 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2776 // free large pages.
2777 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2778 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2779 }
2780
2781 bool os::numa_topology_changed() { return false; }
2782
2783 size_t os::numa_get_groups_num() {
2784 int max_node = Linux::numa_max_node();
2785 return max_node > 0 ? max_node + 1 : 1;
2786 }
2787
2788 int os::numa_get_group_id() {
2789 int cpu_id = Linux::sched_getcpu();
2790 if (cpu_id != -1) {
2791 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2792 if (lgrp_id != -1) {
2793 return lgrp_id;
2794 }
2795 }
2796 return 0;
2797 }
2798
2799 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2800 for (size_t i = 0; i < size; i++) {
2801 ids[i] = i;
2802 }
2803 return size;
2804 }
2805
2806 bool os::get_page_info(char *start, page_info* info) {
2807 return false;
2808 }
2809
2810 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2811 return end;
2812 }
2813
2814
2815 int os::Linux::sched_getcpu_syscall(void) {
2816 unsigned int cpu;
2817 int retval = -1;
2818
2819 #if defined(IA32)
2820 # ifndef SYS_getcpu
2821 # define SYS_getcpu 318
2822 # endif
2823 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2824 #elif defined(AMD64)
2825 // Unfortunately we have to bring all these macros here from vsyscall.h
2826 // to be able to compile on old linuxes.
2827 # define __NR_vgetcpu 2
2828 # define VSYSCALL_START (-10UL << 20)
2829 # define VSYSCALL_SIZE 1024
2830 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2831 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2832 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2833 retval = vgetcpu(&cpu, NULL, NULL);
2834 #endif
2835
2836 return (retval == -1) ? retval : cpu;
2837 }
2838
2839 // Something to do with the numa-aware allocator needs these symbols
2840 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2841 extern "C" JNIEXPORT void numa_error(char *where) { }
2842 extern "C" JNIEXPORT int fork1() { return fork(); }
2843
2844
2845 // If we are running with libnuma version > 2, then we should
2846 // be trying to use symbols with versions 1.1
2847 // If we are running with earlier version, which did not have symbol versions,
2848 // we should use the base version.
2849 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2850 void *f = dlvsym(handle, name, "libnuma_1.1");
2851 if (f == NULL) {
2852 f = dlsym(handle, name);
2853 }
2854 return f;
2855 }
2856
2857 bool os::Linux::libnuma_init() {
2858 // sched_getcpu() should be in libc.
2859 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2860 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2861
2862 // If it's not, try a direct syscall.
2863 if (sched_getcpu() == -1)
2864 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2865
2866 if (sched_getcpu() != -1) { // Does it work?
2867 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2868 if (handle != NULL) {
2869 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2870 libnuma_dlsym(handle, "numa_node_to_cpus")));
2871 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2872 libnuma_dlsym(handle, "numa_max_node")));
2873 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2874 libnuma_dlsym(handle, "numa_available")));
2875 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2876 libnuma_dlsym(handle, "numa_tonode_memory")));
2877 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2878 libnuma_dlsym(handle, "numa_interleave_memory")));
2879 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2880 libnuma_dlsym(handle, "numa_set_bind_policy")));
2881
2882
2883 if (numa_available() != -1) {
2884 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2885 // Create a cpu -> node mapping
2886 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2887 rebuild_cpu_to_node_map();
2888 return true;
2889 }
2890 }
2891 }
2892 return false;
2893 }
2894
2895 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2896 // The table is later used in get_node_by_cpu().
2897 void os::Linux::rebuild_cpu_to_node_map() {
2898 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2899 // in libnuma (possible values are starting from 16,
2900 // and continuing up with every other power of 2, but less
2901 // than the maximum number of CPUs supported by kernel), and
2902 // is a subject to change (in libnuma version 2 the requirements
2903 // are more reasonable) we'll just hardcode the number they use
2904 // in the library.
2905 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2906
2907 size_t cpu_num = os::active_processor_count();
2908 size_t cpu_map_size = NCPUS / BitsPerCLong;
2909 size_t cpu_map_valid_size =
2910 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2911
2912 cpu_to_node()->clear();
2913 cpu_to_node()->at_grow(cpu_num - 1);
2914 size_t node_num = numa_get_groups_num();
2915
2916 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2917 for (size_t i = 0; i < node_num; i++) {
2918 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2919 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2920 if (cpu_map[j] != 0) {
2921 for (size_t k = 0; k < BitsPerCLong; k++) {
2922 if (cpu_map[j] & (1UL << k)) {
2923 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2924 }
2925 }
2926 }
2927 }
2928 }
2929 }
2930 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
2931 }
2932
2933 int os::Linux::get_node_by_cpu(int cpu_id) {
2934 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2935 return cpu_to_node()->at(cpu_id);
2936 }
2937 return -1;
2938 }
2939
2940 GrowableArray<int>* os::Linux::_cpu_to_node;
2941 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2942 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2943 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2944 os::Linux::numa_available_func_t os::Linux::_numa_available;
2945 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2946 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2947 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2948 unsigned long* os::Linux::_numa_all_nodes;
2949
2950 bool os::pd_uncommit_memory(char* addr, size_t size) {
2951 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2952 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2953 return res != (uintptr_t) MAP_FAILED;
2954 }
2955
2956 static
2957 address get_stack_commited_bottom(address bottom, size_t size) {
2958 address nbot = bottom;
2959 address ntop = bottom + size;
2960
2961 size_t page_sz = os::vm_page_size();
2962 unsigned pages = size / page_sz;
2963
2964 unsigned char vec[1];
2965 unsigned imin = 1, imax = pages + 1, imid;
2966 int mincore_return_value = 0;
2967
2968 assert(imin <= imax, "Unexpected page size");
2969
2970 while (imin < imax) {
2971 imid = (imax + imin) / 2;
2972 nbot = ntop - (imid * page_sz);
2973
2974 // Use a trick with mincore to check whether the page is mapped or not.
2975 // mincore sets vec to 1 if page resides in memory and to 0 if page
2976 // is swapped output but if page we are asking for is unmapped
2977 // it returns -1,ENOMEM
2978 mincore_return_value = mincore(nbot, page_sz, vec);
2979
2980 if (mincore_return_value == -1) {
2981 // Page is not mapped go up
2982 // to find first mapped page
2983 if (errno != EAGAIN) {
2984 assert(errno == ENOMEM, "Unexpected mincore errno");
2985 imax = imid;
2986 }
2987 } else {
2988 // Page is mapped go down
2989 // to find first not mapped page
2990 imin = imid + 1;
2991 }
2992 }
2993
2994 nbot = nbot + page_sz;
2995
2996 // Adjust stack bottom one page up if last checked page is not mapped
2997 if (mincore_return_value == -1) {
2998 nbot = nbot + page_sz;
2999 }
3000
3001 return nbot;
3002 }
3003
3004
3005 // Linux uses a growable mapping for the stack, and if the mapping for
3006 // the stack guard pages is not removed when we detach a thread the
3007 // stack cannot grow beyond the pages where the stack guard was
3008 // mapped. If at some point later in the process the stack expands to
3009 // that point, the Linux kernel cannot expand the stack any further
3010 // because the guard pages are in the way, and a segfault occurs.
3011 //
3012 // However, it's essential not to split the stack region by unmapping
3013 // a region (leaving a hole) that's already part of the stack mapping,
3014 // so if the stack mapping has already grown beyond the guard pages at
3015 // the time we create them, we have to truncate the stack mapping.
3016 // So, we need to know the extent of the stack mapping when
3017 // create_stack_guard_pages() is called.
3018
3019 // We only need this for stacks that are growable: at the time of
3020 // writing thread stacks don't use growable mappings (i.e. those
3021 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3022 // only applies to the main thread.
3023
3024 // If the (growable) stack mapping already extends beyond the point
3025 // where we're going to put our guard pages, truncate the mapping at
3026 // that point by munmap()ping it. This ensures that when we later
3027 // munmap() the guard pages we don't leave a hole in the stack
3028 // mapping. This only affects the main/initial thread
3029
3030 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3031
3032 if (os::Linux::is_initial_thread()) {
3033 // As we manually grow stack up to bottom inside create_attached_thread(),
3034 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3035 // we don't need to do anything special.
3036 // Check it first, before calling heavy function.
3037 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3038 unsigned char vec[1];
3039
3040 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3041 // Fallback to slow path on all errors, including EAGAIN
3042 stack_extent = (uintptr_t) get_stack_commited_bottom(
3043 os::Linux::initial_thread_stack_bottom(),
3044 (size_t)addr - stack_extent);
3045 }
3046
3047 if (stack_extent < (uintptr_t)addr) {
3048 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3049 }
3050 }
3051
3052 return os::commit_memory(addr, size, !ExecMem);
3053 }
3054
3055 // If this is a growable mapping, remove the guard pages entirely by
3056 // munmap()ping them. If not, just call uncommit_memory(). This only
3057 // affects the main/initial thread, but guard against future OS changes
3058 // It's safe to always unmap guard pages for initial thread because we
3059 // always place it right after end of the mapped region
3060
3061 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3062 uintptr_t stack_extent, stack_base;
3063
3064 if (os::Linux::is_initial_thread()) {
3065 return ::munmap(addr, size) == 0;
3066 }
3067
3068 return os::uncommit_memory(addr, size);
3069 }
3070
3071 static address _highest_vm_reserved_address = NULL;
3072
3073 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3074 // at 'requested_addr'. If there are existing memory mappings at the same
3075 // location, however, they will be overwritten. If 'fixed' is false,
3076 // 'requested_addr' is only treated as a hint, the return value may or
3077 // may not start from the requested address. Unlike Linux mmap(), this
3078 // function returns NULL to indicate failure.
3079 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3080 char * addr;
3081 int flags;
3082
3083 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3084 if (fixed) {
3085 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3086 flags |= MAP_FIXED;
3087 }
3088
3089 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3090 // touch an uncommitted page. Otherwise, the read/write might
3091 // succeed if we have enough swap space to back the physical page.
3092 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3093 flags, -1, 0);
3094
3095 if (addr != MAP_FAILED) {
3096 // anon_mmap() should only get called during VM initialization,
3097 // don't need lock (actually we can skip locking even it can be called
3098 // from multiple threads, because _highest_vm_reserved_address is just a
3099 // hint about the upper limit of non-stack memory regions.)
3100 if ((address)addr + bytes > _highest_vm_reserved_address) {
3101 _highest_vm_reserved_address = (address)addr + bytes;
3102 }
3103 }
3104
3105 return addr == MAP_FAILED ? NULL : addr;
3106 }
3107
3108 // Don't update _highest_vm_reserved_address, because there might be memory
3109 // regions above addr + size. If so, releasing a memory region only creates
3110 // a hole in the address space, it doesn't help prevent heap-stack collision.
3111 //
3112 static int anon_munmap(char * addr, size_t size) {
3113 return ::munmap(addr, size) == 0;
3114 }
3115
3116 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3117 size_t alignment_hint) {
3118 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3119 }
3120
3121 bool os::pd_release_memory(char* addr, size_t size) {
3122 return anon_munmap(addr, size);
3123 }
3124
3125 static address highest_vm_reserved_address() {
3126 return _highest_vm_reserved_address;
3127 }
3128
3129 static bool linux_mprotect(char* addr, size_t size, int prot) {
3130 // Linux wants the mprotect address argument to be page aligned.
3131 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3132
3133 // According to SUSv3, mprotect() should only be used with mappings
3134 // established by mmap(), and mmap() always maps whole pages. Unaligned
3135 // 'addr' likely indicates problem in the VM (e.g. trying to change
3136 // protection of malloc'ed or statically allocated memory). Check the
3137 // caller if you hit this assert.
3138 assert(addr == bottom, "sanity check");
3139
3140 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3141 return ::mprotect(bottom, size, prot) == 0;
3142 }
3143
3144 // Set protections specified
3145 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3146 bool is_committed) {
3147 unsigned int p = 0;
3148 switch (prot) {
3149 case MEM_PROT_NONE: p = PROT_NONE; break;
3150 case MEM_PROT_READ: p = PROT_READ; break;
3151 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3152 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3153 default:
3154 ShouldNotReachHere();
3155 }
3156 // is_committed is unused.
3157 return linux_mprotect(addr, bytes, p);
3158 }
3159
3160 bool os::guard_memory(char* addr, size_t size) {
3161 return linux_mprotect(addr, size, PROT_NONE);
3162 }
3163
3164 bool os::unguard_memory(char* addr, size_t size) {
3165 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3166 }
3167
3168 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
3169 bool result = false;
3170 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3171 MAP_ANONYMOUS|MAP_PRIVATE,
3172 -1, 0);
3173 if (p != MAP_FAILED) {
3174 void *aligned_p = align_ptr_up(p, page_size);
3175
3176 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3177
3178 munmap(p, page_size * 2);
3179 }
3180
3181 if (warn && !result) {
3182 warning("TransparentHugePages is not supported by the operating system.");
3183 }
3184
3185 return result;
3186 }
3187
3188 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3189 bool result = false;
3190 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3191 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3192 -1, 0);
3193
3194 if (p != MAP_FAILED) {
3195 // We don't know if this really is a huge page or not.
3196 FILE *fp = fopen("/proc/self/maps", "r");
3197 if (fp) {
3198 while (!feof(fp)) {
3199 char chars[257];
3200 long x = 0;
3201 if (fgets(chars, sizeof(chars), fp)) {
3202 if (sscanf(chars, "%lx-%*x", &x) == 1
3203 && x == (long)p) {
3204 if (strstr (chars, "hugepage")) {
3205 result = true;
3206 break;
3207 }
3208 }
3209 }
3210 }
3211 fclose(fp);
3212 }
3213 munmap(p, page_size);
3214 }
3215
3216 if (warn && !result) {
3217 warning("HugeTLBFS is not supported by the operating system.");
3218 }
3219
3220 return result;
3221 }
3222
3223 /*
3224 * Set the coredump_filter bits to include largepages in core dump (bit 6)
3225 *
3226 * From the coredump_filter documentation:
3227 *
3228 * - (bit 0) anonymous private memory
3229 * - (bit 1) anonymous shared memory
3230 * - (bit 2) file-backed private memory
3231 * - (bit 3) file-backed shared memory
3232 * - (bit 4) ELF header pages in file-backed private memory areas (it is
3233 * effective only if the bit 2 is cleared)
3234 * - (bit 5) hugetlb private memory
3235 * - (bit 6) hugetlb shared memory
3236 */
3237 static void set_coredump_filter(void) {
3238 FILE *f;
3239 long cdm;
3240
3241 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3242 return;
3243 }
3244
3245 if (fscanf(f, "%lx", &cdm) != 1) {
3246 fclose(f);
3247 return;
3248 }
3249
3250 rewind(f);
3251
3252 if ((cdm & LARGEPAGES_BIT) == 0) {
3253 cdm |= LARGEPAGES_BIT;
3254 fprintf(f, "%#lx", cdm);
3255 }
3256
3257 fclose(f);
3258 }
3259
3260 // Large page support
3261
3262 static size_t _large_page_size = 0;
3263
3264 size_t os::Linux::find_large_page_size() {
3265 size_t large_page_size = 0;
3266
3267 // large_page_size on Linux is used to round up heap size. x86 uses either
3268 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3269 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3270 // page as large as 256M.
3271 //
3272 // Here we try to figure out page size by parsing /proc/meminfo and looking
3273 // for a line with the following format:
3274 // Hugepagesize: 2048 kB
3275 //
3276 // If we can't determine the value (e.g. /proc is not mounted, or the text
3277 // format has been changed), we'll use the largest page size supported by
3278 // the processor.
3279
3280 #ifndef ZERO
3281 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3282 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3283 #endif // ZERO
3284
3285 FILE *fp = fopen("/proc/meminfo", "r");
3286 if (fp) {
3287 while (!feof(fp)) {
3288 int x = 0;
3289 char buf[16];
3290 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3291 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3292 large_page_size = x * K;
3293 break;
3294 }
3295 } else {
3296 // skip to next line
3297 for (;;) {
3298 int ch = fgetc(fp);
3299 if (ch == EOF || ch == (int)'\n') break;
3300 }
3301 }
3302 }
3303 fclose(fp);
3304 }
3305
3306 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3307 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3308 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3309 proper_unit_for_byte_size(large_page_size));
3310 }
3311
3312 return large_page_size;
3313 }
3314
3315 size_t os::Linux::setup_large_page_size() {
3316 _large_page_size = Linux::find_large_page_size();
3317 const size_t default_page_size = (size_t)Linux::page_size();
3318 if (_large_page_size > default_page_size) {
3319 _page_sizes[0] = _large_page_size;
3320 _page_sizes[1] = default_page_size;
3321 _page_sizes[2] = 0;
3322 }
3323
3324 return _large_page_size;
3325 }
3326
3327 bool os::Linux::setup_large_page_type(size_t page_size) {
3328 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3329 FLAG_IS_DEFAULT(UseSHM) &&
3330 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3331
3332 // The type of large pages has not been specified by the user.
3333
3334 // Try UseHugeTLBFS and then UseSHM.
3335 UseHugeTLBFS = UseSHM = true;
3336
3337 // Don't try UseTransparentHugePages since there are known
3338 // performance issues with it turned on. This might change in the future.
3339 UseTransparentHugePages = false;
3340 }
3341
3342 if (UseTransparentHugePages) {
3343 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3344 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3345 UseHugeTLBFS = false;
3346 UseSHM = false;
3347 return true;
3348 }
3349 UseTransparentHugePages = false;
3350 }
3351
3352 if (UseHugeTLBFS) {
3353 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3354 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3355 UseSHM = false;
3356 return true;
3357 }
3358 UseHugeTLBFS = false;
3359 }
3360
3361 return UseSHM;
3362 }
3363
3364 void os::large_page_init() {
3365 if (!UseLargePages &&
3366 !UseTransparentHugePages &&
3367 !UseHugeTLBFS &&
3368 !UseSHM) {
3369 // Not using large pages.
3370 return;
3371 }
3372
3373 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3374 // The user explicitly turned off large pages.
3375 // Ignore the rest of the large pages flags.
3376 UseTransparentHugePages = false;
3377 UseHugeTLBFS = false;
3378 UseSHM = false;
3379 return;
3380 }
3381
3382 size_t large_page_size = Linux::setup_large_page_size();
3383 UseLargePages = Linux::setup_large_page_type(large_page_size);
3384
3385 set_coredump_filter();
3386 }
3387
3388 #ifndef SHM_HUGETLB
3389 #define SHM_HUGETLB 04000
3390 #endif
3391
3392 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3393 // "exec" is passed in but not used. Creating the shared image for
3394 // the code cache doesn't have an SHM_X executable permission to check.
3395 assert(UseLargePages && UseSHM, "only for SHM large pages");
3396 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3397
3398 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
3399 return NULL; // Fallback to small pages.
3400 }
3401
3402 key_t key = IPC_PRIVATE;
3403 char *addr;
3404
3405 bool warn_on_failure = UseLargePages &&
3406 (!FLAG_IS_DEFAULT(UseLargePages) ||
3407 !FLAG_IS_DEFAULT(UseSHM) ||
3408 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3409 );
3410 char msg[128];
3411
3412 // Create a large shared memory region to attach to based on size.
3413 // Currently, size is the total size of the heap
3414 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3415 if (shmid == -1) {
3416 // Possible reasons for shmget failure:
3417 // 1. shmmax is too small for Java heap.
3418 // > check shmmax value: cat /proc/sys/kernel/shmmax
3419 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3420 // 2. not enough large page memory.
3421 // > check available large pages: cat /proc/meminfo
3422 // > increase amount of large pages:
3423 // echo new_value > /proc/sys/vm/nr_hugepages
3424 // Note 1: different Linux may use different name for this property,
3425 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3426 // Note 2: it's possible there's enough physical memory available but
3427 // they are so fragmented after a long run that they can't
3428 // coalesce into large pages. Try to reserve large pages when
3429 // the system is still "fresh".
3430 if (warn_on_failure) {
3431 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3432 warning(msg);
3433 }
3434 return NULL;
3435 }
3436
3437 // attach to the region
3438 addr = (char*)shmat(shmid, req_addr, 0);
3439 int err = errno;
3440
3441 // Remove shmid. If shmat() is successful, the actual shared memory segment
3442 // will be deleted when it's detached by shmdt() or when the process
3443 // terminates. If shmat() is not successful this will remove the shared
3444 // segment immediately.
3445 shmctl(shmid, IPC_RMID, NULL);
3446
3447 if ((intptr_t)addr == -1) {
3448 if (warn_on_failure) {
3449 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3450 warning(msg);
3451 }
3452 return NULL;
3453 }
3454
3455 return addr;
3456 }
3457
3458 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
3459 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3460
3461 bool warn_on_failure = UseLargePages &&
3462 (!FLAG_IS_DEFAULT(UseLargePages) ||
3463 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3464 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3465
3466 if (warn_on_failure) {
3467 char msg[128];
3468 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3469 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3470 warning(msg);
3471 }
3472 }
3473
3474 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
3475 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3476 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3477 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3478
3479 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3480 char* addr = (char*)::mmap(req_addr, bytes, prot,
3481 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3482 -1, 0);
3483
3484 if (addr == MAP_FAILED) {
3485 warn_on_large_pages_failure(req_addr, bytes, errno);
3486 return NULL;
3487 }
3488
3489 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3490
3491 return addr;
3492 }
3493
3494 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3495 size_t large_page_size = os::large_page_size();
3496
3497 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3498
3499 // Allocate small pages.
3500
3501 char* start;
3502 if (req_addr != NULL) {
3503 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3504 assert(is_size_aligned(bytes, alignment), "Must be");
3505 start = os::reserve_memory(bytes, req_addr);
3506 assert(start == NULL || start == req_addr, "Must be");
3507 } else {
3508 start = os::reserve_memory_aligned(bytes, alignment);
3509 }
3510
3511 if (start == NULL) {
3512 return NULL;
3513 }
3514
3515 assert(is_ptr_aligned(start, alignment), "Must be");
3516
3517 // os::reserve_memory_special will record this memory area.
3518 // Need to release it here to prevent overlapping reservations.
3519 MemTracker::record_virtual_memory_release((address)start, bytes);
3520
3521 char* end = start + bytes;
3522
3523 // Find the regions of the allocated chunk that can be promoted to large pages.
3524 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3525 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3526
3527 size_t lp_bytes = lp_end - lp_start;
3528
3529 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3530
3531 if (lp_bytes == 0) {
3532 // The mapped region doesn't even span the start and the end of a large page.
3533 // Fall back to allocate a non-special area.
3534 ::munmap(start, end - start);
3535 return NULL;
3536 }
3537
3538 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3539
3540
3541 void* result;
3542
3543 if (start != lp_start) {
3544 result = ::mmap(start, lp_start - start, prot,
3545 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3546 -1, 0);
3547 if (result == MAP_FAILED) {
3548 ::munmap(lp_start, end - lp_start);
3549 return NULL;
3550 }
3551 }
3552
3553 result = ::mmap(lp_start, lp_bytes, prot,
3554 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3555 -1, 0);
3556 if (result == MAP_FAILED) {
3557 warn_on_large_pages_failure(req_addr, bytes, errno);
3558 // If the mmap above fails, the large pages region will be unmapped and we
3559 // have regions before and after with small pages. Release these regions.
3560 //
3561 // | mapped | unmapped | mapped |
3562 // ^ ^ ^ ^
3563 // start lp_start lp_end end
3564 //
3565 ::munmap(start, lp_start - start);
3566 ::munmap(lp_end, end - lp_end);
3567 return NULL;
3568 }
3569
3570 if (lp_end != end) {
3571 result = ::mmap(lp_end, end - lp_end, prot,
3572 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3573 -1, 0);
3574 if (result == MAP_FAILED) {
3575 ::munmap(start, lp_end - start);
3576 return NULL;
3577 }
3578 }
3579
3580 return start;
3581 }
3582
3583 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3584 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3585 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3586 assert(is_power_of_2(alignment), "Must be");
3587 assert(is_power_of_2(os::large_page_size()), "Must be");
3588 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3589
3590 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3591 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3592 } else {
3593 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3594 }
3595 }
3596
3597 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3598 assert(UseLargePages, "only for large pages");
3599
3600 char* addr;
3601 if (UseSHM) {
3602 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3603 } else {
3604 assert(UseHugeTLBFS, "must be");
3605 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3606 }
3607
3608 if (addr != NULL) {
3609 if (UseNUMAInterleaving) {
3610 numa_make_global(addr, bytes);
3611 }
3612
3613 // The memory is committed
3614 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, mtNone, CALLER_PC);
3615 }
3616
3617 return addr;
3618 }
3619
3620 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3621 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3622 return shmdt(base) == 0;
3623 }
3624
3625 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3626 return pd_release_memory(base, bytes);
3627 }
3628
3629 bool os::release_memory_special(char* base, size_t bytes) {
3630 assert(UseLargePages, "only for large pages");
3631
3632 MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3633
3634 bool res;
3635 if (UseSHM) {
3636 res = os::Linux::release_memory_special_shm(base, bytes);
3637 } else {
3638 assert(UseHugeTLBFS, "must be");
3639 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3640 }
3641
3642 if (res) {
3643 tkr.record((address)base, bytes);
3644 } else {
3645 tkr.discard();
3646 }
3647
3648 return res;
3649 }
3650
3651 size_t os::large_page_size() {
3652 return _large_page_size;
3653 }
3654
3655 // With SysV SHM the entire memory region must be allocated as shared
3656 // memory.
3657 // HugeTLBFS allows application to commit large page memory on demand.
3658 // However, when committing memory with HugeTLBFS fails, the region
3659 // that was supposed to be committed will lose the old reservation
3660 // and allow other threads to steal that memory region. Because of this
3661 // behavior we can't commit HugeTLBFS memory.
3662 bool os::can_commit_large_page_memory() {
3663 return UseTransparentHugePages;
3664 }
3665
3666 bool os::can_execute_large_page_memory() {
3667 return UseTransparentHugePages || UseHugeTLBFS;
3668 }
3669
3670 // Reserve memory at an arbitrary address, only if that area is
3671 // available (and not reserved for something else).
3672
3673 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3674 const int max_tries = 10;
3675 char* base[max_tries];
3676 size_t size[max_tries];
3677 const size_t gap = 0x000000;
3678
3679 // Assert only that the size is a multiple of the page size, since
3680 // that's all that mmap requires, and since that's all we really know
3681 // about at this low abstraction level. If we need higher alignment,
3682 // we can either pass an alignment to this method or verify alignment
3683 // in one of the methods further up the call chain. See bug 5044738.
3684 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3685
3686 // Repeatedly allocate blocks until the block is allocated at the
3687 // right spot. Give up after max_tries. Note that reserve_memory() will
3688 // automatically update _highest_vm_reserved_address if the call is
3689 // successful. The variable tracks the highest memory address every reserved
3690 // by JVM. It is used to detect heap-stack collision if running with
3691 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3692 // space than needed, it could confuse the collision detecting code. To
3693 // solve the problem, save current _highest_vm_reserved_address and
3694 // calculate the correct value before return.
3695 address old_highest = _highest_vm_reserved_address;
3696
3697 // Linux mmap allows caller to pass an address as hint; give it a try first,
3698 // if kernel honors the hint then we can return immediately.
3699 char * addr = anon_mmap(requested_addr, bytes, false);
3700 if (addr == requested_addr) {
3701 return requested_addr;
3702 }
3703
3704 if (addr != NULL) {
3705 // mmap() is successful but it fails to reserve at the requested address
3706 anon_munmap(addr, bytes);
3707 }
3708
3709 int i;
3710 for (i = 0; i < max_tries; ++i) {
3711 base[i] = reserve_memory(bytes);
3712
3713 if (base[i] != NULL) {
3714 // Is this the block we wanted?
3715 if (base[i] == requested_addr) {
3716 size[i] = bytes;
3717 break;
3718 }
3719
3720 // Does this overlap the block we wanted? Give back the overlapped
3721 // parts and try again.
3722
3723 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3724 if (top_overlap >= 0 && top_overlap < bytes) {
3725 unmap_memory(base[i], top_overlap);
3726 base[i] += top_overlap;
3727 size[i] = bytes - top_overlap;
3728 } else {
3729 size_t bottom_overlap = base[i] + bytes - requested_addr;
3730 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3731 unmap_memory(requested_addr, bottom_overlap);
3732 size[i] = bytes - bottom_overlap;
3733 } else {
3734 size[i] = bytes;
3735 }
3736 }
3737 }
3738 }
3739
3740 // Give back the unused reserved pieces.
3741
3742 for (int j = 0; j < i; ++j) {
3743 if (base[j] != NULL) {
3744 unmap_memory(base[j], size[j]);
3745 }
3746 }
3747
3748 if (i < max_tries) {
3749 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3750 return requested_addr;
3751 } else {
3752 _highest_vm_reserved_address = old_highest;
3753 return NULL;
3754 }
3755 }
3756
3757 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3758 return ::read(fd, buf, nBytes);
3759 }
3760
3761 //
3762 // Short sleep, direct OS call.
3763 //
3764 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3765 // sched_yield(2) will actually give up the CPU:
3766 //
3767 // * Alone on this pariticular CPU, keeps running.
3768 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3769 // (pre 2.6.39).
3770 //
3771 // So calling this with 0 is an alternative.
3772 //
3773 void os::naked_short_sleep(jlong ms) {
3774 struct timespec req;
3775
3776 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3777 req.tv_sec = 0;
3778 if (ms > 0) {
3779 req.tv_nsec = (ms % 1000) * 1000000;
3780 }
3781 else {
3782 req.tv_nsec = 1;
3783 }
3784
3785 nanosleep(&req, NULL);
3786
3787 return;
3788 }
3789
3790 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3791 void os::infinite_sleep() {
3792 while (true) { // sleep forever ...
3793 ::sleep(100); // ... 100 seconds at a time
3794 }
3795 }
3796
3797 // Used to convert frequent JVM_Yield() to nops
3798 bool os::dont_yield() {
3799 return DontYieldALot;
3800 }
3801
3802 void os::yield() {
3803 sched_yield();
3804 }
3805
3806 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3807
3808 void os::yield_all(int attempts) {
3809 // Yields to all threads, including threads with lower priorities
3810 // Threads on Linux are all with same priority. The Solaris style
3811 // os::yield_all() with nanosleep(1ms) is not necessary.
3812 sched_yield();
3813 }
3814
3815 // Called from the tight loops to possibly influence time-sharing heuristics
3816 void os::loop_breaker(int attempts) {
3817 os::yield_all(attempts);
3818 }
3819
3820 ////////////////////////////////////////////////////////////////////////////////
3821 // thread priority support
3822
3823 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3824 // only supports dynamic priority, static priority must be zero. For real-time
3825 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3826 // However, for large multi-threaded applications, SCHED_RR is not only slower
3827 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3828 // of 5 runs - Sep 2005).
3829 //
3830 // The following code actually changes the niceness of kernel-thread/LWP. It
3831 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3832 // not the entire user process, and user level threads are 1:1 mapped to kernel
3833 // threads. It has always been the case, but could change in the future. For
3834 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3835 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3836
3837 int os::java_to_os_priority[CriticalPriority + 1] = {
3838 19, // 0 Entry should never be used
3839
3840 4, // 1 MinPriority
3841 3, // 2
3842 2, // 3
3843
3844 1, // 4
3845 0, // 5 NormPriority
3846 -1, // 6
3847
3848 -2, // 7
3849 -3, // 8
3850 -4, // 9 NearMaxPriority
3851
3852 -5, // 10 MaxPriority
3853
3854 -5 // 11 CriticalPriority
3855 };
3856
3857 static int prio_init() {
3858 if (ThreadPriorityPolicy == 1) {
3859 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3860 // if effective uid is not root. Perhaps, a more elegant way of doing
3861 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3862 if (geteuid() != 0) {
3863 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3864 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3865 }
3866 ThreadPriorityPolicy = 0;
3867 }
3868 }
3869 if (UseCriticalJavaThreadPriority) {
3870 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3871 }
3872 return 0;
3873 }
3874
3875 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3876 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3877
3878 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3879 return (ret == 0) ? OS_OK : OS_ERR;
3880 }
3881
3882 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3883 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3884 *priority_ptr = java_to_os_priority[NormPriority];
3885 return OS_OK;
3886 }
3887
3888 errno = 0;
3889 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3890 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3891 }
3892
3893 // Hint to the underlying OS that a task switch would not be good.
3894 // Void return because it's a hint and can fail.
3895 void os::hint_no_preempt() {}
3896
3897 ////////////////////////////////////////////////////////////////////////////////
3898 // suspend/resume support
3899
3900 // the low-level signal-based suspend/resume support is a remnant from the
3901 // old VM-suspension that used to be for java-suspension, safepoints etc,
3902 // within hotspot. Now there is a single use-case for this:
3903 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3904 // that runs in the watcher thread.
3905 // The remaining code is greatly simplified from the more general suspension
3906 // code that used to be used.
3907 //
3908 // The protocol is quite simple:
3909 // - suspend:
3910 // - sends a signal to the target thread
3911 // - polls the suspend state of the osthread using a yield loop
3912 // - target thread signal handler (SR_handler) sets suspend state
3913 // and blocks in sigsuspend until continued
3914 // - resume:
3915 // - sets target osthread state to continue
3916 // - sends signal to end the sigsuspend loop in the SR_handler
3917 //
3918 // Note that the SR_lock plays no role in this suspend/resume protocol.
3919 //
3920
3921 static void resume_clear_context(OSThread *osthread) {
3922 osthread->set_ucontext(NULL);
3923 osthread->set_siginfo(NULL);
3924 }
3925
3926 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3927 osthread->set_ucontext(context);
3928 osthread->set_siginfo(siginfo);
3929 }
3930
3931 //
3932 // Handler function invoked when a thread's execution is suspended or
3933 // resumed. We have to be careful that only async-safe functions are
3934 // called here (Note: most pthread functions are not async safe and
3935 // should be avoided.)
3936 //
3937 // Note: sigwait() is a more natural fit than sigsuspend() from an
3938 // interface point of view, but sigwait() prevents the signal hander
3939 // from being run. libpthread would get very confused by not having
3940 // its signal handlers run and prevents sigwait()'s use with the
3941 // mutex granting granting signal.
3942 //
3943 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
3944 //
3945 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3946 // Save and restore errno to avoid confusing native code with EINTR
3947 // after sigsuspend.
3948 int old_errno = errno;
3949
3950 Thread* thread = Thread::current();
3951 OSThread* osthread = thread->osthread();
3952 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
3953
3954 os::SuspendResume::State current = osthread->sr.state();
3955 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
3956 suspend_save_context(osthread, siginfo, context);
3957
3958 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
3959 os::SuspendResume::State state = osthread->sr.suspended();
3960 if (state == os::SuspendResume::SR_SUSPENDED) {
3961 sigset_t suspend_set; // signals for sigsuspend()
3962
3963 // get current set of blocked signals and unblock resume signal
3964 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3965 sigdelset(&suspend_set, SR_signum);
3966
3967 sr_semaphore.signal();
3968 // wait here until we are resumed
3969 while (1) {
3970 sigsuspend(&suspend_set);
3971
3972 os::SuspendResume::State result = osthread->sr.running();
3973 if (result == os::SuspendResume::SR_RUNNING) {
3974 sr_semaphore.signal();
3975 break;
3976 }
3977 }
3978
3979 } else if (state == os::SuspendResume::SR_RUNNING) {
3980 // request was cancelled, continue
3981 } else {
3982 ShouldNotReachHere();
3983 }
3984
3985 resume_clear_context(osthread);
3986 } else if (current == os::SuspendResume::SR_RUNNING) {
3987 // request was cancelled, continue
3988 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
3989 // ignore
3990 } else {
3991 // ignore
3992 }
3993
3994 errno = old_errno;
3995 }
3996
3997
3998 static int SR_initialize() {
3999 struct sigaction act;
4000 char *s;
4001 /* Get signal number to use for suspend/resume */
4002 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4003 int sig = ::strtol(s, 0, 10);
4004 if (sig > 0 || sig < _NSIG) {
4005 SR_signum = sig;
4006 }
4007 }
4008
4009 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4010 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4011
4012 sigemptyset(&SR_sigset);
4013 sigaddset(&SR_sigset, SR_signum);
4014
4015 /* Set up signal handler for suspend/resume */
4016 act.sa_flags = SA_RESTART|SA_SIGINFO;
4017 act.sa_handler = (void (*)(int)) SR_handler;
4018
4019 // SR_signum is blocked by default.
4020 // 4528190 - We also need to block pthread restart signal (32 on all
4021 // supported Linux platforms). Note that LinuxThreads need to block
4022 // this signal for all threads to work properly. So we don't have
4023 // to use hard-coded signal number when setting up the mask.
4024 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4025
4026 if (sigaction(SR_signum, &act, 0) == -1) {
4027 return -1;
4028 }
4029
4030 // Save signal flag
4031 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4032 return 0;
4033 }
4034
4035 static int sr_notify(OSThread* osthread) {
4036 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4037 assert_status(status == 0, status, "pthread_kill");
4038 return status;
4039 }
4040
4041 // "Randomly" selected value for how long we want to spin
4042 // before bailing out on suspending a thread, also how often
4043 // we send a signal to a thread we want to resume
4044 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4045 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4046
4047 // returns true on success and false on error - really an error is fatal
4048 // but this seems the normal response to library errors
4049 static bool do_suspend(OSThread* osthread) {
4050 assert(osthread->sr.is_running(), "thread should be running");
4051 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4052
4053 // mark as suspended and send signal
4054 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4055 // failed to switch, state wasn't running?
4056 ShouldNotReachHere();
4057 return false;
4058 }
4059
4060 if (sr_notify(osthread) != 0) {
4061 ShouldNotReachHere();
4062 }
4063
4064 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4065 while (true) {
4066 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4067 break;
4068 } else {
4069 // timeout
4070 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4071 if (cancelled == os::SuspendResume::SR_RUNNING) {
4072 return false;
4073 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4074 // make sure that we consume the signal on the semaphore as well
4075 sr_semaphore.wait();
4076 break;
4077 } else {
4078 ShouldNotReachHere();
4079 return false;
4080 }
4081 }
4082 }
4083
4084 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4085 return true;
4086 }
4087
4088 static void do_resume(OSThread* osthread) {
4089 assert(osthread->sr.is_suspended(), "thread should be suspended");
4090 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4091
4092 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4093 // failed to switch to WAKEUP_REQUEST
4094 ShouldNotReachHere();
4095 return;
4096 }
4097
4098 while (true) {
4099 if (sr_notify(osthread) == 0) {
4100 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4101 if (osthread->sr.is_running()) {
4102 return;
4103 }
4104 }
4105 } else {
4106 ShouldNotReachHere();
4107 }
4108 }
4109
4110 guarantee(osthread->sr.is_running(), "Must be running!");
4111 }
4112
4113 ///////////////////////////////////////////////////////////////////////////////////
4114 // signal handling (except suspend/resume)
4115
4116 // This routine may be used by user applications as a "hook" to catch signals.
4117 // The user-defined signal handler must pass unrecognized signals to this
4118 // routine, and if it returns true (non-zero), then the signal handler must
4119 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4120 // routine will never retun false (zero), but instead will execute a VM panic
4121 // routine kill the process.
4122 //
4123 // If this routine returns false, it is OK to call it again. This allows
4124 // the user-defined signal handler to perform checks either before or after
4125 // the VM performs its own checks. Naturally, the user code would be making
4126 // a serious error if it tried to handle an exception (such as a null check
4127 // or breakpoint) that the VM was generating for its own correct operation.
4128 //
4129 // This routine may recognize any of the following kinds of signals:
4130 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4131 // It should be consulted by handlers for any of those signals.
4132 //
4133 // The caller of this routine must pass in the three arguments supplied
4134 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4135 // field of the structure passed to sigaction(). This routine assumes that
4136 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4137 //
4138 // Note that the VM will print warnings if it detects conflicting signal
4139 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4140 //
4141 extern "C" JNIEXPORT int
4142 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
4143 void* ucontext, int abort_if_unrecognized);
4144
4145 void signalHandler(int sig, siginfo_t* info, void* uc) {
4146 assert(info != NULL && uc != NULL, "it must be old kernel");
4147 int orig_errno = errno; // Preserve errno value over signal handler.
4148 JVM_handle_linux_signal(sig, info, uc, true);
4149 errno = orig_errno;
4150 }
4151
4152
4153 // This boolean allows users to forward their own non-matching signals
4154 // to JVM_handle_linux_signal, harmlessly.
4155 bool os::Linux::signal_handlers_are_installed = false;
4156
4157 // For signal-chaining
4158 struct sigaction os::Linux::sigact[MAXSIGNUM];
4159 unsigned int os::Linux::sigs = 0;
4160 bool os::Linux::libjsig_is_loaded = false;
4161 typedef struct sigaction *(*get_signal_t)(int);
4162 get_signal_t os::Linux::get_signal_action = NULL;
4163
4164 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4165 struct sigaction *actp = NULL;
4166
4167 if (libjsig_is_loaded) {
4168 // Retrieve the old signal handler from libjsig
4169 actp = (*get_signal_action)(sig);
4170 }
4171 if (actp == NULL) {
4172 // Retrieve the preinstalled signal handler from jvm
4173 actp = get_preinstalled_handler(sig);
4174 }
4175
4176 return actp;
4177 }
4178
4179 static bool call_chained_handler(struct sigaction *actp, int sig,
4180 siginfo_t *siginfo, void *context) {
4181 // Call the old signal handler
4182 if (actp->sa_handler == SIG_DFL) {
4183 // It's more reasonable to let jvm treat it as an unexpected exception
4184 // instead of taking the default action.
4185 return false;
4186 } else if (actp->sa_handler != SIG_IGN) {
4187 if ((actp->sa_flags & SA_NODEFER) == 0) {
4188 // automaticlly block the signal
4189 sigaddset(&(actp->sa_mask), sig);
4190 }
4191
4192 sa_handler_t hand;
4193 sa_sigaction_t sa;
4194 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4195 // retrieve the chained handler
4196 if (siginfo_flag_set) {
4197 sa = actp->sa_sigaction;
4198 } else {
4199 hand = actp->sa_handler;
4200 }
4201
4202 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4203 actp->sa_handler = SIG_DFL;
4204 }
4205
4206 // try to honor the signal mask
4207 sigset_t oset;
4208 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4209
4210 // call into the chained handler
4211 if (siginfo_flag_set) {
4212 (*sa)(sig, siginfo, context);
4213 } else {
4214 (*hand)(sig);
4215 }
4216
4217 // restore the signal mask
4218 pthread_sigmask(SIG_SETMASK, &oset, 0);
4219 }
4220 // Tell jvm's signal handler the signal is taken care of.
4221 return true;
4222 }
4223
4224 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4225 bool chained = false;
4226 // signal-chaining
4227 if (UseSignalChaining) {
4228 struct sigaction *actp = get_chained_signal_action(sig);
4229 if (actp != NULL) {
4230 chained = call_chained_handler(actp, sig, siginfo, context);
4231 }
4232 }
4233 return chained;
4234 }
4235
4236 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4237 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
4238 return &sigact[sig];
4239 }
4240 return NULL;
4241 }
4242
4243 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4244 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4245 sigact[sig] = oldAct;
4246 sigs |= (unsigned int)1 << sig;
4247 }
4248
4249 // for diagnostic
4250 int os::Linux::sigflags[MAXSIGNUM];
4251
4252 int os::Linux::get_our_sigflags(int sig) {
4253 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4254 return sigflags[sig];
4255 }
4256
4257 void os::Linux::set_our_sigflags(int sig, int flags) {
4258 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4259 sigflags[sig] = flags;
4260 }
4261
4262 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4263 // Check for overwrite.
4264 struct sigaction oldAct;
4265 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4266
4267 void* oldhand = oldAct.sa_sigaction
4268 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4269 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4270 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4271 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4272 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4273 if (AllowUserSignalHandlers || !set_installed) {
4274 // Do not overwrite; user takes responsibility to forward to us.
4275 return;
4276 } else if (UseSignalChaining) {
4277 // save the old handler in jvm
4278 save_preinstalled_handler(sig, oldAct);
4279 // libjsig also interposes the sigaction() call below and saves the
4280 // old sigaction on it own.
4281 } else {
4282 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
4283 "%#lx for signal %d.", (long)oldhand, sig));
4284 }
4285 }
4286
4287 struct sigaction sigAct;
4288 sigfillset(&(sigAct.sa_mask));
4289 sigAct.sa_handler = SIG_DFL;
4290 if (!set_installed) {
4291 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4292 } else {
4293 sigAct.sa_sigaction = signalHandler;
4294 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4295 }
4296 // Save flags, which are set by ours
4297 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4298 sigflags[sig] = sigAct.sa_flags;
4299
4300 int ret = sigaction(sig, &sigAct, &oldAct);
4301 assert(ret == 0, "check");
4302
4303 void* oldhand2 = oldAct.sa_sigaction
4304 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4305 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4306 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4307 }
4308
4309 // install signal handlers for signals that HotSpot needs to
4310 // handle in order to support Java-level exception handling.
4311
4312 void os::Linux::install_signal_handlers() {
4313 if (!signal_handlers_are_installed) {
4314 signal_handlers_are_installed = true;
4315
4316 // signal-chaining
4317 typedef void (*signal_setting_t)();
4318 signal_setting_t begin_signal_setting = NULL;
4319 signal_setting_t end_signal_setting = NULL;
4320 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4321 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4322 if (begin_signal_setting != NULL) {
4323 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4324 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4325 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4326 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4327 libjsig_is_loaded = true;
4328 assert(UseSignalChaining, "should enable signal-chaining");
4329 }
4330 if (libjsig_is_loaded) {
4331 // Tell libjsig jvm is setting signal handlers
4332 (*begin_signal_setting)();
4333 }
4334
4335 set_signal_handler(SIGSEGV, true);
4336 set_signal_handler(SIGPIPE, true);
4337 set_signal_handler(SIGBUS, true);
4338 set_signal_handler(SIGILL, true);
4339 set_signal_handler(SIGFPE, true);
4340 #if defined(PPC64)
4341 set_signal_handler(SIGTRAP, true);
4342 #endif
4343 set_signal_handler(SIGXFSZ, true);
4344
4345 if (libjsig_is_loaded) {
4346 // Tell libjsig jvm finishes setting signal handlers
4347 (*end_signal_setting)();
4348 }
4349
4350 // We don't activate signal checker if libjsig is in place, we trust ourselves
4351 // and if UserSignalHandler is installed all bets are off.
4352 // Log that signal checking is off only if -verbose:jni is specified.
4353 if (CheckJNICalls) {
4354 if (libjsig_is_loaded) {
4355 if (PrintJNIResolving) {
4356 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4357 }
4358 check_signals = false;
4359 }
4360 if (AllowUserSignalHandlers) {
4361 if (PrintJNIResolving) {
4362 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4363 }
4364 check_signals = false;
4365 }
4366 }
4367 }
4368 }
4369
4370 // This is the fastest way to get thread cpu time on Linux.
4371 // Returns cpu time (user+sys) for any thread, not only for current.
4372 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4373 // It might work on 2.6.10+ with a special kernel/glibc patch.
4374 // For reference, please, see IEEE Std 1003.1-2004:
4375 // http://www.unix.org/single_unix_specification
4376
4377 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4378 struct timespec tp;
4379 int rc = os::Linux::clock_gettime(clockid, &tp);
4380 assert(rc == 0, "clock_gettime is expected to return 0 code");
4381
4382 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4383 }
4384
4385 /////
4386 // glibc on Linux platform uses non-documented flag
4387 // to indicate, that some special sort of signal
4388 // trampoline is used.
4389 // We will never set this flag, and we should
4390 // ignore this flag in our diagnostic
4391 #ifdef SIGNIFICANT_SIGNAL_MASK
4392 #undef SIGNIFICANT_SIGNAL_MASK
4393 #endif
4394 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4395
4396 static const char* get_signal_handler_name(address handler,
4397 char* buf, int buflen) {
4398 int offset;
4399 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4400 if (found) {
4401 // skip directory names
4402 const char *p1, *p2;
4403 p1 = buf;
4404 size_t len = strlen(os::file_separator());
4405 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4406 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4407 } else {
4408 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4409 }
4410 return buf;
4411 }
4412
4413 static void print_signal_handler(outputStream* st, int sig,
4414 char* buf, size_t buflen) {
4415 struct sigaction sa;
4416
4417 sigaction(sig, NULL, &sa);
4418
4419 // See comment for SIGNIFICANT_SIGNAL_MASK define
4420 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4421
4422 st->print("%s: ", os::exception_name(sig, buf, buflen));
4423
4424 address handler = (sa.sa_flags & SA_SIGINFO)
4425 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4426 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4427
4428 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4429 st->print("SIG_DFL");
4430 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4431 st->print("SIG_IGN");
4432 } else {
4433 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4434 }
4435
4436 st->print(", sa_mask[0]=");
4437 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4438
4439 address rh = VMError::get_resetted_sighandler(sig);
4440 // May be, handler was resetted by VMError?
4441 if(rh != NULL) {
4442 handler = rh;
4443 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4444 }
4445
4446 st->print(", sa_flags=");
4447 os::Posix::print_sa_flags(st, sa.sa_flags);
4448
4449 // Check: is it our handler?
4450 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4451 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4452 // It is our signal handler
4453 // check for flags, reset system-used one!
4454 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4455 st->print(
4456 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4457 os::Linux::get_our_sigflags(sig));
4458 }
4459 }
4460 st->cr();
4461 }
4462
4463
4464 #define DO_SIGNAL_CHECK(sig) \
4465 if (!sigismember(&check_signal_done, sig)) \
4466 os::Linux::check_signal_handler(sig)
4467
4468 // This method is a periodic task to check for misbehaving JNI applications
4469 // under CheckJNI, we can add any periodic checks here
4470
4471 void os::run_periodic_checks() {
4472
4473 if (check_signals == false) return;
4474
4475 // SEGV and BUS if overridden could potentially prevent
4476 // generation of hs*.log in the event of a crash, debugging
4477 // such a case can be very challenging, so we absolutely
4478 // check the following for a good measure:
4479 DO_SIGNAL_CHECK(SIGSEGV);
4480 DO_SIGNAL_CHECK(SIGILL);
4481 DO_SIGNAL_CHECK(SIGFPE);
4482 DO_SIGNAL_CHECK(SIGBUS);
4483 DO_SIGNAL_CHECK(SIGPIPE);
4484 DO_SIGNAL_CHECK(SIGXFSZ);
4485 #if defined(PPC64)
4486 DO_SIGNAL_CHECK(SIGTRAP);
4487 #endif
4488
4489 // ReduceSignalUsage allows the user to override these handlers
4490 // see comments at the very top and jvm_solaris.h
4491 if (!ReduceSignalUsage) {
4492 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4493 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4494 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4495 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4496 }
4497
4498 DO_SIGNAL_CHECK(SR_signum);
4499 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4500 }
4501
4502 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4503
4504 static os_sigaction_t os_sigaction = NULL;
4505
4506 void os::Linux::check_signal_handler(int sig) {
4507 char buf[O_BUFLEN];
4508 address jvmHandler = NULL;
4509
4510
4511 struct sigaction act;
4512 if (os_sigaction == NULL) {
4513 // only trust the default sigaction, in case it has been interposed
4514 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4515 if (os_sigaction == NULL) return;
4516 }
4517
4518 os_sigaction(sig, (struct sigaction*)NULL, &act);
4519
4520
4521 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4522
4523 address thisHandler = (act.sa_flags & SA_SIGINFO)
4524 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4525 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4526
4527
4528 switch(sig) {
4529 case SIGSEGV:
4530 case SIGBUS:
4531 case SIGFPE:
4532 case SIGPIPE:
4533 case SIGILL:
4534 case SIGXFSZ:
4535 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4536 break;
4537
4538 case SHUTDOWN1_SIGNAL:
4539 case SHUTDOWN2_SIGNAL:
4540 case SHUTDOWN3_SIGNAL:
4541 case BREAK_SIGNAL:
4542 jvmHandler = (address)user_handler();
4543 break;
4544
4545 case INTERRUPT_SIGNAL:
4546 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4547 break;
4548
4549 default:
4550 if (sig == SR_signum) {
4551 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4552 } else {
4553 return;
4554 }
4555 break;
4556 }
4557
4558 if (thisHandler != jvmHandler) {
4559 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4560 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4561 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4562 // No need to check this sig any longer
4563 sigaddset(&check_signal_done, sig);
4564 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4565 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4566 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4567 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4568 // No need to check this sig any longer
4569 sigaddset(&check_signal_done, sig);
4570 }
4571
4572 // Dump all the signal
4573 if (sigismember(&check_signal_done, sig)) {
4574 print_signal_handlers(tty, buf, O_BUFLEN);
4575 }
4576 }
4577
4578 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4579
4580 extern bool signal_name(int signo, char* buf, size_t len);
4581
4582 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4583 if (0 < exception_code && exception_code <= SIGRTMAX) {
4584 // signal
4585 if (!signal_name(exception_code, buf, size)) {
4586 jio_snprintf(buf, size, "SIG%d", exception_code);
4587 }
4588 return buf;
4589 } else {
4590 return NULL;
4591 }
4592 }
4593
4594 // this is called _before_ the most of global arguments have been parsed
4595 void os::init(void) {
4596 char dummy; /* used to get a guess on initial stack address */
4597 // first_hrtime = gethrtime();
4598
4599 // With LinuxThreads the JavaMain thread pid (primordial thread)
4600 // is different than the pid of the java launcher thread.
4601 // So, on Linux, the launcher thread pid is passed to the VM
4602 // via the sun.java.launcher.pid property.
4603 // Use this property instead of getpid() if it was correctly passed.
4604 // See bug 6351349.
4605 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4606
4607 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4608
4609 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4610
4611 init_random(1234567);
4612
4613 ThreadCritical::initialize();
4614
4615 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4616 if (Linux::page_size() == -1) {
4617 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4618 strerror(errno)));
4619 }
4620 init_page_sizes((size_t) Linux::page_size());
4621
4622 Linux::initialize_system_info();
4623
4624 // main_thread points to the aboriginal thread
4625 Linux::_main_thread = pthread_self();
4626
4627 Linux::clock_init();
4628 initial_time_count = javaTimeNanos();
4629
4630 // pthread_condattr initialization for monotonic clock
4631 int status;
4632 pthread_condattr_t* _condattr = os::Linux::condAttr();
4633 if ((status = pthread_condattr_init(_condattr)) != 0) {
4634 fatal(err_msg("pthread_condattr_init: %s", strerror(status)));
4635 }
4636 // Only set the clock if CLOCK_MONOTONIC is available
4637 if (os::supports_monotonic_clock()) {
4638 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4639 if (status == EINVAL) {
4640 warning("Unable to use monotonic clock with relative timed-waits" \
4641 " - changes to the time-of-day clock may have adverse affects");
4642 } else {
4643 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status)));
4644 }
4645 }
4646 }
4647 // else it defaults to CLOCK_REALTIME
4648
4649 pthread_mutex_init(&dl_mutex, NULL);
4650
4651 // If the pagesize of the VM is greater than 8K determine the appropriate
4652 // number of initial guard pages. The user can change this with the
4653 // command line arguments, if needed.
4654 if (vm_page_size() > (int)Linux::vm_default_page_size()) {
4655 StackYellowPages = 1;
4656 StackRedPages = 1;
4657 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size();
4658 }
4659 }
4660
4661 // To install functions for atexit system call
4662 extern "C" {
4663 static void perfMemory_exit_helper() {
4664 perfMemory_exit();
4665 }
4666 }
4667
4668 // this is called _after_ the global arguments have been parsed
4669 jint os::init_2(void)
4670 {
4671 Linux::fast_thread_clock_init();
4672
4673 // Allocate a single page and mark it as readable for safepoint polling
4674 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4675 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4676
4677 os::set_polling_page( polling_page );
4678
4679 #ifndef PRODUCT
4680 if(Verbose && PrintMiscellaneous)
4681 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4682 #endif
4683
4684 if (!UseMembar) {
4685 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4686 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4687 os::set_memory_serialize_page( mem_serialize_page );
4688
4689 #ifndef PRODUCT
4690 if(Verbose && PrintMiscellaneous)
4691 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4692 #endif
4693 }
4694
4695 // initialize suspend/resume support - must do this before signal_sets_init()
4696 if (SR_initialize() != 0) {
4697 perror("SR_initialize failed");
4698 return JNI_ERR;
4699 }
4700
4701 Linux::signal_sets_init();
4702 Linux::install_signal_handlers();
4703
4704 // Check minimum allowable stack size for thread creation and to initialize
4705 // the java system classes, including StackOverflowError - depends on page
4706 // size. Add a page for compiler2 recursion in main thread.
4707 // Add in 2*BytesPerWord times page size to account for VM stack during
4708 // class initialization depending on 32 or 64 bit VM.
4709 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4710 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() +
4711 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
4712
4713 size_t threadStackSizeInBytes = ThreadStackSize * K;
4714 if (threadStackSizeInBytes != 0 &&
4715 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4716 tty->print_cr("\nThe stack size specified is too small, "
4717 "Specify at least %dk",
4718 os::Linux::min_stack_allowed/ K);
4719 return JNI_ERR;
4720 }
4721
4722 // Make the stack size a multiple of the page size so that
4723 // the yellow/red zones can be guarded.
4724 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4725 vm_page_size()));
4726
4727 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4728
4729 #if defined(IA32)
4730 workaround_expand_exec_shield_cs_limit();
4731 #endif
4732
4733 Linux::libpthread_init();
4734 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4735 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4736 Linux::glibc_version(), Linux::libpthread_version(),
4737 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4738 }
4739
4740 if (UseNUMA) {
4741 if (!Linux::libnuma_init()) {
4742 UseNUMA = false;
4743 } else {
4744 if ((Linux::numa_max_node() < 1)) {
4745 // There's only one node(they start from 0), disable NUMA.
4746 UseNUMA = false;
4747 }
4748 }
4749 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4750 // we can make the adaptive lgrp chunk resizing work. If the user specified
4751 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4752 // disable adaptive resizing.
4753 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4754 if (FLAG_IS_DEFAULT(UseNUMA)) {
4755 UseNUMA = false;
4756 } else {
4757 if (FLAG_IS_DEFAULT(UseLargePages) &&
4758 FLAG_IS_DEFAULT(UseSHM) &&
4759 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4760 UseLargePages = false;
4761 } else {
4762 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
4763 UseAdaptiveSizePolicy = false;
4764 UseAdaptiveNUMAChunkSizing = false;
4765 }
4766 }
4767 }
4768 if (!UseNUMA && ForceNUMA) {
4769 UseNUMA = true;
4770 }
4771 }
4772
4773 if (MaxFDLimit) {
4774 // set the number of file descriptors to max. print out error
4775 // if getrlimit/setrlimit fails but continue regardless.
4776 struct rlimit nbr_files;
4777 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4778 if (status != 0) {
4779 if (PrintMiscellaneous && (Verbose || WizardMode))
4780 perror("os::init_2 getrlimit failed");
4781 } else {
4782 nbr_files.rlim_cur = nbr_files.rlim_max;
4783 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4784 if (status != 0) {
4785 if (PrintMiscellaneous && (Verbose || WizardMode))
4786 perror("os::init_2 setrlimit failed");
4787 }
4788 }
4789 }
4790
4791 // Initialize lock used to serialize thread creation (see os::create_thread)
4792 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4793
4794 // at-exit methods are called in the reverse order of their registration.
4795 // atexit functions are called on return from main or as a result of a
4796 // call to exit(3C). There can be only 32 of these functions registered
4797 // and atexit() does not set errno.
4798
4799 if (PerfAllowAtExitRegistration) {
4800 // only register atexit functions if PerfAllowAtExitRegistration is set.
4801 // atexit functions can be delayed until process exit time, which
4802 // can be problematic for embedded VM situations. Embedded VMs should
4803 // call DestroyJavaVM() to assure that VM resources are released.
4804
4805 // note: perfMemory_exit_helper atexit function may be removed in
4806 // the future if the appropriate cleanup code can be added to the
4807 // VM_Exit VMOperation's doit method.
4808 if (atexit(perfMemory_exit_helper) != 0) {
4809 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4810 }
4811 }
4812
4813 // initialize thread priority policy
4814 prio_init();
4815
4816 return JNI_OK;
4817 }
4818
4819 // this is called at the end of vm_initialization
4820 void os::init_3(void) {
4821 #ifdef JAVASE_EMBEDDED
4822 // Start the MemNotifyThread
4823 if (LowMemoryProtection) {
4824 MemNotifyThread::start();
4825 }
4826 return;
4827 #endif
4828 }
4829
4830 // Mark the polling page as unreadable
4831 void os::make_polling_page_unreadable(void) {
4832 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4833 fatal("Could not disable polling page");
4834 };
4835
4836 // Mark the polling page as readable
4837 void os::make_polling_page_readable(void) {
4838 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4839 fatal("Could not enable polling page");
4840 }
4841 };
4842
4843 int os::active_processor_count() {
4844 // Linux doesn't yet have a (official) notion of processor sets,
4845 // so just return the number of online processors.
4846 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4847 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4848 return online_cpus;
4849 }
4850
4851 void os::set_native_thread_name(const char *name) {
4852 // Not yet implemented.
4853 return;
4854 }
4855
4856 bool os::distribute_processes(uint length, uint* distribution) {
4857 // Not yet implemented.
4858 return false;
4859 }
4860
4861 bool os::bind_to_processor(uint processor_id) {
4862 // Not yet implemented.
4863 return false;
4864 }
4865
4866 ///
4867
4868 void os::SuspendedThreadTask::internal_do_task() {
4869 if (do_suspend(_thread->osthread())) {
4870 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
4871 do_task(context);
4872 do_resume(_thread->osthread());
4873 }
4874 }
4875
4876 class PcFetcher : public os::SuspendedThreadTask {
4877 public:
4878 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
4879 ExtendedPC result();
4880 protected:
4881 void do_task(const os::SuspendedThreadTaskContext& context);
4882 private:
4883 ExtendedPC _epc;
4884 };
4885
4886 ExtendedPC PcFetcher::result() {
4887 guarantee(is_done(), "task is not done yet.");
4888 return _epc;
4889 }
4890
4891 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
4892 Thread* thread = context.thread();
4893 OSThread* osthread = thread->osthread();
4894 if (osthread->ucontext() != NULL) {
4895 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext());
4896 } else {
4897 // NULL context is unexpected, double-check this is the VMThread
4898 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4899 }
4900 }
4901
4902 // Suspends the target using the signal mechanism and then grabs the PC before
4903 // resuming the target. Used by the flat-profiler only
4904 ExtendedPC os::get_thread_pc(Thread* thread) {
4905 // Make sure that it is called by the watcher for the VMThread
4906 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4907 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4908
4909 PcFetcher fetcher(thread);
4910 fetcher.run();
4911 return fetcher.result();
4912 }
4913
4914 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4915 {
4916 if (is_NPTL()) {
4917 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4918 } else {
4919 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4920 // word back to default 64bit precision if condvar is signaled. Java
4921 // wants 53bit precision. Save and restore current value.
4922 int fpu = get_fpu_control_word();
4923 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4924 set_fpu_control_word(fpu);
4925 return status;
4926 }
4927 }
4928
4929 ////////////////////////////////////////////////////////////////////////////////
4930 // debug support
4931
4932 bool os::find(address addr, outputStream* st) {
4933 Dl_info dlinfo;
4934 memset(&dlinfo, 0, sizeof(dlinfo));
4935 if (dladdr(addr, &dlinfo) != 0) {
4936 st->print(PTR_FORMAT ": ", addr);
4937 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
4938 st->print("%s+%#x", dlinfo.dli_sname,
4939 addr - (intptr_t)dlinfo.dli_saddr);
4940 } else if (dlinfo.dli_fbase != NULL) {
4941 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4942 } else {
4943 st->print("<absolute address>");
4944 }
4945 if (dlinfo.dli_fname != NULL) {
4946 st->print(" in %s", dlinfo.dli_fname);
4947 }
4948 if (dlinfo.dli_fbase != NULL) {
4949 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4950 }
4951 st->cr();
4952
4953 if (Verbose) {
4954 // decode some bytes around the PC
4955 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
4956 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
4957 address lowest = (address) dlinfo.dli_sname;
4958 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4959 if (begin < lowest) begin = lowest;
4960 Dl_info dlinfo2;
4961 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
4962 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4963 end = (address) dlinfo2.dli_saddr;
4964 Disassembler::decode(begin, end, st);
4965 }
4966 return true;
4967 }
4968 return false;
4969 }
4970
4971 ////////////////////////////////////////////////////////////////////////////////
4972 // misc
4973
4974 // This does not do anything on Linux. This is basically a hook for being
4975 // able to use structured exception handling (thread-local exception filters)
4976 // on, e.g., Win32.
4977 void
4978 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4979 JavaCallArguments* args, Thread* thread) {
4980 f(value, method, args, thread);
4981 }
4982
4983 void os::print_statistics() {
4984 }
4985
4986 int os::message_box(const char* title, const char* message) {
4987 int i;
4988 fdStream err(defaultStream::error_fd());
4989 for (i = 0; i < 78; i++) err.print_raw("=");
4990 err.cr();
4991 err.print_raw_cr(title);
4992 for (i = 0; i < 78; i++) err.print_raw("-");
4993 err.cr();
4994 err.print_raw_cr(message);
4995 for (i = 0; i < 78; i++) err.print_raw("=");
4996 err.cr();
4997
4998 char buf[16];
4999 // Prevent process from exiting upon "read error" without consuming all CPU
5000 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5001
5002 return buf[0] == 'y' || buf[0] == 'Y';
5003 }
5004
5005 int os::stat(const char *path, struct stat *sbuf) {
5006 char pathbuf[MAX_PATH];
5007 if (strlen(path) > MAX_PATH - 1) {
5008 errno = ENAMETOOLONG;
5009 return -1;
5010 }
5011 os::native_path(strcpy(pathbuf, path));
5012 return ::stat(pathbuf, sbuf);
5013 }
5014
5015 bool os::check_heap(bool force) {
5016 return true;
5017 }
5018
5019 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
5020 return ::vsnprintf(buf, count, format, args);
5021 }
5022
5023 // Is a (classpath) directory empty?
5024 bool os::dir_is_empty(const char* path) {
5025 DIR *dir = NULL;
5026 struct dirent *ptr;
5027
5028 dir = opendir(path);
5029 if (dir == NULL) return true;
5030
5031 /* Scan the directory */
5032 bool result = true;
5033 char buf[sizeof(struct dirent) + MAX_PATH];
5034 while (result && (ptr = ::readdir(dir)) != NULL) {
5035 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5036 result = false;
5037 }
5038 }
5039 closedir(dir);
5040 return result;
5041 }
5042
5043 // This code originates from JDK's sysOpen and open64_w
5044 // from src/solaris/hpi/src/system_md.c
5045
5046 #ifndef O_DELETE
5047 #define O_DELETE 0x10000
5048 #endif
5049
5050 // Open a file. Unlink the file immediately after open returns
5051 // if the specified oflag has the O_DELETE flag set.
5052 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
5053
5054 int os::open(const char *path, int oflag, int mode) {
5055
5056 if (strlen(path) > MAX_PATH - 1) {
5057 errno = ENAMETOOLONG;
5058 return -1;
5059 }
5060 int fd;
5061 int o_delete = (oflag & O_DELETE);
5062 oflag = oflag & ~O_DELETE;
5063
5064 fd = ::open64(path, oflag, mode);
5065 if (fd == -1) return -1;
5066
5067 //If the open succeeded, the file might still be a directory
5068 {
5069 struct stat64 buf64;
5070 int ret = ::fstat64(fd, &buf64);
5071 int st_mode = buf64.st_mode;
5072
5073 if (ret != -1) {
5074 if ((st_mode & S_IFMT) == S_IFDIR) {
5075 errno = EISDIR;
5076 ::close(fd);
5077 return -1;
5078 }
5079 } else {
5080 ::close(fd);
5081 return -1;
5082 }
5083 }
5084
5085 /*
5086 * All file descriptors that are opened in the JVM and not
5087 * specifically destined for a subprocess should have the
5088 * close-on-exec flag set. If we don't set it, then careless 3rd
5089 * party native code might fork and exec without closing all
5090 * appropriate file descriptors (e.g. as we do in closeDescriptors in
5091 * UNIXProcess.c), and this in turn might:
5092 *
5093 * - cause end-of-file to fail to be detected on some file
5094 * descriptors, resulting in mysterious hangs, or
5095 *
5096 * - might cause an fopen in the subprocess to fail on a system
5097 * suffering from bug 1085341.
5098 *
5099 * (Yes, the default setting of the close-on-exec flag is a Unix
5100 * design flaw)
5101 *
5102 * See:
5103 * 1085341: 32-bit stdio routines should support file descriptors >255
5104 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5105 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5106 */
5107 #ifdef FD_CLOEXEC
5108 {
5109 int flags = ::fcntl(fd, F_GETFD);
5110 if (flags != -1)
5111 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5112 }
5113 #endif
5114
5115 if (o_delete != 0) {
5116 ::unlink(path);
5117 }
5118 return fd;
5119 }
5120
5121
5122 // create binary file, rewriting existing file if required
5123 int os::create_binary_file(const char* path, bool rewrite_existing) {
5124 int oflags = O_WRONLY | O_CREAT;
5125 if (!rewrite_existing) {
5126 oflags |= O_EXCL;
5127 }
5128 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5129 }
5130
5131 // return current position of file pointer
5132 jlong os::current_file_offset(int fd) {
5133 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5134 }
5135
5136 // move file pointer to the specified offset
5137 jlong os::seek_to_file_offset(int fd, jlong offset) {
5138 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5139 }
5140
5141 // This code originates from JDK's sysAvailable
5142 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5143
5144 int os::available(int fd, jlong *bytes) {
5145 jlong cur, end;
5146 int mode;
5147 struct stat64 buf64;
5148
5149 if (::fstat64(fd, &buf64) >= 0) {
5150 mode = buf64.st_mode;
5151 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5152 /*
5153 * XXX: is the following call interruptible? If so, this might
5154 * need to go through the INTERRUPT_IO() wrapper as for other
5155 * blocking, interruptible calls in this file.
5156 */
5157 int n;
5158 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5159 *bytes = n;
5160 return 1;
5161 }
5162 }
5163 }
5164 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5165 return 0;
5166 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5167 return 0;
5168 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5169 return 0;
5170 }
5171 *bytes = end - cur;
5172 return 1;
5173 }
5174
5175 int os::socket_available(int fd, jint *pbytes) {
5176 // Linux doc says EINTR not returned, unlike Solaris
5177 int ret = ::ioctl(fd, FIONREAD, pbytes);
5178
5179 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
5180 // is expected to return 0 on failure and 1 on success to the jdk.
5181 return (ret < 0) ? 0 : 1;
5182 }
5183
5184 // Map a block of memory.
5185 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5186 char *addr, size_t bytes, bool read_only,
5187 bool allow_exec) {
5188 int prot;
5189 int flags = MAP_PRIVATE;
5190
5191 if (read_only) {
5192 prot = PROT_READ;
5193 } else {
5194 prot = PROT_READ | PROT_WRITE;
5195 }
5196
5197 if (allow_exec) {
5198 prot |= PROT_EXEC;
5199 }
5200
5201 if (addr != NULL) {
5202 flags |= MAP_FIXED;
5203 }
5204
5205 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5206 fd, file_offset);
5207 if (mapped_address == MAP_FAILED) {
5208 return NULL;
5209 }
5210 return mapped_address;
5211 }
5212
5213
5214 // Remap a block of memory.
5215 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5216 char *addr, size_t bytes, bool read_only,
5217 bool allow_exec) {
5218 // same as map_memory() on this OS
5219 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5220 allow_exec);
5221 }
5222
5223
5224 // Unmap a block of memory.
5225 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5226 return munmap(addr, bytes) == 0;
5227 }
5228
5229 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5230
5231 static clockid_t thread_cpu_clockid(Thread* thread) {
5232 pthread_t tid = thread->osthread()->pthread_id();
5233 clockid_t clockid;
5234
5235 // Get thread clockid
5236 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5237 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5238 return clockid;
5239 }
5240
5241 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5242 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5243 // of a thread.
5244 //
5245 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5246 // the fast estimate available on the platform.
5247
5248 jlong os::current_thread_cpu_time() {
5249 if (os::Linux::supports_fast_thread_cpu_time()) {
5250 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5251 } else {
5252 // return user + sys since the cost is the same
5253 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5254 }
5255 }
5256
5257 jlong os::thread_cpu_time(Thread* thread) {
5258 // consistent with what current_thread_cpu_time() returns
5259 if (os::Linux::supports_fast_thread_cpu_time()) {
5260 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5261 } else {
5262 return slow_thread_cpu_time(thread, true /* user + sys */);
5263 }
5264 }
5265
5266 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5267 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5268 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5269 } else {
5270 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5271 }
5272 }
5273
5274 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5275 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5276 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5277 } else {
5278 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5279 }
5280 }
5281
5282 //
5283 // -1 on error.
5284 //
5285
5286 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5287 static bool proc_task_unchecked = true;
5288 pid_t tid = thread->osthread()->thread_id();
5289 char *s;
5290 char stat[2048];
5291 int statlen;
5292 char proc_name[64];
5293 int count;
5294 long sys_time, user_time;
5295 char cdummy;
5296 int idummy;
5297 long ldummy;
5298 FILE *fp;
5299
5300 snprintf(proc_name, 64, "/proc/%d/stat", tid);
5301
5302 // The /proc/<tid>/stat aggregates per-process usage on
5303 // new Linux kernels 2.6+ where NPTL is supported.
5304 // The /proc/self/task/<tid>/stat still has the per-thread usage.
5305 // See bug 6328462.
5306 // There possibly can be cases where there is no directory
5307 // /proc/self/task, so we check its availability.
5308 if (proc_task_unchecked && os::Linux::is_NPTL()) {
5309 // This is executed only once
5310 proc_task_unchecked = false;
5311 fp = fopen("/proc/self/task", "r");
5312 if (fp != NULL) {
5313 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5314 fclose(fp);
5315 }
5316 }
5317
5318 fp = fopen(proc_name, "r");
5319 if ( fp == NULL ) return -1;
5320 statlen = fread(stat, 1, 2047, fp);
5321 stat[statlen] = '\0';
5322 fclose(fp);
5323
5324 // Skip pid and the command string. Note that we could be dealing with
5325 // weird command names, e.g. user could decide to rename java launcher
5326 // to "java 1.4.2 :)", then the stat file would look like
5327 // 1234 (java 1.4.2 :)) R ... ...
5328 // We don't really need to know the command string, just find the last
5329 // occurrence of ")" and then start parsing from there. See bug 4726580.
5330 s = strrchr(stat, ')');
5331 if (s == NULL ) return -1;
5332
5333 // Skip blank chars
5334 do s++; while (isspace(*s));
5335
5336 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5337 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5338 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5339 &user_time, &sys_time);
5340 if ( count != 13 ) return -1;
5341 if (user_sys_cpu_time) {
5342 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5343 } else {
5344 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5345 }
5346 }
5347
5348 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5349 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5350 info_ptr->may_skip_backward = false; // elapsed time not wall time
5351 info_ptr->may_skip_forward = false; // elapsed time not wall time
5352 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5353 }
5354
5355 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5356 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5357 info_ptr->may_skip_backward = false; // elapsed time not wall time
5358 info_ptr->may_skip_forward = false; // elapsed time not wall time
5359 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5360 }
5361
5362 bool os::is_thread_cpu_time_supported() {
5363 return true;
5364 }
5365
5366 // System loadavg support. Returns -1 if load average cannot be obtained.
5367 // Linux doesn't yet have a (official) notion of processor sets,
5368 // so just return the system wide load average.
5369 int os::loadavg(double loadavg[], int nelem) {
5370 return ::getloadavg(loadavg, nelem);
5371 }
5372
5373 void os::pause() {
5374 char filename[MAX_PATH];
5375 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5376 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
5377 } else {
5378 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5379 }
5380
5381 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5382 if (fd != -1) {
5383 struct stat buf;
5384 ::close(fd);
5385 while (::stat(filename, &buf) == 0) {
5386 (void)::poll(NULL, 0, 100);
5387 }
5388 } else {
5389 jio_fprintf(stderr,
5390 "Could not open pause file '%s', continuing immediately.\n", filename);
5391 }
5392 }
5393
5394
5395 // Refer to the comments in os_solaris.cpp park-unpark.
5396 //
5397 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5398 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5399 // For specifics regarding the bug see GLIBC BUGID 261237 :
5400 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5401 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5402 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5403 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5404 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5405 // and monitorenter when we're using 1-0 locking. All those operations may result in
5406 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5407 // of libpthread avoids the problem, but isn't practical.
5408 //
5409 // Possible remedies:
5410 //
5411 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5412 // This is palliative and probabilistic, however. If the thread is preempted
5413 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5414 // than the minimum period may have passed, and the abstime may be stale (in the
5415 // past) resultin in a hang. Using this technique reduces the odds of a hang
5416 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5417 //
5418 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5419 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5420 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5421 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5422 // thread.
5423 //
5424 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5425 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5426 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5427 // This also works well. In fact it avoids kernel-level scalability impediments
5428 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5429 // timers in a graceful fashion.
5430 //
5431 // 4. When the abstime value is in the past it appears that control returns
5432 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5433 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5434 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5435 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5436 // It may be possible to avoid reinitialization by checking the return
5437 // value from pthread_cond_timedwait(). In addition to reinitializing the
5438 // condvar we must establish the invariant that cond_signal() is only called
5439 // within critical sections protected by the adjunct mutex. This prevents
5440 // cond_signal() from "seeing" a condvar that's in the midst of being
5441 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5442 // desirable signal-after-unlock optimization that avoids futile context switching.
5443 //
5444 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5445 // structure when a condvar is used or initialized. cond_destroy() would
5446 // release the helper structure. Our reinitialize-after-timedwait fix
5447 // put excessive stress on malloc/free and locks protecting the c-heap.
5448 //
5449 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5450 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5451 // and only enabling the work-around for vulnerable environments.
5452
5453 // utility to compute the abstime argument to timedwait:
5454 // millis is the relative timeout time
5455 // abstime will be the absolute timeout time
5456 // TODO: replace compute_abstime() with unpackTime()
5457
5458 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5459 if (millis < 0) millis = 0;
5460
5461 jlong seconds = millis / 1000;
5462 millis %= 1000;
5463 if (seconds > 50000000) { // see man cond_timedwait(3T)
5464 seconds = 50000000;
5465 }
5466
5467 if (os::supports_monotonic_clock()) {
5468 struct timespec now;
5469 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5470 assert_status(status == 0, status, "clock_gettime");
5471 abstime->tv_sec = now.tv_sec + seconds;
5472 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5473 if (nanos >= NANOSECS_PER_SEC) {
5474 abstime->tv_sec += 1;
5475 nanos -= NANOSECS_PER_SEC;
5476 }
5477 abstime->tv_nsec = nanos;
5478 } else {
5479 struct timeval now;
5480 int status = gettimeofday(&now, NULL);
5481 assert(status == 0, "gettimeofday");
5482 abstime->tv_sec = now.tv_sec + seconds;
5483 long usec = now.tv_usec + millis * 1000;
5484 if (usec >= 1000000) {
5485 abstime->tv_sec += 1;
5486 usec -= 1000000;
5487 }
5488 abstime->tv_nsec = usec * 1000;
5489 }
5490 return abstime;
5491 }
5492
5493
5494 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5495 // Conceptually TryPark() should be equivalent to park(0).
5496
5497 int os::PlatformEvent::TryPark() {
5498 for (;;) {
5499 const int v = _Event ;
5500 guarantee ((v == 0) || (v == 1), "invariant") ;
5501 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5502 }
5503 }
5504
5505 void os::PlatformEvent::park() { // AKA "down()"
5506 // Invariant: Only the thread associated with the Event/PlatformEvent
5507 // may call park().
5508 // TODO: assert that _Assoc != NULL or _Assoc == Self
5509 int v ;
5510 for (;;) {
5511 v = _Event ;
5512 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5513 }
5514 guarantee (v >= 0, "invariant") ;
5515 if (v == 0) {
5516 // Do this the hard way by blocking ...
5517 int status = pthread_mutex_lock(_mutex);
5518 assert_status(status == 0, status, "mutex_lock");
5519 guarantee (_nParked == 0, "invariant") ;
5520 ++ _nParked ;
5521 while (_Event < 0) {
5522 status = pthread_cond_wait(_cond, _mutex);
5523 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5524 // Treat this the same as if the wait was interrupted
5525 if (status == ETIME) { status = EINTR; }
5526 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5527 }
5528 -- _nParked ;
5529
5530 _Event = 0 ;
5531 status = pthread_mutex_unlock(_mutex);
5532 assert_status(status == 0, status, "mutex_unlock");
5533 // Paranoia to ensure our locked and lock-free paths interact
5534 // correctly with each other.
5535 OrderAccess::fence();
5536 }
5537 guarantee (_Event >= 0, "invariant") ;
5538 }
5539
5540 int os::PlatformEvent::park(jlong millis) {
5541 guarantee (_nParked == 0, "invariant") ;
5542
5543 int v ;
5544 for (;;) {
5545 v = _Event ;
5546 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5547 }
5548 guarantee (v >= 0, "invariant") ;
5549 if (v != 0) return OS_OK ;
5550
5551 // We do this the hard way, by blocking the thread.
5552 // Consider enforcing a minimum timeout value.
5553 struct timespec abst;
5554 compute_abstime(&abst, millis);
5555
5556 int ret = OS_TIMEOUT;
5557 int status = pthread_mutex_lock(_mutex);
5558 assert_status(status == 0, status, "mutex_lock");
5559 guarantee (_nParked == 0, "invariant") ;
5560 ++_nParked ;
5561
5562 // Object.wait(timo) will return because of
5563 // (a) notification
5564 // (b) timeout
5565 // (c) thread.interrupt
5566 //
5567 // Thread.interrupt and object.notify{All} both call Event::set.
5568 // That is, we treat thread.interrupt as a special case of notification.
5569 // The underlying Solaris implementation, cond_timedwait, admits
5570 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5571 // JVM from making those visible to Java code. As such, we must
5572 // filter out spurious wakeups. We assume all ETIME returns are valid.
5573 //
5574 // TODO: properly differentiate simultaneous notify+interrupt.
5575 // In that case, we should propagate the notify to another waiter.
5576
5577 while (_Event < 0) {
5578 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5579 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5580 pthread_cond_destroy (_cond);
5581 pthread_cond_init (_cond, os::Linux::condAttr()) ;
5582 }
5583 assert_status(status == 0 || status == EINTR ||
5584 status == ETIME || status == ETIMEDOUT,
5585 status, "cond_timedwait");
5586 if (!FilterSpuriousWakeups) break ; // previous semantics
5587 if (status == ETIME || status == ETIMEDOUT) break ;
5588 // We consume and ignore EINTR and spurious wakeups.
5589 }
5590 --_nParked ;
5591 if (_Event >= 0) {
5592 ret = OS_OK;
5593 }
5594 _Event = 0 ;
5595 status = pthread_mutex_unlock(_mutex);
5596 assert_status(status == 0, status, "mutex_unlock");
5597 assert (_nParked == 0, "invariant") ;
5598 // Paranoia to ensure our locked and lock-free paths interact
5599 // correctly with each other.
5600 OrderAccess::fence();
5601 return ret;
5602 }
5603
5604 void os::PlatformEvent::unpark() {
5605 // Transitions for _Event:
5606 // 0 :=> 1
5607 // 1 :=> 1
5608 // -1 :=> either 0 or 1; must signal target thread
5609 // That is, we can safely transition _Event from -1 to either
5610 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back
5611 // unpark() calls.
5612 // See also: "Semaphores in Plan 9" by Mullender & Cox
5613 //
5614 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5615 // that it will take two back-to-back park() calls for the owning
5616 // thread to block. This has the benefit of forcing a spurious return
5617 // from the first park() call after an unpark() call which will help
5618 // shake out uses of park() and unpark() without condition variables.
5619
5620 if (Atomic::xchg(1, &_Event) >= 0) return;
5621
5622 // Wait for the thread associated with the event to vacate
5623 int status = pthread_mutex_lock(_mutex);
5624 assert_status(status == 0, status, "mutex_lock");
5625 int AnyWaiters = _nParked;
5626 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5627 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5628 AnyWaiters = 0;
5629 pthread_cond_signal(_cond);
5630 }
5631 status = pthread_mutex_unlock(_mutex);
5632 assert_status(status == 0, status, "mutex_unlock");
5633 if (AnyWaiters != 0) {
5634 status = pthread_cond_signal(_cond);
5635 assert_status(status == 0, status, "cond_signal");
5636 }
5637
5638 // Note that we signal() _after dropping the lock for "immortal" Events.
5639 // This is safe and avoids a common class of futile wakeups. In rare
5640 // circumstances this can cause a thread to return prematurely from
5641 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5642 // simply re-test the condition and re-park itself.
5643 }
5644
5645
5646 // JSR166
5647 // -------------------------------------------------------
5648
5649 /*
5650 * The solaris and linux implementations of park/unpark are fairly
5651 * conservative for now, but can be improved. They currently use a
5652 * mutex/condvar pair, plus a a count.
5653 * Park decrements count if > 0, else does a condvar wait. Unpark
5654 * sets count to 1 and signals condvar. Only one thread ever waits
5655 * on the condvar. Contention seen when trying to park implies that someone
5656 * is unparking you, so don't wait. And spurious returns are fine, so there
5657 * is no need to track notifications.
5658 */
5659
5660 #define MAX_SECS 100000000
5661 /*
5662 * This code is common to linux and solaris and will be moved to a
5663 * common place in dolphin.
5664 *
5665 * The passed in time value is either a relative time in nanoseconds
5666 * or an absolute time in milliseconds. Either way it has to be unpacked
5667 * into suitable seconds and nanoseconds components and stored in the
5668 * given timespec structure.
5669 * Given time is a 64-bit value and the time_t used in the timespec is only
5670 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5671 * overflow if times way in the future are given. Further on Solaris versions
5672 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5673 * number of seconds, in abstime, is less than current_time + 100,000,000.
5674 * As it will be 28 years before "now + 100000000" will overflow we can
5675 * ignore overflow and just impose a hard-limit on seconds using the value
5676 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5677 * years from "now".
5678 */
5679
5680 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5681 assert (time > 0, "convertTime");
5682 time_t max_secs = 0;
5683
5684 if (!os::supports_monotonic_clock() || isAbsolute) {
5685 struct timeval now;
5686 int status = gettimeofday(&now, NULL);
5687 assert(status == 0, "gettimeofday");
5688
5689 max_secs = now.tv_sec + MAX_SECS;
5690
5691 if (isAbsolute) {
5692 jlong secs = time / 1000;
5693 if (secs > max_secs) {
5694 absTime->tv_sec = max_secs;
5695 } else {
5696 absTime->tv_sec = secs;
5697 }
5698 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5699 } else {
5700 jlong secs = time / NANOSECS_PER_SEC;
5701 if (secs >= MAX_SECS) {
5702 absTime->tv_sec = max_secs;
5703 absTime->tv_nsec = 0;
5704 } else {
5705 absTime->tv_sec = now.tv_sec + secs;
5706 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5707 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5708 absTime->tv_nsec -= NANOSECS_PER_SEC;
5709 ++absTime->tv_sec; // note: this must be <= max_secs
5710 }
5711 }
5712 }
5713 } else {
5714 // must be relative using monotonic clock
5715 struct timespec now;
5716 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5717 assert_status(status == 0, status, "clock_gettime");
5718 max_secs = now.tv_sec + MAX_SECS;
5719 jlong secs = time / NANOSECS_PER_SEC;
5720 if (secs >= MAX_SECS) {
5721 absTime->tv_sec = max_secs;
5722 absTime->tv_nsec = 0;
5723 } else {
5724 absTime->tv_sec = now.tv_sec + secs;
5725 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5726 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5727 absTime->tv_nsec -= NANOSECS_PER_SEC;
5728 ++absTime->tv_sec; // note: this must be <= max_secs
5729 }
5730 }
5731 }
5732 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5733 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5734 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5735 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5736 }
5737
5738 /*
5739 * Certain structures, for example Semaphores, are always associated
5740 * with CLOCK_REALTIME derived absolute time representations.
5741 * This helper will yield an absolute realtime representation for the passed
5742 * in relative time. We should be able to use clock_gettime for most
5743 * supported Linux's, but if that is not possible we will fallback to use
5744 * gettimeofday.
5745 *
5746 * utility to compute the abstime argument using CLOCK_REALTIME where possible.
5747 *
5748 * relTime is the relative time in nanoseconds.
5749 * absTime will be the absolute time in seconds and nanoseconds.
5750 */
5751 static void absoluteRealTimeForRelativeTime(timespec* absTime, jlong relTime) {
5752 assert(absTime != NULL, "invariant");
5753 assert(relTime > 0, "invariant");
5754
5755 time_t max_secs = 0;
5756 jlong secs = relTime / NANOSECS_PER_SEC;
5757
5758 if (os::supports_monotonic_clock()) { // check avail of clock_gettime
5759 struct timespec now;
5760 int status = os::Linux::clock_gettime(CLOCK_REALTIME, &now);
5761 assert_status(status == 0, status, "clock_gettime");
5762 max_secs = now.tv_sec + MAX_SECS;
5763 if (secs >= MAX_SECS) {
5764 absTime->tv_sec = max_secs;
5765 absTime->tv_nsec = 0;
5766 } else {
5767 absTime->tv_sec = now.tv_sec + secs;
5768 absTime->tv_nsec = (relTime % NANOSECS_PER_SEC) + now.tv_nsec;
5769 }
5770 } else {
5771 struct timeval now;
5772 int status = gettimeofday(&now, NULL);
5773 assert(status == 0, "gettimeofday");
5774 max_secs = now.tv_sec + MAX_SECS;
5775 if (secs >= MAX_SECS) {
5776 absTime->tv_sec = max_secs;
5777 absTime->tv_nsec = 0;
5778 } else {
5779 absTime->tv_sec = now.tv_sec + secs;
5780 absTime->tv_nsec = (relTime % NANOSECS_PER_SEC) + now.tv_usec*1000;
5781 }
5782 }
5783
5784 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5785 absTime->tv_nsec -= NANOSECS_PER_SEC;
5786 ++absTime->tv_sec; // note: this must be <= max_secs
5787 }
5788
5789 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5790 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5791 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5792 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5793 }
5794
5795 void Parker::park(bool isAbsolute, jlong time) {
5796 // Ideally we'd do something useful while spinning, such
5797 // as calling unpackTime().
5798
5799 // Optional fast-path check:
5800 // Return immediately if a permit is available.
5801 // We depend on Atomic::xchg() having full barrier semantics
5802 // since we are doing a lock-free update to _counter.
5803 if (Atomic::xchg(0, &_counter) > 0) return;
5804
5805 Thread* thread = Thread::current();
5806 assert(thread->is_Java_thread(), "Must be JavaThread");
5807 JavaThread *jt = (JavaThread *)thread;
5808
5809 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5810 // Check interrupt before trying to wait
5811 if (Thread::is_interrupted(thread, false)) {
5812 return;
5813 }
5814
5815 // Next, demultiplex/decode time arguments
5816 timespec absTime;
5817 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5818 return;
5819 }
5820 if (time > 0) {
5821 unpackTime(&absTime, isAbsolute, time);
5822 }
5823
5824
5825 // Enter safepoint region
5826 // Beware of deadlocks such as 6317397.
5827 // The per-thread Parker:: mutex is a classic leaf-lock.
5828 // In particular a thread must never block on the Threads_lock while
5829 // holding the Parker:: mutex. If safepoints are pending both the
5830 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5831 ThreadBlockInVM tbivm(jt);
5832
5833 // Don't wait if cannot get lock since interference arises from
5834 // unblocking. Also. check interrupt before trying wait
5835 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5836 return;
5837 }
5838
5839 int status ;
5840 if (_counter > 0) { // no wait needed
5841 _counter = 0;
5842 status = pthread_mutex_unlock(_mutex);
5843 assert (status == 0, "invariant") ;
5844 // Paranoia to ensure our locked and lock-free paths interact
5845 // correctly with each other and Java-level accesses.
5846 OrderAccess::fence();
5847 return;
5848 }
5849
5850 #ifdef ASSERT
5851 // Don't catch signals while blocked; let the running threads have the signals.
5852 // (This allows a debugger to break into the running thread.)
5853 sigset_t oldsigs;
5854 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5855 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5856 #endif
5857
5858 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5859 jt->set_suspend_equivalent();
5860 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5861
5862 assert(_cur_index == -1, "invariant");
5863 if (time == 0) {
5864 _cur_index = REL_INDEX; // arbitrary choice when not timed
5865 status = pthread_cond_wait (&_cond[_cur_index], _mutex) ;
5866 } else {
5867 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5868 status = os::Linux::safe_cond_timedwait (&_cond[_cur_index], _mutex, &absTime) ;
5869 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5870 pthread_cond_destroy (&_cond[_cur_index]) ;
5871 pthread_cond_init (&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr());
5872 }
5873 }
5874 _cur_index = -1;
5875 assert_status(status == 0 || status == EINTR ||
5876 status == ETIME || status == ETIMEDOUT,
5877 status, "cond_timedwait");
5878
5879 #ifdef ASSERT
5880 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5881 #endif
5882
5883 _counter = 0 ;
5884 status = pthread_mutex_unlock(_mutex) ;
5885 assert_status(status == 0, status, "invariant") ;
5886 // Paranoia to ensure our locked and lock-free paths interact
5887 // correctly with each other and Java-level accesses.
5888 OrderAccess::fence();
5889
5890 // If externally suspended while waiting, re-suspend
5891 if (jt->handle_special_suspend_equivalent_condition()) {
5892 jt->java_suspend_self();
5893 }
5894 }
5895
5896 void Parker::unpark() {
5897 int s, status ;
5898 status = pthread_mutex_lock(_mutex);
5899 assert (status == 0, "invariant") ;
5900 s = _counter;
5901 _counter = 1;
5902 if (s < 1) {
5903 // thread might be parked
5904 if (_cur_index != -1) {
5905 // thread is definitely parked
5906 if (WorkAroundNPTLTimedWaitHang) {
5907 status = pthread_cond_signal (&_cond[_cur_index]);
5908 assert (status == 0, "invariant");
5909 status = pthread_mutex_unlock(_mutex);
5910 assert (status == 0, "invariant");
5911 } else {
5912 status = pthread_mutex_unlock(_mutex);
5913 assert (status == 0, "invariant");
5914 status = pthread_cond_signal (&_cond[_cur_index]);
5915 assert (status == 0, "invariant");
5916 }
5917 } else {
5918 pthread_mutex_unlock(_mutex);
5919 assert (status == 0, "invariant") ;
5920 }
5921 } else {
5922 pthread_mutex_unlock(_mutex);
5923 assert (status == 0, "invariant") ;
5924 }
5925 }
5926
5927
5928 extern char** environ;
5929
5930 #ifndef __NR_fork
5931 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5932 #endif
5933
5934 #ifndef __NR_execve
5935 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5936 #endif
5937
5938 // Run the specified command in a separate process. Return its exit value,
5939 // or -1 on failure (e.g. can't fork a new process).
5940 // Unlike system(), this function can be called from signal handler. It
5941 // doesn't block SIGINT et al.
5942 int os::fork_and_exec(char* cmd) {
5943 const char * argv[4] = {"sh", "-c", cmd, NULL};
5944
5945 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5946 // pthread_atfork handlers and reset pthread library. All we need is a
5947 // separate process to execve. Make a direct syscall to fork process.
5948 // On IA64 there's no fork syscall, we have to use fork() and hope for
5949 // the best...
5950 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5951 IA64_ONLY(fork();)
5952
5953 if (pid < 0) {
5954 // fork failed
5955 return -1;
5956
5957 } else if (pid == 0) {
5958 // child process
5959
5960 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5961 // first to kill every thread on the thread list. Because this list is
5962 // not reset by fork() (see notes above), execve() will instead kill
5963 // every thread in the parent process. We know this is the only thread
5964 // in the new process, so make a system call directly.
5965 // IA64 should use normal execve() from glibc to match the glibc fork()
5966 // above.
5967 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5968 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5969
5970 // execve failed
5971 _exit(-1);
5972
5973 } else {
5974 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5975 // care about the actual exit code, for now.
5976
5977 int status;
5978
5979 // Wait for the child process to exit. This returns immediately if
5980 // the child has already exited. */
5981 while (waitpid(pid, &status, 0) < 0) {
5982 switch (errno) {
5983 case ECHILD: return 0;
5984 case EINTR: break;
5985 default: return -1;
5986 }
5987 }
5988
5989 if (WIFEXITED(status)) {
5990 // The child exited normally; get its exit code.
5991 return WEXITSTATUS(status);
5992 } else if (WIFSIGNALED(status)) {
5993 // The child exited because of a signal
5994 // The best value to return is 0x80 + signal number,
5995 // because that is what all Unix shells do, and because
5996 // it allows callers to distinguish between process exit and
5997 // process death by signal.
5998 return 0x80 + WTERMSIG(status);
5999 } else {
6000 // Unknown exit code; pass it through
6001 return status;
6002 }
6003 }
6004 }
6005
6006 // is_headless_jre()
6007 //
6008 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
6009 // in order to report if we are running in a headless jre
6010 //
6011 // Since JDK8 xawt/libmawt.so was moved into the same directory
6012 // as libawt.so, and renamed libawt_xawt.so
6013 //
6014 bool os::is_headless_jre() {
6015 struct stat statbuf;
6016 char buf[MAXPATHLEN];
6017 char libmawtpath[MAXPATHLEN];
6018 const char *xawtstr = "/xawt/libmawt.so";
6019 const char *new_xawtstr = "/libawt_xawt.so";
6020 char *p;
6021
6022 // Get path to libjvm.so
6023 os::jvm_path(buf, sizeof(buf));
6024
6025 // Get rid of libjvm.so
6026 p = strrchr(buf, '/');
6027 if (p == NULL) return false;
6028 else *p = '\0';
6029
6030 // Get rid of client or server
6031 p = strrchr(buf, '/');
6032 if (p == NULL) return false;
6033 else *p = '\0';
6034
6035 // check xawt/libmawt.so
6036 strcpy(libmawtpath, buf);
6037 strcat(libmawtpath, xawtstr);
6038 if (::stat(libmawtpath, &statbuf) == 0) return false;
6039
6040 // check libawt_xawt.so
6041 strcpy(libmawtpath, buf);
6042 strcat(libmawtpath, new_xawtstr);
6043 if (::stat(libmawtpath, &statbuf) == 0) return false;
6044
6045 return true;
6046 }
6047
6048 // Get the default path to the core file
6049 // Returns the length of the string
6050 int os::get_core_path(char* buffer, size_t bufferSize) {
6051 const char* p = get_current_directory(buffer, bufferSize);
6052
6053 if (p == NULL) {
6054 assert(p != NULL, "failed to get current directory");
6055 return 0;
6056 }
6057
6058 return strlen(buffer);
6059 }
6060
6061 #ifdef JAVASE_EMBEDDED
6062 //
6063 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
6064 //
6065 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
6066
6067 // ctor
6068 //
6069 MemNotifyThread::MemNotifyThread(int fd): Thread() {
6070 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
6071 _fd = fd;
6072
6073 if (os::create_thread(this, os::os_thread)) {
6074 _memnotify_thread = this;
6075 os::set_priority(this, NearMaxPriority);
6076 os::start_thread(this);
6077 }
6078 }
6079
6080 // Where all the work gets done
6081 //
6082 void MemNotifyThread::run() {
6083 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
6084
6085 // Set up the select arguments
6086 fd_set rfds;
6087 if (_fd != -1) {
6088 FD_ZERO(&rfds);
6089 FD_SET(_fd, &rfds);
6090 }
6091
6092 // Now wait for the mem_notify device to wake up
6093 while (1) {
6094 // Wait for the mem_notify device to signal us..
6095 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
6096 if (rc == -1) {
6097 perror("select!\n");
6098 break;
6099 } else if (rc) {
6100 //ssize_t free_before = os::available_memory();
6101 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
6102
6103 // The kernel is telling us there is not much memory left...
6104 // try to do something about that
6105
6106 // If we are not already in a GC, try one.
6107 if (!Universe::heap()->is_gc_active()) {
6108 Universe::heap()->collect(GCCause::_allocation_failure);
6109
6110 //ssize_t free_after = os::available_memory();
6111 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
6112 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
6113 }
6114 // We might want to do something like the following if we find the GC's are not helping...
6115 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
6116 }
6117 }
6118 }
6119
6120 //
6121 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
6122 //
6123 void MemNotifyThread::start() {
6124 int fd;
6125 fd = open ("/dev/mem_notify", O_RDONLY, 0);
6126 if (fd < 0) {
6127 return;
6128 }
6129
6130 if (memnotify_thread() == NULL) {
6131 new MemNotifyThread(fd);
6132 }
6133 }
6134
6135 #endif // JAVASE_EMBEDDED
6136
6137
6138 /////////////// Unit tests ///////////////
6139
6140 #ifndef PRODUCT
6141
6142 #define test_log(...) \
6143 do {\
6144 if (VerboseInternalVMTests) { \
6145 tty->print_cr(__VA_ARGS__); \
6146 tty->flush(); \
6147 }\
6148 } while (false)
6149
6150 class TestReserveMemorySpecial : AllStatic {
6151 public:
6152 static void small_page_write(void* addr, size_t size) {
6153 size_t page_size = os::vm_page_size();
6154
6155 char* end = (char*)addr + size;
6156 for (char* p = (char*)addr; p < end; p += page_size) {
6157 *p = 1;
6158 }
6159 }
6160
6161 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6162 if (!UseHugeTLBFS) {
6163 return;
6164 }
6165
6166 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6167
6168 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6169
6170 if (addr != NULL) {
6171 small_page_write(addr, size);
6172
6173 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6174 }
6175 }
6176
6177 static void test_reserve_memory_special_huge_tlbfs_only() {
6178 if (!UseHugeTLBFS) {
6179 return;
6180 }
6181
6182 size_t lp = os::large_page_size();
6183
6184 for (size_t size = lp; size <= lp * 10; size += lp) {
6185 test_reserve_memory_special_huge_tlbfs_only(size);
6186 }
6187 }
6188
6189 static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) {
6190 if (!UseHugeTLBFS) {
6191 return;
6192 }
6193
6194 test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")",
6195 size, alignment);
6196
6197 assert(size >= os::large_page_size(), "Incorrect input to test");
6198
6199 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6200
6201 if (addr != NULL) {
6202 small_page_write(addr, size);
6203
6204 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6205 }
6206 }
6207
6208 static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) {
6209 size_t lp = os::large_page_size();
6210 size_t ag = os::vm_allocation_granularity();
6211
6212 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6213 test_reserve_memory_special_huge_tlbfs_mixed(size, alignment);
6214 }
6215 }
6216
6217 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6218 size_t lp = os::large_page_size();
6219 size_t ag = os::vm_allocation_granularity();
6220
6221 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp);
6222 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag);
6223 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2);
6224 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2);
6225 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag);
6226 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag);
6227 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2);
6228 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10);
6229 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2);
6230 }
6231
6232 static void test_reserve_memory_special_huge_tlbfs() {
6233 if (!UseHugeTLBFS) {
6234 return;
6235 }
6236
6237 test_reserve_memory_special_huge_tlbfs_only();
6238 test_reserve_memory_special_huge_tlbfs_mixed();
6239 }
6240
6241 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6242 if (!UseSHM) {
6243 return;
6244 }
6245
6246 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6247
6248 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6249
6250 if (addr != NULL) {
6251 assert(is_ptr_aligned(addr, alignment), "Check");
6252 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6253
6254 small_page_write(addr, size);
6255
6256 os::Linux::release_memory_special_shm(addr, size);
6257 }
6258 }
6259
6260 static void test_reserve_memory_special_shm() {
6261 size_t lp = os::large_page_size();
6262 size_t ag = os::vm_allocation_granularity();
6263
6264 for (size_t size = ag; size < lp * 3; size += ag) {
6265 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6266 test_reserve_memory_special_shm(size, alignment);
6267 }
6268 }
6269 }
6270
6271 static void test() {
6272 test_reserve_memory_special_huge_tlbfs();
6273 test_reserve_memory_special_shm();
6274 }
6275 };
6276
6277 void TestReserveMemorySpecial_test() {
6278 TestReserveMemorySpecial::test();
6279 }
6280
6281 #endif