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
158 #ifdef JAVASE_EMBEDDED
159 class MemNotifyThread: public Thread {
160 friend class VMStructs;
161 public:
162 virtual void run();
163
164 private:
165 static MemNotifyThread* _memnotify_thread;
166 int _fd;
167
168 public:
169
170 // Constructor
171 MemNotifyThread(int fd);
172
173 // Tester
174 bool is_memnotify_thread() const { return true; }
175
176 // Printing
177 char* name() const { return (char*)"Linux MemNotify Thread"; }
178
179 // Returns the single instance of the MemNotifyThread
180 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
181
182 // Create and start the single instance of MemNotifyThread
183 static void start();
184 };
185 #endif // JAVASE_EMBEDDED
186
187 // utility functions
188
189 static int SR_initialize();
190
191 julong os::available_memory() {
192 return Linux::available_memory();
193 }
194
195 julong os::Linux::available_memory() {
196 // values in struct sysinfo are "unsigned long"
197 struct sysinfo si;
198 sysinfo(&si);
199
200 return (julong)si.freeram * si.mem_unit;
201 }
202
203 julong os::physical_memory() {
204 return Linux::physical_memory();
205 }
206
207 ////////////////////////////////////////////////////////////////////////////////
208 // environment support
209
210 bool os::getenv(const char* name, char* buf, int len) {
211 const char* val = ::getenv(name);
212 if (val != NULL && strlen(val) < (size_t)len) {
213 strcpy(buf, val);
214 return true;
215 }
216 if (len > 0) buf[0] = 0; // return a null string
217 return false;
218 }
219
220
221 // Return true if user is running as root.
222
223 bool os::have_special_privileges() {
224 static bool init = false;
225 static bool privileges = false;
226 if (!init) {
227 privileges = (getuid() != geteuid()) || (getgid() != getegid());
228 init = true;
229 }
230 return privileges;
231 }
232
233
234 #ifndef SYS_gettid
235 // i386: 224, ia64: 1105, amd64: 186, sparc 143
236 #ifdef __ia64__
237 #define SYS_gettid 1105
238 #elif __i386__
239 #define SYS_gettid 224
240 #elif __amd64__
241 #define SYS_gettid 186
242 #elif __sparc__
243 #define SYS_gettid 143
244 #else
245 #error define gettid for the arch
246 #endif
247 #endif
248
249 // Cpu architecture string
250 #if defined(ZERO)
251 static char cpu_arch[] = ZERO_LIBARCH;
252 #elif defined(IA64)
253 static char cpu_arch[] = "ia64";
254 #elif defined(IA32)
255 static char cpu_arch[] = "i386";
256 #elif defined(AMD64)
257 static char cpu_arch[] = "amd64";
258 #elif defined(ARM)
259 static char cpu_arch[] = "arm";
260 #elif defined(PPC32)
261 static char cpu_arch[] = "ppc";
262 #elif defined(PPC64)
263 static char cpu_arch[] = "ppc64";
264 #elif defined(SPARC)
265 # ifdef _LP64
266 static char cpu_arch[] = "sparcv9";
267 # else
268 static char cpu_arch[] = "sparc";
269 # endif
270 #else
271 #error Add appropriate cpu_arch setting
272 #endif
273
274
275 // pid_t gettid()
276 //
277 // Returns the kernel thread id of the currently running thread. Kernel
278 // thread id is used to access /proc.
279 //
280 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
281 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
282 //
283 pid_t os::Linux::gettid() {
284 int rslt = syscall(SYS_gettid);
285 if (rslt == -1) {
286 // old kernel, no NPTL support
287 return getpid();
288 } else {
289 return (pid_t)rslt;
290 }
291 }
292
293 // Most versions of linux have a bug where the number of processors are
294 // determined by looking at the /proc file system. In a chroot environment,
295 // the system call returns 1. This causes the VM to act as if it is
296 // a single processor and elide locking (see is_MP() call).
297 static bool unsafe_chroot_detected = false;
298 static const char *unstable_chroot_error = "/proc file system not found.\n"
299 "Java may be unstable running multithreaded in a chroot "
300 "environment on Linux when /proc filesystem is not mounted.";
301
302 void os::Linux::initialize_system_info() {
303 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
304 if (processor_count() == 1) {
305 pid_t pid = os::Linux::gettid();
306 char fname[32];
307 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
308 FILE *fp = fopen(fname, "r");
309 if (fp == NULL) {
310 unsafe_chroot_detected = true;
311 } else {
312 fclose(fp);
313 }
314 }
315 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
316 assert(processor_count() > 0, "linux error");
317 }
318
319 void os::init_system_properties_values() {
320 // char arch[12];
321 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
322
323 // The next steps are taken in the product version:
324 //
325 // Obtain the JAVA_HOME value from the location of libjvm.so.
326 // This library should be located at:
327 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
328 //
329 // If "/jre/lib/" appears at the right place in the path, then we
330 // assume libjvm.so is installed in a JDK and we use this path.
331 //
332 // Otherwise exit with message: "Could not create the Java virtual machine."
333 //
334 // The following extra steps are taken in the debugging version:
335 //
336 // If "/jre/lib/" does NOT appear at the right place in the path
337 // instead of exit check for $JAVA_HOME environment variable.
338 //
339 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
340 // then we append a fake suffix "hotspot/libjvm.so" to this path so
341 // it looks like libjvm.so is installed there
342 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
343 //
344 // Otherwise exit.
345 //
346 // Important note: if the location of libjvm.so changes this
347 // code needs to be changed accordingly.
348
349 // The next few definitions allow the code to be verbatim:
350 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal)
351 #define getenv(n) ::getenv(n)
352
353 /*
354 * See ld(1):
355 * The linker uses the following search paths to locate required
356 * shared libraries:
357 * 1: ...
358 * ...
359 * 7: The default directories, normally /lib and /usr/lib.
360 */
361 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
362 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
363 #else
364 #define DEFAULT_LIBPATH "/lib:/usr/lib"
365 #endif
366
367 #define EXTENSIONS_DIR "/lib/ext"
368 #define ENDORSED_DIR "/lib/endorsed"
369 #define REG_DIR "/usr/java/packages"
370
371 {
372 /* sysclasspath, java_home, dll_dir */
373 {
374 char *home_path;
375 char *dll_path;
376 char *pslash;
377 char buf[MAXPATHLEN];
378 os::jvm_path(buf, sizeof(buf));
379
380 // Found the full path to libjvm.so.
381 // Now cut the path to <java_home>/jre if we can.
382 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
383 pslash = strrchr(buf, '/');
384 if (pslash != NULL)
385 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
386 dll_path = malloc(strlen(buf) + 1);
387 if (dll_path == NULL)
388 return;
389 strcpy(dll_path, buf);
390 Arguments::set_dll_dir(dll_path);
391
392 if (pslash != NULL) {
393 pslash = strrchr(buf, '/');
394 if (pslash != NULL) {
395 *pslash = '\0'; /* get rid of /<arch> */
396 pslash = strrchr(buf, '/');
397 if (pslash != NULL)
398 *pslash = '\0'; /* get rid of /lib */
399 }
400 }
401
402 home_path = malloc(strlen(buf) + 1);
403 if (home_path == NULL)
404 return;
405 strcpy(home_path, buf);
406 Arguments::set_java_home(home_path);
407
408 if (!set_boot_path('/', ':'))
409 return;
410 }
411
412 /*
413 * Where to look for native libraries
414 *
415 * Note: Due to a legacy implementation, most of the library path
416 * is set in the launcher. This was to accomodate linking restrictions
417 * on legacy Linux implementations (which are no longer supported).
418 * Eventually, all the library path setting will be done here.
419 *
420 * However, to prevent the proliferation of improperly built native
421 * libraries, the new path component /usr/java/packages is added here.
422 * Eventually, all the library path setting will be done here.
423 */
424 {
425 char *ld_library_path;
426
427 /*
428 * Construct the invariant part of ld_library_path. Note that the
429 * space for the colon and the trailing null are provided by the
430 * nulls included by the sizeof operator (so actually we allocate
431 * a byte more than necessary).
432 */
433 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
434 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
435 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
436
437 /*
438 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
439 * should always exist (until the legacy problem cited above is
440 * addressed).
441 */
442 char *v = getenv("LD_LIBRARY_PATH");
443 if (v != NULL) {
444 char *t = ld_library_path;
445 /* That's +1 for the colon and +1 for the trailing '\0' */
446 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
447 sprintf(ld_library_path, "%s:%s", v, t);
448 }
449 Arguments::set_library_path(ld_library_path);
450 }
451
452 /*
453 * Extensions directories.
454 *
455 * Note that the space for the colon and the trailing null are provided
456 * by the nulls included by the sizeof operator (so actually one byte more
457 * than necessary is allocated).
458 */
459 {
460 char *buf = malloc(strlen(Arguments::get_java_home()) +
461 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
462 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
463 Arguments::get_java_home());
464 Arguments::set_ext_dirs(buf);
465 }
466
467 /* Endorsed standards default directory. */
468 {
469 char * buf;
470 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
471 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
472 Arguments::set_endorsed_dirs(buf);
473 }
474 }
475
476 #undef malloc
477 #undef getenv
478 #undef EXTENSIONS_DIR
479 #undef ENDORSED_DIR
480
481 // Done
482 return;
483 }
484
485 ////////////////////////////////////////////////////////////////////////////////
486 // breakpoint support
487
488 void os::breakpoint() {
489 BREAKPOINT;
490 }
491
492 extern "C" void breakpoint() {
493 // use debugger to set breakpoint here
494 }
495
496 ////////////////////////////////////////////////////////////////////////////////
497 // signal support
498
499 debug_only(static bool signal_sets_initialized = false);
500 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
501
502 bool os::Linux::is_sig_ignored(int sig) {
503 struct sigaction oact;
504 sigaction(sig, (struct sigaction*)NULL, &oact);
505 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
506 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
507 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
508 return true;
509 else
510 return false;
511 }
512
513 void os::Linux::signal_sets_init() {
514 // Should also have an assertion stating we are still single-threaded.
515 assert(!signal_sets_initialized, "Already initialized");
516 // Fill in signals that are necessarily unblocked for all threads in
517 // the VM. Currently, we unblock the following signals:
518 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
519 // by -Xrs (=ReduceSignalUsage));
520 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
521 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
522 // the dispositions or masks wrt these signals.
523 // Programs embedding the VM that want to use the above signals for their
524 // own purposes must, at this time, use the "-Xrs" option to prevent
525 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
526 // (See bug 4345157, and other related bugs).
527 // In reality, though, unblocking these signals is really a nop, since
528 // these signals are not blocked by default.
529 sigemptyset(&unblocked_sigs);
530 sigemptyset(&allowdebug_blocked_sigs);
531 sigaddset(&unblocked_sigs, SIGILL);
532 sigaddset(&unblocked_sigs, SIGSEGV);
533 sigaddset(&unblocked_sigs, SIGBUS);
534 sigaddset(&unblocked_sigs, SIGFPE);
535 #if defined(PPC64)
536 sigaddset(&unblocked_sigs, SIGTRAP);
537 #endif
538 sigaddset(&unblocked_sigs, SR_signum);
539
540 if (!ReduceSignalUsage) {
541 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
542 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
543 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
544 }
545 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
546 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
547 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
548 }
549 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
550 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
551 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
552 }
553 }
554 // Fill in signals that are blocked by all but the VM thread.
555 sigemptyset(&vm_sigs);
556 if (!ReduceSignalUsage)
557 sigaddset(&vm_sigs, BREAK_SIGNAL);
558 debug_only(signal_sets_initialized = true);
559
560 }
561
562 // These are signals that are unblocked while a thread is running Java.
563 // (For some reason, they get blocked by default.)
564 sigset_t* os::Linux::unblocked_signals() {
565 assert(signal_sets_initialized, "Not initialized");
566 return &unblocked_sigs;
567 }
568
569 // These are the signals that are blocked while a (non-VM) thread is
570 // running Java. Only the VM thread handles these signals.
571 sigset_t* os::Linux::vm_signals() {
572 assert(signal_sets_initialized, "Not initialized");
573 return &vm_sigs;
574 }
575
576 // These are signals that are blocked during cond_wait to allow debugger in
577 sigset_t* os::Linux::allowdebug_blocked_signals() {
578 assert(signal_sets_initialized, "Not initialized");
579 return &allowdebug_blocked_sigs;
580 }
581
582 void os::Linux::hotspot_sigmask(Thread* thread) {
583
584 //Save caller's signal mask before setting VM signal mask
585 sigset_t caller_sigmask;
586 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
587
588 OSThread* osthread = thread->osthread();
589 osthread->set_caller_sigmask(caller_sigmask);
590
591 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
592
593 if (!ReduceSignalUsage) {
594 if (thread->is_VM_thread()) {
595 // Only the VM thread handles BREAK_SIGNAL ...
596 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
597 } else {
598 // ... all other threads block BREAK_SIGNAL
599 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
600 }
601 }
602 }
603
604 //////////////////////////////////////////////////////////////////////////////
605 // detecting pthread library
606
607 void os::Linux::libpthread_init() {
608 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
609 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
610 // generic name for earlier versions.
611 // Define macros here so we can build HotSpot on old systems.
612 # ifndef _CS_GNU_LIBC_VERSION
613 # define _CS_GNU_LIBC_VERSION 2
614 # endif
615 # ifndef _CS_GNU_LIBPTHREAD_VERSION
616 # define _CS_GNU_LIBPTHREAD_VERSION 3
617 # endif
618
619 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
620 if (n > 0) {
621 char *str = (char *)malloc(n, mtInternal);
622 confstr(_CS_GNU_LIBC_VERSION, str, n);
623 os::Linux::set_glibc_version(str);
624 } else {
625 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
626 static char _gnu_libc_version[32];
627 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
628 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
629 os::Linux::set_glibc_version(_gnu_libc_version);
630 }
631
632 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
633 if (n > 0) {
634 char *str = (char *)malloc(n, mtInternal);
635 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
636 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
637 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
638 // is the case. LinuxThreads has a hard limit on max number of threads.
639 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
640 // On the other hand, NPTL does not have such a limit, sysconf()
641 // will return -1 and errno is not changed. Check if it is really NPTL.
642 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
643 strstr(str, "NPTL") &&
644 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
645 free(str);
646 os::Linux::set_libpthread_version("linuxthreads");
647 } else {
648 os::Linux::set_libpthread_version(str);
649 }
650 } else {
651 // glibc before 2.3.2 only has LinuxThreads.
652 os::Linux::set_libpthread_version("linuxthreads");
653 }
654
655 if (strstr(libpthread_version(), "NPTL")) {
656 os::Linux::set_is_NPTL();
657 } else {
658 os::Linux::set_is_LinuxThreads();
659 }
660
661 // LinuxThreads have two flavors: floating-stack mode, which allows variable
662 // stack size; and fixed-stack mode. NPTL is always floating-stack.
663 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
664 os::Linux::set_is_floating_stack();
665 }
666 }
667
668 /////////////////////////////////////////////////////////////////////////////
669 // thread stack
670
671 // Force Linux kernel to expand current thread stack. If "bottom" is close
672 // to the stack guard, caller should block all signals.
673 //
674 // MAP_GROWSDOWN:
675 // A special mmap() flag that is used to implement thread stacks. It tells
676 // kernel that the memory region should extend downwards when needed. This
677 // allows early versions of LinuxThreads to only mmap the first few pages
678 // when creating a new thread. Linux kernel will automatically expand thread
679 // stack as needed (on page faults).
680 //
681 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
682 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
683 // region, it's hard to tell if the fault is due to a legitimate stack
684 // access or because of reading/writing non-exist memory (e.g. buffer
685 // overrun). As a rule, if the fault happens below current stack pointer,
686 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
687 // application (see Linux kernel fault.c).
688 //
689 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
690 // stack overflow detection.
691 //
692 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
693 // not use this flag. However, the stack of initial thread is not created
694 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
695 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
696 // and then attach the thread to JVM.
697 //
698 // To get around the problem and allow stack banging on Linux, we need to
699 // manually expand thread stack after receiving the SIGSEGV.
700 //
701 // There are two ways to expand thread stack to address "bottom", we used
702 // both of them in JVM before 1.5:
703 // 1. adjust stack pointer first so that it is below "bottom", and then
704 // touch "bottom"
705 // 2. mmap() the page in question
706 //
707 // Now alternate signal stack is gone, it's harder to use 2. For instance,
708 // if current sp is already near the lower end of page 101, and we need to
709 // call mmap() to map page 100, it is possible that part of the mmap() frame
710 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
711 // That will destroy the mmap() frame and cause VM to crash.
712 //
713 // The following code works by adjusting sp first, then accessing the "bottom"
714 // page to force a page fault. Linux kernel will then automatically expand the
715 // stack mapping.
716 //
717 // _expand_stack_to() assumes its frame size is less than page size, which
718 // should always be true if the function is not inlined.
719
720 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
721 #define NOINLINE
722 #else
723 #define NOINLINE __attribute__ ((noinline))
724 #endif
725
726 static void _expand_stack_to(address bottom) NOINLINE;
727
728 static void _expand_stack_to(address bottom) {
729 address sp;
730 size_t size;
731 volatile char *p;
732
733 // Adjust bottom to point to the largest address within the same page, it
734 // gives us a one-page buffer if alloca() allocates slightly more memory.
735 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
736 bottom += os::Linux::page_size() - 1;
737
738 // sp might be slightly above current stack pointer; if that's the case, we
739 // will alloca() a little more space than necessary, which is OK. Don't use
740 // os::current_stack_pointer(), as its result can be slightly below current
741 // stack pointer, causing us to not alloca enough to reach "bottom".
742 sp = (address)&sp;
743
744 if (sp > bottom) {
745 size = sp - bottom;
746 p = (volatile char *)alloca(size);
747 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
748 p[0] = '\0';
749 }
750 }
751
752 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
753 assert(t!=NULL, "just checking");
754 assert(t->osthread()->expanding_stack(), "expand should be set");
755 assert(t->stack_base() != NULL, "stack_base was not initialized");
756
757 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
758 sigset_t mask_all, old_sigset;
759 sigfillset(&mask_all);
760 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
761 _expand_stack_to(addr);
762 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
763 return true;
764 }
765 return false;
766 }
767
768 //////////////////////////////////////////////////////////////////////////////
769 // create new thread
770
771 static address highest_vm_reserved_address();
772
773 // check if it's safe to start a new thread
774 static bool _thread_safety_check(Thread* thread) {
775 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
776 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
777 // Heap is mmap'ed at lower end of memory space. Thread stacks are
778 // allocated (MAP_FIXED) from high address space. Every thread stack
779 // occupies a fixed size slot (usually 2Mbytes, but user can change
780 // it to other values if they rebuild LinuxThreads).
781 //
782 // Problem with MAP_FIXED is that mmap() can still succeed even part of
783 // the memory region has already been mmap'ed. That means if we have too
784 // many threads and/or very large heap, eventually thread stack will
785 // collide with heap.
786 //
787 // Here we try to prevent heap/stack collision by comparing current
788 // stack bottom with the highest address that has been mmap'ed by JVM
789 // plus a safety margin for memory maps created by native code.
790 //
791 // This feature can be disabled by setting ThreadSafetyMargin to 0
792 //
793 if (ThreadSafetyMargin > 0) {
794 address stack_bottom = os::current_stack_base() - os::current_stack_size();
795
796 // not safe if our stack extends below the safety margin
797 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
798 } else {
799 return true;
800 }
801 } else {
802 // Floating stack LinuxThreads or NPTL:
803 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
804 // there's not enough space left, pthread_create() will fail. If we come
805 // here, that means enough space has been reserved for stack.
806 return true;
807 }
808 }
809
810 // Thread start routine for all newly created threads
811 static void *java_start(Thread *thread) {
812 // Try to randomize the cache line index of hot stack frames.
813 // This helps when threads of the same stack traces evict each other's
814 // cache lines. The threads can be either from the same JVM instance, or
815 // from different JVM instances. The benefit is especially true for
816 // processors with hyperthreading technology.
817 static int counter = 0;
818 int pid = os::current_process_id();
819 alloca(((pid ^ counter++) & 7) * 128);
820
821 ThreadLocalStorage::set_thread(thread);
822
823 OSThread* osthread = thread->osthread();
824 Monitor* sync = osthread->startThread_lock();
825
826 // non floating stack LinuxThreads needs extra check, see above
827 if (!_thread_safety_check(thread)) {
828 // notify parent thread
829 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
830 osthread->set_state(ZOMBIE);
831 sync->notify_all();
832 return NULL;
833 }
834
835 // thread_id is kernel thread id (similar to Solaris LWP id)
836 osthread->set_thread_id(os::Linux::gettid());
837
838 if (UseNUMA) {
839 int lgrp_id = os::numa_get_group_id();
840 if (lgrp_id != -1) {
841 thread->set_lgrp_id(lgrp_id);
842 }
843 }
844 // initialize signal mask for this thread
845 os::Linux::hotspot_sigmask(thread);
846
847 // initialize floating point control register
848 os::Linux::init_thread_fpu_state();
849
850 // handshaking with parent thread
851 {
852 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
853
854 // notify parent thread
855 osthread->set_state(INITIALIZED);
856 sync->notify_all();
857
858 // wait until os::start_thread()
859 while (osthread->get_state() == INITIALIZED) {
860 sync->wait(Mutex::_no_safepoint_check_flag);
861 }
862 }
863
864 // call one more level start routine
865 thread->run();
866
867 return 0;
868 }
869
870 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
871 assert(thread->osthread() == NULL, "caller responsible");
872
873 // Allocate the OSThread object
874 OSThread* osthread = new OSThread(NULL, NULL);
875 if (osthread == NULL) {
876 return false;
877 }
878
879 // set the correct thread state
880 osthread->set_thread_type(thr_type);
881
882 // Initial state is ALLOCATED but not INITIALIZED
883 osthread->set_state(ALLOCATED);
884
885 thread->set_osthread(osthread);
886
887 // init thread attributes
888 pthread_attr_t attr;
889 pthread_attr_init(&attr);
890 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
891
892 // stack size
893 if (os::Linux::supports_variable_stack_size()) {
894 // calculate stack size if it's not specified by caller
895 if (stack_size == 0) {
896 stack_size = os::Linux::default_stack_size(thr_type);
897
898 switch (thr_type) {
899 case os::java_thread:
900 // Java threads use ThreadStackSize which default value can be
901 // changed with the flag -Xss
902 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
903 stack_size = JavaThread::stack_size_at_create();
904 break;
905 case os::compiler_thread:
906 if (CompilerThreadStackSize > 0) {
907 stack_size = (size_t)(CompilerThreadStackSize * K);
908 break;
909 } // else fall through:
910 // use VMThreadStackSize if CompilerThreadStackSize is not defined
911 case os::vm_thread:
912 case os::pgc_thread:
913 case os::cgc_thread:
914 case os::watcher_thread:
915 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
916 break;
917 }
918 }
919
920 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
921 pthread_attr_setstacksize(&attr, stack_size);
922 } else {
923 // let pthread_create() pick the default value.
924 }
925
926 // glibc guard page
927 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
928
929 ThreadState state;
930
931 {
932 // Serialize thread creation if we are running with fixed stack LinuxThreads
933 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
934 if (lock) {
935 os::Linux::createThread_lock()->lock_without_safepoint_check();
936 }
937
938 pthread_t tid;
939 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
940
941 pthread_attr_destroy(&attr);
942
943 if (ret != 0) {
944 if (PrintMiscellaneous && (Verbose || WizardMode)) {
945 perror("pthread_create()");
946 }
947 // Need to clean up stuff we've allocated so far
948 thread->set_osthread(NULL);
949 delete osthread;
950 if (lock) os::Linux::createThread_lock()->unlock();
951 return false;
952 }
953
954 // Store pthread info into the OSThread
955 osthread->set_pthread_id(tid);
956
957 // Wait until child thread is either initialized or aborted
958 {
959 Monitor* sync_with_child = osthread->startThread_lock();
960 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
961 while ((state = osthread->get_state()) == ALLOCATED) {
962 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
963 }
964 }
965
966 if (lock) {
967 os::Linux::createThread_lock()->unlock();
968 }
969 }
970
971 // Aborted due to thread limit being reached
972 if (state == ZOMBIE) {
973 thread->set_osthread(NULL);
974 delete osthread;
975 return false;
976 }
977
978 // The thread is returned suspended (in state INITIALIZED),
979 // and is started higher up in the call chain
980 assert(state == INITIALIZED, "race condition");
981 return true;
982 }
983
984 /////////////////////////////////////////////////////////////////////////////
985 // attach existing thread
986
987 // bootstrap the main thread
988 bool os::create_main_thread(JavaThread* thread) {
989 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
990 return create_attached_thread(thread);
991 }
992
993 bool os::create_attached_thread(JavaThread* thread) {
994 #ifdef ASSERT
995 thread->verify_not_published();
996 #endif
997
998 // Allocate the OSThread object
999 OSThread* osthread = new OSThread(NULL, NULL);
1000
1001 if (osthread == NULL) {
1002 return false;
1003 }
1004
1005 // Store pthread info into the OSThread
1006 osthread->set_thread_id(os::Linux::gettid());
1007 osthread->set_pthread_id(::pthread_self());
1008
1009 // initialize floating point control register
1010 os::Linux::init_thread_fpu_state();
1011
1012 // Initial thread state is RUNNABLE
1013 osthread->set_state(RUNNABLE);
1014
1015 thread->set_osthread(osthread);
1016
1017 if (UseNUMA) {
1018 int lgrp_id = os::numa_get_group_id();
1019 if (lgrp_id != -1) {
1020 thread->set_lgrp_id(lgrp_id);
1021 }
1022 }
1023
1024 if (os::Linux::is_initial_thread()) {
1025 // If current thread is initial thread, its stack is mapped on demand,
1026 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1027 // the entire stack region to avoid SEGV in stack banging.
1028 // It is also useful to get around the heap-stack-gap problem on SuSE
1029 // kernel (see 4821821 for details). We first expand stack to the top
1030 // of yellow zone, then enable stack yellow zone (order is significant,
1031 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1032 // is no gap between the last two virtual memory regions.
1033
1034 JavaThread *jt = (JavaThread *)thread;
1035 address addr = jt->stack_yellow_zone_base();
1036 assert(addr != NULL, "initialization problem?");
1037 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1038
1039 osthread->set_expanding_stack();
1040 os::Linux::manually_expand_stack(jt, addr);
1041 osthread->clear_expanding_stack();
1042 }
1043
1044 // initialize signal mask for this thread
1045 // and save the caller's signal mask
1046 os::Linux::hotspot_sigmask(thread);
1047
1048 return true;
1049 }
1050
1051 void os::pd_start_thread(Thread* thread) {
1052 OSThread * osthread = thread->osthread();
1053 assert(osthread->get_state() != INITIALIZED, "just checking");
1054 Monitor* sync_with_child = osthread->startThread_lock();
1055 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1056 sync_with_child->notify();
1057 }
1058
1059 // Free Linux resources related to the OSThread
1060 void os::free_thread(OSThread* osthread) {
1061 assert(osthread != NULL, "osthread not set");
1062
1063 if (Thread::current()->osthread() == osthread) {
1064 // Restore caller's signal mask
1065 sigset_t sigmask = osthread->caller_sigmask();
1066 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1067 }
1068
1069 delete osthread;
1070 }
1071
1072 //////////////////////////////////////////////////////////////////////////////
1073 // thread local storage
1074
1075 int os::allocate_thread_local_storage() {
1076 pthread_key_t key;
1077 int rslt = pthread_key_create(&key, NULL);
1078 assert(rslt == 0, "cannot allocate thread local storage");
1079 return (int)key;
1080 }
1081
1082 // Note: This is currently not used by VM, as we don't destroy TLS key
1083 // on VM exit.
1084 void os::free_thread_local_storage(int index) {
1085 int rslt = pthread_key_delete((pthread_key_t)index);
1086 assert(rslt == 0, "invalid index");
1087 }
1088
1089 void os::thread_local_storage_at_put(int index, void* value) {
1090 int rslt = pthread_setspecific((pthread_key_t)index, value);
1091 assert(rslt == 0, "pthread_setspecific failed");
1092 }
1093
1094 extern "C" Thread* get_thread() {
1095 return ThreadLocalStorage::thread();
1096 }
1097
1098 //////////////////////////////////////////////////////////////////////////////
1099 // initial thread
1100
1101 // Check if current thread is the initial thread, similar to Solaris thr_main.
1102 bool os::Linux::is_initial_thread(void) {
1103 char dummy;
1104 // If called before init complete, thread stack bottom will be null.
1105 // Can be called if fatal error occurs before initialization.
1106 if (initial_thread_stack_bottom() == NULL) return false;
1107 assert(initial_thread_stack_bottom() != NULL &&
1108 initial_thread_stack_size() != 0,
1109 "os::init did not locate initial thread's stack region");
1110 if ((address)&dummy >= initial_thread_stack_bottom() &&
1111 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1112 return true;
1113 else return false;
1114 }
1115
1116 // Find the virtual memory area that contains addr
1117 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1118 FILE *fp = fopen("/proc/self/maps", "r");
1119 if (fp) {
1120 address low, high;
1121 while (!feof(fp)) {
1122 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1123 if (low <= addr && addr < high) {
1124 if (vma_low) *vma_low = low;
1125 if (vma_high) *vma_high = high;
1126 fclose (fp);
1127 return true;
1128 }
1129 }
1130 for (;;) {
1131 int ch = fgetc(fp);
1132 if (ch == EOF || ch == (int)'\n') break;
1133 }
1134 }
1135 fclose(fp);
1136 }
1137 return false;
1138 }
1139
1140 // Locate initial thread stack. This special handling of initial thread stack
1141 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1142 // bogus value for initial thread.
1143 void os::Linux::capture_initial_stack(size_t max_size) {
1144 // stack size is the easy part, get it from RLIMIT_STACK
1145 size_t stack_size;
1146 struct rlimit rlim;
1147 getrlimit(RLIMIT_STACK, &rlim);
1148 stack_size = rlim.rlim_cur;
1149
1150 // 6308388: a bug in ld.so will relocate its own .data section to the
1151 // lower end of primordial stack; reduce ulimit -s value a little bit
1152 // so we won't install guard page on ld.so's data section.
1153 stack_size -= 2 * page_size();
1154
1155 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1156 // 7.1, in both cases we will get 2G in return value.
1157 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1158 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1159 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1160 // in case other parts in glibc still assumes 2M max stack size.
1161 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1162 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1163 if (stack_size > 2 * K * K IA64_ONLY(*2))
1164 stack_size = 2 * K * K IA64_ONLY(*2);
1165 // Try to figure out where the stack base (top) is. This is harder.
1166 //
1167 // When an application is started, glibc saves the initial stack pointer in
1168 // a global variable "__libc_stack_end", which is then used by system
1169 // libraries. __libc_stack_end should be pretty close to stack top. The
1170 // variable is available since the very early days. However, because it is
1171 // a private interface, it could disappear in the future.
1172 //
1173 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1174 // to __libc_stack_end, it is very close to stack top, but isn't the real
1175 // stack top. Note that /proc may not exist if VM is running as a chroot
1176 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1177 // /proc/<pid>/stat could change in the future (though unlikely).
1178 //
1179 // We try __libc_stack_end first. If that doesn't work, look for
1180 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1181 // as a hint, which should work well in most cases.
1182
1183 uintptr_t stack_start;
1184
1185 // try __libc_stack_end first
1186 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1187 if (p && *p) {
1188 stack_start = *p;
1189 } else {
1190 // see if we can get the start_stack field from /proc/self/stat
1191 FILE *fp;
1192 int pid;
1193 char state;
1194 int ppid;
1195 int pgrp;
1196 int session;
1197 int nr;
1198 int tpgrp;
1199 unsigned long flags;
1200 unsigned long minflt;
1201 unsigned long cminflt;
1202 unsigned long majflt;
1203 unsigned long cmajflt;
1204 unsigned long utime;
1205 unsigned long stime;
1206 long cutime;
1207 long cstime;
1208 long prio;
1209 long nice;
1210 long junk;
1211 long it_real;
1212 uintptr_t start;
1213 uintptr_t vsize;
1214 intptr_t rss;
1215 uintptr_t rsslim;
1216 uintptr_t scodes;
1217 uintptr_t ecode;
1218 int i;
1219
1220 // Figure what the primordial thread stack base is. Code is inspired
1221 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1222 // followed by command name surrounded by parentheses, state, etc.
1223 char stat[2048];
1224 int statlen;
1225
1226 fp = fopen("/proc/self/stat", "r");
1227 if (fp) {
1228 statlen = fread(stat, 1, 2047, fp);
1229 stat[statlen] = '\0';
1230 fclose(fp);
1231
1232 // Skip pid and the command string. Note that we could be dealing with
1233 // weird command names, e.g. user could decide to rename java launcher
1234 // to "java 1.4.2 :)", then the stat file would look like
1235 // 1234 (java 1.4.2 :)) R ... ...
1236 // We don't really need to know the command string, just find the last
1237 // occurrence of ")" and then start parsing from there. See bug 4726580.
1238 char * s = strrchr(stat, ')');
1239
1240 i = 0;
1241 if (s) {
1242 // Skip blank chars
1243 do s++; while (isspace(*s));
1244
1245 #define _UFM UINTX_FORMAT
1246 #define _DFM INTX_FORMAT
1247
1248 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1249 /* 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 */
1250 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,
1251 &state, /* 3 %c */
1252 &ppid, /* 4 %d */
1253 &pgrp, /* 5 %d */
1254 &session, /* 6 %d */
1255 &nr, /* 7 %d */
1256 &tpgrp, /* 8 %d */
1257 &flags, /* 9 %lu */
1258 &minflt, /* 10 %lu */
1259 &cminflt, /* 11 %lu */
1260 &majflt, /* 12 %lu */
1261 &cmajflt, /* 13 %lu */
1262 &utime, /* 14 %lu */
1263 &stime, /* 15 %lu */
1264 &cutime, /* 16 %ld */
1265 &cstime, /* 17 %ld */
1266 &prio, /* 18 %ld */
1267 &nice, /* 19 %ld */
1268 &junk, /* 20 %ld */
1269 &it_real, /* 21 %ld */
1270 &start, /* 22 UINTX_FORMAT */
1271 &vsize, /* 23 UINTX_FORMAT */
1272 &rss, /* 24 INTX_FORMAT */
1273 &rsslim, /* 25 UINTX_FORMAT */
1274 &scodes, /* 26 UINTX_FORMAT */
1275 &ecode, /* 27 UINTX_FORMAT */
1276 &stack_start); /* 28 UINTX_FORMAT */
1277 }
1278
1279 #undef _UFM
1280 #undef _DFM
1281
1282 if (i != 28 - 2) {
1283 assert(false, "Bad conversion from /proc/self/stat");
1284 // product mode - assume we are the initial thread, good luck in the
1285 // embedded case.
1286 warning("Can't detect initial thread stack location - bad conversion");
1287 stack_start = (uintptr_t) &rlim;
1288 }
1289 } else {
1290 // For some reason we can't open /proc/self/stat (for example, running on
1291 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1292 // most cases, so don't abort:
1293 warning("Can't detect initial thread stack location - no /proc/self/stat");
1294 stack_start = (uintptr_t) &rlim;
1295 }
1296 }
1297
1298 // Now we have a pointer (stack_start) very close to the stack top, the
1299 // next thing to do is to figure out the exact location of stack top. We
1300 // can find out the virtual memory area that contains stack_start by
1301 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1302 // and its upper limit is the real stack top. (again, this would fail if
1303 // running inside chroot, because /proc may not exist.)
1304
1305 uintptr_t stack_top;
1306 address low, high;
1307 if (find_vma((address)stack_start, &low, &high)) {
1308 // success, "high" is the true stack top. (ignore "low", because initial
1309 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1310 stack_top = (uintptr_t)high;
1311 } else {
1312 // failed, likely because /proc/self/maps does not exist
1313 warning("Can't detect initial thread stack location - find_vma failed");
1314 // best effort: stack_start is normally within a few pages below the real
1315 // stack top, use it as stack top, and reduce stack size so we won't put
1316 // guard page outside stack.
1317 stack_top = stack_start;
1318 stack_size -= 16 * page_size();
1319 }
1320
1321 // stack_top could be partially down the page so align it
1322 stack_top = align_size_up(stack_top, page_size());
1323
1324 if (max_size && stack_size > max_size) {
1325 _initial_thread_stack_size = max_size;
1326 } else {
1327 _initial_thread_stack_size = stack_size;
1328 }
1329
1330 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1331 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1332 }
1333
1334 ////////////////////////////////////////////////////////////////////////////////
1335 // time support
1336
1337 // Time since start-up in seconds to a fine granularity.
1338 // Used by VMSelfDestructTimer and the MemProfiler.
1339 double os::elapsedTime() {
1340
1341 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1342 }
1343
1344 jlong os::elapsed_counter() {
1345 return javaTimeNanos() - initial_time_count;
1346 }
1347
1348 jlong os::elapsed_frequency() {
1349 return NANOSECS_PER_SEC; // nanosecond resolution
1350 }
1351
1352 bool os::supports_vtime() { return true; }
1353 bool os::enable_vtime() { return false; }
1354 bool os::vtime_enabled() { return false; }
1355
1356 double os::elapsedVTime() {
1357 struct rusage usage;
1358 int retval = getrusage(RUSAGE_THREAD, &usage);
1359 if (retval == 0) {
1360 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);
1361 } else {
1362 // better than nothing, but not much
1363 return elapsedTime();
1364 }
1365 }
1366
1367 jlong os::javaTimeMillis() {
1368 timeval time;
1369 int status = gettimeofday(&time, NULL);
1370 assert(status != -1, "linux error");
1371 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1372 }
1373
1374 #ifndef CLOCK_MONOTONIC
1375 #define CLOCK_MONOTONIC (1)
1376 #endif
1377
1378 void os::Linux::clock_init() {
1379 // we do dlopen's in this particular order due to bug in linux
1380 // dynamical loader (see 6348968) leading to crash on exit
1381 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1382 if (handle == NULL) {
1383 handle = dlopen("librt.so", RTLD_LAZY);
1384 }
1385
1386 if (handle) {
1387 int (*clock_getres_func)(clockid_t, struct timespec*) =
1388 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1389 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1390 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1391 if (clock_getres_func && clock_gettime_func) {
1392 // See if monotonic clock is supported by the kernel. Note that some
1393 // early implementations simply return kernel jiffies (updated every
1394 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1395 // for nano time (though the monotonic property is still nice to have).
1396 // It's fixed in newer kernels, however clock_getres() still returns
1397 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1398 // resolution for now. Hopefully as people move to new kernels, this
1399 // won't be a problem.
1400 struct timespec res;
1401 struct timespec tp;
1402 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1403 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1404 // yes, monotonic clock is supported
1405 _clock_gettime = clock_gettime_func;
1406 return;
1407 } else {
1408 // close librt if there is no monotonic clock
1409 dlclose(handle);
1410 }
1411 }
1412 }
1413 warning("No monotonic clock was available - timed services may " \
1414 "be adversely affected if the time-of-day clock changes");
1415 }
1416
1417 #ifndef SYS_clock_getres
1418
1419 #if defined(IA32) || defined(AMD64)
1420 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1421 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1422 #else
1423 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1424 #define sys_clock_getres(x,y) -1
1425 #endif
1426
1427 #else
1428 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1429 #endif
1430
1431 void os::Linux::fast_thread_clock_init() {
1432 if (!UseLinuxPosixThreadCPUClocks) {
1433 return;
1434 }
1435 clockid_t clockid;
1436 struct timespec tp;
1437 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1438 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1439
1440 // Switch to using fast clocks for thread cpu time if
1441 // the sys_clock_getres() returns 0 error code.
1442 // Note, that some kernels may support the current thread
1443 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1444 // returned by the pthread_getcpuclockid().
1445 // If the fast Posix clocks are supported then the sys_clock_getres()
1446 // must return at least tp.tv_sec == 0 which means a resolution
1447 // better than 1 sec. This is extra check for reliability.
1448
1449 if(pthread_getcpuclockid_func &&
1450 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1451 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1452
1453 _supports_fast_thread_cpu_time = true;
1454 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1455 }
1456 }
1457
1458 jlong os::javaTimeNanos() {
1459 if (os::supports_monotonic_clock()) {
1460 struct timespec tp;
1461 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1462 assert(status == 0, "gettime error");
1463 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1464 return result;
1465 } else {
1466 timeval time;
1467 int status = gettimeofday(&time, NULL);
1468 assert(status != -1, "linux error");
1469 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1470 return 1000 * usecs;
1471 }
1472 }
1473
1474 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1475 if (os::supports_monotonic_clock()) {
1476 info_ptr->max_value = ALL_64_BITS;
1477
1478 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1479 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1480 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1481 } else {
1482 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1483 info_ptr->max_value = ALL_64_BITS;
1484
1485 // gettimeofday is a real time clock so it skips
1486 info_ptr->may_skip_backward = true;
1487 info_ptr->may_skip_forward = true;
1488 }
1489
1490 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1491 }
1492
1493 // Return the real, user, and system times in seconds from an
1494 // arbitrary fixed point in the past.
1495 bool os::getTimesSecs(double* process_real_time,
1496 double* process_user_time,
1497 double* process_system_time) {
1498 struct tms ticks;
1499 clock_t real_ticks = times(&ticks);
1500
1501 if (real_ticks == (clock_t) (-1)) {
1502 return false;
1503 } else {
1504 double ticks_per_second = (double) clock_tics_per_sec;
1505 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1506 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1507 *process_real_time = ((double) real_ticks) / ticks_per_second;
1508
1509 return true;
1510 }
1511 }
1512
1513
1514 char * os::local_time_string(char *buf, size_t buflen) {
1515 struct tm t;
1516 time_t long_time;
1517 time(&long_time);
1518 localtime_r(&long_time, &t);
1519 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1520 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1521 t.tm_hour, t.tm_min, t.tm_sec);
1522 return buf;
1523 }
1524
1525 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1526 return localtime_r(clock, res);
1527 }
1528
1529 ////////////////////////////////////////////////////////////////////////////////
1530 // runtime exit support
1531
1532 // Note: os::shutdown() might be called very early during initialization, or
1533 // called from signal handler. Before adding something to os::shutdown(), make
1534 // sure it is async-safe and can handle partially initialized VM.
1535 void os::shutdown() {
1536
1537 // allow PerfMemory to attempt cleanup of any persistent resources
1538 perfMemory_exit();
1539
1540 // needs to remove object in file system
1541 AttachListener::abort();
1542
1543 // flush buffered output, finish log files
1544 ostream_abort();
1545
1546 // Check for abort hook
1547 abort_hook_t abort_hook = Arguments::abort_hook();
1548 if (abort_hook != NULL) {
1549 abort_hook();
1550 }
1551
1552 }
1553
1554 // Note: os::abort() might be called very early during initialization, or
1555 // called from signal handler. Before adding something to os::abort(), make
1556 // sure it is async-safe and can handle partially initialized VM.
1557 void os::abort(bool dump_core) {
1558 os::shutdown();
1559 if (dump_core) {
1560 #ifndef PRODUCT
1561 fdStream out(defaultStream::output_fd());
1562 out.print_raw("Current thread is ");
1563 char buf[16];
1564 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1565 out.print_raw_cr(buf);
1566 out.print_raw_cr("Dumping core ...");
1567 #endif
1568 ::abort(); // dump core
1569 }
1570
1571 ::exit(1);
1572 }
1573
1574 // Die immediately, no exit hook, no abort hook, no cleanup.
1575 void os::die() {
1576 // _exit() on LinuxThreads only kills current thread
1577 ::abort();
1578 }
1579
1580 // unused on linux for now.
1581 void os::set_error_file(const char *logfile) {}
1582
1583
1584 // This method is a copy of JDK's sysGetLastErrorString
1585 // from src/solaris/hpi/src/system_md.c
1586
1587 size_t os::lasterror(char *buf, size_t len) {
1588
1589 if (errno == 0) return 0;
1590
1591 const char *s = ::strerror(errno);
1592 size_t n = ::strlen(s);
1593 if (n >= len) {
1594 n = len - 1;
1595 }
1596 ::strncpy(buf, s, n);
1597 buf[n] = '\0';
1598 return n;
1599 }
1600
1601 intx os::current_thread_id() { return (intx)pthread_self(); }
1602 int os::current_process_id() {
1603
1604 // Under the old linux thread library, linux gives each thread
1605 // its own process id. Because of this each thread will return
1606 // a different pid if this method were to return the result
1607 // of getpid(2). Linux provides no api that returns the pid
1608 // of the launcher thread for the vm. This implementation
1609 // returns a unique pid, the pid of the launcher thread
1610 // that starts the vm 'process'.
1611
1612 // Under the NPTL, getpid() returns the same pid as the
1613 // launcher thread rather than a unique pid per thread.
1614 // Use gettid() if you want the old pre NPTL behaviour.
1615
1616 // if you are looking for the result of a call to getpid() that
1617 // returns a unique pid for the calling thread, then look at the
1618 // OSThread::thread_id() method in osThread_linux.hpp file
1619
1620 return (int)(_initial_pid ? _initial_pid : getpid());
1621 }
1622
1623 // DLL functions
1624
1625 const char* os::dll_file_extension() { return ".so"; }
1626
1627 // This must be hard coded because it's the system's temporary
1628 // directory not the java application's temp directory, ala java.io.tmpdir.
1629 const char* os::get_temp_directory() { return "/tmp"; }
1630
1631 static bool file_exists(const char* filename) {
1632 struct stat statbuf;
1633 if (filename == NULL || strlen(filename) == 0) {
1634 return false;
1635 }
1636 return os::stat(filename, &statbuf) == 0;
1637 }
1638
1639 bool os::dll_build_name(char* buffer, size_t buflen,
1640 const char* pname, const char* fname) {
1641 bool retval = false;
1642 // Copied from libhpi
1643 const size_t pnamelen = pname ? strlen(pname) : 0;
1644
1645 // Return error on buffer overflow.
1646 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1647 return retval;
1648 }
1649
1650 if (pnamelen == 0) {
1651 snprintf(buffer, buflen, "lib%s.so", fname);
1652 retval = true;
1653 } else if (strchr(pname, *os::path_separator()) != NULL) {
1654 int n;
1655 char** pelements = split_path(pname, &n);
1656 if (pelements == NULL) {
1657 return false;
1658 }
1659 for (int i = 0 ; i < n ; i++) {
1660 // Really shouldn't be NULL, but check can't hurt
1661 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1662 continue; // skip the empty path values
1663 }
1664 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1665 if (file_exists(buffer)) {
1666 retval = true;
1667 break;
1668 }
1669 }
1670 // release the storage
1671 for (int i = 0 ; i < n ; i++) {
1672 if (pelements[i] != NULL) {
1673 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1674 }
1675 }
1676 if (pelements != NULL) {
1677 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1678 }
1679 } else {
1680 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1681 retval = true;
1682 }
1683 return retval;
1684 }
1685
1686 // check if addr is inside libjvm.so
1687 bool os::address_is_in_vm(address addr) {
1688 static address libjvm_base_addr;
1689 Dl_info dlinfo;
1690
1691 if (libjvm_base_addr == NULL) {
1692 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1693 libjvm_base_addr = (address)dlinfo.dli_fbase;
1694 }
1695 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1696 }
1697
1698 if (dladdr((void *)addr, &dlinfo) != 0) {
1699 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1700 }
1701
1702 return false;
1703 }
1704
1705 bool os::dll_address_to_function_name(address addr, char *buf,
1706 int buflen, int *offset) {
1707 // buf is not optional, but offset is optional
1708 assert(buf != NULL, "sanity check");
1709
1710 Dl_info dlinfo;
1711
1712 if (dladdr((void*)addr, &dlinfo) != 0) {
1713 // see if we have a matching symbol
1714 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1715 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1716 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1717 }
1718 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1719 return true;
1720 }
1721 // no matching symbol so try for just file info
1722 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1723 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1724 buf, buflen, offset, dlinfo.dli_fname)) {
1725 return true;
1726 }
1727 }
1728 }
1729
1730 buf[0] = '\0';
1731 if (offset != NULL) *offset = -1;
1732 return false;
1733 }
1734
1735 struct _address_to_library_name {
1736 address addr; // input : memory address
1737 size_t buflen; // size of fname
1738 char* fname; // output: library name
1739 address base; // library base addr
1740 };
1741
1742 static int address_to_library_name_callback(struct dl_phdr_info *info,
1743 size_t size, void *data) {
1744 int i;
1745 bool found = false;
1746 address libbase = NULL;
1747 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1748
1749 // iterate through all loadable segments
1750 for (i = 0; i < info->dlpi_phnum; i++) {
1751 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1752 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1753 // base address of a library is the lowest address of its loaded
1754 // segments.
1755 if (libbase == NULL || libbase > segbase) {
1756 libbase = segbase;
1757 }
1758 // see if 'addr' is within current segment
1759 if (segbase <= d->addr &&
1760 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1761 found = true;
1762 }
1763 }
1764 }
1765
1766 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1767 // so dll_address_to_library_name() can fall through to use dladdr() which
1768 // can figure out executable name from argv[0].
1769 if (found && info->dlpi_name && info->dlpi_name[0]) {
1770 d->base = libbase;
1771 if (d->fname) {
1772 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1773 }
1774 return 1;
1775 }
1776 return 0;
1777 }
1778
1779 bool os::dll_address_to_library_name(address addr, char* buf,
1780 int buflen, int* offset) {
1781 // buf is not optional, but offset is optional
1782 assert(buf != NULL, "sanity check");
1783
1784 Dl_info dlinfo;
1785 struct _address_to_library_name data;
1786
1787 // There is a bug in old glibc dladdr() implementation that it could resolve
1788 // to wrong library name if the .so file has a base address != NULL. Here
1789 // we iterate through the program headers of all loaded libraries to find
1790 // out which library 'addr' really belongs to. This workaround can be
1791 // removed once the minimum requirement for glibc is moved to 2.3.x.
1792 data.addr = addr;
1793 data.fname = buf;
1794 data.buflen = buflen;
1795 data.base = NULL;
1796 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1797
1798 if (rslt) {
1799 // buf already contains library name
1800 if (offset) *offset = addr - data.base;
1801 return true;
1802 }
1803 if (dladdr((void*)addr, &dlinfo) != 0) {
1804 if (dlinfo.dli_fname != NULL) {
1805 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1806 }
1807 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1808 *offset = addr - (address)dlinfo.dli_fbase;
1809 }
1810 return true;
1811 }
1812
1813 buf[0] = '\0';
1814 if (offset) *offset = -1;
1815 return false;
1816 }
1817
1818 // Loads .dll/.so and
1819 // in case of error it checks if .dll/.so was built for the
1820 // same architecture as Hotspot is running on
1821
1822
1823 // Remember the stack's state. The Linux dynamic linker will change
1824 // the stack to 'executable' at most once, so we must safepoint only once.
1825 bool os::Linux::_stack_is_executable = false;
1826
1827 // VM operation that loads a library. This is necessary if stack protection
1828 // of the Java stacks can be lost during loading the library. If we
1829 // do not stop the Java threads, they can stack overflow before the stacks
1830 // are protected again.
1831 class VM_LinuxDllLoad: public VM_Operation {
1832 private:
1833 const char *_filename;
1834 char *_ebuf;
1835 int _ebuflen;
1836 void *_lib;
1837 public:
1838 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1839 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1840 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1841 void doit() {
1842 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1843 os::Linux::_stack_is_executable = true;
1844 }
1845 void* loaded_library() { return _lib; }
1846 };
1847
1848 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1849 {
1850 void * result = NULL;
1851 bool load_attempted = false;
1852
1853 // Check whether the library to load might change execution rights
1854 // of the stack. If they are changed, the protection of the stack
1855 // guard pages will be lost. We need a safepoint to fix this.
1856 //
1857 // See Linux man page execstack(8) for more info.
1858 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1859 ElfFile ef(filename);
1860 if (!ef.specifies_noexecstack()) {
1861 if (!is_init_completed()) {
1862 os::Linux::_stack_is_executable = true;
1863 // This is OK - No Java threads have been created yet, and hence no
1864 // stack guard pages to fix.
1865 //
1866 // This should happen only when you are building JDK7 using a very
1867 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1868 //
1869 // Dynamic loader will make all stacks executable after
1870 // this function returns, and will not do that again.
1871 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1872 } else {
1873 warning("You have loaded library %s which might have disabled stack guard. "
1874 "The VM will try to fix the stack guard now.\n"
1875 "It's highly recommended that you fix the library with "
1876 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1877 filename);
1878
1879 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1880 JavaThread *jt = JavaThread::current();
1881 if (jt->thread_state() != _thread_in_native) {
1882 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1883 // that requires ExecStack. Cannot enter safe point. Let's give up.
1884 warning("Unable to fix stack guard. Giving up.");
1885 } else {
1886 if (!LoadExecStackDllInVMThread) {
1887 // This is for the case where the DLL has an static
1888 // constructor function that executes JNI code. We cannot
1889 // load such DLLs in the VMThread.
1890 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1891 }
1892
1893 ThreadInVMfromNative tiv(jt);
1894 debug_only(VMNativeEntryWrapper vew;)
1895
1896 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1897 VMThread::execute(&op);
1898 if (LoadExecStackDllInVMThread) {
1899 result = op.loaded_library();
1900 }
1901 load_attempted = true;
1902 }
1903 }
1904 }
1905 }
1906
1907 if (!load_attempted) {
1908 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1909 }
1910
1911 if (result != NULL) {
1912 // Successful loading
1913 return result;
1914 }
1915
1916 Elf32_Ehdr elf_head;
1917 int diag_msg_max_length=ebuflen-strlen(ebuf);
1918 char* diag_msg_buf=ebuf+strlen(ebuf);
1919
1920 if (diag_msg_max_length==0) {
1921 // No more space in ebuf for additional diagnostics message
1922 return NULL;
1923 }
1924
1925
1926 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1927
1928 if (file_descriptor < 0) {
1929 // Can't open library, report dlerror() message
1930 return NULL;
1931 }
1932
1933 bool failed_to_read_elf_head=
1934 (sizeof(elf_head)!=
1935 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1936
1937 ::close(file_descriptor);
1938 if (failed_to_read_elf_head) {
1939 // file i/o error - report dlerror() msg
1940 return NULL;
1941 }
1942
1943 typedef struct {
1944 Elf32_Half code; // Actual value as defined in elf.h
1945 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1946 char elf_class; // 32 or 64 bit
1947 char endianess; // MSB or LSB
1948 char* name; // String representation
1949 } arch_t;
1950
1951 #ifndef EM_486
1952 #define EM_486 6 /* Intel 80486 */
1953 #endif
1954
1955 static const arch_t arch_array[]={
1956 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1957 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1958 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1959 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1960 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1961 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1962 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1963 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1964 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1965 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1966 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1967 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1968 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1969 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1970 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1971 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1972 };
1973
1974 #if (defined IA32)
1975 static Elf32_Half running_arch_code=EM_386;
1976 #elif (defined AMD64)
1977 static Elf32_Half running_arch_code=EM_X86_64;
1978 #elif (defined IA64)
1979 static Elf32_Half running_arch_code=EM_IA_64;
1980 #elif (defined __sparc) && (defined _LP64)
1981 static Elf32_Half running_arch_code=EM_SPARCV9;
1982 #elif (defined __sparc) && (!defined _LP64)
1983 static Elf32_Half running_arch_code=EM_SPARC;
1984 #elif (defined __powerpc64__)
1985 static Elf32_Half running_arch_code=EM_PPC64;
1986 #elif (defined __powerpc__)
1987 static Elf32_Half running_arch_code=EM_PPC;
1988 #elif (defined ARM)
1989 static Elf32_Half running_arch_code=EM_ARM;
1990 #elif (defined S390)
1991 static Elf32_Half running_arch_code=EM_S390;
1992 #elif (defined ALPHA)
1993 static Elf32_Half running_arch_code=EM_ALPHA;
1994 #elif (defined MIPSEL)
1995 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1996 #elif (defined PARISC)
1997 static Elf32_Half running_arch_code=EM_PARISC;
1998 #elif (defined MIPS)
1999 static Elf32_Half running_arch_code=EM_MIPS;
2000 #elif (defined M68K)
2001 static Elf32_Half running_arch_code=EM_68K;
2002 #else
2003 #error Method os::dll_load requires that one of following is defined:\
2004 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
2005 #endif
2006
2007 // Identify compatability class for VM's architecture and library's architecture
2008 // Obtain string descriptions for architectures
2009
2010 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
2011 int running_arch_index=-1;
2012
2013 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
2014 if (running_arch_code == arch_array[i].code) {
2015 running_arch_index = i;
2016 }
2017 if (lib_arch.code == arch_array[i].code) {
2018 lib_arch.compat_class = arch_array[i].compat_class;
2019 lib_arch.name = arch_array[i].name;
2020 }
2021 }
2022
2023 assert(running_arch_index != -1,
2024 "Didn't find running architecture code (running_arch_code) in arch_array");
2025 if (running_arch_index == -1) {
2026 // Even though running architecture detection failed
2027 // we may still continue with reporting dlerror() message
2028 return NULL;
2029 }
2030
2031 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
2032 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
2033 return NULL;
2034 }
2035
2036 #ifndef S390
2037 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
2038 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
2039 return NULL;
2040 }
2041 #endif // !S390
2042
2043 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
2044 if ( lib_arch.name!=NULL ) {
2045 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2046 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
2047 lib_arch.name, arch_array[running_arch_index].name);
2048 } else {
2049 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2050 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
2051 lib_arch.code,
2052 arch_array[running_arch_index].name);
2053 }
2054 }
2055
2056 return NULL;
2057 }
2058
2059 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) {
2060 void * result = ::dlopen(filename, RTLD_LAZY);
2061 if (result == NULL) {
2062 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
2063 ebuf[ebuflen-1] = '\0';
2064 }
2065 return result;
2066 }
2067
2068 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) {
2069 void * result = NULL;
2070 if (LoadExecStackDllInVMThread) {
2071 result = dlopen_helper(filename, ebuf, ebuflen);
2072 }
2073
2074 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2075 // library that requires an executable stack, or which does not have this
2076 // stack attribute set, dlopen changes the stack attribute to executable. The
2077 // read protection of the guard pages gets lost.
2078 //
2079 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2080 // may have been queued at the same time.
2081
2082 if (!_stack_is_executable) {
2083 JavaThread *jt = Threads::first();
2084
2085 while (jt) {
2086 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2087 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions
2088 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(),
2089 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) {
2090 warning("Attempt to reguard stack yellow zone failed.");
2091 }
2092 }
2093 jt = jt->next();
2094 }
2095 }
2096
2097 return result;
2098 }
2099
2100 /*
2101 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
2102 * chances are you might want to run the generated bits against glibc-2.0
2103 * libdl.so, so always use locking for any version of glibc.
2104 */
2105 void* os::dll_lookup(void* handle, const char* name) {
2106 pthread_mutex_lock(&dl_mutex);
2107 void* res = dlsym(handle, name);
2108 pthread_mutex_unlock(&dl_mutex);
2109 return res;
2110 }
2111
2112 void* os::get_default_process_handle() {
2113 return (void*)::dlopen(NULL, RTLD_LAZY);
2114 }
2115
2116 static bool _print_ascii_file(const char* filename, outputStream* st) {
2117 int fd = ::open(filename, O_RDONLY);
2118 if (fd == -1) {
2119 return false;
2120 }
2121
2122 char buf[32];
2123 int bytes;
2124 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2125 st->print_raw(buf, bytes);
2126 }
2127
2128 ::close(fd);
2129
2130 return true;
2131 }
2132
2133 void os::print_dll_info(outputStream *st) {
2134 st->print_cr("Dynamic libraries:");
2135
2136 char fname[32];
2137 pid_t pid = os::Linux::gettid();
2138
2139 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2140
2141 if (!_print_ascii_file(fname, st)) {
2142 st->print("Can not get library information for pid = %d\n", pid);
2143 }
2144 }
2145
2146 void os::print_os_info_brief(outputStream* st) {
2147 os::Linux::print_distro_info(st);
2148
2149 os::Posix::print_uname_info(st);
2150
2151 os::Linux::print_libversion_info(st);
2152
2153 }
2154
2155 void os::print_os_info(outputStream* st) {
2156 st->print("OS:");
2157
2158 os::Linux::print_distro_info(st);
2159
2160 os::Posix::print_uname_info(st);
2161
2162 // Print warning if unsafe chroot environment detected
2163 if (unsafe_chroot_detected) {
2164 st->print("WARNING!! ");
2165 st->print_cr(unstable_chroot_error);
2166 }
2167
2168 os::Linux::print_libversion_info(st);
2169
2170 os::Posix::print_rlimit_info(st);
2171
2172 os::Posix::print_load_average(st);
2173
2174 os::Linux::print_full_memory_info(st);
2175 }
2176
2177 // Try to identify popular distros.
2178 // Most Linux distributions have a /etc/XXX-release file, which contains
2179 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2180 // file that also contains the OS version string. Some have more than one
2181 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2182 // /etc/redhat-release.), so the order is important.
2183 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2184 // their own specific XXX-release file as well as a redhat-release file.
2185 // Because of this the XXX-release file needs to be searched for before the
2186 // redhat-release file.
2187 // Since Red Hat has a lsb-release file that is not very descriptive the
2188 // search for redhat-release needs to be before lsb-release.
2189 // Since the lsb-release file is the new standard it needs to be searched
2190 // before the older style release files.
2191 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2192 // next to last resort. The os-release file is a new standard that contains
2193 // distribution information and the system-release file seems to be an old
2194 // standard that has been replaced by the lsb-release and os-release files.
2195 // Searching for the debian_version file is the last resort. It contains
2196 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2197 // "Debian " is printed before the contents of the debian_version file.
2198 void os::Linux::print_distro_info(outputStream* st) {
2199 if (!_print_ascii_file("/etc/oracle-release", st) &&
2200 !_print_ascii_file("/etc/mandriva-release", st) &&
2201 !_print_ascii_file("/etc/mandrake-release", st) &&
2202 !_print_ascii_file("/etc/sun-release", st) &&
2203 !_print_ascii_file("/etc/redhat-release", st) &&
2204 !_print_ascii_file("/etc/lsb-release", st) &&
2205 !_print_ascii_file("/etc/SuSE-release", st) &&
2206 !_print_ascii_file("/etc/turbolinux-release", st) &&
2207 !_print_ascii_file("/etc/gentoo-release", st) &&
2208 !_print_ascii_file("/etc/ltib-release", st) &&
2209 !_print_ascii_file("/etc/angstrom-version", st) &&
2210 !_print_ascii_file("/etc/system-release", st) &&
2211 !_print_ascii_file("/etc/os-release", st)) {
2212
2213 if (file_exists("/etc/debian_version")) {
2214 st->print("Debian ");
2215 _print_ascii_file("/etc/debian_version", st);
2216 } else {
2217 st->print("Linux");
2218 }
2219 }
2220 st->cr();
2221 }
2222
2223 void os::Linux::print_libversion_info(outputStream* st) {
2224 // libc, pthread
2225 st->print("libc:");
2226 st->print(os::Linux::glibc_version()); st->print(" ");
2227 st->print(os::Linux::libpthread_version()); st->print(" ");
2228 if (os::Linux::is_LinuxThreads()) {
2229 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2230 }
2231 st->cr();
2232 }
2233
2234 void os::Linux::print_full_memory_info(outputStream* st) {
2235 st->print("\n/proc/meminfo:\n");
2236 _print_ascii_file("/proc/meminfo", st);
2237 st->cr();
2238 }
2239
2240 void os::print_memory_info(outputStream* st) {
2241
2242 st->print("Memory:");
2243 st->print(" %dk page", os::vm_page_size()>>10);
2244
2245 // values in struct sysinfo are "unsigned long"
2246 struct sysinfo si;
2247 sysinfo(&si);
2248
2249 st->print(", physical " UINT64_FORMAT "k",
2250 os::physical_memory() >> 10);
2251 st->print("(" UINT64_FORMAT "k free)",
2252 os::available_memory() >> 10);
2253 st->print(", swap " UINT64_FORMAT "k",
2254 ((jlong)si.totalswap * si.mem_unit) >> 10);
2255 st->print("(" UINT64_FORMAT "k free)",
2256 ((jlong)si.freeswap * si.mem_unit) >> 10);
2257 st->cr();
2258 }
2259
2260 void os::pd_print_cpu_info(outputStream* st) {
2261 st->print("\n/proc/cpuinfo:\n");
2262 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2263 st->print(" <Not Available>");
2264 }
2265 st->cr();
2266 }
2267
2268 void os::print_siginfo(outputStream* st, void* siginfo) {
2269 const siginfo_t* si = (const siginfo_t*)siginfo;
2270
2271 os::Posix::print_siginfo_brief(st, si);
2272
2273 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2274 UseSharedSpaces) {
2275 FileMapInfo* mapinfo = FileMapInfo::current_info();
2276 if (mapinfo->is_in_shared_space(si->si_addr)) {
2277 st->print("\n\nError accessing class data sharing archive." \
2278 " Mapped file inaccessible during execution, " \
2279 " possible disk/network problem.");
2280 }
2281 }
2282 st->cr();
2283 }
2284
2285
2286 static void print_signal_handler(outputStream* st, int sig,
2287 char* buf, size_t buflen);
2288
2289 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2290 st->print_cr("Signal Handlers:");
2291 print_signal_handler(st, SIGSEGV, buf, buflen);
2292 print_signal_handler(st, SIGBUS , buf, buflen);
2293 print_signal_handler(st, SIGFPE , buf, buflen);
2294 print_signal_handler(st, SIGPIPE, buf, buflen);
2295 print_signal_handler(st, SIGXFSZ, buf, buflen);
2296 print_signal_handler(st, SIGILL , buf, buflen);
2297 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2298 print_signal_handler(st, SR_signum, buf, buflen);
2299 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2300 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2301 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2302 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2303 #if defined(PPC64)
2304 print_signal_handler(st, SIGTRAP, buf, buflen);
2305 #endif
2306 }
2307
2308 static char saved_jvm_path[MAXPATHLEN] = {0};
2309
2310 // Find the full path to the current module, libjvm.so
2311 void os::jvm_path(char *buf, jint buflen) {
2312 // Error checking.
2313 if (buflen < MAXPATHLEN) {
2314 assert(false, "must use a large-enough buffer");
2315 buf[0] = '\0';
2316 return;
2317 }
2318 // Lazy resolve the path to current module.
2319 if (saved_jvm_path[0] != 0) {
2320 strcpy(buf, saved_jvm_path);
2321 return;
2322 }
2323
2324 char dli_fname[MAXPATHLEN];
2325 bool ret = dll_address_to_library_name(
2326 CAST_FROM_FN_PTR(address, os::jvm_path),
2327 dli_fname, sizeof(dli_fname), NULL);
2328 assert(ret, "cannot locate libjvm");
2329 char *rp = NULL;
2330 if (ret && dli_fname[0] != '\0') {
2331 rp = realpath(dli_fname, buf);
2332 }
2333 if (rp == NULL)
2334 return;
2335
2336 if (Arguments::sun_java_launcher_is_altjvm()) {
2337 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2338 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so".
2339 // If "/jre/lib/" appears at the right place in the string, then
2340 // assume we are installed in a JDK and we're done. Otherwise, check
2341 // for a JAVA_HOME environment variable and fix up the path so it
2342 // looks like libjvm.so is installed there (append a fake suffix
2343 // hotspot/libjvm.so).
2344 const char *p = buf + strlen(buf) - 1;
2345 for (int count = 0; p > buf && count < 5; ++count) {
2346 for (--p; p > buf && *p != '/'; --p)
2347 /* empty */ ;
2348 }
2349
2350 if (strncmp(p, "/jre/lib/", 9) != 0) {
2351 // Look for JAVA_HOME in the environment.
2352 char* java_home_var = ::getenv("JAVA_HOME");
2353 if (java_home_var != NULL && java_home_var[0] != 0) {
2354 char* jrelib_p;
2355 int len;
2356
2357 // Check the current module name "libjvm.so".
2358 p = strrchr(buf, '/');
2359 assert(strstr(p, "/libjvm") == p, "invalid library name");
2360
2361 rp = realpath(java_home_var, buf);
2362 if (rp == NULL)
2363 return;
2364
2365 // determine if this is a legacy image or modules image
2366 // modules image doesn't have "jre" subdirectory
2367 len = strlen(buf);
2368 jrelib_p = buf + len;
2369 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2370 if (0 != access(buf, F_OK)) {
2371 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2372 }
2373
2374 if (0 == access(buf, F_OK)) {
2375 // Use current module name "libjvm.so"
2376 len = strlen(buf);
2377 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2378 } else {
2379 // Go back to path of .so
2380 rp = realpath(dli_fname, buf);
2381 if (rp == NULL)
2382 return;
2383 }
2384 }
2385 }
2386 }
2387
2388 strcpy(saved_jvm_path, buf);
2389 }
2390
2391 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2392 // no prefix required, not even "_"
2393 }
2394
2395 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2396 // no suffix required
2397 }
2398
2399 ////////////////////////////////////////////////////////////////////////////////
2400 // sun.misc.Signal support
2401
2402 static volatile jint sigint_count = 0;
2403
2404 static void
2405 UserHandler(int sig, void *siginfo, void *context) {
2406 // 4511530 - sem_post is serialized and handled by the manager thread. When
2407 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2408 // don't want to flood the manager thread with sem_post requests.
2409 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2410 return;
2411
2412 // Ctrl-C is pressed during error reporting, likely because the error
2413 // handler fails to abort. Let VM die immediately.
2414 if (sig == SIGINT && is_error_reported()) {
2415 os::die();
2416 }
2417
2418 os::signal_notify(sig);
2419 }
2420
2421 void* os::user_handler() {
2422 return CAST_FROM_FN_PTR(void*, UserHandler);
2423 }
2424
2425 class Semaphore : public StackObj {
2426 public:
2427 Semaphore();
2428 ~Semaphore();
2429 void signal();
2430 void wait();
2431 bool trywait();
2432 bool timedwait(unsigned int sec, int nsec);
2433 private:
2434 sem_t _semaphore;
2435 };
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 unpackTime(&ts, false, (sec * NANOSECS_PER_SEC) + nsec);
2461
2462 while (1) {
2463 int result = sem_timedwait(&_semaphore, &ts);
2464 if (result == 0) {
2465 return true;
2466 } else if (errno == EINTR) {
2467 continue;
2468 } else if (errno == ETIMEDOUT) {
2469 return false;
2470 } else {
2471 return false;
2472 }
2473 }
2474 }
2475
2476 extern "C" {
2477 typedef void (*sa_handler_t)(int);
2478 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2479 }
2480
2481 void* os::signal(int signal_number, void* handler) {
2482 struct sigaction sigAct, oldSigAct;
2483
2484 sigfillset(&(sigAct.sa_mask));
2485 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2486 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2487
2488 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2489 // -1 means registration failed
2490 return (void *)-1;
2491 }
2492
2493 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2494 }
2495
2496 void os::signal_raise(int signal_number) {
2497 ::raise(signal_number);
2498 }
2499
2500 /*
2501 * The following code is moved from os.cpp for making this
2502 * code platform specific, which it is by its very nature.
2503 */
2504
2505 // Will be modified when max signal is changed to be dynamic
2506 int os::sigexitnum_pd() {
2507 return NSIG;
2508 }
2509
2510 // a counter for each possible signal value
2511 static volatile jint pending_signals[NSIG+1] = { 0 };
2512
2513 // Linux(POSIX) specific hand shaking semaphore.
2514 static sem_t sig_sem;
2515 static Semaphore sr_semaphore;
2516
2517 void os::signal_init_pd() {
2518 // Initialize signal structures
2519 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2520
2521 // Initialize signal semaphore
2522 ::sem_init(&sig_sem, 0, 0);
2523 }
2524
2525 void os::signal_notify(int sig) {
2526 Atomic::inc(&pending_signals[sig]);
2527 ::sem_post(&sig_sem);
2528 }
2529
2530 static int check_pending_signals(bool wait) {
2531 Atomic::store(0, &sigint_count);
2532 for (;;) {
2533 for (int i = 0; i < NSIG + 1; i++) {
2534 jint n = pending_signals[i];
2535 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2536 return i;
2537 }
2538 }
2539 if (!wait) {
2540 return -1;
2541 }
2542 JavaThread *thread = JavaThread::current();
2543 ThreadBlockInVM tbivm(thread);
2544
2545 bool threadIsSuspended;
2546 do {
2547 thread->set_suspend_equivalent();
2548 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2549 ::sem_wait(&sig_sem);
2550
2551 // were we externally suspended while we were waiting?
2552 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2553 if (threadIsSuspended) {
2554 //
2555 // The semaphore has been incremented, but while we were waiting
2556 // another thread suspended us. We don't want to continue running
2557 // while suspended because that would surprise the thread that
2558 // suspended us.
2559 //
2560 ::sem_post(&sig_sem);
2561
2562 thread->java_suspend_self();
2563 }
2564 } while (threadIsSuspended);
2565 }
2566 }
2567
2568 int os::signal_lookup() {
2569 return check_pending_signals(false);
2570 }
2571
2572 int os::signal_wait() {
2573 return check_pending_signals(true);
2574 }
2575
2576 ////////////////////////////////////////////////////////////////////////////////
2577 // Virtual Memory
2578
2579 int os::vm_page_size() {
2580 // Seems redundant as all get out
2581 assert(os::Linux::page_size() != -1, "must call os::init");
2582 return os::Linux::page_size();
2583 }
2584
2585 // Solaris allocates memory by pages.
2586 int os::vm_allocation_granularity() {
2587 assert(os::Linux::page_size() != -1, "must call os::init");
2588 return os::Linux::page_size();
2589 }
2590
2591 // Rationale behind this function:
2592 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2593 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2594 // samples for JITted code. Here we create private executable mapping over the code cache
2595 // and then we can use standard (well, almost, as mapping can change) way to provide
2596 // info for the reporting script by storing timestamp and location of symbol
2597 void linux_wrap_code(char* base, size_t size) {
2598 static volatile jint cnt = 0;
2599
2600 if (!UseOprofile) {
2601 return;
2602 }
2603
2604 char buf[PATH_MAX+1];
2605 int num = Atomic::add(1, &cnt);
2606
2607 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2608 os::get_temp_directory(), os::current_process_id(), num);
2609 unlink(buf);
2610
2611 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2612
2613 if (fd != -1) {
2614 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2615 if (rv != (off_t)-1) {
2616 if (::write(fd, "", 1) == 1) {
2617 mmap(base, size,
2618 PROT_READ|PROT_WRITE|PROT_EXEC,
2619 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2620 }
2621 }
2622 ::close(fd);
2623 unlink(buf);
2624 }
2625 }
2626
2627 static bool recoverable_mmap_error(int err) {
2628 // See if the error is one we can let the caller handle. This
2629 // list of errno values comes from JBS-6843484. I can't find a
2630 // Linux man page that documents this specific set of errno
2631 // values so while this list currently matches Solaris, it may
2632 // change as we gain experience with this failure mode.
2633 switch (err) {
2634 case EBADF:
2635 case EINVAL:
2636 case ENOTSUP:
2637 // let the caller deal with these errors
2638 return true;
2639
2640 default:
2641 // Any remaining errors on this OS can cause our reserved mapping
2642 // to be lost. That can cause confusion where different data
2643 // structures think they have the same memory mapped. The worst
2644 // scenario is if both the VM and a library think they have the
2645 // same memory mapped.
2646 return false;
2647 }
2648 }
2649
2650 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2651 int err) {
2652 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2653 ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2654 strerror(err), err);
2655 }
2656
2657 static void warn_fail_commit_memory(char* addr, size_t size,
2658 size_t alignment_hint, bool exec,
2659 int err) {
2660 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2661 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size,
2662 alignment_hint, exec, strerror(err), err);
2663 }
2664
2665 // NOTE: Linux kernel does not really reserve the pages for us.
2666 // All it does is to check if there are enough free pages
2667 // left at the time of mmap(). This could be a potential
2668 // problem.
2669 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2670 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2671 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2672 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2673 if (res != (uintptr_t) MAP_FAILED) {
2674 if (UseNUMAInterleaving) {
2675 numa_make_global(addr, size);
2676 }
2677 return 0;
2678 }
2679
2680 int err = errno; // save errno from mmap() call above
2681
2682 if (!recoverable_mmap_error(err)) {
2683 warn_fail_commit_memory(addr, size, exec, err);
2684 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2685 }
2686
2687 return err;
2688 }
2689
2690 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2691 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2692 }
2693
2694 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2695 const char* mesg) {
2696 assert(mesg != NULL, "mesg must be specified");
2697 int err = os::Linux::commit_memory_impl(addr, size, exec);
2698 if (err != 0) {
2699 // the caller wants all commit errors to exit with the specified mesg:
2700 warn_fail_commit_memory(addr, size, exec, err);
2701 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2702 }
2703 }
2704
2705 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2706 #ifndef MAP_HUGETLB
2707 #define MAP_HUGETLB 0x40000
2708 #endif
2709
2710 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2711 #ifndef MADV_HUGEPAGE
2712 #define MADV_HUGEPAGE 14
2713 #endif
2714
2715 int os::Linux::commit_memory_impl(char* addr, size_t size,
2716 size_t alignment_hint, bool exec) {
2717 int err = os::Linux::commit_memory_impl(addr, size, exec);
2718 if (err == 0) {
2719 realign_memory(addr, size, alignment_hint);
2720 }
2721 return err;
2722 }
2723
2724 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2725 bool exec) {
2726 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2727 }
2728
2729 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2730 size_t alignment_hint, bool exec,
2731 const char* mesg) {
2732 assert(mesg != NULL, "mesg must be specified");
2733 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2734 if (err != 0) {
2735 // the caller wants all commit errors to exit with the specified mesg:
2736 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2737 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2738 }
2739 }
2740
2741 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2742 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2743 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2744 // be supported or the memory may already be backed by huge pages.
2745 ::madvise(addr, bytes, MADV_HUGEPAGE);
2746 }
2747 }
2748
2749 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2750 // This method works by doing an mmap over an existing mmaping and effectively discarding
2751 // the existing pages. However it won't work for SHM-based large pages that cannot be
2752 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2753 // small pages on top of the SHM segment. This method always works for small pages, so we
2754 // allow that in any case.
2755 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2756 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2757 }
2758 }
2759
2760 void os::numa_make_global(char *addr, size_t bytes) {
2761 Linux::numa_interleave_memory(addr, bytes);
2762 }
2763
2764 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2765 // bind policy to MPOL_PREFERRED for the current thread.
2766 #define USE_MPOL_PREFERRED 0
2767
2768 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2769 // To make NUMA and large pages more robust when both enabled, we need to ease
2770 // the requirements on where the memory should be allocated. MPOL_BIND is the
2771 // default policy and it will force memory to be allocated on the specified
2772 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2773 // the specified node, but will not force it. Using this policy will prevent
2774 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2775 // free large pages.
2776 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2777 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2778 }
2779
2780 bool os::numa_topology_changed() { return false; }
2781
2782 size_t os::numa_get_groups_num() {
2783 int max_node = Linux::numa_max_node();
2784 return max_node > 0 ? max_node + 1 : 1;
2785 }
2786
2787 int os::numa_get_group_id() {
2788 int cpu_id = Linux::sched_getcpu();
2789 if (cpu_id != -1) {
2790 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2791 if (lgrp_id != -1) {
2792 return lgrp_id;
2793 }
2794 }
2795 return 0;
2796 }
2797
2798 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2799 for (size_t i = 0; i < size; i++) {
2800 ids[i] = i;
2801 }
2802 return size;
2803 }
2804
2805 bool os::get_page_info(char *start, page_info* info) {
2806 return false;
2807 }
2808
2809 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2810 return end;
2811 }
2812
2813
2814 int os::Linux::sched_getcpu_syscall(void) {
2815 unsigned int cpu;
2816 int retval = -1;
2817
2818 #if defined(IA32)
2819 # ifndef SYS_getcpu
2820 # define SYS_getcpu 318
2821 # endif
2822 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2823 #elif defined(AMD64)
2824 // Unfortunately we have to bring all these macros here from vsyscall.h
2825 // to be able to compile on old linuxes.
2826 # define __NR_vgetcpu 2
2827 # define VSYSCALL_START (-10UL << 20)
2828 # define VSYSCALL_SIZE 1024
2829 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2830 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2831 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2832 retval = vgetcpu(&cpu, NULL, NULL);
2833 #endif
2834
2835 return (retval == -1) ? retval : cpu;
2836 }
2837
2838 // Something to do with the numa-aware allocator needs these symbols
2839 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2840 extern "C" JNIEXPORT void numa_error(char *where) { }
2841 extern "C" JNIEXPORT int fork1() { return fork(); }
2842
2843
2844 // If we are running with libnuma version > 2, then we should
2845 // be trying to use symbols with versions 1.1
2846 // If we are running with earlier version, which did not have symbol versions,
2847 // we should use the base version.
2848 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2849 void *f = dlvsym(handle, name, "libnuma_1.1");
2850 if (f == NULL) {
2851 f = dlsym(handle, name);
2852 }
2853 return f;
2854 }
2855
2856 bool os::Linux::libnuma_init() {
2857 // sched_getcpu() should be in libc.
2858 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2859 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2860
2861 // If it's not, try a direct syscall.
2862 if (sched_getcpu() == -1)
2863 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2864
2865 if (sched_getcpu() != -1) { // Does it work?
2866 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2867 if (handle != NULL) {
2868 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2869 libnuma_dlsym(handle, "numa_node_to_cpus")));
2870 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2871 libnuma_dlsym(handle, "numa_max_node")));
2872 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2873 libnuma_dlsym(handle, "numa_available")));
2874 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2875 libnuma_dlsym(handle, "numa_tonode_memory")));
2876 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2877 libnuma_dlsym(handle, "numa_interleave_memory")));
2878 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2879 libnuma_dlsym(handle, "numa_set_bind_policy")));
2880
2881
2882 if (numa_available() != -1) {
2883 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2884 // Create a cpu -> node mapping
2885 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2886 rebuild_cpu_to_node_map();
2887 return true;
2888 }
2889 }
2890 }
2891 return false;
2892 }
2893
2894 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2895 // The table is later used in get_node_by_cpu().
2896 void os::Linux::rebuild_cpu_to_node_map() {
2897 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2898 // in libnuma (possible values are starting from 16,
2899 // and continuing up with every other power of 2, but less
2900 // than the maximum number of CPUs supported by kernel), and
2901 // is a subject to change (in libnuma version 2 the requirements
2902 // are more reasonable) we'll just hardcode the number they use
2903 // in the library.
2904 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2905
2906 size_t cpu_num = os::active_processor_count();
2907 size_t cpu_map_size = NCPUS / BitsPerCLong;
2908 size_t cpu_map_valid_size =
2909 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2910
2911 cpu_to_node()->clear();
2912 cpu_to_node()->at_grow(cpu_num - 1);
2913 size_t node_num = numa_get_groups_num();
2914
2915 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2916 for (size_t i = 0; i < node_num; i++) {
2917 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2918 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2919 if (cpu_map[j] != 0) {
2920 for (size_t k = 0; k < BitsPerCLong; k++) {
2921 if (cpu_map[j] & (1UL << k)) {
2922 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2923 }
2924 }
2925 }
2926 }
2927 }
2928 }
2929 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
2930 }
2931
2932 int os::Linux::get_node_by_cpu(int cpu_id) {
2933 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2934 return cpu_to_node()->at(cpu_id);
2935 }
2936 return -1;
2937 }
2938
2939 GrowableArray<int>* os::Linux::_cpu_to_node;
2940 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2941 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2942 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2943 os::Linux::numa_available_func_t os::Linux::_numa_available;
2944 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2945 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2946 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2947 unsigned long* os::Linux::_numa_all_nodes;
2948
2949 bool os::pd_uncommit_memory(char* addr, size_t size) {
2950 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2951 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2952 return res != (uintptr_t) MAP_FAILED;
2953 }
2954
2955 static
2956 address get_stack_commited_bottom(address bottom, size_t size) {
2957 address nbot = bottom;
2958 address ntop = bottom + size;
2959
2960 size_t page_sz = os::vm_page_size();
2961 unsigned pages = size / page_sz;
2962
2963 unsigned char vec[1];
2964 unsigned imin = 1, imax = pages + 1, imid;
2965 int mincore_return_value = 0;
2966
2967 assert(imin <= imax, "Unexpected page size");
2968
2969 while (imin < imax) {
2970 imid = (imax + imin) / 2;
2971 nbot = ntop - (imid * page_sz);
2972
2973 // Use a trick with mincore to check whether the page is mapped or not.
2974 // mincore sets vec to 1 if page resides in memory and to 0 if page
2975 // is swapped output but if page we are asking for is unmapped
2976 // it returns -1,ENOMEM
2977 mincore_return_value = mincore(nbot, page_sz, vec);
2978
2979 if (mincore_return_value == -1) {
2980 // Page is not mapped go up
2981 // to find first mapped page
2982 if (errno != EAGAIN) {
2983 assert(errno == ENOMEM, "Unexpected mincore errno");
2984 imax = imid;
2985 }
2986 } else {
2987 // Page is mapped go down
2988 // to find first not mapped page
2989 imin = imid + 1;
2990 }
2991 }
2992
2993 nbot = nbot + page_sz;
2994
2995 // Adjust stack bottom one page up if last checked page is not mapped
2996 if (mincore_return_value == -1) {
2997 nbot = nbot + page_sz;
2998 }
2999
3000 return nbot;
3001 }
3002
3003
3004 // Linux uses a growable mapping for the stack, and if the mapping for
3005 // the stack guard pages is not removed when we detach a thread the
3006 // stack cannot grow beyond the pages where the stack guard was
3007 // mapped. If at some point later in the process the stack expands to
3008 // that point, the Linux kernel cannot expand the stack any further
3009 // because the guard pages are in the way, and a segfault occurs.
3010 //
3011 // However, it's essential not to split the stack region by unmapping
3012 // a region (leaving a hole) that's already part of the stack mapping,
3013 // so if the stack mapping has already grown beyond the guard pages at
3014 // the time we create them, we have to truncate the stack mapping.
3015 // So, we need to know the extent of the stack mapping when
3016 // create_stack_guard_pages() is called.
3017
3018 // We only need this for stacks that are growable: at the time of
3019 // writing thread stacks don't use growable mappings (i.e. those
3020 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3021 // only applies to the main thread.
3022
3023 // If the (growable) stack mapping already extends beyond the point
3024 // where we're going to put our guard pages, truncate the mapping at
3025 // that point by munmap()ping it. This ensures that when we later
3026 // munmap() the guard pages we don't leave a hole in the stack
3027 // mapping. This only affects the main/initial thread
3028
3029 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3030
3031 if (os::Linux::is_initial_thread()) {
3032 // As we manually grow stack up to bottom inside create_attached_thread(),
3033 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3034 // we don't need to do anything special.
3035 // Check it first, before calling heavy function.
3036 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3037 unsigned char vec[1];
3038
3039 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3040 // Fallback to slow path on all errors, including EAGAIN
3041 stack_extent = (uintptr_t) get_stack_commited_bottom(
3042 os::Linux::initial_thread_stack_bottom(),
3043 (size_t)addr - stack_extent);
3044 }
3045
3046 if (stack_extent < (uintptr_t)addr) {
3047 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3048 }
3049 }
3050
3051 return os::commit_memory(addr, size, !ExecMem);
3052 }
3053
3054 // If this is a growable mapping, remove the guard pages entirely by
3055 // munmap()ping them. If not, just call uncommit_memory(). This only
3056 // affects the main/initial thread, but guard against future OS changes
3057 // It's safe to always unmap guard pages for initial thread because we
3058 // always place it right after end of the mapped region
3059
3060 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3061 uintptr_t stack_extent, stack_base;
3062
3063 if (os::Linux::is_initial_thread()) {
3064 return ::munmap(addr, size) == 0;
3065 }
3066
3067 return os::uncommit_memory(addr, size);
3068 }
3069
3070 static address _highest_vm_reserved_address = NULL;
3071
3072 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3073 // at 'requested_addr'. If there are existing memory mappings at the same
3074 // location, however, they will be overwritten. If 'fixed' is false,
3075 // 'requested_addr' is only treated as a hint, the return value may or
3076 // may not start from the requested address. Unlike Linux mmap(), this
3077 // function returns NULL to indicate failure.
3078 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3079 char * addr;
3080 int flags;
3081
3082 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3083 if (fixed) {
3084 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3085 flags |= MAP_FIXED;
3086 }
3087
3088 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3089 // touch an uncommitted page. Otherwise, the read/write might
3090 // succeed if we have enough swap space to back the physical page.
3091 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3092 flags, -1, 0);
3093
3094 if (addr != MAP_FAILED) {
3095 // anon_mmap() should only get called during VM initialization,
3096 // don't need lock (actually we can skip locking even it can be called
3097 // from multiple threads, because _highest_vm_reserved_address is just a
3098 // hint about the upper limit of non-stack memory regions.)
3099 if ((address)addr + bytes > _highest_vm_reserved_address) {
3100 _highest_vm_reserved_address = (address)addr + bytes;
3101 }
3102 }
3103
3104 return addr == MAP_FAILED ? NULL : addr;
3105 }
3106
3107 // Don't update _highest_vm_reserved_address, because there might be memory
3108 // regions above addr + size. If so, releasing a memory region only creates
3109 // a hole in the address space, it doesn't help prevent heap-stack collision.
3110 //
3111 static int anon_munmap(char * addr, size_t size) {
3112 return ::munmap(addr, size) == 0;
3113 }
3114
3115 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3116 size_t alignment_hint) {
3117 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3118 }
3119
3120 bool os::pd_release_memory(char* addr, size_t size) {
3121 return anon_munmap(addr, size);
3122 }
3123
3124 static address highest_vm_reserved_address() {
3125 return _highest_vm_reserved_address;
3126 }
3127
3128 static bool linux_mprotect(char* addr, size_t size, int prot) {
3129 // Linux wants the mprotect address argument to be page aligned.
3130 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3131
3132 // According to SUSv3, mprotect() should only be used with mappings
3133 // established by mmap(), and mmap() always maps whole pages. Unaligned
3134 // 'addr' likely indicates problem in the VM (e.g. trying to change
3135 // protection of malloc'ed or statically allocated memory). Check the
3136 // caller if you hit this assert.
3137 assert(addr == bottom, "sanity check");
3138
3139 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3140 return ::mprotect(bottom, size, prot) == 0;
3141 }
3142
3143 // Set protections specified
3144 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3145 bool is_committed) {
3146 unsigned int p = 0;
3147 switch (prot) {
3148 case MEM_PROT_NONE: p = PROT_NONE; break;
3149 case MEM_PROT_READ: p = PROT_READ; break;
3150 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3151 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3152 default:
3153 ShouldNotReachHere();
3154 }
3155 // is_committed is unused.
3156 return linux_mprotect(addr, bytes, p);
3157 }
3158
3159 bool os::guard_memory(char* addr, size_t size) {
3160 return linux_mprotect(addr, size, PROT_NONE);
3161 }
3162
3163 bool os::unguard_memory(char* addr, size_t size) {
3164 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3165 }
3166
3167 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
3168 bool result = false;
3169 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3170 MAP_ANONYMOUS|MAP_PRIVATE,
3171 -1, 0);
3172 if (p != MAP_FAILED) {
3173 void *aligned_p = align_ptr_up(p, page_size);
3174
3175 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3176
3177 munmap(p, page_size * 2);
3178 }
3179
3180 if (warn && !result) {
3181 warning("TransparentHugePages is not supported by the operating system.");
3182 }
3183
3184 return result;
3185 }
3186
3187 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3188 bool result = false;
3189 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3190 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3191 -1, 0);
3192
3193 if (p != MAP_FAILED) {
3194 // We don't know if this really is a huge page or not.
3195 FILE *fp = fopen("/proc/self/maps", "r");
3196 if (fp) {
3197 while (!feof(fp)) {
3198 char chars[257];
3199 long x = 0;
3200 if (fgets(chars, sizeof(chars), fp)) {
3201 if (sscanf(chars, "%lx-%*x", &x) == 1
3202 && x == (long)p) {
3203 if (strstr (chars, "hugepage")) {
3204 result = true;
3205 break;
3206 }
3207 }
3208 }
3209 }
3210 fclose(fp);
3211 }
3212 munmap(p, page_size);
3213 }
3214
3215 if (warn && !result) {
3216 warning("HugeTLBFS is not supported by the operating system.");
3217 }
3218
3219 return result;
3220 }
3221
3222 /*
3223 * Set the coredump_filter bits to include largepages in core dump (bit 6)
3224 *
3225 * From the coredump_filter documentation:
3226 *
3227 * - (bit 0) anonymous private memory
3228 * - (bit 1) anonymous shared memory
3229 * - (bit 2) file-backed private memory
3230 * - (bit 3) file-backed shared memory
3231 * - (bit 4) ELF header pages in file-backed private memory areas (it is
3232 * effective only if the bit 2 is cleared)
3233 * - (bit 5) hugetlb private memory
3234 * - (bit 6) hugetlb shared memory
3235 */
3236 static void set_coredump_filter(void) {
3237 FILE *f;
3238 long cdm;
3239
3240 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3241 return;
3242 }
3243
3244 if (fscanf(f, "%lx", &cdm) != 1) {
3245 fclose(f);
3246 return;
3247 }
3248
3249 rewind(f);
3250
3251 if ((cdm & LARGEPAGES_BIT) == 0) {
3252 cdm |= LARGEPAGES_BIT;
3253 fprintf(f, "%#lx", cdm);
3254 }
3255
3256 fclose(f);
3257 }
3258
3259 // Large page support
3260
3261 static size_t _large_page_size = 0;
3262
3263 size_t os::Linux::find_large_page_size() {
3264 size_t large_page_size = 0;
3265
3266 // large_page_size on Linux is used to round up heap size. x86 uses either
3267 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3268 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3269 // page as large as 256M.
3270 //
3271 // Here we try to figure out page size by parsing /proc/meminfo and looking
3272 // for a line with the following format:
3273 // Hugepagesize: 2048 kB
3274 //
3275 // If we can't determine the value (e.g. /proc is not mounted, or the text
3276 // format has been changed), we'll use the largest page size supported by
3277 // the processor.
3278
3279 #ifndef ZERO
3280 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3281 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3282 #endif // ZERO
3283
3284 FILE *fp = fopen("/proc/meminfo", "r");
3285 if (fp) {
3286 while (!feof(fp)) {
3287 int x = 0;
3288 char buf[16];
3289 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3290 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3291 large_page_size = x * K;
3292 break;
3293 }
3294 } else {
3295 // skip to next line
3296 for (;;) {
3297 int ch = fgetc(fp);
3298 if (ch == EOF || ch == (int)'\n') break;
3299 }
3300 }
3301 }
3302 fclose(fp);
3303 }
3304
3305 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3306 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3307 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3308 proper_unit_for_byte_size(large_page_size));
3309 }
3310
3311 return large_page_size;
3312 }
3313
3314 size_t os::Linux::setup_large_page_size() {
3315 _large_page_size = Linux::find_large_page_size();
3316 const size_t default_page_size = (size_t)Linux::page_size();
3317 if (_large_page_size > default_page_size) {
3318 _page_sizes[0] = _large_page_size;
3319 _page_sizes[1] = default_page_size;
3320 _page_sizes[2] = 0;
3321 }
3322
3323 return _large_page_size;
3324 }
3325
3326 bool os::Linux::setup_large_page_type(size_t page_size) {
3327 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3328 FLAG_IS_DEFAULT(UseSHM) &&
3329 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3330
3331 // The type of large pages has not been specified by the user.
3332
3333 // Try UseHugeTLBFS and then UseSHM.
3334 UseHugeTLBFS = UseSHM = true;
3335
3336 // Don't try UseTransparentHugePages since there are known
3337 // performance issues with it turned on. This might change in the future.
3338 UseTransparentHugePages = false;
3339 }
3340
3341 if (UseTransparentHugePages) {
3342 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3343 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3344 UseHugeTLBFS = false;
3345 UseSHM = false;
3346 return true;
3347 }
3348 UseTransparentHugePages = false;
3349 }
3350
3351 if (UseHugeTLBFS) {
3352 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3353 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3354 UseSHM = false;
3355 return true;
3356 }
3357 UseHugeTLBFS = false;
3358 }
3359
3360 return UseSHM;
3361 }
3362
3363 void os::large_page_init() {
3364 if (!UseLargePages &&
3365 !UseTransparentHugePages &&
3366 !UseHugeTLBFS &&
3367 !UseSHM) {
3368 // Not using large pages.
3369 return;
3370 }
3371
3372 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3373 // The user explicitly turned off large pages.
3374 // Ignore the rest of the large pages flags.
3375 UseTransparentHugePages = false;
3376 UseHugeTLBFS = false;
3377 UseSHM = false;
3378 return;
3379 }
3380
3381 size_t large_page_size = Linux::setup_large_page_size();
3382 UseLargePages = Linux::setup_large_page_type(large_page_size);
3383
3384 set_coredump_filter();
3385 }
3386
3387 #ifndef SHM_HUGETLB
3388 #define SHM_HUGETLB 04000
3389 #endif
3390
3391 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3392 // "exec" is passed in but not used. Creating the shared image for
3393 // the code cache doesn't have an SHM_X executable permission to check.
3394 assert(UseLargePages && UseSHM, "only for SHM large pages");
3395 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3396
3397 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
3398 return NULL; // Fallback to small pages.
3399 }
3400
3401 key_t key = IPC_PRIVATE;
3402 char *addr;
3403
3404 bool warn_on_failure = UseLargePages &&
3405 (!FLAG_IS_DEFAULT(UseLargePages) ||
3406 !FLAG_IS_DEFAULT(UseSHM) ||
3407 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3408 );
3409 char msg[128];
3410
3411 // Create a large shared memory region to attach to based on size.
3412 // Currently, size is the total size of the heap
3413 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3414 if (shmid == -1) {
3415 // Possible reasons for shmget failure:
3416 // 1. shmmax is too small for Java heap.
3417 // > check shmmax value: cat /proc/sys/kernel/shmmax
3418 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3419 // 2. not enough large page memory.
3420 // > check available large pages: cat /proc/meminfo
3421 // > increase amount of large pages:
3422 // echo new_value > /proc/sys/vm/nr_hugepages
3423 // Note 1: different Linux may use different name for this property,
3424 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3425 // Note 2: it's possible there's enough physical memory available but
3426 // they are so fragmented after a long run that they can't
3427 // coalesce into large pages. Try to reserve large pages when
3428 // the system is still "fresh".
3429 if (warn_on_failure) {
3430 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3431 warning(msg);
3432 }
3433 return NULL;
3434 }
3435
3436 // attach to the region
3437 addr = (char*)shmat(shmid, req_addr, 0);
3438 int err = errno;
3439
3440 // Remove shmid. If shmat() is successful, the actual shared memory segment
3441 // will be deleted when it's detached by shmdt() or when the process
3442 // terminates. If shmat() is not successful this will remove the shared
3443 // segment immediately.
3444 shmctl(shmid, IPC_RMID, NULL);
3445
3446 if ((intptr_t)addr == -1) {
3447 if (warn_on_failure) {
3448 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3449 warning(msg);
3450 }
3451 return NULL;
3452 }
3453
3454 return addr;
3455 }
3456
3457 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
3458 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3459
3460 bool warn_on_failure = UseLargePages &&
3461 (!FLAG_IS_DEFAULT(UseLargePages) ||
3462 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3463 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3464
3465 if (warn_on_failure) {
3466 char msg[128];
3467 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3468 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3469 warning(msg);
3470 }
3471 }
3472
3473 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
3474 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3475 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3476 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3477
3478 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3479 char* addr = (char*)::mmap(req_addr, bytes, prot,
3480 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3481 -1, 0);
3482
3483 if (addr == MAP_FAILED) {
3484 warn_on_large_pages_failure(req_addr, bytes, errno);
3485 return NULL;
3486 }
3487
3488 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3489
3490 return addr;
3491 }
3492
3493 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3494 size_t large_page_size = os::large_page_size();
3495
3496 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3497
3498 // Allocate small pages.
3499
3500 char* start;
3501 if (req_addr != NULL) {
3502 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3503 assert(is_size_aligned(bytes, alignment), "Must be");
3504 start = os::reserve_memory(bytes, req_addr);
3505 assert(start == NULL || start == req_addr, "Must be");
3506 } else {
3507 start = os::reserve_memory_aligned(bytes, alignment);
3508 }
3509
3510 if (start == NULL) {
3511 return NULL;
3512 }
3513
3514 assert(is_ptr_aligned(start, alignment), "Must be");
3515
3516 // os::reserve_memory_special will record this memory area.
3517 // Need to release it here to prevent overlapping reservations.
3518 MemTracker::record_virtual_memory_release((address)start, bytes);
3519
3520 char* end = start + bytes;
3521
3522 // Find the regions of the allocated chunk that can be promoted to large pages.
3523 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3524 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3525
3526 size_t lp_bytes = lp_end - lp_start;
3527
3528 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3529
3530 if (lp_bytes == 0) {
3531 // The mapped region doesn't even span the start and the end of a large page.
3532 // Fall back to allocate a non-special area.
3533 ::munmap(start, end - start);
3534 return NULL;
3535 }
3536
3537 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3538
3539
3540 void* result;
3541
3542 if (start != lp_start) {
3543 result = ::mmap(start, lp_start - start, prot,
3544 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3545 -1, 0);
3546 if (result == MAP_FAILED) {
3547 ::munmap(lp_start, end - lp_start);
3548 return NULL;
3549 }
3550 }
3551
3552 result = ::mmap(lp_start, lp_bytes, prot,
3553 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3554 -1, 0);
3555 if (result == MAP_FAILED) {
3556 warn_on_large_pages_failure(req_addr, bytes, errno);
3557 // If the mmap above fails, the large pages region will be unmapped and we
3558 // have regions before and after with small pages. Release these regions.
3559 //
3560 // | mapped | unmapped | mapped |
3561 // ^ ^ ^ ^
3562 // start lp_start lp_end end
3563 //
3564 ::munmap(start, lp_start - start);
3565 ::munmap(lp_end, end - lp_end);
3566 return NULL;
3567 }
3568
3569 if (lp_end != end) {
3570 result = ::mmap(lp_end, end - lp_end, prot,
3571 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3572 -1, 0);
3573 if (result == MAP_FAILED) {
3574 ::munmap(start, lp_end - start);
3575 return NULL;
3576 }
3577 }
3578
3579 return start;
3580 }
3581
3582 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3583 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3584 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3585 assert(is_power_of_2(alignment), "Must be");
3586 assert(is_power_of_2(os::large_page_size()), "Must be");
3587 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3588
3589 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3590 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3591 } else {
3592 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3593 }
3594 }
3595
3596 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3597 assert(UseLargePages, "only for large pages");
3598
3599 char* addr;
3600 if (UseSHM) {
3601 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3602 } else {
3603 assert(UseHugeTLBFS, "must be");
3604 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3605 }
3606
3607 if (addr != NULL) {
3608 if (UseNUMAInterleaving) {
3609 numa_make_global(addr, bytes);
3610 }
3611
3612 // The memory is committed
3613 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, mtNone, CALLER_PC);
3614 }
3615
3616 return addr;
3617 }
3618
3619 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3620 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3621 return shmdt(base) == 0;
3622 }
3623
3624 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3625 return pd_release_memory(base, bytes);
3626 }
3627
3628 bool os::release_memory_special(char* base, size_t bytes) {
3629 assert(UseLargePages, "only for large pages");
3630
3631 MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3632
3633 bool res;
3634 if (UseSHM) {
3635 res = os::Linux::release_memory_special_shm(base, bytes);
3636 } else {
3637 assert(UseHugeTLBFS, "must be");
3638 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3639 }
3640
3641 if (res) {
3642 tkr.record((address)base, bytes);
3643 } else {
3644 tkr.discard();
3645 }
3646
3647 return res;
3648 }
3649
3650 size_t os::large_page_size() {
3651 return _large_page_size;
3652 }
3653
3654 // With SysV SHM the entire memory region must be allocated as shared
3655 // memory.
3656 // HugeTLBFS allows application to commit large page memory on demand.
3657 // However, when committing memory with HugeTLBFS fails, the region
3658 // that was supposed to be committed will lose the old reservation
3659 // and allow other threads to steal that memory region. Because of this
3660 // behavior we can't commit HugeTLBFS memory.
3661 bool os::can_commit_large_page_memory() {
3662 return UseTransparentHugePages;
3663 }
3664
3665 bool os::can_execute_large_page_memory() {
3666 return UseTransparentHugePages || UseHugeTLBFS;
3667 }
3668
3669 // Reserve memory at an arbitrary address, only if that area is
3670 // available (and not reserved for something else).
3671
3672 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3673 const int max_tries = 10;
3674 char* base[max_tries];
3675 size_t size[max_tries];
3676 const size_t gap = 0x000000;
3677
3678 // Assert only that the size is a multiple of the page size, since
3679 // that's all that mmap requires, and since that's all we really know
3680 // about at this low abstraction level. If we need higher alignment,
3681 // we can either pass an alignment to this method or verify alignment
3682 // in one of the methods further up the call chain. See bug 5044738.
3683 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3684
3685 // Repeatedly allocate blocks until the block is allocated at the
3686 // right spot. Give up after max_tries. Note that reserve_memory() will
3687 // automatically update _highest_vm_reserved_address if the call is
3688 // successful. The variable tracks the highest memory address every reserved
3689 // by JVM. It is used to detect heap-stack collision if running with
3690 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3691 // space than needed, it could confuse the collision detecting code. To
3692 // solve the problem, save current _highest_vm_reserved_address and
3693 // calculate the correct value before return.
3694 address old_highest = _highest_vm_reserved_address;
3695
3696 // Linux mmap allows caller to pass an address as hint; give it a try first,
3697 // if kernel honors the hint then we can return immediately.
3698 char * addr = anon_mmap(requested_addr, bytes, false);
3699 if (addr == requested_addr) {
3700 return requested_addr;
3701 }
3702
3703 if (addr != NULL) {
3704 // mmap() is successful but it fails to reserve at the requested address
3705 anon_munmap(addr, bytes);
3706 }
3707
3708 int i;
3709 for (i = 0; i < max_tries; ++i) {
3710 base[i] = reserve_memory(bytes);
3711
3712 if (base[i] != NULL) {
3713 // Is this the block we wanted?
3714 if (base[i] == requested_addr) {
3715 size[i] = bytes;
3716 break;
3717 }
3718
3719 // Does this overlap the block we wanted? Give back the overlapped
3720 // parts and try again.
3721
3722 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3723 if (top_overlap >= 0 && top_overlap < bytes) {
3724 unmap_memory(base[i], top_overlap);
3725 base[i] += top_overlap;
3726 size[i] = bytes - top_overlap;
3727 } else {
3728 size_t bottom_overlap = base[i] + bytes - requested_addr;
3729 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3730 unmap_memory(requested_addr, bottom_overlap);
3731 size[i] = bytes - bottom_overlap;
3732 } else {
3733 size[i] = bytes;
3734 }
3735 }
3736 }
3737 }
3738
3739 // Give back the unused reserved pieces.
3740
3741 for (int j = 0; j < i; ++j) {
3742 if (base[j] != NULL) {
3743 unmap_memory(base[j], size[j]);
3744 }
3745 }
3746
3747 if (i < max_tries) {
3748 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3749 return requested_addr;
3750 } else {
3751 _highest_vm_reserved_address = old_highest;
3752 return NULL;
3753 }
3754 }
3755
3756 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3757 return ::read(fd, buf, nBytes);
3758 }
3759
3760 //
3761 // Short sleep, direct OS call.
3762 //
3763 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3764 // sched_yield(2) will actually give up the CPU:
3765 //
3766 // * Alone on this pariticular CPU, keeps running.
3767 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3768 // (pre 2.6.39).
3769 //
3770 // So calling this with 0 is an alternative.
3771 //
3772 void os::naked_short_sleep(jlong ms) {
3773 struct timespec req;
3774
3775 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3776 req.tv_sec = 0;
3777 if (ms > 0) {
3778 req.tv_nsec = (ms % 1000) * 1000000;
3779 }
3780 else {
3781 req.tv_nsec = 1;
3782 }
3783
3784 nanosleep(&req, NULL);
3785
3786 return;
3787 }
3788
3789 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3790 void os::infinite_sleep() {
3791 while (true) { // sleep forever ...
3792 ::sleep(100); // ... 100 seconds at a time
3793 }
3794 }
3795
3796 // Used to convert frequent JVM_Yield() to nops
3797 bool os::dont_yield() {
3798 return DontYieldALot;
3799 }
3800
3801 void os::yield() {
3802 sched_yield();
3803 }
3804
3805 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3806
3807 void os::yield_all(int attempts) {
3808 // Yields to all threads, including threads with lower priorities
3809 // Threads on Linux are all with same priority. The Solaris style
3810 // os::yield_all() with nanosleep(1ms) is not necessary.
3811 sched_yield();
3812 }
3813
3814 // Called from the tight loops to possibly influence time-sharing heuristics
3815 void os::loop_breaker(int attempts) {
3816 os::yield_all(attempts);
3817 }
3818
3819 ////////////////////////////////////////////////////////////////////////////////
3820 // thread priority support
3821
3822 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3823 // only supports dynamic priority, static priority must be zero. For real-time
3824 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3825 // However, for large multi-threaded applications, SCHED_RR is not only slower
3826 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3827 // of 5 runs - Sep 2005).
3828 //
3829 // The following code actually changes the niceness of kernel-thread/LWP. It
3830 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3831 // not the entire user process, and user level threads are 1:1 mapped to kernel
3832 // threads. It has always been the case, but could change in the future. For
3833 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3834 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3835
3836 int os::java_to_os_priority[CriticalPriority + 1] = {
3837 19, // 0 Entry should never be used
3838
3839 4, // 1 MinPriority
3840 3, // 2
3841 2, // 3
3842
3843 1, // 4
3844 0, // 5 NormPriority
3845 -1, // 6
3846
3847 -2, // 7
3848 -3, // 8
3849 -4, // 9 NearMaxPriority
3850
3851 -5, // 10 MaxPriority
3852
3853 -5 // 11 CriticalPriority
3854 };
3855
3856 static int prio_init() {
3857 if (ThreadPriorityPolicy == 1) {
3858 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3859 // if effective uid is not root. Perhaps, a more elegant way of doing
3860 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3861 if (geteuid() != 0) {
3862 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3863 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3864 }
3865 ThreadPriorityPolicy = 0;
3866 }
3867 }
3868 if (UseCriticalJavaThreadPriority) {
3869 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3870 }
3871 return 0;
3872 }
3873
3874 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3875 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3876
3877 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3878 return (ret == 0) ? OS_OK : OS_ERR;
3879 }
3880
3881 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3882 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3883 *priority_ptr = java_to_os_priority[NormPriority];
3884 return OS_OK;
3885 }
3886
3887 errno = 0;
3888 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3889 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3890 }
3891
3892 // Hint to the underlying OS that a task switch would not be good.
3893 // Void return because it's a hint and can fail.
3894 void os::hint_no_preempt() {}
3895
3896 ////////////////////////////////////////////////////////////////////////////////
3897 // suspend/resume support
3898
3899 // the low-level signal-based suspend/resume support is a remnant from the
3900 // old VM-suspension that used to be for java-suspension, safepoints etc,
3901 // within hotspot. Now there is a single use-case for this:
3902 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3903 // that runs in the watcher thread.
3904 // The remaining code is greatly simplified from the more general suspension
3905 // code that used to be used.
3906 //
3907 // The protocol is quite simple:
3908 // - suspend:
3909 // - sends a signal to the target thread
3910 // - polls the suspend state of the osthread using a yield loop
3911 // - target thread signal handler (SR_handler) sets suspend state
3912 // and blocks in sigsuspend until continued
3913 // - resume:
3914 // - sets target osthread state to continue
3915 // - sends signal to end the sigsuspend loop in the SR_handler
3916 //
3917 // Note that the SR_lock plays no role in this suspend/resume protocol.
3918 //
3919
3920 static void resume_clear_context(OSThread *osthread) {
3921 osthread->set_ucontext(NULL);
3922 osthread->set_siginfo(NULL);
3923 }
3924
3925 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3926 osthread->set_ucontext(context);
3927 osthread->set_siginfo(siginfo);
3928 }
3929
3930 //
3931 // Handler function invoked when a thread's execution is suspended or
3932 // resumed. We have to be careful that only async-safe functions are
3933 // called here (Note: most pthread functions are not async safe and
3934 // should be avoided.)
3935 //
3936 // Note: sigwait() is a more natural fit than sigsuspend() from an
3937 // interface point of view, but sigwait() prevents the signal hander
3938 // from being run. libpthread would get very confused by not having
3939 // its signal handlers run and prevents sigwait()'s use with the
3940 // mutex granting granting signal.
3941 //
3942 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
3943 //
3944 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3945 // Save and restore errno to avoid confusing native code with EINTR
3946 // after sigsuspend.
3947 int old_errno = errno;
3948
3949 Thread* thread = Thread::current();
3950 OSThread* osthread = thread->osthread();
3951 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
3952
3953 os::SuspendResume::State current = osthread->sr.state();
3954 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
3955 suspend_save_context(osthread, siginfo, context);
3956
3957 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
3958 os::SuspendResume::State state = osthread->sr.suspended();
3959 if (state == os::SuspendResume::SR_SUSPENDED) {
3960 sigset_t suspend_set; // signals for sigsuspend()
3961
3962 // get current set of blocked signals and unblock resume signal
3963 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3964 sigdelset(&suspend_set, SR_signum);
3965
3966 sr_semaphore.signal();
3967 // wait here until we are resumed
3968 while (1) {
3969 sigsuspend(&suspend_set);
3970
3971 os::SuspendResume::State result = osthread->sr.running();
3972 if (result == os::SuspendResume::SR_RUNNING) {
3973 sr_semaphore.signal();
3974 break;
3975 }
3976 }
3977
3978 } else if (state == os::SuspendResume::SR_RUNNING) {
3979 // request was cancelled, continue
3980 } else {
3981 ShouldNotReachHere();
3982 }
3983
3984 resume_clear_context(osthread);
3985 } else if (current == os::SuspendResume::SR_RUNNING) {
3986 // request was cancelled, continue
3987 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
3988 // ignore
3989 } else {
3990 // ignore
3991 }
3992
3993 errno = old_errno;
3994 }
3995
3996
3997 static int SR_initialize() {
3998 struct sigaction act;
3999 char *s;
4000 /* Get signal number to use for suspend/resume */
4001 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4002 int sig = ::strtol(s, 0, 10);
4003 if (sig > 0 || sig < _NSIG) {
4004 SR_signum = sig;
4005 }
4006 }
4007
4008 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4009 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4010
4011 sigemptyset(&SR_sigset);
4012 sigaddset(&SR_sigset, SR_signum);
4013
4014 /* Set up signal handler for suspend/resume */
4015 act.sa_flags = SA_RESTART|SA_SIGINFO;
4016 act.sa_handler = (void (*)(int)) SR_handler;
4017
4018 // SR_signum is blocked by default.
4019 // 4528190 - We also need to block pthread restart signal (32 on all
4020 // supported Linux platforms). Note that LinuxThreads need to block
4021 // this signal for all threads to work properly. So we don't have
4022 // to use hard-coded signal number when setting up the mask.
4023 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4024
4025 if (sigaction(SR_signum, &act, 0) == -1) {
4026 return -1;
4027 }
4028
4029 // Save signal flag
4030 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4031 return 0;
4032 }
4033
4034 static int sr_notify(OSThread* osthread) {
4035 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4036 assert_status(status == 0, status, "pthread_kill");
4037 return status;
4038 }
4039
4040 // "Randomly" selected value for how long we want to spin
4041 // before bailing out on suspending a thread, also how often
4042 // we send a signal to a thread we want to resume
4043 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4044 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4045
4046 // returns true on success and false on error - really an error is fatal
4047 // but this seems the normal response to library errors
4048 static bool do_suspend(OSThread* osthread) {
4049 assert(osthread->sr.is_running(), "thread should be running");
4050 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4051
4052 // mark as suspended and send signal
4053 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4054 // failed to switch, state wasn't running?
4055 ShouldNotReachHere();
4056 return false;
4057 }
4058
4059 if (sr_notify(osthread) != 0) {
4060 ShouldNotReachHere();
4061 }
4062
4063 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4064 while (true) {
4065 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4066 break;
4067 } else {
4068 // timeout
4069 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4070 if (cancelled == os::SuspendResume::SR_RUNNING) {
4071 return false;
4072 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4073 // make sure that we consume the signal on the semaphore as well
4074 sr_semaphore.wait();
4075 break;
4076 } else {
4077 ShouldNotReachHere();
4078 return false;
4079 }
4080 }
4081 }
4082
4083 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4084 return true;
4085 }
4086
4087 static void do_resume(OSThread* osthread) {
4088 assert(osthread->sr.is_suspended(), "thread should be suspended");
4089 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4090
4091 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4092 // failed to switch to WAKEUP_REQUEST
4093 ShouldNotReachHere();
4094 return;
4095 }
4096
4097 while (true) {
4098 if (sr_notify(osthread) == 0) {
4099 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4100 if (osthread->sr.is_running()) {
4101 return;
4102 }
4103 }
4104 } else {
4105 ShouldNotReachHere();
4106 }
4107 }
4108
4109 guarantee(osthread->sr.is_running(), "Must be running!");
4110 }
4111
4112 ///////////////////////////////////////////////////////////////////////////////////
4113 // signal handling (except suspend/resume)
4114
4115 // This routine may be used by user applications as a "hook" to catch signals.
4116 // The user-defined signal handler must pass unrecognized signals to this
4117 // routine, and if it returns true (non-zero), then the signal handler must
4118 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4119 // routine will never retun false (zero), but instead will execute a VM panic
4120 // routine kill the process.
4121 //
4122 // If this routine returns false, it is OK to call it again. This allows
4123 // the user-defined signal handler to perform checks either before or after
4124 // the VM performs its own checks. Naturally, the user code would be making
4125 // a serious error if it tried to handle an exception (such as a null check
4126 // or breakpoint) that the VM was generating for its own correct operation.
4127 //
4128 // This routine may recognize any of the following kinds of signals:
4129 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4130 // It should be consulted by handlers for any of those signals.
4131 //
4132 // The caller of this routine must pass in the three arguments supplied
4133 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4134 // field of the structure passed to sigaction(). This routine assumes that
4135 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4136 //
4137 // Note that the VM will print warnings if it detects conflicting signal
4138 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4139 //
4140 extern "C" JNIEXPORT int
4141 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
4142 void* ucontext, int abort_if_unrecognized);
4143
4144 void signalHandler(int sig, siginfo_t* info, void* uc) {
4145 assert(info != NULL && uc != NULL, "it must be old kernel");
4146 int orig_errno = errno; // Preserve errno value over signal handler.
4147 JVM_handle_linux_signal(sig, info, uc, true);
4148 errno = orig_errno;
4149 }
4150
4151
4152 // This boolean allows users to forward their own non-matching signals
4153 // to JVM_handle_linux_signal, harmlessly.
4154 bool os::Linux::signal_handlers_are_installed = false;
4155
4156 // For signal-chaining
4157 struct sigaction os::Linux::sigact[MAXSIGNUM];
4158 unsigned int os::Linux::sigs = 0;
4159 bool os::Linux::libjsig_is_loaded = false;
4160 typedef struct sigaction *(*get_signal_t)(int);
4161 get_signal_t os::Linux::get_signal_action = NULL;
4162
4163 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4164 struct sigaction *actp = NULL;
4165
4166 if (libjsig_is_loaded) {
4167 // Retrieve the old signal handler from libjsig
4168 actp = (*get_signal_action)(sig);
4169 }
4170 if (actp == NULL) {
4171 // Retrieve the preinstalled signal handler from jvm
4172 actp = get_preinstalled_handler(sig);
4173 }
4174
4175 return actp;
4176 }
4177
4178 static bool call_chained_handler(struct sigaction *actp, int sig,
4179 siginfo_t *siginfo, void *context) {
4180 // Call the old signal handler
4181 if (actp->sa_handler == SIG_DFL) {
4182 // It's more reasonable to let jvm treat it as an unexpected exception
4183 // instead of taking the default action.
4184 return false;
4185 } else if (actp->sa_handler != SIG_IGN) {
4186 if ((actp->sa_flags & SA_NODEFER) == 0) {
4187 // automaticlly block the signal
4188 sigaddset(&(actp->sa_mask), sig);
4189 }
4190
4191 sa_handler_t hand;
4192 sa_sigaction_t sa;
4193 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4194 // retrieve the chained handler
4195 if (siginfo_flag_set) {
4196 sa = actp->sa_sigaction;
4197 } else {
4198 hand = actp->sa_handler;
4199 }
4200
4201 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4202 actp->sa_handler = SIG_DFL;
4203 }
4204
4205 // try to honor the signal mask
4206 sigset_t oset;
4207 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4208
4209 // call into the chained handler
4210 if (siginfo_flag_set) {
4211 (*sa)(sig, siginfo, context);
4212 } else {
4213 (*hand)(sig);
4214 }
4215
4216 // restore the signal mask
4217 pthread_sigmask(SIG_SETMASK, &oset, 0);
4218 }
4219 // Tell jvm's signal handler the signal is taken care of.
4220 return true;
4221 }
4222
4223 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4224 bool chained = false;
4225 // signal-chaining
4226 if (UseSignalChaining) {
4227 struct sigaction *actp = get_chained_signal_action(sig);
4228 if (actp != NULL) {
4229 chained = call_chained_handler(actp, sig, siginfo, context);
4230 }
4231 }
4232 return chained;
4233 }
4234
4235 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4236 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
4237 return &sigact[sig];
4238 }
4239 return NULL;
4240 }
4241
4242 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4243 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4244 sigact[sig] = oldAct;
4245 sigs |= (unsigned int)1 << sig;
4246 }
4247
4248 // for diagnostic
4249 int os::Linux::sigflags[MAXSIGNUM];
4250
4251 int os::Linux::get_our_sigflags(int sig) {
4252 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4253 return sigflags[sig];
4254 }
4255
4256 void os::Linux::set_our_sigflags(int sig, int flags) {
4257 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4258 sigflags[sig] = flags;
4259 }
4260
4261 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4262 // Check for overwrite.
4263 struct sigaction oldAct;
4264 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4265
4266 void* oldhand = oldAct.sa_sigaction
4267 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4268 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4269 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4270 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4271 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4272 if (AllowUserSignalHandlers || !set_installed) {
4273 // Do not overwrite; user takes responsibility to forward to us.
4274 return;
4275 } else if (UseSignalChaining) {
4276 // save the old handler in jvm
4277 save_preinstalled_handler(sig, oldAct);
4278 // libjsig also interposes the sigaction() call below and saves the
4279 // old sigaction on it own.
4280 } else {
4281 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
4282 "%#lx for signal %d.", (long)oldhand, sig));
4283 }
4284 }
4285
4286 struct sigaction sigAct;
4287 sigfillset(&(sigAct.sa_mask));
4288 sigAct.sa_handler = SIG_DFL;
4289 if (!set_installed) {
4290 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4291 } else {
4292 sigAct.sa_sigaction = signalHandler;
4293 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4294 }
4295 // Save flags, which are set by ours
4296 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4297 sigflags[sig] = sigAct.sa_flags;
4298
4299 int ret = sigaction(sig, &sigAct, &oldAct);
4300 assert(ret == 0, "check");
4301
4302 void* oldhand2 = oldAct.sa_sigaction
4303 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4304 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4305 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4306 }
4307
4308 // install signal handlers for signals that HotSpot needs to
4309 // handle in order to support Java-level exception handling.
4310
4311 void os::Linux::install_signal_handlers() {
4312 if (!signal_handlers_are_installed) {
4313 signal_handlers_are_installed = true;
4314
4315 // signal-chaining
4316 typedef void (*signal_setting_t)();
4317 signal_setting_t begin_signal_setting = NULL;
4318 signal_setting_t end_signal_setting = NULL;
4319 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4320 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4321 if (begin_signal_setting != NULL) {
4322 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4323 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4324 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4325 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4326 libjsig_is_loaded = true;
4327 assert(UseSignalChaining, "should enable signal-chaining");
4328 }
4329 if (libjsig_is_loaded) {
4330 // Tell libjsig jvm is setting signal handlers
4331 (*begin_signal_setting)();
4332 }
4333
4334 set_signal_handler(SIGSEGV, true);
4335 set_signal_handler(SIGPIPE, true);
4336 set_signal_handler(SIGBUS, true);
4337 set_signal_handler(SIGILL, true);
4338 set_signal_handler(SIGFPE, true);
4339 #if defined(PPC64)
4340 set_signal_handler(SIGTRAP, true);
4341 #endif
4342 set_signal_handler(SIGXFSZ, true);
4343
4344 if (libjsig_is_loaded) {
4345 // Tell libjsig jvm finishes setting signal handlers
4346 (*end_signal_setting)();
4347 }
4348
4349 // We don't activate signal checker if libjsig is in place, we trust ourselves
4350 // and if UserSignalHandler is installed all bets are off.
4351 // Log that signal checking is off only if -verbose:jni is specified.
4352 if (CheckJNICalls) {
4353 if (libjsig_is_loaded) {
4354 if (PrintJNIResolving) {
4355 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4356 }
4357 check_signals = false;
4358 }
4359 if (AllowUserSignalHandlers) {
4360 if (PrintJNIResolving) {
4361 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4362 }
4363 check_signals = false;
4364 }
4365 }
4366 }
4367 }
4368
4369 // This is the fastest way to get thread cpu time on Linux.
4370 // Returns cpu time (user+sys) for any thread, not only for current.
4371 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4372 // It might work on 2.6.10+ with a special kernel/glibc patch.
4373 // For reference, please, see IEEE Std 1003.1-2004:
4374 // http://www.unix.org/single_unix_specification
4375
4376 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4377 struct timespec tp;
4378 int rc = os::Linux::clock_gettime(clockid, &tp);
4379 assert(rc == 0, "clock_gettime is expected to return 0 code");
4380
4381 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4382 }
4383
4384 /////
4385 // glibc on Linux platform uses non-documented flag
4386 // to indicate, that some special sort of signal
4387 // trampoline is used.
4388 // We will never set this flag, and we should
4389 // ignore this flag in our diagnostic
4390 #ifdef SIGNIFICANT_SIGNAL_MASK
4391 #undef SIGNIFICANT_SIGNAL_MASK
4392 #endif
4393 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4394
4395 static const char* get_signal_handler_name(address handler,
4396 char* buf, int buflen) {
4397 int offset;
4398 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4399 if (found) {
4400 // skip directory names
4401 const char *p1, *p2;
4402 p1 = buf;
4403 size_t len = strlen(os::file_separator());
4404 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4405 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4406 } else {
4407 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4408 }
4409 return buf;
4410 }
4411
4412 static void print_signal_handler(outputStream* st, int sig,
4413 char* buf, size_t buflen) {
4414 struct sigaction sa;
4415
4416 sigaction(sig, NULL, &sa);
4417
4418 // See comment for SIGNIFICANT_SIGNAL_MASK define
4419 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4420
4421 st->print("%s: ", os::exception_name(sig, buf, buflen));
4422
4423 address handler = (sa.sa_flags & SA_SIGINFO)
4424 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4425 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4426
4427 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4428 st->print("SIG_DFL");
4429 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4430 st->print("SIG_IGN");
4431 } else {
4432 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4433 }
4434
4435 st->print(", sa_mask[0]=");
4436 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4437
4438 address rh = VMError::get_resetted_sighandler(sig);
4439 // May be, handler was resetted by VMError?
4440 if(rh != NULL) {
4441 handler = rh;
4442 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4443 }
4444
4445 st->print(", sa_flags=");
4446 os::Posix::print_sa_flags(st, sa.sa_flags);
4447
4448 // Check: is it our handler?
4449 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4450 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4451 // It is our signal handler
4452 // check for flags, reset system-used one!
4453 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4454 st->print(
4455 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4456 os::Linux::get_our_sigflags(sig));
4457 }
4458 }
4459 st->cr();
4460 }
4461
4462
4463 #define DO_SIGNAL_CHECK(sig) \
4464 if (!sigismember(&check_signal_done, sig) && (isatty(fileno(stdin)) || sig != SIGINT)) \
4465 os::Linux::check_signal_handler(sig)
4466
4467 // This method is a periodic task to check for misbehaving JNI applications
4468 // under CheckJNI, we can add any periodic checks here
4469
4470 void os::run_periodic_checks() {
4471
4472 if (check_signals == false) return;
4473
4474 // SEGV and BUS if overridden could potentially prevent
4475 // generation of hs*.log in the event of a crash, debugging
4476 // such a case can be very challenging, so we absolutely
4477 // check the following for a good measure:
4478 DO_SIGNAL_CHECK(SIGSEGV);
4479 DO_SIGNAL_CHECK(SIGILL);
4480 DO_SIGNAL_CHECK(SIGFPE);
4481 DO_SIGNAL_CHECK(SIGBUS);
4482 DO_SIGNAL_CHECK(SIGPIPE);
4483 DO_SIGNAL_CHECK(SIGXFSZ);
4484 #if defined(PPC64)
4485 DO_SIGNAL_CHECK(SIGTRAP);
4486 #endif
4487
4488 // ReduceSignalUsage allows the user to override these handlers
4489 // see comments at the very top and jvm_solaris.h
4490 if (!ReduceSignalUsage) {
4491 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4492 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4493 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4494 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4495 }
4496
4497 DO_SIGNAL_CHECK(SR_signum);
4498 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4499 }
4500
4501 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4502
4503 static os_sigaction_t os_sigaction = NULL;
4504
4505 void os::Linux::check_signal_handler(int sig) {
4506 char buf[O_BUFLEN];
4507 address jvmHandler = NULL;
4508
4509
4510 struct sigaction act;
4511 if (os_sigaction == NULL) {
4512 // only trust the default sigaction, in case it has been interposed
4513 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4514 if (os_sigaction == NULL) return;
4515 }
4516
4517 os_sigaction(sig, (struct sigaction*)NULL, &act);
4518
4519
4520 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4521
4522 address thisHandler = (act.sa_flags & SA_SIGINFO)
4523 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4524 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4525
4526
4527 switch(sig) {
4528 case SIGSEGV:
4529 case SIGBUS:
4530 case SIGFPE:
4531 case SIGPIPE:
4532 case SIGILL:
4533 case SIGXFSZ:
4534 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4535 break;
4536
4537 case SHUTDOWN1_SIGNAL:
4538 case SHUTDOWN2_SIGNAL:
4539 case SHUTDOWN3_SIGNAL:
4540 case BREAK_SIGNAL:
4541 jvmHandler = (address)user_handler();
4542 break;
4543
4544 case INTERRUPT_SIGNAL:
4545 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4546 break;
4547
4548 default:
4549 if (sig == SR_signum) {
4550 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4551 } else {
4552 return;
4553 }
4554 break;
4555 }
4556
4557 if (thisHandler != jvmHandler) {
4558 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4559 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4560 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4561 // No need to check this sig any longer
4562 sigaddset(&check_signal_done, sig);
4563 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4564 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4565 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4566 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4567 // No need to check this sig any longer
4568 sigaddset(&check_signal_done, sig);
4569 }
4570
4571 // Dump all the signal
4572 if (sigismember(&check_signal_done, sig)) {
4573 print_signal_handlers(tty, buf, O_BUFLEN);
4574 }
4575 }
4576
4577 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4578
4579 extern bool signal_name(int signo, char* buf, size_t len);
4580
4581 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4582 if (0 < exception_code && exception_code <= SIGRTMAX) {
4583 // signal
4584 if (!signal_name(exception_code, buf, size)) {
4585 jio_snprintf(buf, size, "SIG%d", exception_code);
4586 }
4587 return buf;
4588 } else {
4589 return NULL;
4590 }
4591 }
4592
4593 // this is called _before_ the most of global arguments have been parsed
4594 void os::init(void) {
4595 char dummy; /* used to get a guess on initial stack address */
4596 // first_hrtime = gethrtime();
4597
4598 // With LinuxThreads the JavaMain thread pid (primordial thread)
4599 // is different than the pid of the java launcher thread.
4600 // So, on Linux, the launcher thread pid is passed to the VM
4601 // via the sun.java.launcher.pid property.
4602 // Use this property instead of getpid() if it was correctly passed.
4603 // See bug 6351349.
4604 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4605
4606 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4607
4608 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4609
4610 init_random(1234567);
4611
4612 ThreadCritical::initialize();
4613
4614 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4615 if (Linux::page_size() == -1) {
4616 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4617 strerror(errno)));
4618 }
4619 init_page_sizes((size_t) Linux::page_size());
4620
4621 Linux::initialize_system_info();
4622
4623 // main_thread points to the aboriginal thread
4624 Linux::_main_thread = pthread_self();
4625
4626 Linux::clock_init();
4627 initial_time_count = javaTimeNanos();
4628
4629 // pthread_condattr initialization for monotonic clock
4630 int status;
4631 pthread_condattr_t* _condattr = os::Linux::condAttr();
4632 if ((status = pthread_condattr_init(_condattr)) != 0) {
4633 fatal(err_msg("pthread_condattr_init: %s", strerror(status)));
4634 }
4635 // Only set the clock if CLOCK_MONOTONIC is available
4636 if (os::supports_monotonic_clock()) {
4637 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4638 if (status == EINVAL) {
4639 warning("Unable to use monotonic clock with relative timed-waits" \
4640 " - changes to the time-of-day clock may have adverse affects");
4641 } else {
4642 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status)));
4643 }
4644 }
4645 }
4646 // else it defaults to CLOCK_REALTIME
4647
4648 pthread_mutex_init(&dl_mutex, NULL);
4649
4650 // If the pagesize of the VM is greater than 8K determine the appropriate
4651 // number of initial guard pages. The user can change this with the
4652 // command line arguments, if needed.
4653 if (vm_page_size() > (int)Linux::vm_default_page_size()) {
4654 StackYellowPages = 1;
4655 StackRedPages = 1;
4656 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size();
4657 }
4658 }
4659
4660 // To install functions for atexit system call
4661 extern "C" {
4662 static void perfMemory_exit_helper() {
4663 perfMemory_exit();
4664 }
4665 }
4666
4667 // this is called _after_ the global arguments have been parsed
4668 jint os::init_2(void)
4669 {
4670 Linux::fast_thread_clock_init();
4671
4672 // Allocate a single page and mark it as readable for safepoint polling
4673 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4674 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4675
4676 os::set_polling_page( polling_page );
4677
4678 #ifndef PRODUCT
4679 if(Verbose && PrintMiscellaneous)
4680 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4681 #endif
4682
4683 if (!UseMembar) {
4684 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4685 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4686 os::set_memory_serialize_page( mem_serialize_page );
4687
4688 #ifndef PRODUCT
4689 if(Verbose && PrintMiscellaneous)
4690 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4691 #endif
4692 }
4693
4694 // initialize suspend/resume support - must do this before signal_sets_init()
4695 if (SR_initialize() != 0) {
4696 perror("SR_initialize failed");
4697 return JNI_ERR;
4698 }
4699
4700 Linux::signal_sets_init();
4701 Linux::install_signal_handlers();
4702
4703 // Check minimum allowable stack size for thread creation and to initialize
4704 // the java system classes, including StackOverflowError - depends on page
4705 // size. Add a page for compiler2 recursion in main thread.
4706 // Add in 2*BytesPerWord times page size to account for VM stack during
4707 // class initialization depending on 32 or 64 bit VM.
4708 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4709 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() +
4710 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
4711
4712 size_t threadStackSizeInBytes = ThreadStackSize * K;
4713 if (threadStackSizeInBytes != 0 &&
4714 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4715 tty->print_cr("\nThe stack size specified is too small, "
4716 "Specify at least %dk",
4717 os::Linux::min_stack_allowed/ K);
4718 return JNI_ERR;
4719 }
4720
4721 // Make the stack size a multiple of the page size so that
4722 // the yellow/red zones can be guarded.
4723 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4724 vm_page_size()));
4725
4726 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4727
4728 #if defined(IA32)
4729 workaround_expand_exec_shield_cs_limit();
4730 #endif
4731
4732 Linux::libpthread_init();
4733 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4734 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4735 Linux::glibc_version(), Linux::libpthread_version(),
4736 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4737 }
4738
4739 if (UseNUMA) {
4740 if (!Linux::libnuma_init()) {
4741 UseNUMA = false;
4742 } else {
4743 if ((Linux::numa_max_node() < 1)) {
4744 // There's only one node(they start from 0), disable NUMA.
4745 UseNUMA = false;
4746 }
4747 }
4748 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4749 // we can make the adaptive lgrp chunk resizing work. If the user specified
4750 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4751 // disable adaptive resizing.
4752 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4753 if (FLAG_IS_DEFAULT(UseNUMA)) {
4754 UseNUMA = false;
4755 } else {
4756 if (FLAG_IS_DEFAULT(UseLargePages) &&
4757 FLAG_IS_DEFAULT(UseSHM) &&
4758 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4759 UseLargePages = false;
4760 } else {
4761 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
4762 UseAdaptiveSizePolicy = false;
4763 UseAdaptiveNUMAChunkSizing = false;
4764 }
4765 }
4766 }
4767 if (!UseNUMA && ForceNUMA) {
4768 UseNUMA = true;
4769 }
4770 }
4771
4772 if (MaxFDLimit) {
4773 // set the number of file descriptors to max. print out error
4774 // if getrlimit/setrlimit fails but continue regardless.
4775 struct rlimit nbr_files;
4776 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4777 if (status != 0) {
4778 if (PrintMiscellaneous && (Verbose || WizardMode))
4779 perror("os::init_2 getrlimit failed");
4780 } else {
4781 nbr_files.rlim_cur = nbr_files.rlim_max;
4782 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4783 if (status != 0) {
4784 if (PrintMiscellaneous && (Verbose || WizardMode))
4785 perror("os::init_2 setrlimit failed");
4786 }
4787 }
4788 }
4789
4790 // Initialize lock used to serialize thread creation (see os::create_thread)
4791 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4792
4793 // at-exit methods are called in the reverse order of their registration.
4794 // atexit functions are called on return from main or as a result of a
4795 // call to exit(3C). There can be only 32 of these functions registered
4796 // and atexit() does not set errno.
4797
4798 if (PerfAllowAtExitRegistration) {
4799 // only register atexit functions if PerfAllowAtExitRegistration is set.
4800 // atexit functions can be delayed until process exit time, which
4801 // can be problematic for embedded VM situations. Embedded VMs should
4802 // call DestroyJavaVM() to assure that VM resources are released.
4803
4804 // note: perfMemory_exit_helper atexit function may be removed in
4805 // the future if the appropriate cleanup code can be added to the
4806 // VM_Exit VMOperation's doit method.
4807 if (atexit(perfMemory_exit_helper) != 0) {
4808 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4809 }
4810 }
4811
4812 // initialize thread priority policy
4813 prio_init();
4814
4815 return JNI_OK;
4816 }
4817
4818 // this is called at the end of vm_initialization
4819 void os::init_3(void) {
4820 #ifdef JAVASE_EMBEDDED
4821 // Start the MemNotifyThread
4822 if (LowMemoryProtection) {
4823 MemNotifyThread::start();
4824 }
4825 return;
4826 #endif
4827 }
4828
4829 // Mark the polling page as unreadable
4830 void os::make_polling_page_unreadable(void) {
4831 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4832 fatal("Could not disable polling page");
4833 };
4834
4835 // Mark the polling page as readable
4836 void os::make_polling_page_readable(void) {
4837 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4838 fatal("Could not enable polling page");
4839 }
4840 };
4841
4842 int os::active_processor_count() {
4843 // Linux doesn't yet have a (official) notion of processor sets,
4844 // so just return the number of online processors.
4845 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4846 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4847 return online_cpus;
4848 }
4849
4850 void os::set_native_thread_name(const char *name) {
4851 // Not yet implemented.
4852 return;
4853 }
4854
4855 bool os::distribute_processes(uint length, uint* distribution) {
4856 // Not yet implemented.
4857 return false;
4858 }
4859
4860 bool os::bind_to_processor(uint processor_id) {
4861 // Not yet implemented.
4862 return false;
4863 }
4864
4865 ///
4866
4867 void os::SuspendedThreadTask::internal_do_task() {
4868 if (do_suspend(_thread->osthread())) {
4869 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
4870 do_task(context);
4871 do_resume(_thread->osthread());
4872 }
4873 }
4874
4875 class PcFetcher : public os::SuspendedThreadTask {
4876 public:
4877 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
4878 ExtendedPC result();
4879 protected:
4880 void do_task(const os::SuspendedThreadTaskContext& context);
4881 private:
4882 ExtendedPC _epc;
4883 };
4884
4885 ExtendedPC PcFetcher::result() {
4886 guarantee(is_done(), "task is not done yet.");
4887 return _epc;
4888 }
4889
4890 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
4891 Thread* thread = context.thread();
4892 OSThread* osthread = thread->osthread();
4893 if (osthread->ucontext() != NULL) {
4894 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext());
4895 } else {
4896 // NULL context is unexpected, double-check this is the VMThread
4897 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4898 }
4899 }
4900
4901 // Suspends the target using the signal mechanism and then grabs the PC before
4902 // resuming the target. Used by the flat-profiler only
4903 ExtendedPC os::get_thread_pc(Thread* thread) {
4904 // Make sure that it is called by the watcher for the VMThread
4905 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4906 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4907
4908 PcFetcher fetcher(thread);
4909 fetcher.run();
4910 return fetcher.result();
4911 }
4912
4913 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4914 {
4915 if (is_NPTL()) {
4916 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4917 } else {
4918 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4919 // word back to default 64bit precision if condvar is signaled. Java
4920 // wants 53bit precision. Save and restore current value.
4921 int fpu = get_fpu_control_word();
4922 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4923 set_fpu_control_word(fpu);
4924 return status;
4925 }
4926 }
4927
4928 ////////////////////////////////////////////////////////////////////////////////
4929 // debug support
4930
4931 bool os::find(address addr, outputStream* st) {
4932 Dl_info dlinfo;
4933 memset(&dlinfo, 0, sizeof(dlinfo));
4934 if (dladdr(addr, &dlinfo) != 0) {
4935 st->print(PTR_FORMAT ": ", addr);
4936 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
4937 st->print("%s+%#x", dlinfo.dli_sname,
4938 addr - (intptr_t)dlinfo.dli_saddr);
4939 } else if (dlinfo.dli_fbase != NULL) {
4940 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4941 } else {
4942 st->print("<absolute address>");
4943 }
4944 if (dlinfo.dli_fname != NULL) {
4945 st->print(" in %s", dlinfo.dli_fname);
4946 }
4947 if (dlinfo.dli_fbase != NULL) {
4948 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4949 }
4950 st->cr();
4951
4952 if (Verbose) {
4953 // decode some bytes around the PC
4954 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
4955 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
4956 address lowest = (address) dlinfo.dli_sname;
4957 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4958 if (begin < lowest) begin = lowest;
4959 Dl_info dlinfo2;
4960 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
4961 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4962 end = (address) dlinfo2.dli_saddr;
4963 Disassembler::decode(begin, end, st);
4964 }
4965 return true;
4966 }
4967 return false;
4968 }
4969
4970 ////////////////////////////////////////////////////////////////////////////////
4971 // misc
4972
4973 // This does not do anything on Linux. This is basically a hook for being
4974 // able to use structured exception handling (thread-local exception filters)
4975 // on, e.g., Win32.
4976 void
4977 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4978 JavaCallArguments* args, Thread* thread) {
4979 f(value, method, args, thread);
4980 }
4981
4982 void os::print_statistics() {
4983 }
4984
4985 int os::message_box(const char* title, const char* message) {
4986 int i;
4987 fdStream err(defaultStream::error_fd());
4988 for (i = 0; i < 78; i++) err.print_raw("=");
4989 err.cr();
4990 err.print_raw_cr(title);
4991 for (i = 0; i < 78; i++) err.print_raw("-");
4992 err.cr();
4993 err.print_raw_cr(message);
4994 for (i = 0; i < 78; i++) err.print_raw("=");
4995 err.cr();
4996
4997 char buf[16];
4998 // Prevent process from exiting upon "read error" without consuming all CPU
4999 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5000
5001 return buf[0] == 'y' || buf[0] == 'Y';
5002 }
5003
5004 int os::stat(const char *path, struct stat *sbuf) {
5005 char pathbuf[MAX_PATH];
5006 if (strlen(path) > MAX_PATH - 1) {
5007 errno = ENAMETOOLONG;
5008 return -1;
5009 }
5010 os::native_path(strcpy(pathbuf, path));
5011 return ::stat(pathbuf, sbuf);
5012 }
5013
5014 bool os::check_heap(bool force) {
5015 return true;
5016 }
5017
5018 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
5019 return ::vsnprintf(buf, count, format, args);
5020 }
5021
5022 // Is a (classpath) directory empty?
5023 bool os::dir_is_empty(const char* path) {
5024 DIR *dir = NULL;
5025 struct dirent *ptr;
5026
5027 dir = opendir(path);
5028 if (dir == NULL) return true;
5029
5030 /* Scan the directory */
5031 bool result = true;
5032 char buf[sizeof(struct dirent) + MAX_PATH];
5033 while (result && (ptr = ::readdir(dir)) != NULL) {
5034 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5035 result = false;
5036 }
5037 }
5038 closedir(dir);
5039 return result;
5040 }
5041
5042 // This code originates from JDK's sysOpen and open64_w
5043 // from src/solaris/hpi/src/system_md.c
5044
5045 #ifndef O_DELETE
5046 #define O_DELETE 0x10000
5047 #endif
5048
5049 // Open a file. Unlink the file immediately after open returns
5050 // if the specified oflag has the O_DELETE flag set.
5051 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
5052
5053 int os::open(const char *path, int oflag, int mode) {
5054
5055 if (strlen(path) > MAX_PATH - 1) {
5056 errno = ENAMETOOLONG;
5057 return -1;
5058 }
5059 int fd;
5060 int o_delete = (oflag & O_DELETE);
5061 oflag = oflag & ~O_DELETE;
5062
5063 fd = ::open64(path, oflag, mode);
5064 if (fd == -1) return -1;
5065
5066 //If the open succeeded, the file might still be a directory
5067 {
5068 struct stat64 buf64;
5069 int ret = ::fstat64(fd, &buf64);
5070 int st_mode = buf64.st_mode;
5071
5072 if (ret != -1) {
5073 if ((st_mode & S_IFMT) == S_IFDIR) {
5074 errno = EISDIR;
5075 ::close(fd);
5076 return -1;
5077 }
5078 } else {
5079 ::close(fd);
5080 return -1;
5081 }
5082 }
5083
5084 /*
5085 * All file descriptors that are opened in the JVM and not
5086 * specifically destined for a subprocess should have the
5087 * close-on-exec flag set. If we don't set it, then careless 3rd
5088 * party native code might fork and exec without closing all
5089 * appropriate file descriptors (e.g. as we do in closeDescriptors in
5090 * UNIXProcess.c), and this in turn might:
5091 *
5092 * - cause end-of-file to fail to be detected on some file
5093 * descriptors, resulting in mysterious hangs, or
5094 *
5095 * - might cause an fopen in the subprocess to fail on a system
5096 * suffering from bug 1085341.
5097 *
5098 * (Yes, the default setting of the close-on-exec flag is a Unix
5099 * design flaw)
5100 *
5101 * See:
5102 * 1085341: 32-bit stdio routines should support file descriptors >255
5103 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5104 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5105 */
5106 #ifdef FD_CLOEXEC
5107 {
5108 int flags = ::fcntl(fd, F_GETFD);
5109 if (flags != -1)
5110 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5111 }
5112 #endif
5113
5114 if (o_delete != 0) {
5115 ::unlink(path);
5116 }
5117 return fd;
5118 }
5119
5120
5121 // create binary file, rewriting existing file if required
5122 int os::create_binary_file(const char* path, bool rewrite_existing) {
5123 int oflags = O_WRONLY | O_CREAT;
5124 if (!rewrite_existing) {
5125 oflags |= O_EXCL;
5126 }
5127 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5128 }
5129
5130 // return current position of file pointer
5131 jlong os::current_file_offset(int fd) {
5132 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5133 }
5134
5135 // move file pointer to the specified offset
5136 jlong os::seek_to_file_offset(int fd, jlong offset) {
5137 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5138 }
5139
5140 // This code originates from JDK's sysAvailable
5141 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5142
5143 int os::available(int fd, jlong *bytes) {
5144 jlong cur, end;
5145 int mode;
5146 struct stat64 buf64;
5147
5148 if (::fstat64(fd, &buf64) >= 0) {
5149 mode = buf64.st_mode;
5150 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5151 /*
5152 * XXX: is the following call interruptible? If so, this might
5153 * need to go through the INTERRUPT_IO() wrapper as for other
5154 * blocking, interruptible calls in this file.
5155 */
5156 int n;
5157 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5158 *bytes = n;
5159 return 1;
5160 }
5161 }
5162 }
5163 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5164 return 0;
5165 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5166 return 0;
5167 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5168 return 0;
5169 }
5170 *bytes = end - cur;
5171 return 1;
5172 }
5173
5174 int os::socket_available(int fd, jint *pbytes) {
5175 // Linux doc says EINTR not returned, unlike Solaris
5176 int ret = ::ioctl(fd, FIONREAD, pbytes);
5177
5178 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
5179 // is expected to return 0 on failure and 1 on success to the jdk.
5180 return (ret < 0) ? 0 : 1;
5181 }
5182
5183 // Map a block of memory.
5184 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5185 char *addr, size_t bytes, bool read_only,
5186 bool allow_exec) {
5187 int prot;
5188 int flags = MAP_PRIVATE;
5189
5190 if (read_only) {
5191 prot = PROT_READ;
5192 } else {
5193 prot = PROT_READ | PROT_WRITE;
5194 }
5195
5196 if (allow_exec) {
5197 prot |= PROT_EXEC;
5198 }
5199
5200 if (addr != NULL) {
5201 flags |= MAP_FIXED;
5202 }
5203
5204 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5205 fd, file_offset);
5206 if (mapped_address == MAP_FAILED) {
5207 return NULL;
5208 }
5209 return mapped_address;
5210 }
5211
5212
5213 // Remap a block of memory.
5214 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5215 char *addr, size_t bytes, bool read_only,
5216 bool allow_exec) {
5217 // same as map_memory() on this OS
5218 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5219 allow_exec);
5220 }
5221
5222
5223 // Unmap a block of memory.
5224 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5225 return munmap(addr, bytes) == 0;
5226 }
5227
5228 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5229
5230 static clockid_t thread_cpu_clockid(Thread* thread) {
5231 pthread_t tid = thread->osthread()->pthread_id();
5232 clockid_t clockid;
5233
5234 // Get thread clockid
5235 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5236 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5237 return clockid;
5238 }
5239
5240 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5241 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5242 // of a thread.
5243 //
5244 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5245 // the fast estimate available on the platform.
5246
5247 jlong os::current_thread_cpu_time() {
5248 if (os::Linux::supports_fast_thread_cpu_time()) {
5249 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5250 } else {
5251 // return user + sys since the cost is the same
5252 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5253 }
5254 }
5255
5256 jlong os::thread_cpu_time(Thread* thread) {
5257 // consistent with what current_thread_cpu_time() returns
5258 if (os::Linux::supports_fast_thread_cpu_time()) {
5259 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5260 } else {
5261 return slow_thread_cpu_time(thread, true /* user + sys */);
5262 }
5263 }
5264
5265 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5266 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5267 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5268 } else {
5269 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5270 }
5271 }
5272
5273 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5274 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5275 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5276 } else {
5277 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5278 }
5279 }
5280
5281 //
5282 // -1 on error.
5283 //
5284
5285 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5286 static bool proc_task_unchecked = true;
5287 pid_t tid = thread->osthread()->thread_id();
5288 char *s;
5289 char stat[2048];
5290 int statlen;
5291 char proc_name[64];
5292 int count;
5293 long sys_time, user_time;
5294 char cdummy;
5295 int idummy;
5296 long ldummy;
5297 FILE *fp;
5298
5299 snprintf(proc_name, 64, "/proc/%d/stat", tid);
5300
5301 // The /proc/<tid>/stat aggregates per-process usage on
5302 // new Linux kernels 2.6+ where NPTL is supported.
5303 // The /proc/self/task/<tid>/stat still has the per-thread usage.
5304 // See bug 6328462.
5305 // There possibly can be cases where there is no directory
5306 // /proc/self/task, so we check its availability.
5307 if (proc_task_unchecked && os::Linux::is_NPTL()) {
5308 // This is executed only once
5309 proc_task_unchecked = false;
5310 fp = fopen("/proc/self/task", "r");
5311 if (fp != NULL) {
5312 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5313 fclose(fp);
5314 }
5315 }
5316
5317 fp = fopen(proc_name, "r");
5318 if ( fp == NULL ) return -1;
5319 statlen = fread(stat, 1, 2047, fp);
5320 stat[statlen] = '\0';
5321 fclose(fp);
5322
5323 // Skip pid and the command string. Note that we could be dealing with
5324 // weird command names, e.g. user could decide to rename java launcher
5325 // to "java 1.4.2 :)", then the stat file would look like
5326 // 1234 (java 1.4.2 :)) R ... ...
5327 // We don't really need to know the command string, just find the last
5328 // occurrence of ")" and then start parsing from there. See bug 4726580.
5329 s = strrchr(stat, ')');
5330 if (s == NULL ) return -1;
5331
5332 // Skip blank chars
5333 do s++; while (isspace(*s));
5334
5335 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5336 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5337 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5338 &user_time, &sys_time);
5339 if ( count != 13 ) return -1;
5340 if (user_sys_cpu_time) {
5341 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5342 } else {
5343 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5344 }
5345 }
5346
5347 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5348 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5349 info_ptr->may_skip_backward = false; // elapsed time not wall time
5350 info_ptr->may_skip_forward = false; // elapsed time not wall time
5351 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5352 }
5353
5354 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5355 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5356 info_ptr->may_skip_backward = false; // elapsed time not wall time
5357 info_ptr->may_skip_forward = false; // elapsed time not wall time
5358 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5359 }
5360
5361 bool os::is_thread_cpu_time_supported() {
5362 return true;
5363 }
5364
5365 // System loadavg support. Returns -1 if load average cannot be obtained.
5366 // Linux doesn't yet have a (official) notion of processor sets,
5367 // so just return the system wide load average.
5368 int os::loadavg(double loadavg[], int nelem) {
5369 return ::getloadavg(loadavg, nelem);
5370 }
5371
5372 void os::pause() {
5373 char filename[MAX_PATH];
5374 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5375 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
5376 } else {
5377 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5378 }
5379
5380 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5381 if (fd != -1) {
5382 struct stat buf;
5383 ::close(fd);
5384 while (::stat(filename, &buf) == 0) {
5385 (void)::poll(NULL, 0, 100);
5386 }
5387 } else {
5388 jio_fprintf(stderr,
5389 "Could not open pause file '%s', continuing immediately.\n", filename);
5390 }
5391 }
5392
5393
5394 // Refer to the comments in os_solaris.cpp park-unpark.
5395 //
5396 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5397 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5398 // For specifics regarding the bug see GLIBC BUGID 261237 :
5399 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5400 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5401 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5402 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5403 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5404 // and monitorenter when we're using 1-0 locking. All those operations may result in
5405 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5406 // of libpthread avoids the problem, but isn't practical.
5407 //
5408 // Possible remedies:
5409 //
5410 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5411 // This is palliative and probabilistic, however. If the thread is preempted
5412 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5413 // than the minimum period may have passed, and the abstime may be stale (in the
5414 // past) resultin in a hang. Using this technique reduces the odds of a hang
5415 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5416 //
5417 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5418 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5419 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5420 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5421 // thread.
5422 //
5423 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5424 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5425 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5426 // This also works well. In fact it avoids kernel-level scalability impediments
5427 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5428 // timers in a graceful fashion.
5429 //
5430 // 4. When the abstime value is in the past it appears that control returns
5431 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5432 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5433 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5434 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5435 // It may be possible to avoid reinitialization by checking the return
5436 // value from pthread_cond_timedwait(). In addition to reinitializing the
5437 // condvar we must establish the invariant that cond_signal() is only called
5438 // within critical sections protected by the adjunct mutex. This prevents
5439 // cond_signal() from "seeing" a condvar that's in the midst of being
5440 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5441 // desirable signal-after-unlock optimization that avoids futile context switching.
5442 //
5443 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5444 // structure when a condvar is used or initialized. cond_destroy() would
5445 // release the helper structure. Our reinitialize-after-timedwait fix
5446 // put excessive stress on malloc/free and locks protecting the c-heap.
5447 //
5448 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5449 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5450 // and only enabling the work-around for vulnerable environments.
5451
5452 // utility to compute the abstime argument to timedwait:
5453 // millis is the relative timeout time
5454 // abstime will be the absolute timeout time
5455 // TODO: replace compute_abstime() with unpackTime()
5456
5457 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5458 if (millis < 0) millis = 0;
5459
5460 jlong seconds = millis / 1000;
5461 millis %= 1000;
5462 if (seconds > 50000000) { // see man cond_timedwait(3T)
5463 seconds = 50000000;
5464 }
5465
5466 if (os::supports_monotonic_clock()) {
5467 struct timespec now;
5468 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5469 assert_status(status == 0, status, "clock_gettime");
5470 abstime->tv_sec = now.tv_sec + seconds;
5471 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5472 if (nanos >= NANOSECS_PER_SEC) {
5473 abstime->tv_sec += 1;
5474 nanos -= NANOSECS_PER_SEC;
5475 }
5476 abstime->tv_nsec = nanos;
5477 } else {
5478 struct timeval now;
5479 int status = gettimeofday(&now, NULL);
5480 assert(status == 0, "gettimeofday");
5481 abstime->tv_sec = now.tv_sec + seconds;
5482 long usec = now.tv_usec + millis * 1000;
5483 if (usec >= 1000000) {
5484 abstime->tv_sec += 1;
5485 usec -= 1000000;
5486 }
5487 abstime->tv_nsec = usec * 1000;
5488 }
5489 return abstime;
5490 }
5491
5492
5493 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5494 // Conceptually TryPark() should be equivalent to park(0).
5495
5496 int os::PlatformEvent::TryPark() {
5497 for (;;) {
5498 const int v = _Event ;
5499 guarantee ((v == 0) || (v == 1), "invariant") ;
5500 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5501 }
5502 }
5503
5504 void os::PlatformEvent::park() { // AKA "down()"
5505 // Invariant: Only the thread associated with the Event/PlatformEvent
5506 // may call park().
5507 // TODO: assert that _Assoc != NULL or _Assoc == Self
5508 int v ;
5509 for (;;) {
5510 v = _Event ;
5511 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5512 }
5513 guarantee (v >= 0, "invariant") ;
5514 if (v == 0) {
5515 // Do this the hard way by blocking ...
5516 int status = pthread_mutex_lock(_mutex);
5517 assert_status(status == 0, status, "mutex_lock");
5518 guarantee (_nParked == 0, "invariant") ;
5519 ++ _nParked ;
5520 while (_Event < 0) {
5521 status = pthread_cond_wait(_cond, _mutex);
5522 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5523 // Treat this the same as if the wait was interrupted
5524 if (status == ETIME) { status = EINTR; }
5525 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5526 }
5527 -- _nParked ;
5528
5529 _Event = 0 ;
5530 status = pthread_mutex_unlock(_mutex);
5531 assert_status(status == 0, status, "mutex_unlock");
5532 // Paranoia to ensure our locked and lock-free paths interact
5533 // correctly with each other.
5534 OrderAccess::fence();
5535 }
5536 guarantee (_Event >= 0, "invariant") ;
5537 }
5538
5539 int os::PlatformEvent::park(jlong millis) {
5540 guarantee (_nParked == 0, "invariant") ;
5541
5542 int v ;
5543 for (;;) {
5544 v = _Event ;
5545 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5546 }
5547 guarantee (v >= 0, "invariant") ;
5548 if (v != 0) return OS_OK ;
5549
5550 // We do this the hard way, by blocking the thread.
5551 // Consider enforcing a minimum timeout value.
5552 struct timespec abst;
5553 compute_abstime(&abst, millis);
5554
5555 int ret = OS_TIMEOUT;
5556 int status = pthread_mutex_lock(_mutex);
5557 assert_status(status == 0, status, "mutex_lock");
5558 guarantee (_nParked == 0, "invariant") ;
5559 ++_nParked ;
5560
5561 // Object.wait(timo) will return because of
5562 // (a) notification
5563 // (b) timeout
5564 // (c) thread.interrupt
5565 //
5566 // Thread.interrupt and object.notify{All} both call Event::set.
5567 // That is, we treat thread.interrupt as a special case of notification.
5568 // The underlying Solaris implementation, cond_timedwait, admits
5569 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5570 // JVM from making those visible to Java code. As such, we must
5571 // filter out spurious wakeups. We assume all ETIME returns are valid.
5572 //
5573 // TODO: properly differentiate simultaneous notify+interrupt.
5574 // In that case, we should propagate the notify to another waiter.
5575
5576 while (_Event < 0) {
5577 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5578 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5579 pthread_cond_destroy (_cond);
5580 pthread_cond_init (_cond, os::Linux::condAttr()) ;
5581 }
5582 assert_status(status == 0 || status == EINTR ||
5583 status == ETIME || status == ETIMEDOUT,
5584 status, "cond_timedwait");
5585 if (!FilterSpuriousWakeups) break ; // previous semantics
5586 if (status == ETIME || status == ETIMEDOUT) break ;
5587 // We consume and ignore EINTR and spurious wakeups.
5588 }
5589 --_nParked ;
5590 if (_Event >= 0) {
5591 ret = OS_OK;
5592 }
5593 _Event = 0 ;
5594 status = pthread_mutex_unlock(_mutex);
5595 assert_status(status == 0, status, "mutex_unlock");
5596 assert (_nParked == 0, "invariant") ;
5597 // Paranoia to ensure our locked and lock-free paths interact
5598 // correctly with each other.
5599 OrderAccess::fence();
5600 return ret;
5601 }
5602
5603 void os::PlatformEvent::unpark() {
5604 // Transitions for _Event:
5605 // 0 :=> 1
5606 // 1 :=> 1
5607 // -1 :=> either 0 or 1; must signal target thread
5608 // That is, we can safely transition _Event from -1 to either
5609 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back
5610 // unpark() calls.
5611 // See also: "Semaphores in Plan 9" by Mullender & Cox
5612 //
5613 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5614 // that it will take two back-to-back park() calls for the owning
5615 // thread to block. This has the benefit of forcing a spurious return
5616 // from the first park() call after an unpark() call which will help
5617 // shake out uses of park() and unpark() without condition variables.
5618
5619 if (Atomic::xchg(1, &_Event) >= 0) return;
5620
5621 // Wait for the thread associated with the event to vacate
5622 int status = pthread_mutex_lock(_mutex);
5623 assert_status(status == 0, status, "mutex_lock");
5624 int AnyWaiters = _nParked;
5625 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5626 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5627 AnyWaiters = 0;
5628 pthread_cond_signal(_cond);
5629 }
5630 status = pthread_mutex_unlock(_mutex);
5631 assert_status(status == 0, status, "mutex_unlock");
5632 if (AnyWaiters != 0) {
5633 status = pthread_cond_signal(_cond);
5634 assert_status(status == 0, status, "cond_signal");
5635 }
5636
5637 // Note that we signal() _after dropping the lock for "immortal" Events.
5638 // This is safe and avoids a common class of futile wakeups. In rare
5639 // circumstances this can cause a thread to return prematurely from
5640 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5641 // simply re-test the condition and re-park itself.
5642 }
5643
5644
5645 // JSR166
5646 // -------------------------------------------------------
5647
5648 /*
5649 * The solaris and linux implementations of park/unpark are fairly
5650 * conservative for now, but can be improved. They currently use a
5651 * mutex/condvar pair, plus a a count.
5652 * Park decrements count if > 0, else does a condvar wait. Unpark
5653 * sets count to 1 and signals condvar. Only one thread ever waits
5654 * on the condvar. Contention seen when trying to park implies that someone
5655 * is unparking you, so don't wait. And spurious returns are fine, so there
5656 * is no need to track notifications.
5657 */
5658
5659 #define MAX_SECS 100000000
5660 /*
5661 * This code is common to linux and solaris and will be moved to a
5662 * common place in dolphin.
5663 *
5664 * The passed in time value is either a relative time in nanoseconds
5665 * or an absolute time in milliseconds. Either way it has to be unpacked
5666 * into suitable seconds and nanoseconds components and stored in the
5667 * given timespec structure.
5668 * Given time is a 64-bit value and the time_t used in the timespec is only
5669 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5670 * overflow if times way in the future are given. Further on Solaris versions
5671 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5672 * number of seconds, in abstime, is less than current_time + 100,000,000.
5673 * As it will be 28 years before "now + 100000000" will overflow we can
5674 * ignore overflow and just impose a hard-limit on seconds using the value
5675 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5676 * years from "now".
5677 */
5678
5679 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5680 assert (time > 0, "convertTime");
5681 time_t max_secs = 0;
5682
5683 if (!os::supports_monotonic_clock() || isAbsolute) {
5684 struct timeval now;
5685 int status = gettimeofday(&now, NULL);
5686 assert(status == 0, "gettimeofday");
5687
5688 max_secs = now.tv_sec + MAX_SECS;
5689
5690 if (isAbsolute) {
5691 jlong secs = time / 1000;
5692 if (secs > max_secs) {
5693 absTime->tv_sec = max_secs;
5694 } else {
5695 absTime->tv_sec = secs;
5696 }
5697 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5698 } else {
5699 jlong secs = time / NANOSECS_PER_SEC;
5700 if (secs >= MAX_SECS) {
5701 absTime->tv_sec = max_secs;
5702 absTime->tv_nsec = 0;
5703 } else {
5704 absTime->tv_sec = now.tv_sec + secs;
5705 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5706 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5707 absTime->tv_nsec -= NANOSECS_PER_SEC;
5708 ++absTime->tv_sec; // note: this must be <= max_secs
5709 }
5710 }
5711 }
5712 } else {
5713 // must be relative using monotonic clock
5714 struct timespec now;
5715 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5716 assert_status(status == 0, status, "clock_gettime");
5717 max_secs = now.tv_sec + MAX_SECS;
5718 jlong secs = time / NANOSECS_PER_SEC;
5719 if (secs >= MAX_SECS) {
5720 absTime->tv_sec = max_secs;
5721 absTime->tv_nsec = 0;
5722 } else {
5723 absTime->tv_sec = now.tv_sec + secs;
5724 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5725 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5726 absTime->tv_nsec -= NANOSECS_PER_SEC;
5727 ++absTime->tv_sec; // note: this must be <= max_secs
5728 }
5729 }
5730 }
5731 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5732 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5733 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5734 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5735 }
5736
5737 void Parker::park(bool isAbsolute, jlong time) {
5738 // Ideally we'd do something useful while spinning, such
5739 // as calling unpackTime().
5740
5741 // Optional fast-path check:
5742 // Return immediately if a permit is available.
5743 // We depend on Atomic::xchg() having full barrier semantics
5744 // since we are doing a lock-free update to _counter.
5745 if (Atomic::xchg(0, &_counter) > 0) return;
5746
5747 Thread* thread = Thread::current();
5748 assert(thread->is_Java_thread(), "Must be JavaThread");
5749 JavaThread *jt = (JavaThread *)thread;
5750
5751 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5752 // Check interrupt before trying to wait
5753 if (Thread::is_interrupted(thread, false)) {
5754 return;
5755 }
5756
5757 // Next, demultiplex/decode time arguments
5758 timespec absTime;
5759 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5760 return;
5761 }
5762 if (time > 0) {
5763 unpackTime(&absTime, isAbsolute, time);
5764 }
5765
5766
5767 // Enter safepoint region
5768 // Beware of deadlocks such as 6317397.
5769 // The per-thread Parker:: mutex is a classic leaf-lock.
5770 // In particular a thread must never block on the Threads_lock while
5771 // holding the Parker:: mutex. If safepoints are pending both the
5772 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5773 ThreadBlockInVM tbivm(jt);
5774
5775 // Don't wait if cannot get lock since interference arises from
5776 // unblocking. Also. check interrupt before trying wait
5777 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5778 return;
5779 }
5780
5781 int status ;
5782 if (_counter > 0) { // no wait needed
5783 _counter = 0;
5784 status = pthread_mutex_unlock(_mutex);
5785 assert (status == 0, "invariant") ;
5786 // Paranoia to ensure our locked and lock-free paths interact
5787 // correctly with each other and Java-level accesses.
5788 OrderAccess::fence();
5789 return;
5790 }
5791
5792 #ifdef ASSERT
5793 // Don't catch signals while blocked; let the running threads have the signals.
5794 // (This allows a debugger to break into the running thread.)
5795 sigset_t oldsigs;
5796 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5797 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5798 #endif
5799
5800 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5801 jt->set_suspend_equivalent();
5802 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5803
5804 assert(_cur_index == -1, "invariant");
5805 if (time == 0) {
5806 _cur_index = REL_INDEX; // arbitrary choice when not timed
5807 status = pthread_cond_wait (&_cond[_cur_index], _mutex) ;
5808 } else {
5809 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5810 status = os::Linux::safe_cond_timedwait (&_cond[_cur_index], _mutex, &absTime) ;
5811 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5812 pthread_cond_destroy (&_cond[_cur_index]) ;
5813 pthread_cond_init (&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr());
5814 }
5815 }
5816 _cur_index = -1;
5817 assert_status(status == 0 || status == EINTR ||
5818 status == ETIME || status == ETIMEDOUT,
5819 status, "cond_timedwait");
5820
5821 #ifdef ASSERT
5822 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5823 #endif
5824
5825 _counter = 0 ;
5826 status = pthread_mutex_unlock(_mutex) ;
5827 assert_status(status == 0, status, "invariant") ;
5828 // Paranoia to ensure our locked and lock-free paths interact
5829 // correctly with each other and Java-level accesses.
5830 OrderAccess::fence();
5831
5832 // If externally suspended while waiting, re-suspend
5833 if (jt->handle_special_suspend_equivalent_condition()) {
5834 jt->java_suspend_self();
5835 }
5836 }
5837
5838 void Parker::unpark() {
5839 int s, status ;
5840 status = pthread_mutex_lock(_mutex);
5841 assert (status == 0, "invariant") ;
5842 s = _counter;
5843 _counter = 1;
5844 if (s < 1) {
5845 // thread might be parked
5846 if (_cur_index != -1) {
5847 // thread is definitely parked
5848 if (WorkAroundNPTLTimedWaitHang) {
5849 status = pthread_cond_signal (&_cond[_cur_index]);
5850 assert (status == 0, "invariant");
5851 status = pthread_mutex_unlock(_mutex);
5852 assert (status == 0, "invariant");
5853 } else {
5854 status = pthread_mutex_unlock(_mutex);
5855 assert (status == 0, "invariant");
5856 status = pthread_cond_signal (&_cond[_cur_index]);
5857 assert (status == 0, "invariant");
5858 }
5859 } else {
5860 pthread_mutex_unlock(_mutex);
5861 assert (status == 0, "invariant") ;
5862 }
5863 } else {
5864 pthread_mutex_unlock(_mutex);
5865 assert (status == 0, "invariant") ;
5866 }
5867 }
5868
5869
5870 extern char** environ;
5871
5872 #ifndef __NR_fork
5873 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5874 #endif
5875
5876 #ifndef __NR_execve
5877 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5878 #endif
5879
5880 // Run the specified command in a separate process. Return its exit value,
5881 // or -1 on failure (e.g. can't fork a new process).
5882 // Unlike system(), this function can be called from signal handler. It
5883 // doesn't block SIGINT et al.
5884 int os::fork_and_exec(char* cmd) {
5885 const char * argv[4] = {"sh", "-c", cmd, NULL};
5886
5887 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5888 // pthread_atfork handlers and reset pthread library. All we need is a
5889 // separate process to execve. Make a direct syscall to fork process.
5890 // On IA64 there's no fork syscall, we have to use fork() and hope for
5891 // the best...
5892 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5893 IA64_ONLY(fork();)
5894
5895 if (pid < 0) {
5896 // fork failed
5897 return -1;
5898
5899 } else if (pid == 0) {
5900 // child process
5901
5902 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5903 // first to kill every thread on the thread list. Because this list is
5904 // not reset by fork() (see notes above), execve() will instead kill
5905 // every thread in the parent process. We know this is the only thread
5906 // in the new process, so make a system call directly.
5907 // IA64 should use normal execve() from glibc to match the glibc fork()
5908 // above.
5909 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5910 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5911
5912 // execve failed
5913 _exit(-1);
5914
5915 } else {
5916 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5917 // care about the actual exit code, for now.
5918
5919 int status;
5920
5921 // Wait for the child process to exit. This returns immediately if
5922 // the child has already exited. */
5923 while (waitpid(pid, &status, 0) < 0) {
5924 switch (errno) {
5925 case ECHILD: return 0;
5926 case EINTR: break;
5927 default: return -1;
5928 }
5929 }
5930
5931 if (WIFEXITED(status)) {
5932 // The child exited normally; get its exit code.
5933 return WEXITSTATUS(status);
5934 } else if (WIFSIGNALED(status)) {
5935 // The child exited because of a signal
5936 // The best value to return is 0x80 + signal number,
5937 // because that is what all Unix shells do, and because
5938 // it allows callers to distinguish between process exit and
5939 // process death by signal.
5940 return 0x80 + WTERMSIG(status);
5941 } else {
5942 // Unknown exit code; pass it through
5943 return status;
5944 }
5945 }
5946 }
5947
5948 // is_headless_jre()
5949 //
5950 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5951 // in order to report if we are running in a headless jre
5952 //
5953 // Since JDK8 xawt/libmawt.so was moved into the same directory
5954 // as libawt.so, and renamed libawt_xawt.so
5955 //
5956 bool os::is_headless_jre() {
5957 struct stat statbuf;
5958 char buf[MAXPATHLEN];
5959 char libmawtpath[MAXPATHLEN];
5960 const char *xawtstr = "/xawt/libmawt.so";
5961 const char *new_xawtstr = "/libawt_xawt.so";
5962 char *p;
5963
5964 // Get path to libjvm.so
5965 os::jvm_path(buf, sizeof(buf));
5966
5967 // Get rid of libjvm.so
5968 p = strrchr(buf, '/');
5969 if (p == NULL) return false;
5970 else *p = '\0';
5971
5972 // Get rid of client or server
5973 p = strrchr(buf, '/');
5974 if (p == NULL) return false;
5975 else *p = '\0';
5976
5977 // check xawt/libmawt.so
5978 strcpy(libmawtpath, buf);
5979 strcat(libmawtpath, xawtstr);
5980 if (::stat(libmawtpath, &statbuf) == 0) return false;
5981
5982 // check libawt_xawt.so
5983 strcpy(libmawtpath, buf);
5984 strcat(libmawtpath, new_xawtstr);
5985 if (::stat(libmawtpath, &statbuf) == 0) return false;
5986
5987 return true;
5988 }
5989
5990 // Get the default path to the core file
5991 // Returns the length of the string
5992 int os::get_core_path(char* buffer, size_t bufferSize) {
5993 const char* p = get_current_directory(buffer, bufferSize);
5994
5995 if (p == NULL) {
5996 assert(p != NULL, "failed to get current directory");
5997 return 0;
5998 }
5999
6000 return strlen(buffer);
6001 }
6002
6003 #ifdef JAVASE_EMBEDDED
6004 //
6005 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
6006 //
6007 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
6008
6009 // ctor
6010 //
6011 MemNotifyThread::MemNotifyThread(int fd): Thread() {
6012 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
6013 _fd = fd;
6014
6015 if (os::create_thread(this, os::os_thread)) {
6016 _memnotify_thread = this;
6017 os::set_priority(this, NearMaxPriority);
6018 os::start_thread(this);
6019 }
6020 }
6021
6022 // Where all the work gets done
6023 //
6024 void MemNotifyThread::run() {
6025 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
6026
6027 // Set up the select arguments
6028 fd_set rfds;
6029 if (_fd != -1) {
6030 FD_ZERO(&rfds);
6031 FD_SET(_fd, &rfds);
6032 }
6033
6034 // Now wait for the mem_notify device to wake up
6035 while (1) {
6036 // Wait for the mem_notify device to signal us..
6037 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
6038 if (rc == -1) {
6039 perror("select!\n");
6040 break;
6041 } else if (rc) {
6042 //ssize_t free_before = os::available_memory();
6043 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
6044
6045 // The kernel is telling us there is not much memory left...
6046 // try to do something about that
6047
6048 // If we are not already in a GC, try one.
6049 if (!Universe::heap()->is_gc_active()) {
6050 Universe::heap()->collect(GCCause::_allocation_failure);
6051
6052 //ssize_t free_after = os::available_memory();
6053 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
6054 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
6055 }
6056 // We might want to do something like the following if we find the GC's are not helping...
6057 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
6058 }
6059 }
6060 }
6061
6062 //
6063 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
6064 //
6065 void MemNotifyThread::start() {
6066 int fd;
6067 fd = open ("/dev/mem_notify", O_RDONLY, 0);
6068 if (fd < 0) {
6069 return;
6070 }
6071
6072 if (memnotify_thread() == NULL) {
6073 new MemNotifyThread(fd);
6074 }
6075 }
6076
6077 #endif // JAVASE_EMBEDDED
6078
6079
6080 /////////////// Unit tests ///////////////
6081
6082 #ifndef PRODUCT
6083
6084 #define test_log(...) \
6085 do {\
6086 if (VerboseInternalVMTests) { \
6087 tty->print_cr(__VA_ARGS__); \
6088 tty->flush(); \
6089 }\
6090 } while (false)
6091
6092 class TestReserveMemorySpecial : AllStatic {
6093 public:
6094 static void small_page_write(void* addr, size_t size) {
6095 size_t page_size = os::vm_page_size();
6096
6097 char* end = (char*)addr + size;
6098 for (char* p = (char*)addr; p < end; p += page_size) {
6099 *p = 1;
6100 }
6101 }
6102
6103 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6104 if (!UseHugeTLBFS) {
6105 return;
6106 }
6107
6108 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6109
6110 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6111
6112 if (addr != NULL) {
6113 small_page_write(addr, size);
6114
6115 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6116 }
6117 }
6118
6119 static void test_reserve_memory_special_huge_tlbfs_only() {
6120 if (!UseHugeTLBFS) {
6121 return;
6122 }
6123
6124 size_t lp = os::large_page_size();
6125
6126 for (size_t size = lp; size <= lp * 10; size += lp) {
6127 test_reserve_memory_special_huge_tlbfs_only(size);
6128 }
6129 }
6130
6131 static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) {
6132 if (!UseHugeTLBFS) {
6133 return;
6134 }
6135
6136 test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")",
6137 size, alignment);
6138
6139 assert(size >= os::large_page_size(), "Incorrect input to test");
6140
6141 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6142
6143 if (addr != NULL) {
6144 small_page_write(addr, size);
6145
6146 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6147 }
6148 }
6149
6150 static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) {
6151 size_t lp = os::large_page_size();
6152 size_t ag = os::vm_allocation_granularity();
6153
6154 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6155 test_reserve_memory_special_huge_tlbfs_mixed(size, alignment);
6156 }
6157 }
6158
6159 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6160 size_t lp = os::large_page_size();
6161 size_t ag = os::vm_allocation_granularity();
6162
6163 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp);
6164 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag);
6165 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2);
6166 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2);
6167 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag);
6168 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag);
6169 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2);
6170 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10);
6171 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2);
6172 }
6173
6174 static void test_reserve_memory_special_huge_tlbfs() {
6175 if (!UseHugeTLBFS) {
6176 return;
6177 }
6178
6179 test_reserve_memory_special_huge_tlbfs_only();
6180 test_reserve_memory_special_huge_tlbfs_mixed();
6181 }
6182
6183 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6184 if (!UseSHM) {
6185 return;
6186 }
6187
6188 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6189
6190 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6191
6192 if (addr != NULL) {
6193 assert(is_ptr_aligned(addr, alignment), "Check");
6194 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6195
6196 small_page_write(addr, size);
6197
6198 os::Linux::release_memory_special_shm(addr, size);
6199 }
6200 }
6201
6202 static void test_reserve_memory_special_shm() {
6203 size_t lp = os::large_page_size();
6204 size_t ag = os::vm_allocation_granularity();
6205
6206 for (size_t size = ag; size < lp * 3; size += ag) {
6207 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6208 test_reserve_memory_special_shm(size, alignment);
6209 }
6210 }
6211 }
6212
6213 static void test() {
6214 test_reserve_memory_special_huge_tlbfs();
6215 test_reserve_memory_special_shm();
6216 }
6217 };
6218
6219 void TestReserveMemorySpecial_test() {
6220 TestReserveMemorySpecial::test();
6221 }
6222
6223 #endif