1 /*
2 * Copyright (c) 1999, 2011, 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 # define __STDC_FORMAT_MACROS
26
27 // no precompiled headers
28 #include "classfile/classLoader.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/icBuffer.hpp"
32 #include "code/vtableStubs.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "jvm_linux.h"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/filemap.hpp"
38 #include "mutex_linux.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_share_linux.hpp"
41 #include "prims/jniFastGetField.hpp"
42 #include "prims/jvm.h"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/extendedPC.hpp"
46 #include "runtime/globals.hpp"
47 #include "runtime/interfaceSupport.hpp"
48 #include "runtime/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/threadCritical.hpp"
58 #include "runtime/timer.hpp"
59 #include "services/attachListener.hpp"
60 #include "services/runtimeService.hpp"
61 #include "thread_linux.inline.hpp"
62 #include "utilities/decoder.hpp"
63 #include "utilities/defaultStream.hpp"
64 #include "utilities/events.hpp"
65 #include "utilities/growableArray.hpp"
66 #include "utilities/vmError.hpp"
67 #ifdef TARGET_ARCH_x86
68 # include "assembler_x86.inline.hpp"
69 # include "nativeInst_x86.hpp"
70 #endif
71 #ifdef TARGET_ARCH_sparc
72 # include "assembler_sparc.inline.hpp"
73 # include "nativeInst_sparc.hpp"
74 #endif
75 #ifdef TARGET_ARCH_zero
76 # include "assembler_zero.inline.hpp"
77 # include "nativeInst_zero.hpp"
78 #endif
79 #ifdef TARGET_ARCH_arm
80 # include "assembler_arm.inline.hpp"
81 # include "nativeInst_arm.hpp"
82 #endif
83 #ifdef TARGET_ARCH_ppc
84 # include "assembler_ppc.inline.hpp"
85 # include "nativeInst_ppc.hpp"
86 #endif
87 #ifdef COMPILER1
88 #include "c1/c1_Runtime1.hpp"
89 #endif
90 #ifdef COMPILER2
91 #include "opto/runtime.hpp"
92 #endif
93
94 // put OS-includes here
95 # include <sys/types.h>
96 # include <sys/mman.h>
97 # include <sys/stat.h>
98 # include <sys/select.h>
99 # include <pthread.h>
100 # include <signal.h>
101 # include <errno.h>
102 # include <dlfcn.h>
103 # include <stdio.h>
104 # include <unistd.h>
105 # include <sys/resource.h>
106 # include <pthread.h>
107 # include <sys/stat.h>
108 # include <sys/time.h>
109 # include <sys/times.h>
110 # include <sys/utsname.h>
111 # include <sys/socket.h>
112 # include <sys/wait.h>
113 # include <pwd.h>
114 # include <poll.h>
115 # include <semaphore.h>
116 # include <fcntl.h>
117 # include <string.h>
118 # include <syscall.h>
119 # include <sys/sysinfo.h>
120 # include <gnu/libc-version.h>
121 # include <sys/ipc.h>
122 # include <sys/shm.h>
123 # include <link.h>
124 # include <stdint.h>
125 # include <inttypes.h>
126 # include <sys/ioctl.h>
127
128 #ifdef AMD64
129 #include <asm/vsyscall.h>
130 #endif
131
132 #define MAX_PATH (2 * K)
133
134 // for timer info max values which include all bits
135 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
136 #define SEC_IN_NANOSECS 1000000000LL
137
138 #define LARGEPAGES_BIT (1 << 6)
139 ////////////////////////////////////////////////////////////////////////////////
140 // global variables
141 julong os::Linux::_physical_memory = 0;
142
143 address os::Linux::_initial_thread_stack_bottom = NULL;
144 uintptr_t os::Linux::_initial_thread_stack_size = 0;
145
146 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
147 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
148 Mutex* os::Linux::_createThread_lock = NULL;
149 pthread_t os::Linux::_main_thread;
150 int os::Linux::_page_size = -1;
151 bool os::Linux::_is_floating_stack = false;
152 bool os::Linux::_is_NPTL = false;
153 bool os::Linux::_supports_fast_thread_cpu_time = false;
154 const char * os::Linux::_glibc_version = NULL;
155 const char * os::Linux::_libpthread_version = NULL;
156
157 static jlong initial_time_count=0;
158
159 static int clock_tics_per_sec = 100;
160
161 // For diagnostics to print a message once. see run_periodic_checks
162 static sigset_t check_signal_done;
163 static bool check_signals = true;;
164
165 static pid_t _initial_pid = 0;
166
167 /* Signal number used to suspend/resume a thread */
168
169 /* do not use any signal number less than SIGSEGV, see 4355769 */
170 static int SR_signum = SIGUSR2;
171 sigset_t SR_sigset;
172
173 /* Used to protect dlsym() calls */
174 static pthread_mutex_t dl_mutex;
175
176 #ifdef JAVASE_EMBEDDED
177 class MemNotifyThread: public Thread {
178 friend class VMStructs;
179 public:
180 virtual void run();
181
182 private:
183 static MemNotifyThread* _memnotify_thread;
184 int _fd;
185
186 public:
187
188 // Constructor
189 MemNotifyThread(int fd);
190
191 // Tester
192 bool is_memnotify_thread() const { return true; }
193
194 // Printing
195 char* name() const { return (char*)"Linux MemNotify Thread"; }
196
197 // Returns the single instance of the MemNotifyThread
198 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
199
200 // Create and start the single instance of MemNotifyThread
201 static void start();
202 };
203 #endif // JAVASE_EMBEDDED
204
205 // utility functions
206
207 static int SR_initialize();
208 static int SR_finalize();
209
210 julong os::available_memory() {
211 return Linux::available_memory();
212 }
213
214 julong os::Linux::available_memory() {
215 // values in struct sysinfo are "unsigned long"
216 struct sysinfo si;
217 sysinfo(&si);
218
219 return (julong)si.freeram * si.mem_unit;
220 }
221
222 julong os::physical_memory() {
223 return Linux::physical_memory();
224 }
225
226 julong os::allocatable_physical_memory(julong size) {
227 #ifdef _LP64
228 return size;
229 #else
230 julong result = MIN2(size, (julong)3800*M);
231 if (!is_allocatable(result)) {
232 // See comments under solaris for alignment considerations
233 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
234 result = MIN2(size, reasonable_size);
235 }
236 return result;
237 #endif // _LP64
238 }
239
240 ////////////////////////////////////////////////////////////////////////////////
241 // environment support
242
243 bool os::getenv(const char* name, char* buf, int len) {
244 const char* val = ::getenv(name);
245 if (val != NULL && strlen(val) < (size_t)len) {
246 strcpy(buf, val);
247 return true;
248 }
249 if (len > 0) buf[0] = 0; // return a null string
250 return false;
251 }
252
253
254 // Return true if user is running as root.
255
256 bool os::have_special_privileges() {
257 static bool init = false;
258 static bool privileges = false;
259 if (!init) {
260 privileges = (getuid() != geteuid()) || (getgid() != getegid());
261 init = true;
262 }
263 return privileges;
264 }
265
266
267 #ifndef SYS_gettid
268 // i386: 224, ia64: 1105, amd64: 186, sparc 143
269 #ifdef __ia64__
270 #define SYS_gettid 1105
271 #elif __i386__
272 #define SYS_gettid 224
273 #elif __amd64__
274 #define SYS_gettid 186
275 #elif __sparc__
276 #define SYS_gettid 143
277 #else
278 #error define gettid for the arch
279 #endif
280 #endif
281
282 // Cpu architecture string
283 #if defined(ZERO)
284 static char cpu_arch[] = ZERO_LIBARCH;
285 #elif defined(IA64)
286 static char cpu_arch[] = "ia64";
287 #elif defined(IA32)
288 static char cpu_arch[] = "i386";
289 #elif defined(AMD64)
290 static char cpu_arch[] = "amd64";
291 #elif defined(ARM)
292 static char cpu_arch[] = "arm";
293 #elif defined(PPC)
294 static char cpu_arch[] = "ppc";
295 #elif defined(SPARC)
296 # ifdef _LP64
297 static char cpu_arch[] = "sparcv9";
298 # else
299 static char cpu_arch[] = "sparc";
300 # endif
301 #else
302 #error Add appropriate cpu_arch setting
303 #endif
304
305
306 // pid_t gettid()
307 //
308 // Returns the kernel thread id of the currently running thread. Kernel
309 // thread id is used to access /proc.
310 //
311 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
312 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
313 //
314 pid_t os::Linux::gettid() {
315 int rslt = syscall(SYS_gettid);
316 if (rslt == -1) {
317 // old kernel, no NPTL support
318 return getpid();
319 } else {
320 return (pid_t)rslt;
321 }
322 }
323
324 // Most versions of linux have a bug where the number of processors are
325 // determined by looking at the /proc file system. In a chroot environment,
326 // the system call returns 1. This causes the VM to act as if it is
327 // a single processor and elide locking (see is_MP() call).
328 static bool unsafe_chroot_detected = false;
329 static const char *unstable_chroot_error = "/proc file system not found.\n"
330 "Java may be unstable running multithreaded in a chroot "
331 "environment on Linux when /proc filesystem is not mounted.";
332
333 void os::Linux::initialize_system_info() {
334 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
335 if (processor_count() == 1) {
336 pid_t pid = os::Linux::gettid();
337 char fname[32];
338 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
339 FILE *fp = fopen(fname, "r");
340 if (fp == NULL) {
341 unsafe_chroot_detected = true;
342 } else {
343 fclose(fp);
344 }
345 }
346 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
347 assert(processor_count() > 0, "linux error");
348 }
349
350 void os::init_system_properties_values() {
351 // char arch[12];
352 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
353
354 // The next steps are taken in the product version:
355 //
356 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
357 // This library should be located at:
358 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
359 //
360 // If "/jre/lib/" appears at the right place in the path, then we
361 // assume libjvm[_g].so is installed in a JDK and we use this path.
362 //
363 // Otherwise exit with message: "Could not create the Java virtual machine."
364 //
365 // The following extra steps are taken in the debugging version:
366 //
367 // If "/jre/lib/" does NOT appear at the right place in the path
368 // instead of exit check for $JAVA_HOME environment variable.
369 //
370 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
371 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
372 // it looks like libjvm[_g].so is installed there
373 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
374 //
375 // Otherwise exit.
376 //
377 // Important note: if the location of libjvm.so changes this
378 // code needs to be changed accordingly.
379
380 // The next few definitions allow the code to be verbatim:
381 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
382 #define getenv(n) ::getenv(n)
383
384 /*
385 * See ld(1):
386 * The linker uses the following search paths to locate required
387 * shared libraries:
388 * 1: ...
389 * ...
390 * 7: The default directories, normally /lib and /usr/lib.
391 */
392 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
393 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
394 #else
395 #define DEFAULT_LIBPATH "/lib:/usr/lib"
396 #endif
397
398 #define EXTENSIONS_DIR "/lib/ext"
399 #define ENDORSED_DIR "/lib/endorsed"
400 #define REG_DIR "/usr/java/packages"
401
402 {
403 /* sysclasspath, java_home, dll_dir */
404 {
405 char *home_path;
406 char *dll_path;
407 char *pslash;
408 char buf[MAXPATHLEN];
409 os::jvm_path(buf, sizeof(buf));
410
411 // Found the full path to libjvm.so.
412 // Now cut the path to <java_home>/jre if we can.
413 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
414 pslash = strrchr(buf, '/');
415 if (pslash != NULL)
416 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
417 dll_path = malloc(strlen(buf) + 1);
418 if (dll_path == NULL)
419 return;
420 strcpy(dll_path, buf);
421 Arguments::set_dll_dir(dll_path);
422
423 if (pslash != NULL) {
424 pslash = strrchr(buf, '/');
425 if (pslash != NULL) {
426 *pslash = '\0'; /* get rid of /<arch> */
427 pslash = strrchr(buf, '/');
428 if (pslash != NULL)
429 *pslash = '\0'; /* get rid of /lib */
430 }
431 }
432
433 home_path = malloc(strlen(buf) + 1);
434 if (home_path == NULL)
435 return;
436 strcpy(home_path, buf);
437 Arguments::set_java_home(home_path);
438
439 if (!set_boot_path('/', ':'))
440 return;
441 }
442
443 /*
444 * Where to look for native libraries
445 *
446 * Note: Due to a legacy implementation, most of the library path
447 * is set in the launcher. This was to accomodate linking restrictions
448 * on legacy Linux implementations (which are no longer supported).
449 * Eventually, all the library path setting will be done here.
450 *
451 * However, to prevent the proliferation of improperly built native
452 * libraries, the new path component /usr/java/packages is added here.
453 * Eventually, all the library path setting will be done here.
454 */
455 {
456 char *ld_library_path;
457
458 /*
459 * Construct the invariant part of ld_library_path. Note that the
460 * space for the colon and the trailing null are provided by the
461 * nulls included by the sizeof operator (so actually we allocate
462 * a byte more than necessary).
463 */
464 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
465 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
466 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
467
468 /*
469 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
470 * should always exist (until the legacy problem cited above is
471 * addressed).
472 */
473 char *v = getenv("LD_LIBRARY_PATH");
474 if (v != NULL) {
475 char *t = ld_library_path;
476 /* That's +1 for the colon and +1 for the trailing '\0' */
477 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
478 sprintf(ld_library_path, "%s:%s", v, t);
479 }
480 Arguments::set_library_path(ld_library_path);
481 }
482
483 /*
484 * Extensions directories.
485 *
486 * Note that the space for the colon and the trailing null are provided
487 * by the nulls included by the sizeof operator (so actually one byte more
488 * than necessary is allocated).
489 */
490 {
491 char *buf = malloc(strlen(Arguments::get_java_home()) +
492 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
493 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
494 Arguments::get_java_home());
495 Arguments::set_ext_dirs(buf);
496 }
497
498 /* Endorsed standards default directory. */
499 {
500 char * buf;
501 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
502 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
503 Arguments::set_endorsed_dirs(buf);
504 }
505 }
506
507 #undef malloc
508 #undef getenv
509 #undef EXTENSIONS_DIR
510 #undef ENDORSED_DIR
511
512 // Done
513 return;
514 }
515
516 ////////////////////////////////////////////////////////////////////////////////
517 // breakpoint support
518
519 void os::breakpoint() {
520 BREAKPOINT;
521 }
522
523 extern "C" void breakpoint() {
524 // use debugger to set breakpoint here
525 }
526
527 ////////////////////////////////////////////////////////////////////////////////
528 // signal support
529
530 debug_only(static bool signal_sets_initialized = false);
531 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
532
533 bool os::Linux::is_sig_ignored(int sig) {
534 struct sigaction oact;
535 sigaction(sig, (struct sigaction*)NULL, &oact);
536 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
537 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
538 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
539 return true;
540 else
541 return false;
542 }
543
544 void os::Linux::signal_sets_init() {
545 // Should also have an assertion stating we are still single-threaded.
546 assert(!signal_sets_initialized, "Already initialized");
547 // Fill in signals that are necessarily unblocked for all threads in
548 // the VM. Currently, we unblock the following signals:
549 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
550 // by -Xrs (=ReduceSignalUsage));
551 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
552 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
553 // the dispositions or masks wrt these signals.
554 // Programs embedding the VM that want to use the above signals for their
555 // own purposes must, at this time, use the "-Xrs" option to prevent
556 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
557 // (See bug 4345157, and other related bugs).
558 // In reality, though, unblocking these signals is really a nop, since
559 // these signals are not blocked by default.
560 sigemptyset(&unblocked_sigs);
561 sigemptyset(&allowdebug_blocked_sigs);
562 sigaddset(&unblocked_sigs, SIGILL);
563 sigaddset(&unblocked_sigs, SIGSEGV);
564 sigaddset(&unblocked_sigs, SIGBUS);
565 sigaddset(&unblocked_sigs, SIGFPE);
566 sigaddset(&unblocked_sigs, SR_signum);
567
568 if (!ReduceSignalUsage) {
569 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
570 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
571 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
572 }
573 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
574 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
575 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
576 }
577 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
578 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
579 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
580 }
581 }
582 // Fill in signals that are blocked by all but the VM thread.
583 sigemptyset(&vm_sigs);
584 if (!ReduceSignalUsage)
585 sigaddset(&vm_sigs, BREAK_SIGNAL);
586 debug_only(signal_sets_initialized = true);
587
588 }
589
590 // These are signals that are unblocked while a thread is running Java.
591 // (For some reason, they get blocked by default.)
592 sigset_t* os::Linux::unblocked_signals() {
593 assert(signal_sets_initialized, "Not initialized");
594 return &unblocked_sigs;
595 }
596
597 // These are the signals that are blocked while a (non-VM) thread is
598 // running Java. Only the VM thread handles these signals.
599 sigset_t* os::Linux::vm_signals() {
600 assert(signal_sets_initialized, "Not initialized");
601 return &vm_sigs;
602 }
603
604 // These are signals that are blocked during cond_wait to allow debugger in
605 sigset_t* os::Linux::allowdebug_blocked_signals() {
606 assert(signal_sets_initialized, "Not initialized");
607 return &allowdebug_blocked_sigs;
608 }
609
610 void os::Linux::hotspot_sigmask(Thread* thread) {
611
612 //Save caller's signal mask before setting VM signal mask
613 sigset_t caller_sigmask;
614 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
615
616 OSThread* osthread = thread->osthread();
617 osthread->set_caller_sigmask(caller_sigmask);
618
619 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
620
621 if (!ReduceSignalUsage) {
622 if (thread->is_VM_thread()) {
623 // Only the VM thread handles BREAK_SIGNAL ...
624 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
625 } else {
626 // ... all other threads block BREAK_SIGNAL
627 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
628 }
629 }
630 }
631
632 //////////////////////////////////////////////////////////////////////////////
633 // detecting pthread library
634
635 void os::Linux::libpthread_init() {
636 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
637 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
638 // generic name for earlier versions.
639 // Define macros here so we can build HotSpot on old systems.
640 # ifndef _CS_GNU_LIBC_VERSION
641 # define _CS_GNU_LIBC_VERSION 2
642 # endif
643 # ifndef _CS_GNU_LIBPTHREAD_VERSION
644 # define _CS_GNU_LIBPTHREAD_VERSION 3
645 # endif
646
647 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
648 if (n > 0) {
649 char *str = (char *)malloc(n);
650 confstr(_CS_GNU_LIBC_VERSION, str, n);
651 os::Linux::set_glibc_version(str);
652 } else {
653 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
654 static char _gnu_libc_version[32];
655 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
656 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
657 os::Linux::set_glibc_version(_gnu_libc_version);
658 }
659
660 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
661 if (n > 0) {
662 char *str = (char *)malloc(n);
663 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
664 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
665 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
666 // is the case. LinuxThreads has a hard limit on max number of threads.
667 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
668 // On the other hand, NPTL does not have such a limit, sysconf()
669 // will return -1 and errno is not changed. Check if it is really NPTL.
670 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
671 strstr(str, "NPTL") &&
672 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
673 free(str);
674 os::Linux::set_libpthread_version("linuxthreads");
675 } else {
676 os::Linux::set_libpthread_version(str);
677 }
678 } else {
679 // glibc before 2.3.2 only has LinuxThreads.
680 os::Linux::set_libpthread_version("linuxthreads");
681 }
682
683 if (strstr(libpthread_version(), "NPTL")) {
684 os::Linux::set_is_NPTL();
685 } else {
686 os::Linux::set_is_LinuxThreads();
687 }
688
689 // LinuxThreads have two flavors: floating-stack mode, which allows variable
690 // stack size; and fixed-stack mode. NPTL is always floating-stack.
691 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
692 os::Linux::set_is_floating_stack();
693 }
694 }
695
696 /////////////////////////////////////////////////////////////////////////////
697 // thread stack
698
699 // Force Linux kernel to expand current thread stack. If "bottom" is close
700 // to the stack guard, caller should block all signals.
701 //
702 // MAP_GROWSDOWN:
703 // A special mmap() flag that is used to implement thread stacks. It tells
704 // kernel that the memory region should extend downwards when needed. This
705 // allows early versions of LinuxThreads to only mmap the first few pages
706 // when creating a new thread. Linux kernel will automatically expand thread
707 // stack as needed (on page faults).
708 //
709 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
710 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
711 // region, it's hard to tell if the fault is due to a legitimate stack
712 // access or because of reading/writing non-exist memory (e.g. buffer
713 // overrun). As a rule, if the fault happens below current stack pointer,
714 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
715 // application (see Linux kernel fault.c).
716 //
717 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
718 // stack overflow detection.
719 //
720 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
721 // not use this flag. However, the stack of initial thread is not created
722 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
723 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
724 // and then attach the thread to JVM.
725 //
726 // To get around the problem and allow stack banging on Linux, we need to
727 // manually expand thread stack after receiving the SIGSEGV.
728 //
729 // There are two ways to expand thread stack to address "bottom", we used
730 // both of them in JVM before 1.5:
731 // 1. adjust stack pointer first so that it is below "bottom", and then
732 // touch "bottom"
733 // 2. mmap() the page in question
734 //
735 // Now alternate signal stack is gone, it's harder to use 2. For instance,
736 // if current sp is already near the lower end of page 101, and we need to
737 // call mmap() to map page 100, it is possible that part of the mmap() frame
738 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
739 // That will destroy the mmap() frame and cause VM to crash.
740 //
741 // The following code works by adjusting sp first, then accessing the "bottom"
742 // page to force a page fault. Linux kernel will then automatically expand the
743 // stack mapping.
744 //
745 // _expand_stack_to() assumes its frame size is less than page size, which
746 // should always be true if the function is not inlined.
747
748 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
749 #define NOINLINE
750 #else
751 #define NOINLINE __attribute__ ((noinline))
752 #endif
753
754 static void _expand_stack_to(address bottom) NOINLINE;
755
756 static void _expand_stack_to(address bottom) {
757 address sp;
758 size_t size;
759 volatile char *p;
760
761 // Adjust bottom to point to the largest address within the same page, it
762 // gives us a one-page buffer if alloca() allocates slightly more memory.
763 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
764 bottom += os::Linux::page_size() - 1;
765
766 // sp might be slightly above current stack pointer; if that's the case, we
767 // will alloca() a little more space than necessary, which is OK. Don't use
768 // os::current_stack_pointer(), as its result can be slightly below current
769 // stack pointer, causing us to not alloca enough to reach "bottom".
770 sp = (address)&sp;
771
772 if (sp > bottom) {
773 size = sp - bottom;
774 p = (volatile char *)alloca(size);
775 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
776 p[0] = '\0';
777 }
778 }
779
780 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
781 assert(t!=NULL, "just checking");
782 assert(t->osthread()->expanding_stack(), "expand should be set");
783 assert(t->stack_base() != NULL, "stack_base was not initialized");
784
785 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
786 sigset_t mask_all, old_sigset;
787 sigfillset(&mask_all);
788 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
789 _expand_stack_to(addr);
790 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
791 return true;
792 }
793 return false;
794 }
795
796 //////////////////////////////////////////////////////////////////////////////
797 // create new thread
798
799 static address highest_vm_reserved_address();
800
801 // check if it's safe to start a new thread
802 static bool _thread_safety_check(Thread* thread) {
803 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
804 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
805 // Heap is mmap'ed at lower end of memory space. Thread stacks are
806 // allocated (MAP_FIXED) from high address space. Every thread stack
807 // occupies a fixed size slot (usually 2Mbytes, but user can change
808 // it to other values if they rebuild LinuxThreads).
809 //
810 // Problem with MAP_FIXED is that mmap() can still succeed even part of
811 // the memory region has already been mmap'ed. That means if we have too
812 // many threads and/or very large heap, eventually thread stack will
813 // collide with heap.
814 //
815 // Here we try to prevent heap/stack collision by comparing current
816 // stack bottom with the highest address that has been mmap'ed by JVM
817 // plus a safety margin for memory maps created by native code.
818 //
819 // This feature can be disabled by setting ThreadSafetyMargin to 0
820 //
821 if (ThreadSafetyMargin > 0) {
822 address stack_bottom = os::current_stack_base() - os::current_stack_size();
823
824 // not safe if our stack extends below the safety margin
825 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
826 } else {
827 return true;
828 }
829 } else {
830 // Floating stack LinuxThreads or NPTL:
831 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
832 // there's not enough space left, pthread_create() will fail. If we come
833 // here, that means enough space has been reserved for stack.
834 return true;
835 }
836 }
837
838 // Thread start routine for all newly created threads
839 static void *java_start(Thread *thread) {
840 // Try to randomize the cache line index of hot stack frames.
841 // This helps when threads of the same stack traces evict each other's
842 // cache lines. The threads can be either from the same JVM instance, or
843 // from different JVM instances. The benefit is especially true for
844 // processors with hyperthreading technology.
845 static int counter = 0;
846 int pid = os::current_process_id();
847 alloca(((pid ^ counter++) & 7) * 128);
848
849 ThreadLocalStorage::set_thread(thread);
850
851 OSThread* osthread = thread->osthread();
852 Monitor* sync = osthread->startThread_lock();
853
854 // non floating stack LinuxThreads needs extra check, see above
855 if (!_thread_safety_check(thread)) {
856 // notify parent thread
857 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
858 osthread->set_state(ZOMBIE);
859 sync->notify_all();
860 return NULL;
861 }
862
863 // thread_id is kernel thread id (similar to Solaris LWP id)
864 osthread->set_thread_id(os::Linux::gettid());
865
866 if (UseNUMA) {
867 int lgrp_id = os::numa_get_group_id();
868 if (lgrp_id != -1) {
869 thread->set_lgrp_id(lgrp_id);
870 }
871 }
872 // initialize signal mask for this thread
873 os::Linux::hotspot_sigmask(thread);
874
875 // initialize floating point control register
876 os::Linux::init_thread_fpu_state();
877
878 // handshaking with parent thread
879 {
880 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
881
882 // notify parent thread
883 osthread->set_state(INITIALIZED);
884 sync->notify_all();
885
886 // wait until os::start_thread()
887 while (osthread->get_state() == INITIALIZED) {
888 sync->wait(Mutex::_no_safepoint_check_flag);
889 }
890 }
891
892 // call one more level start routine
893 thread->run();
894
895 return 0;
896 }
897
898 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
899 assert(thread->osthread() == NULL, "caller responsible");
900
901 // Allocate the OSThread object
902 OSThread* osthread = new OSThread(NULL, NULL);
903 if (osthread == NULL) {
904 return false;
905 }
906
907 // set the correct thread state
908 osthread->set_thread_type(thr_type);
909
910 // Initial state is ALLOCATED but not INITIALIZED
911 osthread->set_state(ALLOCATED);
912
913 thread->set_osthread(osthread);
914
915 // init thread attributes
916 pthread_attr_t attr;
917 pthread_attr_init(&attr);
918 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
919
920 // stack size
921 if (os::Linux::supports_variable_stack_size()) {
922 // calculate stack size if it's not specified by caller
923 if (stack_size == 0) {
924 stack_size = os::Linux::default_stack_size(thr_type);
925
926 switch (thr_type) {
927 case os::java_thread:
928 // Java threads use ThreadStackSize which default value can be
929 // changed with the flag -Xss
930 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
931 stack_size = JavaThread::stack_size_at_create();
932 break;
933 case os::compiler_thread:
934 if (CompilerThreadStackSize > 0) {
935 stack_size = (size_t)(CompilerThreadStackSize * K);
936 break;
937 } // else fall through:
938 // use VMThreadStackSize if CompilerThreadStackSize is not defined
939 case os::vm_thread:
940 case os::pgc_thread:
941 case os::cgc_thread:
942 case os::watcher_thread:
943 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
944 break;
945 }
946 }
947
948 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
949 pthread_attr_setstacksize(&attr, stack_size);
950 } else {
951 // let pthread_create() pick the default value.
952 }
953
954 // glibc guard page
955 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
956
957 ThreadState state;
958
959 {
960 // Serialize thread creation if we are running with fixed stack LinuxThreads
961 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
962 if (lock) {
963 os::Linux::createThread_lock()->lock_without_safepoint_check();
964 }
965
966 pthread_t tid;
967 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
968
969 pthread_attr_destroy(&attr);
970
971 if (ret != 0) {
972 if (PrintMiscellaneous && (Verbose || WizardMode)) {
973 perror("pthread_create()");
974 }
975 // Need to clean up stuff we've allocated so far
976 thread->set_osthread(NULL);
977 delete osthread;
978 if (lock) os::Linux::createThread_lock()->unlock();
979 return false;
980 }
981
982 // Store pthread info into the OSThread
983 osthread->set_pthread_id(tid);
984
985 // Wait until child thread is either initialized or aborted
986 {
987 Monitor* sync_with_child = osthread->startThread_lock();
988 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
989 while ((state = osthread->get_state()) == ALLOCATED) {
990 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
991 }
992 }
993
994 if (lock) {
995 os::Linux::createThread_lock()->unlock();
996 }
997 }
998
999 // Aborted due to thread limit being reached
1000 if (state == ZOMBIE) {
1001 thread->set_osthread(NULL);
1002 delete osthread;
1003 return false;
1004 }
1005
1006 // The thread is returned suspended (in state INITIALIZED),
1007 // and is started higher up in the call chain
1008 assert(state == INITIALIZED, "race condition");
1009 return true;
1010 }
1011
1012 /////////////////////////////////////////////////////////////////////////////
1013 // attach existing thread
1014
1015 // bootstrap the main thread
1016 bool os::create_main_thread(JavaThread* thread) {
1017 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1018 return create_attached_thread(thread);
1019 }
1020
1021 bool os::create_attached_thread(JavaThread* thread) {
1022 #ifdef ASSERT
1023 thread->verify_not_published();
1024 #endif
1025
1026 // Allocate the OSThread object
1027 OSThread* osthread = new OSThread(NULL, NULL);
1028
1029 if (osthread == NULL) {
1030 return false;
1031 }
1032
1033 // Store pthread info into the OSThread
1034 osthread->set_thread_id(os::Linux::gettid());
1035 osthread->set_pthread_id(::pthread_self());
1036
1037 // initialize floating point control register
1038 os::Linux::init_thread_fpu_state();
1039
1040 // Initial thread state is RUNNABLE
1041 osthread->set_state(RUNNABLE);
1042
1043 thread->set_osthread(osthread);
1044
1045 if (UseNUMA) {
1046 int lgrp_id = os::numa_get_group_id();
1047 if (lgrp_id != -1) {
1048 thread->set_lgrp_id(lgrp_id);
1049 }
1050 }
1051
1052 if (os::Linux::is_initial_thread()) {
1053 // If current thread is initial thread, its stack is mapped on demand,
1054 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1055 // the entire stack region to avoid SEGV in stack banging.
1056 // It is also useful to get around the heap-stack-gap problem on SuSE
1057 // kernel (see 4821821 for details). We first expand stack to the top
1058 // of yellow zone, then enable stack yellow zone (order is significant,
1059 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1060 // is no gap between the last two virtual memory regions.
1061
1062 JavaThread *jt = (JavaThread *)thread;
1063 address addr = jt->stack_yellow_zone_base();
1064 assert(addr != NULL, "initialization problem?");
1065 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1066
1067 osthread->set_expanding_stack();
1068 os::Linux::manually_expand_stack(jt, addr);
1069 osthread->clear_expanding_stack();
1070 }
1071
1072 // initialize signal mask for this thread
1073 // and save the caller's signal mask
1074 os::Linux::hotspot_sigmask(thread);
1075
1076 return true;
1077 }
1078
1079 void os::pd_start_thread(Thread* thread) {
1080 OSThread * osthread = thread->osthread();
1081 assert(osthread->get_state() != INITIALIZED, "just checking");
1082 Monitor* sync_with_child = osthread->startThread_lock();
1083 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1084 sync_with_child->notify();
1085 }
1086
1087 // Free Linux resources related to the OSThread
1088 void os::free_thread(OSThread* osthread) {
1089 assert(osthread != NULL, "osthread not set");
1090
1091 if (Thread::current()->osthread() == osthread) {
1092 // Restore caller's signal mask
1093 sigset_t sigmask = osthread->caller_sigmask();
1094 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1095 }
1096
1097 delete osthread;
1098 }
1099
1100 //////////////////////////////////////////////////////////////////////////////
1101 // thread local storage
1102
1103 int os::allocate_thread_local_storage() {
1104 pthread_key_t key;
1105 int rslt = pthread_key_create(&key, NULL);
1106 assert(rslt == 0, "cannot allocate thread local storage");
1107 return (int)key;
1108 }
1109
1110 // Note: This is currently not used by VM, as we don't destroy TLS key
1111 // on VM exit.
1112 void os::free_thread_local_storage(int index) {
1113 int rslt = pthread_key_delete((pthread_key_t)index);
1114 assert(rslt == 0, "invalid index");
1115 }
1116
1117 void os::thread_local_storage_at_put(int index, void* value) {
1118 int rslt = pthread_setspecific((pthread_key_t)index, value);
1119 assert(rslt == 0, "pthread_setspecific failed");
1120 }
1121
1122 extern "C" Thread* get_thread() {
1123 return ThreadLocalStorage::thread();
1124 }
1125
1126 //////////////////////////////////////////////////////////////////////////////
1127 // initial thread
1128
1129 // Check if current thread is the initial thread, similar to Solaris thr_main.
1130 bool os::Linux::is_initial_thread(void) {
1131 char dummy;
1132 // If called before init complete, thread stack bottom will be null.
1133 // Can be called if fatal error occurs before initialization.
1134 if (initial_thread_stack_bottom() == NULL) return false;
1135 assert(initial_thread_stack_bottom() != NULL &&
1136 initial_thread_stack_size() != 0,
1137 "os::init did not locate initial thread's stack region");
1138 if ((address)&dummy >= initial_thread_stack_bottom() &&
1139 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1140 return true;
1141 else return false;
1142 }
1143
1144 // Find the virtual memory area that contains addr
1145 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1146 FILE *fp = fopen("/proc/self/maps", "r");
1147 if (fp) {
1148 address low, high;
1149 while (!feof(fp)) {
1150 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1151 if (low <= addr && addr < high) {
1152 if (vma_low) *vma_low = low;
1153 if (vma_high) *vma_high = high;
1154 fclose (fp);
1155 return true;
1156 }
1157 }
1158 for (;;) {
1159 int ch = fgetc(fp);
1160 if (ch == EOF || ch == (int)'\n') break;
1161 }
1162 }
1163 fclose(fp);
1164 }
1165 return false;
1166 }
1167
1168 // Locate initial thread stack. This special handling of initial thread stack
1169 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1170 // bogus value for initial thread.
1171 void os::Linux::capture_initial_stack(size_t max_size) {
1172 // stack size is the easy part, get it from RLIMIT_STACK
1173 size_t stack_size;
1174 struct rlimit rlim;
1175 getrlimit(RLIMIT_STACK, &rlim);
1176 stack_size = rlim.rlim_cur;
1177
1178 // 6308388: a bug in ld.so will relocate its own .data section to the
1179 // lower end of primordial stack; reduce ulimit -s value a little bit
1180 // so we won't install guard page on ld.so's data section.
1181 stack_size -= 2 * page_size();
1182
1183 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1184 // 7.1, in both cases we will get 2G in return value.
1185 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1186 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1187 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1188 // in case other parts in glibc still assumes 2M max stack size.
1189 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1190 #ifndef IA64
1191 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1192 #else
1193 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1194 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1195 #endif
1196
1197 // Try to figure out where the stack base (top) is. This is harder.
1198 //
1199 // When an application is started, glibc saves the initial stack pointer in
1200 // a global variable "__libc_stack_end", which is then used by system
1201 // libraries. __libc_stack_end should be pretty close to stack top. The
1202 // variable is available since the very early days. However, because it is
1203 // a private interface, it could disappear in the future.
1204 //
1205 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1206 // to __libc_stack_end, it is very close to stack top, but isn't the real
1207 // stack top. Note that /proc may not exist if VM is running as a chroot
1208 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1209 // /proc/<pid>/stat could change in the future (though unlikely).
1210 //
1211 // We try __libc_stack_end first. If that doesn't work, look for
1212 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1213 // as a hint, which should work well in most cases.
1214
1215 uintptr_t stack_start;
1216
1217 // try __libc_stack_end first
1218 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1219 if (p && *p) {
1220 stack_start = *p;
1221 } else {
1222 // see if we can get the start_stack field from /proc/self/stat
1223 FILE *fp;
1224 int pid;
1225 char state;
1226 int ppid;
1227 int pgrp;
1228 int session;
1229 int nr;
1230 int tpgrp;
1231 unsigned long flags;
1232 unsigned long minflt;
1233 unsigned long cminflt;
1234 unsigned long majflt;
1235 unsigned long cmajflt;
1236 unsigned long utime;
1237 unsigned long stime;
1238 long cutime;
1239 long cstime;
1240 long prio;
1241 long nice;
1242 long junk;
1243 long it_real;
1244 uintptr_t start;
1245 uintptr_t vsize;
1246 intptr_t rss;
1247 uintptr_t rsslim;
1248 uintptr_t scodes;
1249 uintptr_t ecode;
1250 int i;
1251
1252 // Figure what the primordial thread stack base is. Code is inspired
1253 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1254 // followed by command name surrounded by parentheses, state, etc.
1255 char stat[2048];
1256 int statlen;
1257
1258 fp = fopen("/proc/self/stat", "r");
1259 if (fp) {
1260 statlen = fread(stat, 1, 2047, fp);
1261 stat[statlen] = '\0';
1262 fclose(fp);
1263
1264 // Skip pid and the command string. Note that we could be dealing with
1265 // weird command names, e.g. user could decide to rename java launcher
1266 // to "java 1.4.2 :)", then the stat file would look like
1267 // 1234 (java 1.4.2 :)) R ... ...
1268 // We don't really need to know the command string, just find the last
1269 // occurrence of ")" and then start parsing from there. See bug 4726580.
1270 char * s = strrchr(stat, ')');
1271
1272 i = 0;
1273 if (s) {
1274 // Skip blank chars
1275 do s++; while (isspace(*s));
1276
1277 #define _UFM UINTX_FORMAT
1278 #define _DFM INTX_FORMAT
1279
1280 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1281 /* 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 */
1282 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,
1283 &state, /* 3 %c */
1284 &ppid, /* 4 %d */
1285 &pgrp, /* 5 %d */
1286 &session, /* 6 %d */
1287 &nr, /* 7 %d */
1288 &tpgrp, /* 8 %d */
1289 &flags, /* 9 %lu */
1290 &minflt, /* 10 %lu */
1291 &cminflt, /* 11 %lu */
1292 &majflt, /* 12 %lu */
1293 &cmajflt, /* 13 %lu */
1294 &utime, /* 14 %lu */
1295 &stime, /* 15 %lu */
1296 &cutime, /* 16 %ld */
1297 &cstime, /* 17 %ld */
1298 &prio, /* 18 %ld */
1299 &nice, /* 19 %ld */
1300 &junk, /* 20 %ld */
1301 &it_real, /* 21 %ld */
1302 &start, /* 22 UINTX_FORMAT */
1303 &vsize, /* 23 UINTX_FORMAT */
1304 &rss, /* 24 INTX_FORMAT */
1305 &rsslim, /* 25 UINTX_FORMAT */
1306 &scodes, /* 26 UINTX_FORMAT */
1307 &ecode, /* 27 UINTX_FORMAT */
1308 &stack_start); /* 28 UINTX_FORMAT */
1309 }
1310
1311 #undef _UFM
1312 #undef _DFM
1313
1314 if (i != 28 - 2) {
1315 assert(false, "Bad conversion from /proc/self/stat");
1316 // product mode - assume we are the initial thread, good luck in the
1317 // embedded case.
1318 warning("Can't detect initial thread stack location - bad conversion");
1319 stack_start = (uintptr_t) &rlim;
1320 }
1321 } else {
1322 // For some reason we can't open /proc/self/stat (for example, running on
1323 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1324 // most cases, so don't abort:
1325 warning("Can't detect initial thread stack location - no /proc/self/stat");
1326 stack_start = (uintptr_t) &rlim;
1327 }
1328 }
1329
1330 // Now we have a pointer (stack_start) very close to the stack top, the
1331 // next thing to do is to figure out the exact location of stack top. We
1332 // can find out the virtual memory area that contains stack_start by
1333 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1334 // and its upper limit is the real stack top. (again, this would fail if
1335 // running inside chroot, because /proc may not exist.)
1336
1337 uintptr_t stack_top;
1338 address low, high;
1339 if (find_vma((address)stack_start, &low, &high)) {
1340 // success, "high" is the true stack top. (ignore "low", because initial
1341 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1342 stack_top = (uintptr_t)high;
1343 } else {
1344 // failed, likely because /proc/self/maps does not exist
1345 warning("Can't detect initial thread stack location - find_vma failed");
1346 // best effort: stack_start is normally within a few pages below the real
1347 // stack top, use it as stack top, and reduce stack size so we won't put
1348 // guard page outside stack.
1349 stack_top = stack_start;
1350 stack_size -= 16 * page_size();
1351 }
1352
1353 // stack_top could be partially down the page so align it
1354 stack_top = align_size_up(stack_top, page_size());
1355
1356 if (max_size && stack_size > max_size) {
1357 _initial_thread_stack_size = max_size;
1358 } else {
1359 _initial_thread_stack_size = stack_size;
1360 }
1361
1362 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1363 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1364 }
1365
1366 ////////////////////////////////////////////////////////////////////////////////
1367 // time support
1368
1369 // Time since start-up in seconds to a fine granularity.
1370 // Used by VMSelfDestructTimer and the MemProfiler.
1371 double os::elapsedTime() {
1372
1373 return (double)(os::elapsed_counter()) * 0.000001;
1374 }
1375
1376 jlong os::elapsed_counter() {
1377 timeval time;
1378 int status = gettimeofday(&time, NULL);
1379 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1380 }
1381
1382 jlong os::elapsed_frequency() {
1383 return (1000 * 1000);
1384 }
1385
1386 // For now, we say that linux does not support vtime. I have no idea
1387 // whether it can actually be made to (DLD, 9/13/05).
1388
1389 bool os::supports_vtime() { return false; }
1390 bool os::enable_vtime() { return false; }
1391 bool os::vtime_enabled() { return false; }
1392 double os::elapsedVTime() {
1393 // better than nothing, but not much
1394 return elapsedTime();
1395 }
1396
1397 jlong os::javaTimeMillis() {
1398 timeval time;
1399 int status = gettimeofday(&time, NULL);
1400 assert(status != -1, "linux error");
1401 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1402 }
1403
1404 #ifndef CLOCK_MONOTONIC
1405 #define CLOCK_MONOTONIC (1)
1406 #endif
1407
1408 void os::Linux::clock_init() {
1409 // we do dlopen's in this particular order due to bug in linux
1410 // dynamical loader (see 6348968) leading to crash on exit
1411 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1412 if (handle == NULL) {
1413 handle = dlopen("librt.so", RTLD_LAZY);
1414 }
1415
1416 if (handle) {
1417 int (*clock_getres_func)(clockid_t, struct timespec*) =
1418 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1419 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1420 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1421 if (clock_getres_func && clock_gettime_func) {
1422 // See if monotonic clock is supported by the kernel. Note that some
1423 // early implementations simply return kernel jiffies (updated every
1424 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1425 // for nano time (though the monotonic property is still nice to have).
1426 // It's fixed in newer kernels, however clock_getres() still returns
1427 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1428 // resolution for now. Hopefully as people move to new kernels, this
1429 // won't be a problem.
1430 struct timespec res;
1431 struct timespec tp;
1432 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1433 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1434 // yes, monotonic clock is supported
1435 _clock_gettime = clock_gettime_func;
1436 } else {
1437 // close librt if there is no monotonic clock
1438 dlclose(handle);
1439 }
1440 }
1441 }
1442 }
1443
1444 #ifndef SYS_clock_getres
1445
1446 #if defined(IA32) || defined(AMD64)
1447 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1448 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1449 #else
1450 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1451 #define sys_clock_getres(x,y) -1
1452 #endif
1453
1454 #else
1455 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1456 #endif
1457
1458 void os::Linux::fast_thread_clock_init() {
1459 if (!UseLinuxPosixThreadCPUClocks) {
1460 return;
1461 }
1462 clockid_t clockid;
1463 struct timespec tp;
1464 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1465 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1466
1467 // Switch to using fast clocks for thread cpu time if
1468 // the sys_clock_getres() returns 0 error code.
1469 // Note, that some kernels may support the current thread
1470 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1471 // returned by the pthread_getcpuclockid().
1472 // If the fast Posix clocks are supported then the sys_clock_getres()
1473 // must return at least tp.tv_sec == 0 which means a resolution
1474 // better than 1 sec. This is extra check for reliability.
1475
1476 if(pthread_getcpuclockid_func &&
1477 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1478 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1479
1480 _supports_fast_thread_cpu_time = true;
1481 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1482 }
1483 }
1484
1485 jlong os::javaTimeNanos() {
1486 if (Linux::supports_monotonic_clock()) {
1487 struct timespec tp;
1488 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1489 assert(status == 0, "gettime error");
1490 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1491 return result;
1492 } else {
1493 timeval time;
1494 int status = gettimeofday(&time, NULL);
1495 assert(status != -1, "linux error");
1496 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1497 return 1000 * usecs;
1498 }
1499 }
1500
1501 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1502 if (Linux::supports_monotonic_clock()) {
1503 info_ptr->max_value = ALL_64_BITS;
1504
1505 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1506 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1507 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1508 } else {
1509 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1510 info_ptr->max_value = ALL_64_BITS;
1511
1512 // gettimeofday is a real time clock so it skips
1513 info_ptr->may_skip_backward = true;
1514 info_ptr->may_skip_forward = true;
1515 }
1516
1517 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1518 }
1519
1520 // Return the real, user, and system times in seconds from an
1521 // arbitrary fixed point in the past.
1522 bool os::getTimesSecs(double* process_real_time,
1523 double* process_user_time,
1524 double* process_system_time) {
1525 struct tms ticks;
1526 clock_t real_ticks = times(&ticks);
1527
1528 if (real_ticks == (clock_t) (-1)) {
1529 return false;
1530 } else {
1531 double ticks_per_second = (double) clock_tics_per_sec;
1532 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1533 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1534 *process_real_time = ((double) real_ticks) / ticks_per_second;
1535
1536 return true;
1537 }
1538 }
1539
1540
1541 char * os::local_time_string(char *buf, size_t buflen) {
1542 struct tm t;
1543 time_t long_time;
1544 time(&long_time);
1545 localtime_r(&long_time, &t);
1546 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1547 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1548 t.tm_hour, t.tm_min, t.tm_sec);
1549 return buf;
1550 }
1551
1552 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1553 return localtime_r(clock, res);
1554 }
1555
1556 ////////////////////////////////////////////////////////////////////////////////
1557 // runtime exit support
1558
1559 // Note: os::shutdown() might be called very early during initialization, or
1560 // called from signal handler. Before adding something to os::shutdown(), make
1561 // sure it is async-safe and can handle partially initialized VM.
1562 void os::shutdown() {
1563
1564 // allow PerfMemory to attempt cleanup of any persistent resources
1565 perfMemory_exit();
1566
1567 // needs to remove object in file system
1568 AttachListener::abort();
1569
1570 // flush buffered output, finish log files
1571 ostream_abort();
1572
1573 // Check for abort hook
1574 abort_hook_t abort_hook = Arguments::abort_hook();
1575 if (abort_hook != NULL) {
1576 abort_hook();
1577 }
1578
1579 }
1580
1581 // Note: os::abort() might be called very early during initialization, or
1582 // called from signal handler. Before adding something to os::abort(), make
1583 // sure it is async-safe and can handle partially initialized VM.
1584 void os::abort(bool dump_core) {
1585 os::shutdown();
1586 if (dump_core) {
1587 #ifndef PRODUCT
1588 fdStream out(defaultStream::output_fd());
1589 out.print_raw("Current thread is ");
1590 char buf[16];
1591 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1592 out.print_raw_cr(buf);
1593 out.print_raw_cr("Dumping core ...");
1594 #endif
1595 ::abort(); // dump core
1596 }
1597
1598 ::exit(1);
1599 }
1600
1601 // Die immediately, no exit hook, no abort hook, no cleanup.
1602 void os::die() {
1603 // _exit() on LinuxThreads only kills current thread
1604 ::abort();
1605 }
1606
1607 // unused on linux for now.
1608 void os::set_error_file(const char *logfile) {}
1609
1610
1611 // This method is a copy of JDK's sysGetLastErrorString
1612 // from src/solaris/hpi/src/system_md.c
1613
1614 size_t os::lasterror(char *buf, size_t len) {
1615
1616 if (errno == 0) return 0;
1617
1618 const char *s = ::strerror(errno);
1619 size_t n = ::strlen(s);
1620 if (n >= len) {
1621 n = len - 1;
1622 }
1623 ::strncpy(buf, s, n);
1624 buf[n] = '\0';
1625 return n;
1626 }
1627
1628 intx os::current_thread_id() { return (intx)pthread_self(); }
1629 int os::current_process_id() {
1630
1631 // Under the old linux thread library, linux gives each thread
1632 // its own process id. Because of this each thread will return
1633 // a different pid if this method were to return the result
1634 // of getpid(2). Linux provides no api that returns the pid
1635 // of the launcher thread for the vm. This implementation
1636 // returns a unique pid, the pid of the launcher thread
1637 // that starts the vm 'process'.
1638
1639 // Under the NPTL, getpid() returns the same pid as the
1640 // launcher thread rather than a unique pid per thread.
1641 // Use gettid() if you want the old pre NPTL behaviour.
1642
1643 // if you are looking for the result of a call to getpid() that
1644 // returns a unique pid for the calling thread, then look at the
1645 // OSThread::thread_id() method in osThread_linux.hpp file
1646
1647 return (int)(_initial_pid ? _initial_pid : getpid());
1648 }
1649
1650 // DLL functions
1651
1652 const char* os::dll_file_extension() { return ".so"; }
1653
1654 // This must be hard coded because it's the system's temporary
1655 // directory not the java application's temp directory, ala java.io.tmpdir.
1656 const char* os::get_temp_directory() { return "/tmp"; }
1657
1658 static bool file_exists(const char* filename) {
1659 struct stat statbuf;
1660 if (filename == NULL || strlen(filename) == 0) {
1661 return false;
1662 }
1663 return os::stat(filename, &statbuf) == 0;
1664 }
1665
1666 void os::dll_build_name(char* buffer, size_t buflen,
1667 const char* pname, const char* fname) {
1668 // Copied from libhpi
1669 const size_t pnamelen = pname ? strlen(pname) : 0;
1670
1671 // Quietly truncate on buffer overflow. Should be an error.
1672 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1673 *buffer = '\0';
1674 return;
1675 }
1676
1677 if (pnamelen == 0) {
1678 snprintf(buffer, buflen, "lib%s.so", fname);
1679 } else if (strchr(pname, *os::path_separator()) != NULL) {
1680 int n;
1681 char** pelements = split_path(pname, &n);
1682 for (int i = 0 ; i < n ; i++) {
1683 // Really shouldn't be NULL, but check can't hurt
1684 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1685 continue; // skip the empty path values
1686 }
1687 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1688 if (file_exists(buffer)) {
1689 break;
1690 }
1691 }
1692 // release the storage
1693 for (int i = 0 ; i < n ; i++) {
1694 if (pelements[i] != NULL) {
1695 FREE_C_HEAP_ARRAY(char, pelements[i]);
1696 }
1697 }
1698 if (pelements != NULL) {
1699 FREE_C_HEAP_ARRAY(char*, pelements);
1700 }
1701 } else {
1702 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1703 }
1704 }
1705
1706 const char* os::get_current_directory(char *buf, int buflen) {
1707 return getcwd(buf, buflen);
1708 }
1709
1710 // check if addr is inside libjvm[_g].so
1711 bool os::address_is_in_vm(address addr) {
1712 static address libjvm_base_addr;
1713 Dl_info dlinfo;
1714
1715 if (libjvm_base_addr == NULL) {
1716 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1717 libjvm_base_addr = (address)dlinfo.dli_fbase;
1718 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1719 }
1720
1721 if (dladdr((void *)addr, &dlinfo)) {
1722 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1723 }
1724
1725 return false;
1726 }
1727
1728 bool os::dll_address_to_function_name(address addr, char *buf,
1729 int buflen, int *offset) {
1730 Dl_info dlinfo;
1731
1732 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1733 if (buf != NULL) {
1734 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1735 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1736 }
1737 }
1738 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1739 return true;
1740 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1741 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1742 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) {
1743 return true;
1744 }
1745 }
1746
1747 if (buf != NULL) buf[0] = '\0';
1748 if (offset != NULL) *offset = -1;
1749 return false;
1750 }
1751
1752 struct _address_to_library_name {
1753 address addr; // input : memory address
1754 size_t buflen; // size of fname
1755 char* fname; // output: library name
1756 address base; // library base addr
1757 };
1758
1759 static int address_to_library_name_callback(struct dl_phdr_info *info,
1760 size_t size, void *data) {
1761 int i;
1762 bool found = false;
1763 address libbase = NULL;
1764 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1765
1766 // iterate through all loadable segments
1767 for (i = 0; i < info->dlpi_phnum; i++) {
1768 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1769 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1770 // base address of a library is the lowest address of its loaded
1771 // segments.
1772 if (libbase == NULL || libbase > segbase) {
1773 libbase = segbase;
1774 }
1775 // see if 'addr' is within current segment
1776 if (segbase <= d->addr &&
1777 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1778 found = true;
1779 }
1780 }
1781 }
1782
1783 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1784 // so dll_address_to_library_name() can fall through to use dladdr() which
1785 // can figure out executable name from argv[0].
1786 if (found && info->dlpi_name && info->dlpi_name[0]) {
1787 d->base = libbase;
1788 if (d->fname) {
1789 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1790 }
1791 return 1;
1792 }
1793 return 0;
1794 }
1795
1796 bool os::dll_address_to_library_name(address addr, char* buf,
1797 int buflen, int* offset) {
1798 Dl_info dlinfo;
1799 struct _address_to_library_name data;
1800
1801 // There is a bug in old glibc dladdr() implementation that it could resolve
1802 // to wrong library name if the .so file has a base address != NULL. Here
1803 // we iterate through the program headers of all loaded libraries to find
1804 // out which library 'addr' really belongs to. This workaround can be
1805 // removed once the minimum requirement for glibc is moved to 2.3.x.
1806 data.addr = addr;
1807 data.fname = buf;
1808 data.buflen = buflen;
1809 data.base = NULL;
1810 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1811
1812 if (rslt) {
1813 // buf already contains library name
1814 if (offset) *offset = addr - data.base;
1815 return true;
1816 } else if (dladdr((void*)addr, &dlinfo)){
1817 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1818 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1819 return true;
1820 } else {
1821 if (buf) buf[0] = '\0';
1822 if (offset) *offset = -1;
1823 return false;
1824 }
1825 }
1826
1827 // Loads .dll/.so and
1828 // in case of error it checks if .dll/.so was built for the
1829 // same architecture as Hotspot is running on
1830
1831 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1832 {
1833 void * result= ::dlopen(filename, RTLD_LAZY);
1834 if (result != NULL) {
1835 // Successful loading
1836 return result;
1837 }
1838
1839 Elf32_Ehdr elf_head;
1840
1841 // Read system error message into ebuf
1842 // It may or may not be overwritten below
1843 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1844 ebuf[ebuflen-1]='\0';
1845 int diag_msg_max_length=ebuflen-strlen(ebuf);
1846 char* diag_msg_buf=ebuf+strlen(ebuf);
1847
1848 if (diag_msg_max_length==0) {
1849 // No more space in ebuf for additional diagnostics message
1850 return NULL;
1851 }
1852
1853
1854 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1855
1856 if (file_descriptor < 0) {
1857 // Can't open library, report dlerror() message
1858 return NULL;
1859 }
1860
1861 bool failed_to_read_elf_head=
1862 (sizeof(elf_head)!=
1863 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1864
1865 ::close(file_descriptor);
1866 if (failed_to_read_elf_head) {
1867 // file i/o error - report dlerror() msg
1868 return NULL;
1869 }
1870
1871 typedef struct {
1872 Elf32_Half code; // Actual value as defined in elf.h
1873 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1874 char elf_class; // 32 or 64 bit
1875 char endianess; // MSB or LSB
1876 char* name; // String representation
1877 } arch_t;
1878
1879 #ifndef EM_486
1880 #define EM_486 6 /* Intel 80486 */
1881 #endif
1882
1883 static const arch_t arch_array[]={
1884 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1885 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1886 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1887 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1888 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1889 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1890 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1891 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1892 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1893 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1894 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1895 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1896 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1897 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1898 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1899 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1900 };
1901
1902 #if (defined IA32)
1903 static Elf32_Half running_arch_code=EM_386;
1904 #elif (defined AMD64)
1905 static Elf32_Half running_arch_code=EM_X86_64;
1906 #elif (defined IA64)
1907 static Elf32_Half running_arch_code=EM_IA_64;
1908 #elif (defined __sparc) && (defined _LP64)
1909 static Elf32_Half running_arch_code=EM_SPARCV9;
1910 #elif (defined __sparc) && (!defined _LP64)
1911 static Elf32_Half running_arch_code=EM_SPARC;
1912 #elif (defined __powerpc64__)
1913 static Elf32_Half running_arch_code=EM_PPC64;
1914 #elif (defined __powerpc__)
1915 static Elf32_Half running_arch_code=EM_PPC;
1916 #elif (defined ARM)
1917 static Elf32_Half running_arch_code=EM_ARM;
1918 #elif (defined S390)
1919 static Elf32_Half running_arch_code=EM_S390;
1920 #elif (defined ALPHA)
1921 static Elf32_Half running_arch_code=EM_ALPHA;
1922 #elif (defined MIPSEL)
1923 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1924 #elif (defined PARISC)
1925 static Elf32_Half running_arch_code=EM_PARISC;
1926 #elif (defined MIPS)
1927 static Elf32_Half running_arch_code=EM_MIPS;
1928 #elif (defined M68K)
1929 static Elf32_Half running_arch_code=EM_68K;
1930 #else
1931 #error Method os::dll_load requires that one of following is defined:\
1932 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1933 #endif
1934
1935 // Identify compatability class for VM's architecture and library's architecture
1936 // Obtain string descriptions for architectures
1937
1938 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1939 int running_arch_index=-1;
1940
1941 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1942 if (running_arch_code == arch_array[i].code) {
1943 running_arch_index = i;
1944 }
1945 if (lib_arch.code == arch_array[i].code) {
1946 lib_arch.compat_class = arch_array[i].compat_class;
1947 lib_arch.name = arch_array[i].name;
1948 }
1949 }
1950
1951 assert(running_arch_index != -1,
1952 "Didn't find running architecture code (running_arch_code) in arch_array");
1953 if (running_arch_index == -1) {
1954 // Even though running architecture detection failed
1955 // we may still continue with reporting dlerror() message
1956 return NULL;
1957 }
1958
1959 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1960 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1961 return NULL;
1962 }
1963
1964 #ifndef S390
1965 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1966 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1967 return NULL;
1968 }
1969 #endif // !S390
1970
1971 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1972 if ( lib_arch.name!=NULL ) {
1973 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1974 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1975 lib_arch.name, arch_array[running_arch_index].name);
1976 } else {
1977 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1978 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1979 lib_arch.code,
1980 arch_array[running_arch_index].name);
1981 }
1982 }
1983
1984 return NULL;
1985 }
1986
1987 /*
1988 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1989 * chances are you might want to run the generated bits against glibc-2.0
1990 * libdl.so, so always use locking for any version of glibc.
1991 */
1992 void* os::dll_lookup(void* handle, const char* name) {
1993 pthread_mutex_lock(&dl_mutex);
1994 void* res = dlsym(handle, name);
1995 pthread_mutex_unlock(&dl_mutex);
1996 return res;
1997 }
1998
1999
2000 static bool _print_ascii_file(const char* filename, outputStream* st) {
2001 int fd = ::open(filename, O_RDONLY);
2002 if (fd == -1) {
2003 return false;
2004 }
2005
2006 char buf[32];
2007 int bytes;
2008 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2009 st->print_raw(buf, bytes);
2010 }
2011
2012 ::close(fd);
2013
2014 return true;
2015 }
2016
2017 void os::print_dll_info(outputStream *st) {
2018 st->print_cr("Dynamic libraries:");
2019
2020 char fname[32];
2021 pid_t pid = os::Linux::gettid();
2022
2023 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2024
2025 if (!_print_ascii_file(fname, st)) {
2026 st->print("Can not get library information for pid = %d\n", pid);
2027 }
2028 }
2029
2030
2031 void os::print_os_info(outputStream* st) {
2032 st->print("OS:");
2033
2034 // Try to identify popular distros.
2035 // Most Linux distributions have /etc/XXX-release file, which contains
2036 // the OS version string. Some have more than one /etc/XXX-release file
2037 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2038 // so the order is important.
2039 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2040 !_print_ascii_file("/etc/sun-release", st) &&
2041 !_print_ascii_file("/etc/redhat-release", st) &&
2042 !_print_ascii_file("/etc/SuSE-release", st) &&
2043 !_print_ascii_file("/etc/turbolinux-release", st) &&
2044 !_print_ascii_file("/etc/gentoo-release", st) &&
2045 !_print_ascii_file("/etc/debian_version", st) &&
2046 !_print_ascii_file("/etc/ltib-release", st) &&
2047 !_print_ascii_file("/etc/angstrom-version", st)) {
2048 st->print("Linux");
2049 }
2050 st->cr();
2051
2052 // kernel
2053 st->print("uname:");
2054 struct utsname name;
2055 uname(&name);
2056 st->print(name.sysname); st->print(" ");
2057 st->print(name.release); st->print(" ");
2058 st->print(name.version); st->print(" ");
2059 st->print(name.machine);
2060 st->cr();
2061
2062 // Print warning if unsafe chroot environment detected
2063 if (unsafe_chroot_detected) {
2064 st->print("WARNING!! ");
2065 st->print_cr(unstable_chroot_error);
2066 }
2067
2068 // libc, pthread
2069 st->print("libc:");
2070 st->print(os::Linux::glibc_version()); st->print(" ");
2071 st->print(os::Linux::libpthread_version()); st->print(" ");
2072 if (os::Linux::is_LinuxThreads()) {
2073 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2074 }
2075 st->cr();
2076
2077 // rlimit
2078 st->print("rlimit:");
2079 struct rlimit rlim;
2080
2081 st->print(" STACK ");
2082 getrlimit(RLIMIT_STACK, &rlim);
2083 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2084 else st->print("%uk", rlim.rlim_cur >> 10);
2085
2086 st->print(", CORE ");
2087 getrlimit(RLIMIT_CORE, &rlim);
2088 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2089 else st->print("%uk", rlim.rlim_cur >> 10);
2090
2091 st->print(", NPROC ");
2092 getrlimit(RLIMIT_NPROC, &rlim);
2093 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2094 else st->print("%d", rlim.rlim_cur);
2095
2096 st->print(", NOFILE ");
2097 getrlimit(RLIMIT_NOFILE, &rlim);
2098 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2099 else st->print("%d", rlim.rlim_cur);
2100
2101 st->print(", AS ");
2102 getrlimit(RLIMIT_AS, &rlim);
2103 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2104 else st->print("%uk", rlim.rlim_cur >> 10);
2105 st->cr();
2106
2107 // load average
2108 st->print("load average:");
2109 double loadavg[3];
2110 os::loadavg(loadavg, 3);
2111 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
2112 st->cr();
2113
2114 // meminfo
2115 st->print("\n/proc/meminfo:\n");
2116 _print_ascii_file("/proc/meminfo", st);
2117 st->cr();
2118 }
2119
2120 void os::pd_print_cpu_info(outputStream* st) {
2121 st->print("\n/proc/cpuinfo:\n");
2122 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2123 st->print(" <Not Available>");
2124 }
2125 st->cr();
2126 }
2127
2128 void os::print_memory_info(outputStream* st) {
2129
2130 st->print("Memory:");
2131 st->print(" %dk page", os::vm_page_size()>>10);
2132
2133 // values in struct sysinfo are "unsigned long"
2134 struct sysinfo si;
2135 sysinfo(&si);
2136
2137 st->print(", physical " UINT64_FORMAT "k",
2138 os::physical_memory() >> 10);
2139 st->print("(" UINT64_FORMAT "k free)",
2140 os::available_memory() >> 10);
2141 st->print(", swap " UINT64_FORMAT "k",
2142 ((jlong)si.totalswap * si.mem_unit) >> 10);
2143 st->print("(" UINT64_FORMAT "k free)",
2144 ((jlong)si.freeswap * si.mem_unit) >> 10);
2145 st->cr();
2146 }
2147
2148 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2149 // but they're the same for all the linux arch that we support
2150 // and they're the same for solaris but there's no common place to put this.
2151 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2152 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2153 "ILL_COPROC", "ILL_BADSTK" };
2154
2155 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2156 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2157 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2158
2159 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2160
2161 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2162
2163 void os::print_siginfo(outputStream* st, void* siginfo) {
2164 st->print("siginfo:");
2165
2166 const int buflen = 100;
2167 char buf[buflen];
2168 siginfo_t *si = (siginfo_t*)siginfo;
2169 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2170 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2171 st->print("si_errno=%s", buf);
2172 } else {
2173 st->print("si_errno=%d", si->si_errno);
2174 }
2175 const int c = si->si_code;
2176 assert(c > 0, "unexpected si_code");
2177 switch (si->si_signo) {
2178 case SIGILL:
2179 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2180 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2181 break;
2182 case SIGFPE:
2183 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2184 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2185 break;
2186 case SIGSEGV:
2187 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2188 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2189 break;
2190 case SIGBUS:
2191 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2192 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2193 break;
2194 default:
2195 st->print(", si_code=%d", si->si_code);
2196 // no si_addr
2197 }
2198
2199 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2200 UseSharedSpaces) {
2201 FileMapInfo* mapinfo = FileMapInfo::current_info();
2202 if (mapinfo->is_in_shared_space(si->si_addr)) {
2203 st->print("\n\nError accessing class data sharing archive." \
2204 " Mapped file inaccessible during execution, " \
2205 " possible disk/network problem.");
2206 }
2207 }
2208 st->cr();
2209 }
2210
2211
2212 static void print_signal_handler(outputStream* st, int sig,
2213 char* buf, size_t buflen);
2214
2215 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2216 st->print_cr("Signal Handlers:");
2217 print_signal_handler(st, SIGSEGV, buf, buflen);
2218 print_signal_handler(st, SIGBUS , buf, buflen);
2219 print_signal_handler(st, SIGFPE , buf, buflen);
2220 print_signal_handler(st, SIGPIPE, buf, buflen);
2221 print_signal_handler(st, SIGXFSZ, buf, buflen);
2222 print_signal_handler(st, SIGILL , buf, buflen);
2223 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2224 print_signal_handler(st, SR_signum, buf, buflen);
2225 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2226 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2227 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2228 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2229 }
2230
2231 static char saved_jvm_path[MAXPATHLEN] = {0};
2232
2233 // Find the full path to the current module, libjvm.so or libjvm_g.so
2234 void os::jvm_path(char *buf, jint buflen) {
2235 // Error checking.
2236 if (buflen < MAXPATHLEN) {
2237 assert(false, "must use a large-enough buffer");
2238 buf[0] = '\0';
2239 return;
2240 }
2241 // Lazy resolve the path to current module.
2242 if (saved_jvm_path[0] != 0) {
2243 strcpy(buf, saved_jvm_path);
2244 return;
2245 }
2246
2247 char dli_fname[MAXPATHLEN];
2248 bool ret = dll_address_to_library_name(
2249 CAST_FROM_FN_PTR(address, os::jvm_path),
2250 dli_fname, sizeof(dli_fname), NULL);
2251 assert(ret != 0, "cannot locate libjvm");
2252 char *rp = realpath(dli_fname, buf);
2253 if (rp == NULL)
2254 return;
2255
2256 if (Arguments::created_by_gamma_launcher()) {
2257 // Support for the gamma launcher. Typical value for buf is
2258 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2259 // the right place in the string, then assume we are installed in a JDK and
2260 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2261 // up the path so it looks like libjvm.so is installed there (append a
2262 // fake suffix hotspot/libjvm.so).
2263 const char *p = buf + strlen(buf) - 1;
2264 for (int count = 0; p > buf && count < 5; ++count) {
2265 for (--p; p > buf && *p != '/'; --p)
2266 /* empty */ ;
2267 }
2268
2269 if (strncmp(p, "/jre/lib/", 9) != 0) {
2270 // Look for JAVA_HOME in the environment.
2271 char* java_home_var = ::getenv("JAVA_HOME");
2272 if (java_home_var != NULL && java_home_var[0] != 0) {
2273 char* jrelib_p;
2274 int len;
2275
2276 // Check the current module name "libjvm.so" or "libjvm_g.so".
2277 p = strrchr(buf, '/');
2278 assert(strstr(p, "/libjvm") == p, "invalid library name");
2279 p = strstr(p, "_g") ? "_g" : "";
2280
2281 rp = realpath(java_home_var, buf);
2282 if (rp == NULL)
2283 return;
2284
2285 // determine if this is a legacy image or modules image
2286 // modules image doesn't have "jre" subdirectory
2287 len = strlen(buf);
2288 jrelib_p = buf + len;
2289 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2290 if (0 != access(buf, F_OK)) {
2291 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2292 }
2293
2294 if (0 == access(buf, F_OK)) {
2295 // Use current module name "libjvm[_g].so" instead of
2296 // "libjvm"debug_only("_g")".so" since for fastdebug version
2297 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2298 len = strlen(buf);
2299 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2300 } else {
2301 // Go back to path of .so
2302 rp = realpath(dli_fname, buf);
2303 if (rp == NULL)
2304 return;
2305 }
2306 }
2307 }
2308 }
2309
2310 strcpy(saved_jvm_path, buf);
2311 }
2312
2313 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2314 // no prefix required, not even "_"
2315 }
2316
2317 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2318 // no suffix required
2319 }
2320
2321 ////////////////////////////////////////////////////////////////////////////////
2322 // sun.misc.Signal support
2323
2324 static volatile jint sigint_count = 0;
2325
2326 static void
2327 UserHandler(int sig, void *siginfo, void *context) {
2328 // 4511530 - sem_post is serialized and handled by the manager thread. When
2329 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2330 // don't want to flood the manager thread with sem_post requests.
2331 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2332 return;
2333
2334 // Ctrl-C is pressed during error reporting, likely because the error
2335 // handler fails to abort. Let VM die immediately.
2336 if (sig == SIGINT && is_error_reported()) {
2337 os::die();
2338 }
2339
2340 os::signal_notify(sig);
2341 }
2342
2343 void* os::user_handler() {
2344 return CAST_FROM_FN_PTR(void*, UserHandler);
2345 }
2346
2347 extern "C" {
2348 typedef void (*sa_handler_t)(int);
2349 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2350 }
2351
2352 void* os::signal(int signal_number, void* handler) {
2353 struct sigaction sigAct, oldSigAct;
2354
2355 sigfillset(&(sigAct.sa_mask));
2356 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2357 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2358
2359 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2360 // -1 means registration failed
2361 return (void *)-1;
2362 }
2363
2364 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2365 }
2366
2367 void os::signal_raise(int signal_number) {
2368 ::raise(signal_number);
2369 }
2370
2371 /*
2372 * The following code is moved from os.cpp for making this
2373 * code platform specific, which it is by its very nature.
2374 */
2375
2376 // Will be modified when max signal is changed to be dynamic
2377 int os::sigexitnum_pd() {
2378 return NSIG;
2379 }
2380
2381 // a counter for each possible signal value
2382 static volatile jint pending_signals[NSIG+1] = { 0 };
2383
2384 // Linux(POSIX) specific hand shaking semaphore.
2385 static sem_t sig_sem;
2386
2387 void os::signal_init_pd() {
2388 // Initialize signal structures
2389 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2390
2391 // Initialize signal semaphore
2392 ::sem_init(&sig_sem, 0, 0);
2393 }
2394
2395 void os::signal_notify(int sig) {
2396 Atomic::inc(&pending_signals[sig]);
2397 ::sem_post(&sig_sem);
2398 }
2399
2400 static int check_pending_signals(bool wait) {
2401 Atomic::store(0, &sigint_count);
2402 for (;;) {
2403 for (int i = 0; i < NSIG + 1; i++) {
2404 jint n = pending_signals[i];
2405 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2406 return i;
2407 }
2408 }
2409 if (!wait) {
2410 return -1;
2411 }
2412 JavaThread *thread = JavaThread::current();
2413 ThreadBlockInVM tbivm(thread);
2414
2415 bool threadIsSuspended;
2416 do {
2417 thread->set_suspend_equivalent();
2418 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2419 ::sem_wait(&sig_sem);
2420
2421 // were we externally suspended while we were waiting?
2422 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2423 if (threadIsSuspended) {
2424 //
2425 // The semaphore has been incremented, but while we were waiting
2426 // another thread suspended us. We don't want to continue running
2427 // while suspended because that would surprise the thread that
2428 // suspended us.
2429 //
2430 ::sem_post(&sig_sem);
2431
2432 thread->java_suspend_self();
2433 }
2434 } while (threadIsSuspended);
2435 }
2436 }
2437
2438 int os::signal_lookup() {
2439 return check_pending_signals(false);
2440 }
2441
2442 int os::signal_wait() {
2443 return check_pending_signals(true);
2444 }
2445
2446 ////////////////////////////////////////////////////////////////////////////////
2447 // Virtual Memory
2448
2449 int os::vm_page_size() {
2450 // Seems redundant as all get out
2451 assert(os::Linux::page_size() != -1, "must call os::init");
2452 return os::Linux::page_size();
2453 }
2454
2455 // Solaris allocates memory by pages.
2456 int os::vm_allocation_granularity() {
2457 assert(os::Linux::page_size() != -1, "must call os::init");
2458 return os::Linux::page_size();
2459 }
2460
2461 // Rationale behind this function:
2462 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2463 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2464 // samples for JITted code. Here we create private executable mapping over the code cache
2465 // and then we can use standard (well, almost, as mapping can change) way to provide
2466 // info for the reporting script by storing timestamp and location of symbol
2467 void linux_wrap_code(char* base, size_t size) {
2468 static volatile jint cnt = 0;
2469
2470 if (!UseOprofile) {
2471 return;
2472 }
2473
2474 char buf[PATH_MAX+1];
2475 int num = Atomic::add(1, &cnt);
2476
2477 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2478 os::get_temp_directory(), os::current_process_id(), num);
2479 unlink(buf);
2480
2481 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2482
2483 if (fd != -1) {
2484 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2485 if (rv != (off_t)-1) {
2486 if (::write(fd, "", 1) == 1) {
2487 mmap(base, size,
2488 PROT_READ|PROT_WRITE|PROT_EXEC,
2489 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2490 }
2491 }
2492 ::close(fd);
2493 unlink(buf);
2494 }
2495 }
2496
2497 // NOTE: Linux kernel does not really reserve the pages for us.
2498 // All it does is to check if there are enough free pages
2499 // left at the time of mmap(). This could be a potential
2500 // problem.
2501 bool os::commit_memory(char* addr, size_t size, bool exec) {
2502 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2503 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2504 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2505 if (UseNUMAInterleaving && (res != (uintptr_t) MAP_FAILED)) {
2506 numa_make_global(addr, size);
2507 }
2508 return res != (uintptr_t) MAP_FAILED;
2509 }
2510
2511 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2512 #ifndef MAP_HUGETLB
2513 #define MAP_HUGETLB 0x40000
2514 #endif
2515
2516 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2517 #ifndef MADV_HUGEPAGE
2518 #define MADV_HUGEPAGE 14
2519 #endif
2520
2521 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2522 bool exec) {
2523 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2524 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2525 uintptr_t res =
2526 (uintptr_t) ::mmap(addr, size, prot,
2527 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2528 -1, 0);
2529 if (UseNUMAInterleaving && (res != (uintptr_t) MAP_FAILED)) {
2530 numa_make_global(addr, size);
2531 }
2532 return res != (uintptr_t) MAP_FAILED;
2533 }
2534
2535 return commit_memory(addr, size, exec);
2536 }
2537
2538 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2539 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2540 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2541 // be supported or the memory may already be backed by huge pages.
2542 ::madvise(addr, bytes, MADV_HUGEPAGE);
2543 }
2544 }
2545
2546 void os::free_memory(char *addr, size_t bytes) {
2547 commit_memory(addr, bytes, false);
2548 }
2549
2550 void os::numa_make_global(char *addr, size_t bytes) {
2551 Linux::numa_interleave_memory(addr, bytes);
2552 }
2553
2554 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2555 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2556 }
2557
2558 bool os::numa_topology_changed() { return false; }
2559
2560 size_t os::numa_get_groups_num() {
2561 int max_node = Linux::numa_max_node();
2562 return max_node > 0 ? max_node + 1 : 1;
2563 }
2564
2565 int os::numa_get_group_id() {
2566 int cpu_id = Linux::sched_getcpu();
2567 if (cpu_id != -1) {
2568 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2569 if (lgrp_id != -1) {
2570 return lgrp_id;
2571 }
2572 }
2573 return 0;
2574 }
2575
2576 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2577 for (size_t i = 0; i < size; i++) {
2578 ids[i] = i;
2579 }
2580 return size;
2581 }
2582
2583 bool os::get_page_info(char *start, page_info* info) {
2584 return false;
2585 }
2586
2587 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2588 return end;
2589 }
2590
2591
2592 int os::Linux::sched_getcpu_syscall(void) {
2593 unsigned int cpu;
2594 int retval = -1;
2595
2596 #if defined(IA32)
2597 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2598 #elif defined(AMD64)
2599 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2600 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2601 retval = vgetcpu(&cpu, NULL, NULL);
2602 #endif
2603
2604 return (retval == -1) ? retval : cpu;
2605 }
2606
2607 // Something to do with the numa-aware allocator needs these symbols
2608 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2609 extern "C" JNIEXPORT void numa_error(char *where) { }
2610 extern "C" JNIEXPORT int fork1() { return fork(); }
2611
2612
2613 // If we are running with libnuma version > 2, then we should
2614 // be trying to use symbols with versions 1.1
2615 // If we are running with earlier version, which did not have symbol versions,
2616 // we should use the base version.
2617 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2618 void *f = dlvsym(handle, name, "libnuma_1.1");
2619 if (f == NULL) {
2620 f = dlsym(handle, name);
2621 }
2622 return f;
2623 }
2624
2625 bool os::Linux::libnuma_init() {
2626 // sched_getcpu() should be in libc.
2627 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2628 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2629
2630 // If it's not, try a direct syscall.
2631 if (sched_getcpu() == -1)
2632 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2633
2634 if (sched_getcpu() != -1) { // Does it work?
2635 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2636 if (handle != NULL) {
2637 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2638 libnuma_dlsym(handle, "numa_node_to_cpus")));
2639 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2640 libnuma_dlsym(handle, "numa_max_node")));
2641 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2642 libnuma_dlsym(handle, "numa_available")));
2643 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2644 libnuma_dlsym(handle, "numa_tonode_memory")));
2645 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2646 libnuma_dlsym(handle, "numa_interleave_memory")));
2647
2648
2649 if (numa_available() != -1) {
2650 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2651 // Create a cpu -> node mapping
2652 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2653 rebuild_cpu_to_node_map();
2654 return true;
2655 }
2656 }
2657 }
2658 return false;
2659 }
2660
2661 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2662 // The table is later used in get_node_by_cpu().
2663 void os::Linux::rebuild_cpu_to_node_map() {
2664 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2665 // in libnuma (possible values are starting from 16,
2666 // and continuing up with every other power of 2, but less
2667 // than the maximum number of CPUs supported by kernel), and
2668 // is a subject to change (in libnuma version 2 the requirements
2669 // are more reasonable) we'll just hardcode the number they use
2670 // in the library.
2671 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2672
2673 size_t cpu_num = os::active_processor_count();
2674 size_t cpu_map_size = NCPUS / BitsPerCLong;
2675 size_t cpu_map_valid_size =
2676 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2677
2678 cpu_to_node()->clear();
2679 cpu_to_node()->at_grow(cpu_num - 1);
2680 size_t node_num = numa_get_groups_num();
2681
2682 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2683 for (size_t i = 0; i < node_num; i++) {
2684 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2685 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2686 if (cpu_map[j] != 0) {
2687 for (size_t k = 0; k < BitsPerCLong; k++) {
2688 if (cpu_map[j] & (1UL << k)) {
2689 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2690 }
2691 }
2692 }
2693 }
2694 }
2695 }
2696 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2697 }
2698
2699 int os::Linux::get_node_by_cpu(int cpu_id) {
2700 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2701 return cpu_to_node()->at(cpu_id);
2702 }
2703 return -1;
2704 }
2705
2706 GrowableArray<int>* os::Linux::_cpu_to_node;
2707 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2708 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2709 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2710 os::Linux::numa_available_func_t os::Linux::_numa_available;
2711 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2712 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2713 unsigned long* os::Linux::_numa_all_nodes;
2714
2715 bool os::uncommit_memory(char* addr, size_t size) {
2716 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2717 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2718 return res != (uintptr_t) MAP_FAILED;
2719 }
2720
2721 // Linux uses a growable mapping for the stack, and if the mapping for
2722 // the stack guard pages is not removed when we detach a thread the
2723 // stack cannot grow beyond the pages where the stack guard was
2724 // mapped. If at some point later in the process the stack expands to
2725 // that point, the Linux kernel cannot expand the stack any further
2726 // because the guard pages are in the way, and a segfault occurs.
2727 //
2728 // However, it's essential not to split the stack region by unmapping
2729 // a region (leaving a hole) that's already part of the stack mapping,
2730 // so if the stack mapping has already grown beyond the guard pages at
2731 // the time we create them, we have to truncate the stack mapping.
2732 // So, we need to know the extent of the stack mapping when
2733 // create_stack_guard_pages() is called.
2734
2735 // Find the bounds of the stack mapping. Return true for success.
2736 //
2737 // We only need this for stacks that are growable: at the time of
2738 // writing thread stacks don't use growable mappings (i.e. those
2739 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2740 // only applies to the main thread.
2741
2742 static
2743 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2744
2745 char buf[128];
2746 int fd, sz;
2747
2748 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2749 return false;
2750 }
2751
2752 const char kw[] = "[stack]";
2753 const int kwlen = sizeof(kw)-1;
2754
2755 // Address part of /proc/self/maps couldn't be more than 128 bytes
2756 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2757 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2758 // Extract addresses
2759 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2760 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2761 if (sp >= *bottom && sp <= *top) {
2762 ::close(fd);
2763 return true;
2764 }
2765 }
2766 }
2767 }
2768
2769 ::close(fd);
2770 return false;
2771 }
2772
2773
2774 // If the (growable) stack mapping already extends beyond the point
2775 // where we're going to put our guard pages, truncate the mapping at
2776 // that point by munmap()ping it. This ensures that when we later
2777 // munmap() the guard pages we don't leave a hole in the stack
2778 // mapping. This only affects the main/initial thread, but guard
2779 // against future OS changes
2780 bool os::create_stack_guard_pages(char* addr, size_t size) {
2781 uintptr_t stack_extent, stack_base;
2782 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2783 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2784 assert(os::Linux::is_initial_thread(),
2785 "growable stack in non-initial thread");
2786 if (stack_extent < (uintptr_t)addr)
2787 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2788 }
2789
2790 return os::commit_memory(addr, size);
2791 }
2792
2793 // If this is a growable mapping, remove the guard pages entirely by
2794 // munmap()ping them. If not, just call uncommit_memory(). This only
2795 // affects the main/initial thread, but guard against future OS changes
2796 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2797 uintptr_t stack_extent, stack_base;
2798 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2799 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2800 assert(os::Linux::is_initial_thread(),
2801 "growable stack in non-initial thread");
2802
2803 return ::munmap(addr, size) == 0;
2804 }
2805
2806 return os::uncommit_memory(addr, size);
2807 }
2808
2809 static address _highest_vm_reserved_address = NULL;
2810
2811 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2812 // at 'requested_addr'. If there are existing memory mappings at the same
2813 // location, however, they will be overwritten. If 'fixed' is false,
2814 // 'requested_addr' is only treated as a hint, the return value may or
2815 // may not start from the requested address. Unlike Linux mmap(), this
2816 // function returns NULL to indicate failure.
2817 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2818 char * addr;
2819 int flags;
2820
2821 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2822 if (fixed) {
2823 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2824 flags |= MAP_FIXED;
2825 }
2826
2827 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2828 // to PROT_EXEC if executable when we commit the page.
2829 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2830 flags, -1, 0);
2831
2832 if (addr != MAP_FAILED) {
2833 // anon_mmap() should only get called during VM initialization,
2834 // don't need lock (actually we can skip locking even it can be called
2835 // from multiple threads, because _highest_vm_reserved_address is just a
2836 // hint about the upper limit of non-stack memory regions.)
2837 if ((address)addr + bytes > _highest_vm_reserved_address) {
2838 _highest_vm_reserved_address = (address)addr + bytes;
2839 }
2840 }
2841
2842 return addr == MAP_FAILED ? NULL : addr;
2843 }
2844
2845 // Don't update _highest_vm_reserved_address, because there might be memory
2846 // regions above addr + size. If so, releasing a memory region only creates
2847 // a hole in the address space, it doesn't help prevent heap-stack collision.
2848 //
2849 static int anon_munmap(char * addr, size_t size) {
2850 return ::munmap(addr, size) == 0;
2851 }
2852
2853 char* os::reserve_memory(size_t bytes, char* requested_addr,
2854 size_t alignment_hint) {
2855 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2856 }
2857
2858 bool os::release_memory(char* addr, size_t size) {
2859 return anon_munmap(addr, size);
2860 }
2861
2862 static address highest_vm_reserved_address() {
2863 return _highest_vm_reserved_address;
2864 }
2865
2866 static bool linux_mprotect(char* addr, size_t size, int prot) {
2867 // Linux wants the mprotect address argument to be page aligned.
2868 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2869
2870 // According to SUSv3, mprotect() should only be used with mappings
2871 // established by mmap(), and mmap() always maps whole pages. Unaligned
2872 // 'addr' likely indicates problem in the VM (e.g. trying to change
2873 // protection of malloc'ed or statically allocated memory). Check the
2874 // caller if you hit this assert.
2875 assert(addr == bottom, "sanity check");
2876
2877 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2878 return ::mprotect(bottom, size, prot) == 0;
2879 }
2880
2881 // Set protections specified
2882 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2883 bool is_committed) {
2884 unsigned int p = 0;
2885 switch (prot) {
2886 case MEM_PROT_NONE: p = PROT_NONE; break;
2887 case MEM_PROT_READ: p = PROT_READ; break;
2888 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2889 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2890 default:
2891 ShouldNotReachHere();
2892 }
2893 // is_committed is unused.
2894 return linux_mprotect(addr, bytes, p);
2895 }
2896
2897 bool os::guard_memory(char* addr, size_t size) {
2898 return linux_mprotect(addr, size, PROT_NONE);
2899 }
2900
2901 bool os::unguard_memory(char* addr, size_t size) {
2902 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2903 }
2904
2905 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2906 bool result = false;
2907 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2908 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2909 -1, 0);
2910
2911 if (p != (void *) -1) {
2912 // We don't know if this really is a huge page or not.
2913 FILE *fp = fopen("/proc/self/maps", "r");
2914 if (fp) {
2915 while (!feof(fp)) {
2916 char chars[257];
2917 long x = 0;
2918 if (fgets(chars, sizeof(chars), fp)) {
2919 if (sscanf(chars, "%lx-%*x", &x) == 1
2920 && x == (long)p) {
2921 if (strstr (chars, "hugepage")) {
2922 result = true;
2923 break;
2924 }
2925 }
2926 }
2927 }
2928 fclose(fp);
2929 }
2930 munmap (p, page_size);
2931 if (result)
2932 return true;
2933 }
2934
2935 if (warn) {
2936 warning("HugeTLBFS is not supported by the operating system.");
2937 }
2938
2939 return result;
2940 }
2941
2942 /*
2943 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2944 *
2945 * From the coredump_filter documentation:
2946 *
2947 * - (bit 0) anonymous private memory
2948 * - (bit 1) anonymous shared memory
2949 * - (bit 2) file-backed private memory
2950 * - (bit 3) file-backed shared memory
2951 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2952 * effective only if the bit 2 is cleared)
2953 * - (bit 5) hugetlb private memory
2954 * - (bit 6) hugetlb shared memory
2955 */
2956 static void set_coredump_filter(void) {
2957 FILE *f;
2958 long cdm;
2959
2960 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2961 return;
2962 }
2963
2964 if (fscanf(f, "%lx", &cdm) != 1) {
2965 fclose(f);
2966 return;
2967 }
2968
2969 rewind(f);
2970
2971 if ((cdm & LARGEPAGES_BIT) == 0) {
2972 cdm |= LARGEPAGES_BIT;
2973 fprintf(f, "%#lx", cdm);
2974 }
2975
2976 fclose(f);
2977 }
2978
2979 // Large page support
2980
2981 static size_t _large_page_size = 0;
2982
2983 void os::large_page_init() {
2984 if (!UseLargePages) {
2985 UseHugeTLBFS = false;
2986 UseSHM = false;
2987 return;
2988 }
2989
2990 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
2991 // If UseLargePages is specified on the command line try both methods,
2992 // if it's default, then try only HugeTLBFS.
2993 if (FLAG_IS_DEFAULT(UseLargePages)) {
2994 UseHugeTLBFS = true;
2995 } else {
2996 UseHugeTLBFS = UseSHM = true;
2997 }
2998 }
2999
3000 if (LargePageSizeInBytes) {
3001 _large_page_size = LargePageSizeInBytes;
3002 } else {
3003 // large_page_size on Linux is used to round up heap size. x86 uses either
3004 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3005 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3006 // page as large as 256M.
3007 //
3008 // Here we try to figure out page size by parsing /proc/meminfo and looking
3009 // for a line with the following format:
3010 // Hugepagesize: 2048 kB
3011 //
3012 // If we can't determine the value (e.g. /proc is not mounted, or the text
3013 // format has been changed), we'll use the largest page size supported by
3014 // the processor.
3015
3016 #ifndef ZERO
3017 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3018 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3019 #endif // ZERO
3020
3021 FILE *fp = fopen("/proc/meminfo", "r");
3022 if (fp) {
3023 while (!feof(fp)) {
3024 int x = 0;
3025 char buf[16];
3026 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3027 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3028 _large_page_size = x * K;
3029 break;
3030 }
3031 } else {
3032 // skip to next line
3033 for (;;) {
3034 int ch = fgetc(fp);
3035 if (ch == EOF || ch == (int)'\n') break;
3036 }
3037 }
3038 }
3039 fclose(fp);
3040 }
3041 }
3042
3043 // print a warning if any large page related flag is specified on command line
3044 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3045
3046 const size_t default_page_size = (size_t)Linux::page_size();
3047 if (_large_page_size > default_page_size) {
3048 _page_sizes[0] = _large_page_size;
3049 _page_sizes[1] = default_page_size;
3050 _page_sizes[2] = 0;
3051 }
3052 UseHugeTLBFS = UseHugeTLBFS &&
3053 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3054
3055 if (UseHugeTLBFS)
3056 UseSHM = false;
3057
3058 UseLargePages = UseHugeTLBFS || UseSHM;
3059
3060 set_coredump_filter();
3061 }
3062
3063 #ifndef SHM_HUGETLB
3064 #define SHM_HUGETLB 04000
3065 #endif
3066
3067 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3068 // "exec" is passed in but not used. Creating the shared image for
3069 // the code cache doesn't have an SHM_X executable permission to check.
3070 assert(UseLargePages && UseSHM, "only for SHM large pages");
3071
3072 key_t key = IPC_PRIVATE;
3073 char *addr;
3074
3075 bool warn_on_failure = UseLargePages &&
3076 (!FLAG_IS_DEFAULT(UseLargePages) ||
3077 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3078 );
3079 char msg[128];
3080
3081 // Create a large shared memory region to attach to based on size.
3082 // Currently, size is the total size of the heap
3083 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3084 if (shmid == -1) {
3085 // Possible reasons for shmget failure:
3086 // 1. shmmax is too small for Java heap.
3087 // > check shmmax value: cat /proc/sys/kernel/shmmax
3088 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3089 // 2. not enough large page memory.
3090 // > check available large pages: cat /proc/meminfo
3091 // > increase amount of large pages:
3092 // echo new_value > /proc/sys/vm/nr_hugepages
3093 // Note 1: different Linux may use different name for this property,
3094 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3095 // Note 2: it's possible there's enough physical memory available but
3096 // they are so fragmented after a long run that they can't
3097 // coalesce into large pages. Try to reserve large pages when
3098 // the system is still "fresh".
3099 if (warn_on_failure) {
3100 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3101 warning(msg);
3102 }
3103 return NULL;
3104 }
3105
3106 // attach to the region
3107 addr = (char*)shmat(shmid, req_addr, 0);
3108 int err = errno;
3109
3110 // Remove shmid. If shmat() is successful, the actual shared memory segment
3111 // will be deleted when it's detached by shmdt() or when the process
3112 // terminates. If shmat() is not successful this will remove the shared
3113 // segment immediately.
3114 shmctl(shmid, IPC_RMID, NULL);
3115
3116 if ((intptr_t)addr == -1) {
3117 if (warn_on_failure) {
3118 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3119 warning(msg);
3120 }
3121 return NULL;
3122 }
3123
3124 if (UseNUMAInterleaving) {
3125 numa_make_global(addr, bytes);
3126 }
3127
3128 return addr;
3129 }
3130
3131 bool os::release_memory_special(char* base, size_t bytes) {
3132 // detaching the SHM segment will also delete it, see reserve_memory_special()
3133 int rslt = shmdt(base);
3134 return rslt == 0;
3135 }
3136
3137 size_t os::large_page_size() {
3138 return _large_page_size;
3139 }
3140
3141 // HugeTLBFS allows application to commit large page memory on demand;
3142 // with SysV SHM the entire memory region must be allocated as shared
3143 // memory.
3144 bool os::can_commit_large_page_memory() {
3145 return UseHugeTLBFS;
3146 }
3147
3148 bool os::can_execute_large_page_memory() {
3149 return UseHugeTLBFS;
3150 }
3151
3152 // Reserve memory at an arbitrary address, only if that area is
3153 // available (and not reserved for something else).
3154
3155 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3156 const int max_tries = 10;
3157 char* base[max_tries];
3158 size_t size[max_tries];
3159 const size_t gap = 0x000000;
3160
3161 // Assert only that the size is a multiple of the page size, since
3162 // that's all that mmap requires, and since that's all we really know
3163 // about at this low abstraction level. If we need higher alignment,
3164 // we can either pass an alignment to this method or verify alignment
3165 // in one of the methods further up the call chain. See bug 5044738.
3166 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3167
3168 // Repeatedly allocate blocks until the block is allocated at the
3169 // right spot. Give up after max_tries. Note that reserve_memory() will
3170 // automatically update _highest_vm_reserved_address if the call is
3171 // successful. The variable tracks the highest memory address every reserved
3172 // by JVM. It is used to detect heap-stack collision if running with
3173 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3174 // space than needed, it could confuse the collision detecting code. To
3175 // solve the problem, save current _highest_vm_reserved_address and
3176 // calculate the correct value before return.
3177 address old_highest = _highest_vm_reserved_address;
3178
3179 // Linux mmap allows caller to pass an address as hint; give it a try first,
3180 // if kernel honors the hint then we can return immediately.
3181 char * addr = anon_mmap(requested_addr, bytes, false);
3182 if (addr == requested_addr) {
3183 return requested_addr;
3184 }
3185
3186 if (addr != NULL) {
3187 // mmap() is successful but it fails to reserve at the requested address
3188 anon_munmap(addr, bytes);
3189 }
3190
3191 int i;
3192 for (i = 0; i < max_tries; ++i) {
3193 base[i] = reserve_memory(bytes);
3194
3195 if (base[i] != NULL) {
3196 // Is this the block we wanted?
3197 if (base[i] == requested_addr) {
3198 size[i] = bytes;
3199 break;
3200 }
3201
3202 // Does this overlap the block we wanted? Give back the overlapped
3203 // parts and try again.
3204
3205 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3206 if (top_overlap >= 0 && top_overlap < bytes) {
3207 unmap_memory(base[i], top_overlap);
3208 base[i] += top_overlap;
3209 size[i] = bytes - top_overlap;
3210 } else {
3211 size_t bottom_overlap = base[i] + bytes - requested_addr;
3212 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3213 unmap_memory(requested_addr, bottom_overlap);
3214 size[i] = bytes - bottom_overlap;
3215 } else {
3216 size[i] = bytes;
3217 }
3218 }
3219 }
3220 }
3221
3222 // Give back the unused reserved pieces.
3223
3224 for (int j = 0; j < i; ++j) {
3225 if (base[j] != NULL) {
3226 unmap_memory(base[j], size[j]);
3227 }
3228 }
3229
3230 if (i < max_tries) {
3231 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3232 return requested_addr;
3233 } else {
3234 _highest_vm_reserved_address = old_highest;
3235 return NULL;
3236 }
3237 }
3238
3239 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3240 return ::read(fd, buf, nBytes);
3241 }
3242
3243 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3244 // Solaris uses poll(), linux uses park().
3245 // Poll() is likely a better choice, assuming that Thread.interrupt()
3246 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3247 // SIGSEGV, see 4355769.
3248
3249 const int NANOSECS_PER_MILLISECS = 1000000;
3250
3251 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3252 assert(thread == Thread::current(), "thread consistency check");
3253
3254 ParkEvent * const slp = thread->_SleepEvent ;
3255 slp->reset() ;
3256 OrderAccess::fence() ;
3257
3258 if (interruptible) {
3259 jlong prevtime = javaTimeNanos();
3260
3261 for (;;) {
3262 if (os::is_interrupted(thread, true)) {
3263 return OS_INTRPT;
3264 }
3265
3266 jlong newtime = javaTimeNanos();
3267
3268 if (newtime - prevtime < 0) {
3269 // time moving backwards, should only happen if no monotonic clock
3270 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3271 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3272 } else {
3273 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3274 }
3275
3276 if(millis <= 0) {
3277 return OS_OK;
3278 }
3279
3280 prevtime = newtime;
3281
3282 {
3283 assert(thread->is_Java_thread(), "sanity check");
3284 JavaThread *jt = (JavaThread *) thread;
3285 ThreadBlockInVM tbivm(jt);
3286 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3287
3288 jt->set_suspend_equivalent();
3289 // cleared by handle_special_suspend_equivalent_condition() or
3290 // java_suspend_self() via check_and_wait_while_suspended()
3291
3292 slp->park(millis);
3293
3294 // were we externally suspended while we were waiting?
3295 jt->check_and_wait_while_suspended();
3296 }
3297 }
3298 } else {
3299 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3300 jlong prevtime = javaTimeNanos();
3301
3302 for (;;) {
3303 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3304 // the 1st iteration ...
3305 jlong newtime = javaTimeNanos();
3306
3307 if (newtime - prevtime < 0) {
3308 // time moving backwards, should only happen if no monotonic clock
3309 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3310 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3311 } else {
3312 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3313 }
3314
3315 if(millis <= 0) break ;
3316
3317 prevtime = newtime;
3318 slp->park(millis);
3319 }
3320 return OS_OK ;
3321 }
3322 }
3323
3324 int os::naked_sleep() {
3325 // %% make the sleep time an integer flag. for now use 1 millisec.
3326 return os::sleep(Thread::current(), 1, false);
3327 }
3328
3329 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3330 void os::infinite_sleep() {
3331 while (true) { // sleep forever ...
3332 ::sleep(100); // ... 100 seconds at a time
3333 }
3334 }
3335
3336 // Used to convert frequent JVM_Yield() to nops
3337 bool os::dont_yield() {
3338 return DontYieldALot;
3339 }
3340
3341 void os::yield() {
3342 sched_yield();
3343 }
3344
3345 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3346
3347 void os::yield_all(int attempts) {
3348 // Yields to all threads, including threads with lower priorities
3349 // Threads on Linux are all with same priority. The Solaris style
3350 // os::yield_all() with nanosleep(1ms) is not necessary.
3351 sched_yield();
3352 }
3353
3354 // Called from the tight loops to possibly influence time-sharing heuristics
3355 void os::loop_breaker(int attempts) {
3356 os::yield_all(attempts);
3357 }
3358
3359 ////////////////////////////////////////////////////////////////////////////////
3360 // thread priority support
3361
3362 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3363 // only supports dynamic priority, static priority must be zero. For real-time
3364 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3365 // However, for large multi-threaded applications, SCHED_RR is not only slower
3366 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3367 // of 5 runs - Sep 2005).
3368 //
3369 // The following code actually changes the niceness of kernel-thread/LWP. It
3370 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3371 // not the entire user process, and user level threads are 1:1 mapped to kernel
3372 // threads. It has always been the case, but could change in the future. For
3373 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3374 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3375
3376 int os::java_to_os_priority[MaxPriority + 1] = {
3377 19, // 0 Entry should never be used
3378
3379 4, // 1 MinPriority
3380 3, // 2
3381 2, // 3
3382
3383 1, // 4
3384 0, // 5 NormPriority
3385 -1, // 6
3386
3387 -2, // 7
3388 -3, // 8
3389 -4, // 9 NearMaxPriority
3390
3391 -5 // 10 MaxPriority
3392 };
3393
3394 static int prio_init() {
3395 if (ThreadPriorityPolicy == 1) {
3396 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3397 // if effective uid is not root. Perhaps, a more elegant way of doing
3398 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3399 if (geteuid() != 0) {
3400 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3401 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3402 }
3403 ThreadPriorityPolicy = 0;
3404 }
3405 }
3406 return 0;
3407 }
3408
3409 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3410 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3411
3412 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3413 return (ret == 0) ? OS_OK : OS_ERR;
3414 }
3415
3416 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3417 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3418 *priority_ptr = java_to_os_priority[NormPriority];
3419 return OS_OK;
3420 }
3421
3422 errno = 0;
3423 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3424 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3425 }
3426
3427 // Hint to the underlying OS that a task switch would not be good.
3428 // Void return because it's a hint and can fail.
3429 void os::hint_no_preempt() {}
3430
3431 ////////////////////////////////////////////////////////////////////////////////
3432 // suspend/resume support
3433
3434 // the low-level signal-based suspend/resume support is a remnant from the
3435 // old VM-suspension that used to be for java-suspension, safepoints etc,
3436 // within hotspot. Now there is a single use-case for this:
3437 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3438 // that runs in the watcher thread.
3439 // The remaining code is greatly simplified from the more general suspension
3440 // code that used to be used.
3441 //
3442 // The protocol is quite simple:
3443 // - suspend:
3444 // - sends a signal to the target thread
3445 // - polls the suspend state of the osthread using a yield loop
3446 // - target thread signal handler (SR_handler) sets suspend state
3447 // and blocks in sigsuspend until continued
3448 // - resume:
3449 // - sets target osthread state to continue
3450 // - sends signal to end the sigsuspend loop in the SR_handler
3451 //
3452 // Note that the SR_lock plays no role in this suspend/resume protocol.
3453 //
3454
3455 static void resume_clear_context(OSThread *osthread) {
3456 osthread->set_ucontext(NULL);
3457 osthread->set_siginfo(NULL);
3458
3459 // notify the suspend action is completed, we have now resumed
3460 osthread->sr.clear_suspended();
3461 }
3462
3463 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3464 osthread->set_ucontext(context);
3465 osthread->set_siginfo(siginfo);
3466 }
3467
3468 //
3469 // Handler function invoked when a thread's execution is suspended or
3470 // resumed. We have to be careful that only async-safe functions are
3471 // called here (Note: most pthread functions are not async safe and
3472 // should be avoided.)
3473 //
3474 // Note: sigwait() is a more natural fit than sigsuspend() from an
3475 // interface point of view, but sigwait() prevents the signal hander
3476 // from being run. libpthread would get very confused by not having
3477 // its signal handlers run and prevents sigwait()'s use with the
3478 // mutex granting granting signal.
3479 //
3480 // Currently only ever called on the VMThread
3481 //
3482 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3483 // Save and restore errno to avoid confusing native code with EINTR
3484 // after sigsuspend.
3485 int old_errno = errno;
3486
3487 Thread* thread = Thread::current();
3488 OSThread* osthread = thread->osthread();
3489 assert(thread->is_VM_thread(), "Must be VMThread");
3490 // read current suspend action
3491 int action = osthread->sr.suspend_action();
3492 if (action == SR_SUSPEND) {
3493 suspend_save_context(osthread, siginfo, context);
3494
3495 // Notify the suspend action is about to be completed. do_suspend()
3496 // waits until SR_SUSPENDED is set and then returns. We will wait
3497 // here for a resume signal and that completes the suspend-other
3498 // action. do_suspend/do_resume is always called as a pair from
3499 // the same thread - so there are no races
3500
3501 // notify the caller
3502 osthread->sr.set_suspended();
3503
3504 sigset_t suspend_set; // signals for sigsuspend()
3505
3506 // get current set of blocked signals and unblock resume signal
3507 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3508 sigdelset(&suspend_set, SR_signum);
3509
3510 // wait here until we are resumed
3511 do {
3512 sigsuspend(&suspend_set);
3513 // ignore all returns until we get a resume signal
3514 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3515
3516 resume_clear_context(osthread);
3517
3518 } else {
3519 assert(action == SR_CONTINUE, "unexpected sr action");
3520 // nothing special to do - just leave the handler
3521 }
3522
3523 errno = old_errno;
3524 }
3525
3526
3527 static int SR_initialize() {
3528 struct sigaction act;
3529 char *s;
3530 /* Get signal number to use for suspend/resume */
3531 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3532 int sig = ::strtol(s, 0, 10);
3533 if (sig > 0 || sig < _NSIG) {
3534 SR_signum = sig;
3535 }
3536 }
3537
3538 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3539 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3540
3541 sigemptyset(&SR_sigset);
3542 sigaddset(&SR_sigset, SR_signum);
3543
3544 /* Set up signal handler for suspend/resume */
3545 act.sa_flags = SA_RESTART|SA_SIGINFO;
3546 act.sa_handler = (void (*)(int)) SR_handler;
3547
3548 // SR_signum is blocked by default.
3549 // 4528190 - We also need to block pthread restart signal (32 on all
3550 // supported Linux platforms). Note that LinuxThreads need to block
3551 // this signal for all threads to work properly. So we don't have
3552 // to use hard-coded signal number when setting up the mask.
3553 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3554
3555 if (sigaction(SR_signum, &act, 0) == -1) {
3556 return -1;
3557 }
3558
3559 // Save signal flag
3560 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3561 return 0;
3562 }
3563
3564 static int SR_finalize() {
3565 return 0;
3566 }
3567
3568
3569 // returns true on success and false on error - really an error is fatal
3570 // but this seems the normal response to library errors
3571 static bool do_suspend(OSThread* osthread) {
3572 // mark as suspended and send signal
3573 osthread->sr.set_suspend_action(SR_SUSPEND);
3574 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3575 assert_status(status == 0, status, "pthread_kill");
3576
3577 // check status and wait until notified of suspension
3578 if (status == 0) {
3579 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3580 os::yield_all(i);
3581 }
3582 osthread->sr.set_suspend_action(SR_NONE);
3583 return true;
3584 }
3585 else {
3586 osthread->sr.set_suspend_action(SR_NONE);
3587 return false;
3588 }
3589 }
3590
3591 static void do_resume(OSThread* osthread) {
3592 assert(osthread->sr.is_suspended(), "thread should be suspended");
3593 osthread->sr.set_suspend_action(SR_CONTINUE);
3594
3595 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3596 assert_status(status == 0, status, "pthread_kill");
3597 // check status and wait unit notified of resumption
3598 if (status == 0) {
3599 for (int i = 0; osthread->sr.is_suspended(); i++) {
3600 os::yield_all(i);
3601 }
3602 }
3603 osthread->sr.set_suspend_action(SR_NONE);
3604 }
3605
3606 ////////////////////////////////////////////////////////////////////////////////
3607 // interrupt support
3608
3609 void os::interrupt(Thread* thread) {
3610 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3611 "possibility of dangling Thread pointer");
3612
3613 OSThread* osthread = thread->osthread();
3614
3615 if (!osthread->interrupted()) {
3616 osthread->set_interrupted(true);
3617 // More than one thread can get here with the same value of osthread,
3618 // resulting in multiple notifications. We do, however, want the store
3619 // to interrupted() to be visible to other threads before we execute unpark().
3620 OrderAccess::fence();
3621 ParkEvent * const slp = thread->_SleepEvent ;
3622 if (slp != NULL) slp->unpark() ;
3623 }
3624
3625 // For JSR166. Unpark even if interrupt status already was set
3626 if (thread->is_Java_thread())
3627 ((JavaThread*)thread)->parker()->unpark();
3628
3629 ParkEvent * ev = thread->_ParkEvent ;
3630 if (ev != NULL) ev->unpark() ;
3631
3632 }
3633
3634 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3635 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3636 "possibility of dangling Thread pointer");
3637
3638 OSThread* osthread = thread->osthread();
3639
3640 bool interrupted = osthread->interrupted();
3641
3642 if (interrupted && clear_interrupted) {
3643 osthread->set_interrupted(false);
3644 // consider thread->_SleepEvent->reset() ... optional optimization
3645 }
3646
3647 return interrupted;
3648 }
3649
3650 ///////////////////////////////////////////////////////////////////////////////////
3651 // signal handling (except suspend/resume)
3652
3653 // This routine may be used by user applications as a "hook" to catch signals.
3654 // The user-defined signal handler must pass unrecognized signals to this
3655 // routine, and if it returns true (non-zero), then the signal handler must
3656 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3657 // routine will never retun false (zero), but instead will execute a VM panic
3658 // routine kill the process.
3659 //
3660 // If this routine returns false, it is OK to call it again. This allows
3661 // the user-defined signal handler to perform checks either before or after
3662 // the VM performs its own checks. Naturally, the user code would be making
3663 // a serious error if it tried to handle an exception (such as a null check
3664 // or breakpoint) that the VM was generating for its own correct operation.
3665 //
3666 // This routine may recognize any of the following kinds of signals:
3667 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3668 // It should be consulted by handlers for any of those signals.
3669 //
3670 // The caller of this routine must pass in the three arguments supplied
3671 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3672 // field of the structure passed to sigaction(). This routine assumes that
3673 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3674 //
3675 // Note that the VM will print warnings if it detects conflicting signal
3676 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3677 //
3678 extern "C" JNIEXPORT int
3679 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3680 void* ucontext, int abort_if_unrecognized);
3681
3682 void signalHandler(int sig, siginfo_t* info, void* uc) {
3683 assert(info != NULL && uc != NULL, "it must be old kernel");
3684 JVM_handle_linux_signal(sig, info, uc, true);
3685 }
3686
3687
3688 // This boolean allows users to forward their own non-matching signals
3689 // to JVM_handle_linux_signal, harmlessly.
3690 bool os::Linux::signal_handlers_are_installed = false;
3691
3692 // For signal-chaining
3693 struct sigaction os::Linux::sigact[MAXSIGNUM];
3694 unsigned int os::Linux::sigs = 0;
3695 bool os::Linux::libjsig_is_loaded = false;
3696 typedef struct sigaction *(*get_signal_t)(int);
3697 get_signal_t os::Linux::get_signal_action = NULL;
3698
3699 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3700 struct sigaction *actp = NULL;
3701
3702 if (libjsig_is_loaded) {
3703 // Retrieve the old signal handler from libjsig
3704 actp = (*get_signal_action)(sig);
3705 }
3706 if (actp == NULL) {
3707 // Retrieve the preinstalled signal handler from jvm
3708 actp = get_preinstalled_handler(sig);
3709 }
3710
3711 return actp;
3712 }
3713
3714 static bool call_chained_handler(struct sigaction *actp, int sig,
3715 siginfo_t *siginfo, void *context) {
3716 // Call the old signal handler
3717 if (actp->sa_handler == SIG_DFL) {
3718 // It's more reasonable to let jvm treat it as an unexpected exception
3719 // instead of taking the default action.
3720 return false;
3721 } else if (actp->sa_handler != SIG_IGN) {
3722 if ((actp->sa_flags & SA_NODEFER) == 0) {
3723 // automaticlly block the signal
3724 sigaddset(&(actp->sa_mask), sig);
3725 }
3726
3727 sa_handler_t hand;
3728 sa_sigaction_t sa;
3729 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3730 // retrieve the chained handler
3731 if (siginfo_flag_set) {
3732 sa = actp->sa_sigaction;
3733 } else {
3734 hand = actp->sa_handler;
3735 }
3736
3737 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3738 actp->sa_handler = SIG_DFL;
3739 }
3740
3741 // try to honor the signal mask
3742 sigset_t oset;
3743 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3744
3745 // call into the chained handler
3746 if (siginfo_flag_set) {
3747 (*sa)(sig, siginfo, context);
3748 } else {
3749 (*hand)(sig);
3750 }
3751
3752 // restore the signal mask
3753 pthread_sigmask(SIG_SETMASK, &oset, 0);
3754 }
3755 // Tell jvm's signal handler the signal is taken care of.
3756 return true;
3757 }
3758
3759 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3760 bool chained = false;
3761 // signal-chaining
3762 if (UseSignalChaining) {
3763 struct sigaction *actp = get_chained_signal_action(sig);
3764 if (actp != NULL) {
3765 chained = call_chained_handler(actp, sig, siginfo, context);
3766 }
3767 }
3768 return chained;
3769 }
3770
3771 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3772 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3773 return &sigact[sig];
3774 }
3775 return NULL;
3776 }
3777
3778 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3779 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3780 sigact[sig] = oldAct;
3781 sigs |= (unsigned int)1 << sig;
3782 }
3783
3784 // for diagnostic
3785 int os::Linux::sigflags[MAXSIGNUM];
3786
3787 int os::Linux::get_our_sigflags(int sig) {
3788 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3789 return sigflags[sig];
3790 }
3791
3792 void os::Linux::set_our_sigflags(int sig, int flags) {
3793 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3794 sigflags[sig] = flags;
3795 }
3796
3797 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3798 // Check for overwrite.
3799 struct sigaction oldAct;
3800 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3801
3802 void* oldhand = oldAct.sa_sigaction
3803 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3804 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3805 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3806 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3807 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3808 if (AllowUserSignalHandlers || !set_installed) {
3809 // Do not overwrite; user takes responsibility to forward to us.
3810 return;
3811 } else if (UseSignalChaining) {
3812 // save the old handler in jvm
3813 save_preinstalled_handler(sig, oldAct);
3814 // libjsig also interposes the sigaction() call below and saves the
3815 // old sigaction on it own.
3816 } else {
3817 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3818 "%#lx for signal %d.", (long)oldhand, sig));
3819 }
3820 }
3821
3822 struct sigaction sigAct;
3823 sigfillset(&(sigAct.sa_mask));
3824 sigAct.sa_handler = SIG_DFL;
3825 if (!set_installed) {
3826 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3827 } else {
3828 sigAct.sa_sigaction = signalHandler;
3829 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3830 }
3831 // Save flags, which are set by ours
3832 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3833 sigflags[sig] = sigAct.sa_flags;
3834
3835 int ret = sigaction(sig, &sigAct, &oldAct);
3836 assert(ret == 0, "check");
3837
3838 void* oldhand2 = oldAct.sa_sigaction
3839 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3840 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3841 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3842 }
3843
3844 // install signal handlers for signals that HotSpot needs to
3845 // handle in order to support Java-level exception handling.
3846
3847 void os::Linux::install_signal_handlers() {
3848 if (!signal_handlers_are_installed) {
3849 signal_handlers_are_installed = true;
3850
3851 // signal-chaining
3852 typedef void (*signal_setting_t)();
3853 signal_setting_t begin_signal_setting = NULL;
3854 signal_setting_t end_signal_setting = NULL;
3855 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3856 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3857 if (begin_signal_setting != NULL) {
3858 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3859 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3860 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3861 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3862 libjsig_is_loaded = true;
3863 assert(UseSignalChaining, "should enable signal-chaining");
3864 }
3865 if (libjsig_is_loaded) {
3866 // Tell libjsig jvm is setting signal handlers
3867 (*begin_signal_setting)();
3868 }
3869
3870 set_signal_handler(SIGSEGV, true);
3871 set_signal_handler(SIGPIPE, true);
3872 set_signal_handler(SIGBUS, true);
3873 set_signal_handler(SIGILL, true);
3874 set_signal_handler(SIGFPE, true);
3875 set_signal_handler(SIGXFSZ, true);
3876
3877 if (libjsig_is_loaded) {
3878 // Tell libjsig jvm finishes setting signal handlers
3879 (*end_signal_setting)();
3880 }
3881
3882 // We don't activate signal checker if libjsig is in place, we trust ourselves
3883 // and if UserSignalHandler is installed all bets are off
3884 if (CheckJNICalls) {
3885 if (libjsig_is_loaded) {
3886 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3887 check_signals = false;
3888 }
3889 if (AllowUserSignalHandlers) {
3890 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3891 check_signals = false;
3892 }
3893 }
3894 }
3895 }
3896
3897 // This is the fastest way to get thread cpu time on Linux.
3898 // Returns cpu time (user+sys) for any thread, not only for current.
3899 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3900 // It might work on 2.6.10+ with a special kernel/glibc patch.
3901 // For reference, please, see IEEE Std 1003.1-2004:
3902 // http://www.unix.org/single_unix_specification
3903
3904 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3905 struct timespec tp;
3906 int rc = os::Linux::clock_gettime(clockid, &tp);
3907 assert(rc == 0, "clock_gettime is expected to return 0 code");
3908
3909 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
3910 }
3911
3912 /////
3913 // glibc on Linux platform uses non-documented flag
3914 // to indicate, that some special sort of signal
3915 // trampoline is used.
3916 // We will never set this flag, and we should
3917 // ignore this flag in our diagnostic
3918 #ifdef SIGNIFICANT_SIGNAL_MASK
3919 #undef SIGNIFICANT_SIGNAL_MASK
3920 #endif
3921 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3922
3923 static const char* get_signal_handler_name(address handler,
3924 char* buf, int buflen) {
3925 int offset;
3926 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3927 if (found) {
3928 // skip directory names
3929 const char *p1, *p2;
3930 p1 = buf;
3931 size_t len = strlen(os::file_separator());
3932 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3933 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3934 } else {
3935 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3936 }
3937 return buf;
3938 }
3939
3940 static void print_signal_handler(outputStream* st, int sig,
3941 char* buf, size_t buflen) {
3942 struct sigaction sa;
3943
3944 sigaction(sig, NULL, &sa);
3945
3946 // See comment for SIGNIFICANT_SIGNAL_MASK define
3947 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3948
3949 st->print("%s: ", os::exception_name(sig, buf, buflen));
3950
3951 address handler = (sa.sa_flags & SA_SIGINFO)
3952 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3953 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3954
3955 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3956 st->print("SIG_DFL");
3957 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3958 st->print("SIG_IGN");
3959 } else {
3960 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3961 }
3962
3963 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3964
3965 address rh = VMError::get_resetted_sighandler(sig);
3966 // May be, handler was resetted by VMError?
3967 if(rh != NULL) {
3968 handler = rh;
3969 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3970 }
3971
3972 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3973
3974 // Check: is it our handler?
3975 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3976 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3977 // It is our signal handler
3978 // check for flags, reset system-used one!
3979 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3980 st->print(
3981 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3982 os::Linux::get_our_sigflags(sig));
3983 }
3984 }
3985 st->cr();
3986 }
3987
3988
3989 #define DO_SIGNAL_CHECK(sig) \
3990 if (!sigismember(&check_signal_done, sig)) \
3991 os::Linux::check_signal_handler(sig)
3992
3993 // This method is a periodic task to check for misbehaving JNI applications
3994 // under CheckJNI, we can add any periodic checks here
3995
3996 void os::run_periodic_checks() {
3997
3998 if (check_signals == false) return;
3999
4000 // SEGV and BUS if overridden could potentially prevent
4001 // generation of hs*.log in the event of a crash, debugging
4002 // such a case can be very challenging, so we absolutely
4003 // check the following for a good measure:
4004 DO_SIGNAL_CHECK(SIGSEGV);
4005 DO_SIGNAL_CHECK(SIGILL);
4006 DO_SIGNAL_CHECK(SIGFPE);
4007 DO_SIGNAL_CHECK(SIGBUS);
4008 DO_SIGNAL_CHECK(SIGPIPE);
4009 DO_SIGNAL_CHECK(SIGXFSZ);
4010
4011
4012 // ReduceSignalUsage allows the user to override these handlers
4013 // see comments at the very top and jvm_solaris.h
4014 if (!ReduceSignalUsage) {
4015 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4016 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4017 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4018 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4019 }
4020
4021 DO_SIGNAL_CHECK(SR_signum);
4022 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4023 }
4024
4025 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4026
4027 static os_sigaction_t os_sigaction = NULL;
4028
4029 void os::Linux::check_signal_handler(int sig) {
4030 char buf[O_BUFLEN];
4031 address jvmHandler = NULL;
4032
4033
4034 struct sigaction act;
4035 if (os_sigaction == NULL) {
4036 // only trust the default sigaction, in case it has been interposed
4037 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4038 if (os_sigaction == NULL) return;
4039 }
4040
4041 os_sigaction(sig, (struct sigaction*)NULL, &act);
4042
4043
4044 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4045
4046 address thisHandler = (act.sa_flags & SA_SIGINFO)
4047 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4048 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4049
4050
4051 switch(sig) {
4052 case SIGSEGV:
4053 case SIGBUS:
4054 case SIGFPE:
4055 case SIGPIPE:
4056 case SIGILL:
4057 case SIGXFSZ:
4058 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4059 break;
4060
4061 case SHUTDOWN1_SIGNAL:
4062 case SHUTDOWN2_SIGNAL:
4063 case SHUTDOWN3_SIGNAL:
4064 case BREAK_SIGNAL:
4065 jvmHandler = (address)user_handler();
4066 break;
4067
4068 case INTERRUPT_SIGNAL:
4069 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4070 break;
4071
4072 default:
4073 if (sig == SR_signum) {
4074 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4075 } else {
4076 return;
4077 }
4078 break;
4079 }
4080
4081 if (thisHandler != jvmHandler) {
4082 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4083 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4084 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4085 // No need to check this sig any longer
4086 sigaddset(&check_signal_done, sig);
4087 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4088 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4089 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4090 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4091 // No need to check this sig any longer
4092 sigaddset(&check_signal_done, sig);
4093 }
4094
4095 // Dump all the signal
4096 if (sigismember(&check_signal_done, sig)) {
4097 print_signal_handlers(tty, buf, O_BUFLEN);
4098 }
4099 }
4100
4101 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4102
4103 extern bool signal_name(int signo, char* buf, size_t len);
4104
4105 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4106 if (0 < exception_code && exception_code <= SIGRTMAX) {
4107 // signal
4108 if (!signal_name(exception_code, buf, size)) {
4109 jio_snprintf(buf, size, "SIG%d", exception_code);
4110 }
4111 return buf;
4112 } else {
4113 return NULL;
4114 }
4115 }
4116
4117 // this is called _before_ the most of global arguments have been parsed
4118 void os::init(void) {
4119 char dummy; /* used to get a guess on initial stack address */
4120 // first_hrtime = gethrtime();
4121
4122 // With LinuxThreads the JavaMain thread pid (primordial thread)
4123 // is different than the pid of the java launcher thread.
4124 // So, on Linux, the launcher thread pid is passed to the VM
4125 // via the sun.java.launcher.pid property.
4126 // Use this property instead of getpid() if it was correctly passed.
4127 // See bug 6351349.
4128 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4129
4130 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4131
4132 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4133
4134 init_random(1234567);
4135
4136 ThreadCritical::initialize();
4137
4138 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4139 if (Linux::page_size() == -1) {
4140 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4141 strerror(errno)));
4142 }
4143 init_page_sizes((size_t) Linux::page_size());
4144
4145 Linux::initialize_system_info();
4146
4147 // main_thread points to the aboriginal thread
4148 Linux::_main_thread = pthread_self();
4149
4150 Linux::clock_init();
4151 initial_time_count = os::elapsed_counter();
4152 pthread_mutex_init(&dl_mutex, NULL);
4153 }
4154
4155 // To install functions for atexit system call
4156 extern "C" {
4157 static void perfMemory_exit_helper() {
4158 perfMemory_exit();
4159 }
4160 }
4161
4162 // this is called _after_ the global arguments have been parsed
4163 jint os::init_2(void)
4164 {
4165 Linux::fast_thread_clock_init();
4166
4167 // Allocate a single page and mark it as readable for safepoint polling
4168 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4169 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4170
4171 os::set_polling_page( polling_page );
4172
4173 #ifndef PRODUCT
4174 if(Verbose && PrintMiscellaneous)
4175 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4176 #endif
4177
4178 if (!UseMembar) {
4179 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4180 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4181 os::set_memory_serialize_page( mem_serialize_page );
4182
4183 #ifndef PRODUCT
4184 if(Verbose && PrintMiscellaneous)
4185 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4186 #endif
4187 }
4188
4189 os::large_page_init();
4190
4191 // initialize suspend/resume support - must do this before signal_sets_init()
4192 if (SR_initialize() != 0) {
4193 perror("SR_initialize failed");
4194 return JNI_ERR;
4195 }
4196
4197 Linux::signal_sets_init();
4198 Linux::install_signal_handlers();
4199
4200 // Check minimum allowable stack size for thread creation and to initialize
4201 // the java system classes, including StackOverflowError - depends on page
4202 // size. Add a page for compiler2 recursion in main thread.
4203 // Add in 2*BytesPerWord times page size to account for VM stack during
4204 // class initialization depending on 32 or 64 bit VM.
4205 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4206 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4207 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4208
4209 size_t threadStackSizeInBytes = ThreadStackSize * K;
4210 if (threadStackSizeInBytes != 0 &&
4211 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4212 tty->print_cr("\nThe stack size specified is too small, "
4213 "Specify at least %dk",
4214 os::Linux::min_stack_allowed/ K);
4215 return JNI_ERR;
4216 }
4217
4218 // Make the stack size a multiple of the page size so that
4219 // the yellow/red zones can be guarded.
4220 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4221 vm_page_size()));
4222
4223 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4224
4225 Linux::libpthread_init();
4226 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4227 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4228 Linux::glibc_version(), Linux::libpthread_version(),
4229 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4230 }
4231
4232 if (UseNUMA) {
4233 if (!Linux::libnuma_init()) {
4234 UseNUMA = false;
4235 } else {
4236 if ((Linux::numa_max_node() < 1)) {
4237 // There's only one node(they start from 0), disable NUMA.
4238 UseNUMA = false;
4239 }
4240 }
4241 // With SHM large pages we cannot uncommit a page, so there's not way
4242 // we can make the adaptive lgrp chunk resizing work. If the user specified
4243 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4244 // disable adaptive resizing.
4245 if (UseNUMA && UseLargePages && UseSHM) {
4246 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4247 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4248 UseLargePages = false;
4249 } else {
4250 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4251 UseAdaptiveSizePolicy = false;
4252 UseAdaptiveNUMAChunkSizing = false;
4253 }
4254 } else {
4255 UseNUMA = false;
4256 }
4257 }
4258 if (!UseNUMA && ForceNUMA) {
4259 UseNUMA = true;
4260 }
4261 }
4262
4263 if (MaxFDLimit) {
4264 // set the number of file descriptors to max. print out error
4265 // if getrlimit/setrlimit fails but continue regardless.
4266 struct rlimit nbr_files;
4267 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4268 if (status != 0) {
4269 if (PrintMiscellaneous && (Verbose || WizardMode))
4270 perror("os::init_2 getrlimit failed");
4271 } else {
4272 nbr_files.rlim_cur = nbr_files.rlim_max;
4273 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4274 if (status != 0) {
4275 if (PrintMiscellaneous && (Verbose || WizardMode))
4276 perror("os::init_2 setrlimit failed");
4277 }
4278 }
4279 }
4280
4281 // Initialize lock used to serialize thread creation (see os::create_thread)
4282 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4283
4284 // at-exit methods are called in the reverse order of their registration.
4285 // atexit functions are called on return from main or as a result of a
4286 // call to exit(3C). There can be only 32 of these functions registered
4287 // and atexit() does not set errno.
4288
4289 if (PerfAllowAtExitRegistration) {
4290 // only register atexit functions if PerfAllowAtExitRegistration is set.
4291 // atexit functions can be delayed until process exit time, which
4292 // can be problematic for embedded VM situations. Embedded VMs should
4293 // call DestroyJavaVM() to assure that VM resources are released.
4294
4295 // note: perfMemory_exit_helper atexit function may be removed in
4296 // the future if the appropriate cleanup code can be added to the
4297 // VM_Exit VMOperation's doit method.
4298 if (atexit(perfMemory_exit_helper) != 0) {
4299 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4300 }
4301 }
4302
4303 // initialize thread priority policy
4304 prio_init();
4305
4306 return JNI_OK;
4307 }
4308
4309 // this is called at the end of vm_initialization
4310 void os::init_3(void)
4311 {
4312 #ifdef JAVASE_EMBEDDED
4313 // Start the MemNotifyThread
4314 if (LowMemoryProtection) {
4315 MemNotifyThread::start();
4316 }
4317 return;
4318 #endif
4319 }
4320
4321 // Mark the polling page as unreadable
4322 void os::make_polling_page_unreadable(void) {
4323 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4324 fatal("Could not disable polling page");
4325 };
4326
4327 // Mark the polling page as readable
4328 void os::make_polling_page_readable(void) {
4329 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4330 fatal("Could not enable polling page");
4331 }
4332 };
4333
4334 int os::active_processor_count() {
4335 // Linux doesn't yet have a (official) notion of processor sets,
4336 // so just return the number of online processors.
4337 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4338 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4339 return online_cpus;
4340 }
4341
4342 bool os::distribute_processes(uint length, uint* distribution) {
4343 // Not yet implemented.
4344 return false;
4345 }
4346
4347 bool os::bind_to_processor(uint processor_id) {
4348 // Not yet implemented.
4349 return false;
4350 }
4351
4352 ///
4353
4354 // Suspends the target using the signal mechanism and then grabs the PC before
4355 // resuming the target. Used by the flat-profiler only
4356 ExtendedPC os::get_thread_pc(Thread* thread) {
4357 // Make sure that it is called by the watcher for the VMThread
4358 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4359 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4360
4361 ExtendedPC epc;
4362
4363 OSThread* osthread = thread->osthread();
4364 if (do_suspend(osthread)) {
4365 if (osthread->ucontext() != NULL) {
4366 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4367 } else {
4368 // NULL context is unexpected, double-check this is the VMThread
4369 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4370 }
4371 do_resume(osthread);
4372 }
4373 // failure means pthread_kill failed for some reason - arguably this is
4374 // a fatal problem, but such problems are ignored elsewhere
4375
4376 return epc;
4377 }
4378
4379 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4380 {
4381 if (is_NPTL()) {
4382 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4383 } else {
4384 #ifndef IA64
4385 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4386 // word back to default 64bit precision if condvar is signaled. Java
4387 // wants 53bit precision. Save and restore current value.
4388 int fpu = get_fpu_control_word();
4389 #endif // IA64
4390 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4391 #ifndef IA64
4392 set_fpu_control_word(fpu);
4393 #endif // IA64
4394 return status;
4395 }
4396 }
4397
4398 ////////////////////////////////////////////////////////////////////////////////
4399 // debug support
4400
4401 static address same_page(address x, address y) {
4402 int page_bits = -os::vm_page_size();
4403 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4404 return x;
4405 else if (x > y)
4406 return (address)(intptr_t(y) | ~page_bits) + 1;
4407 else
4408 return (address)(intptr_t(y) & page_bits);
4409 }
4410
4411 bool os::find(address addr, outputStream* st) {
4412 Dl_info dlinfo;
4413 memset(&dlinfo, 0, sizeof(dlinfo));
4414 if (dladdr(addr, &dlinfo)) {
4415 st->print(PTR_FORMAT ": ", addr);
4416 if (dlinfo.dli_sname != NULL) {
4417 st->print("%s+%#x", dlinfo.dli_sname,
4418 addr - (intptr_t)dlinfo.dli_saddr);
4419 } else if (dlinfo.dli_fname) {
4420 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4421 } else {
4422 st->print("<absolute address>");
4423 }
4424 if (dlinfo.dli_fname) {
4425 st->print(" in %s", dlinfo.dli_fname);
4426 }
4427 if (dlinfo.dli_fbase) {
4428 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4429 }
4430 st->cr();
4431
4432 if (Verbose) {
4433 // decode some bytes around the PC
4434 address begin = same_page(addr-40, addr);
4435 address end = same_page(addr+40, addr);
4436 address lowest = (address) dlinfo.dli_sname;
4437 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4438 if (begin < lowest) begin = lowest;
4439 Dl_info dlinfo2;
4440 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4441 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4442 end = (address) dlinfo2.dli_saddr;
4443 Disassembler::decode(begin, end, st);
4444 }
4445 return true;
4446 }
4447 return false;
4448 }
4449
4450 ////////////////////////////////////////////////////////////////////////////////
4451 // misc
4452
4453 // This does not do anything on Linux. This is basically a hook for being
4454 // able to use structured exception handling (thread-local exception filters)
4455 // on, e.g., Win32.
4456 void
4457 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4458 JavaCallArguments* args, Thread* thread) {
4459 f(value, method, args, thread);
4460 }
4461
4462 void os::print_statistics() {
4463 }
4464
4465 int os::message_box(const char* title, const char* message) {
4466 int i;
4467 fdStream err(defaultStream::error_fd());
4468 for (i = 0; i < 78; i++) err.print_raw("=");
4469 err.cr();
4470 err.print_raw_cr(title);
4471 for (i = 0; i < 78; i++) err.print_raw("-");
4472 err.cr();
4473 err.print_raw_cr(message);
4474 for (i = 0; i < 78; i++) err.print_raw("=");
4475 err.cr();
4476
4477 char buf[16];
4478 // Prevent process from exiting upon "read error" without consuming all CPU
4479 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4480
4481 return buf[0] == 'y' || buf[0] == 'Y';
4482 }
4483
4484 int os::stat(const char *path, struct stat *sbuf) {
4485 char pathbuf[MAX_PATH];
4486 if (strlen(path) > MAX_PATH - 1) {
4487 errno = ENAMETOOLONG;
4488 return -1;
4489 }
4490 os::native_path(strcpy(pathbuf, path));
4491 return ::stat(pathbuf, sbuf);
4492 }
4493
4494 bool os::check_heap(bool force) {
4495 return true;
4496 }
4497
4498 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4499 return ::vsnprintf(buf, count, format, args);
4500 }
4501
4502 // Is a (classpath) directory empty?
4503 bool os::dir_is_empty(const char* path) {
4504 DIR *dir = NULL;
4505 struct dirent *ptr;
4506
4507 dir = opendir(path);
4508 if (dir == NULL) return true;
4509
4510 /* Scan the directory */
4511 bool result = true;
4512 char buf[sizeof(struct dirent) + MAX_PATH];
4513 while (result && (ptr = ::readdir(dir)) != NULL) {
4514 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4515 result = false;
4516 }
4517 }
4518 closedir(dir);
4519 return result;
4520 }
4521
4522 // This code originates from JDK's sysOpen and open64_w
4523 // from src/solaris/hpi/src/system_md.c
4524
4525 #ifndef O_DELETE
4526 #define O_DELETE 0x10000
4527 #endif
4528
4529 // Open a file. Unlink the file immediately after open returns
4530 // if the specified oflag has the O_DELETE flag set.
4531 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4532
4533 int os::open(const char *path, int oflag, int mode) {
4534
4535 if (strlen(path) > MAX_PATH - 1) {
4536 errno = ENAMETOOLONG;
4537 return -1;
4538 }
4539 int fd;
4540 int o_delete = (oflag & O_DELETE);
4541 oflag = oflag & ~O_DELETE;
4542
4543 fd = ::open64(path, oflag, mode);
4544 if (fd == -1) return -1;
4545
4546 //If the open succeeded, the file might still be a directory
4547 {
4548 struct stat64 buf64;
4549 int ret = ::fstat64(fd, &buf64);
4550 int st_mode = buf64.st_mode;
4551
4552 if (ret != -1) {
4553 if ((st_mode & S_IFMT) == S_IFDIR) {
4554 errno = EISDIR;
4555 ::close(fd);
4556 return -1;
4557 }
4558 } else {
4559 ::close(fd);
4560 return -1;
4561 }
4562 }
4563
4564 /*
4565 * All file descriptors that are opened in the JVM and not
4566 * specifically destined for a subprocess should have the
4567 * close-on-exec flag set. If we don't set it, then careless 3rd
4568 * party native code might fork and exec without closing all
4569 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4570 * UNIXProcess.c), and this in turn might:
4571 *
4572 * - cause end-of-file to fail to be detected on some file
4573 * descriptors, resulting in mysterious hangs, or
4574 *
4575 * - might cause an fopen in the subprocess to fail on a system
4576 * suffering from bug 1085341.
4577 *
4578 * (Yes, the default setting of the close-on-exec flag is a Unix
4579 * design flaw)
4580 *
4581 * See:
4582 * 1085341: 32-bit stdio routines should support file descriptors >255
4583 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4584 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4585 */
4586 #ifdef FD_CLOEXEC
4587 {
4588 int flags = ::fcntl(fd, F_GETFD);
4589 if (flags != -1)
4590 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4591 }
4592 #endif
4593
4594 if (o_delete != 0) {
4595 ::unlink(path);
4596 }
4597 return fd;
4598 }
4599
4600
4601 // create binary file, rewriting existing file if required
4602 int os::create_binary_file(const char* path, bool rewrite_existing) {
4603 int oflags = O_WRONLY | O_CREAT;
4604 if (!rewrite_existing) {
4605 oflags |= O_EXCL;
4606 }
4607 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4608 }
4609
4610 // return current position of file pointer
4611 jlong os::current_file_offset(int fd) {
4612 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4613 }
4614
4615 // move file pointer to the specified offset
4616 jlong os::seek_to_file_offset(int fd, jlong offset) {
4617 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4618 }
4619
4620 // This code originates from JDK's sysAvailable
4621 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4622
4623 int os::available(int fd, jlong *bytes) {
4624 jlong cur, end;
4625 int mode;
4626 struct stat64 buf64;
4627
4628 if (::fstat64(fd, &buf64) >= 0) {
4629 mode = buf64.st_mode;
4630 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4631 /*
4632 * XXX: is the following call interruptible? If so, this might
4633 * need to go through the INTERRUPT_IO() wrapper as for other
4634 * blocking, interruptible calls in this file.
4635 */
4636 int n;
4637 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4638 *bytes = n;
4639 return 1;
4640 }
4641 }
4642 }
4643 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4644 return 0;
4645 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4646 return 0;
4647 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4648 return 0;
4649 }
4650 *bytes = end - cur;
4651 return 1;
4652 }
4653
4654 int os::socket_available(int fd, jint *pbytes) {
4655 // Linux doc says EINTR not returned, unlike Solaris
4656 int ret = ::ioctl(fd, FIONREAD, pbytes);
4657
4658 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4659 // is expected to return 0 on failure and 1 on success to the jdk.
4660 return (ret < 0) ? 0 : 1;
4661 }
4662
4663 // Map a block of memory.
4664 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4665 char *addr, size_t bytes, bool read_only,
4666 bool allow_exec) {
4667 int prot;
4668 int flags;
4669
4670 if (read_only) {
4671 prot = PROT_READ;
4672 flags = MAP_SHARED;
4673 } else {
4674 prot = PROT_READ | PROT_WRITE;
4675 flags = MAP_PRIVATE;
4676 }
4677
4678 if (allow_exec) {
4679 prot |= PROT_EXEC;
4680 }
4681
4682 if (addr != NULL) {
4683 flags |= MAP_FIXED;
4684 }
4685
4686 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4687 fd, file_offset);
4688 if (mapped_address == MAP_FAILED) {
4689 return NULL;
4690 }
4691 return mapped_address;
4692 }
4693
4694
4695 // Remap a block of memory.
4696 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4697 char *addr, size_t bytes, bool read_only,
4698 bool allow_exec) {
4699 // same as map_memory() on this OS
4700 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4701 allow_exec);
4702 }
4703
4704
4705 // Unmap a block of memory.
4706 bool os::unmap_memory(char* addr, size_t bytes) {
4707 return munmap(addr, bytes) == 0;
4708 }
4709
4710 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4711
4712 static clockid_t thread_cpu_clockid(Thread* thread) {
4713 pthread_t tid = thread->osthread()->pthread_id();
4714 clockid_t clockid;
4715
4716 // Get thread clockid
4717 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4718 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4719 return clockid;
4720 }
4721
4722 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4723 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4724 // of a thread.
4725 //
4726 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4727 // the fast estimate available on the platform.
4728
4729 jlong os::current_thread_cpu_time() {
4730 if (os::Linux::supports_fast_thread_cpu_time()) {
4731 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4732 } else {
4733 // return user + sys since the cost is the same
4734 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4735 }
4736 }
4737
4738 jlong os::thread_cpu_time(Thread* thread) {
4739 // consistent with what current_thread_cpu_time() returns
4740 if (os::Linux::supports_fast_thread_cpu_time()) {
4741 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4742 } else {
4743 return slow_thread_cpu_time(thread, true /* user + sys */);
4744 }
4745 }
4746
4747 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4748 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4749 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4750 } else {
4751 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4752 }
4753 }
4754
4755 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4756 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4757 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4758 } else {
4759 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4760 }
4761 }
4762
4763 //
4764 // -1 on error.
4765 //
4766
4767 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4768 static bool proc_pid_cpu_avail = true;
4769 static bool proc_task_unchecked = true;
4770 static const char *proc_stat_path = "/proc/%d/stat";
4771 pid_t tid = thread->osthread()->thread_id();
4772 int i;
4773 char *s;
4774 char stat[2048];
4775 int statlen;
4776 char proc_name[64];
4777 int count;
4778 long sys_time, user_time;
4779 char string[64];
4780 char cdummy;
4781 int idummy;
4782 long ldummy;
4783 FILE *fp;
4784
4785 // We first try accessing /proc/<pid>/cpu since this is faster to
4786 // process. If this file is not present (linux kernels 2.5 and above)
4787 // then we open /proc/<pid>/stat.
4788 if ( proc_pid_cpu_avail ) {
4789 sprintf(proc_name, "/proc/%d/cpu", tid);
4790 fp = fopen(proc_name, "r");
4791 if ( fp != NULL ) {
4792 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4793 fclose(fp);
4794 if ( count != 3 ) return -1;
4795
4796 if (user_sys_cpu_time) {
4797 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4798 } else {
4799 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4800 }
4801 }
4802 else proc_pid_cpu_avail = false;
4803 }
4804
4805 // The /proc/<tid>/stat aggregates per-process usage on
4806 // new Linux kernels 2.6+ where NPTL is supported.
4807 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4808 // See bug 6328462.
4809 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4810 // and possibly in some other cases, so we check its availability.
4811 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4812 // This is executed only once
4813 proc_task_unchecked = false;
4814 fp = fopen("/proc/self/task", "r");
4815 if (fp != NULL) {
4816 proc_stat_path = "/proc/self/task/%d/stat";
4817 fclose(fp);
4818 }
4819 }
4820
4821 sprintf(proc_name, proc_stat_path, tid);
4822 fp = fopen(proc_name, "r");
4823 if ( fp == NULL ) return -1;
4824 statlen = fread(stat, 1, 2047, fp);
4825 stat[statlen] = '\0';
4826 fclose(fp);
4827
4828 // Skip pid and the command string. Note that we could be dealing with
4829 // weird command names, e.g. user could decide to rename java launcher
4830 // to "java 1.4.2 :)", then the stat file would look like
4831 // 1234 (java 1.4.2 :)) R ... ...
4832 // We don't really need to know the command string, just find the last
4833 // occurrence of ")" and then start parsing from there. See bug 4726580.
4834 s = strrchr(stat, ')');
4835 i = 0;
4836 if (s == NULL ) return -1;
4837
4838 // Skip blank chars
4839 do s++; while (isspace(*s));
4840
4841 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4842 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4843 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4844 &user_time, &sys_time);
4845 if ( count != 13 ) return -1;
4846 if (user_sys_cpu_time) {
4847 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4848 } else {
4849 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4850 }
4851 }
4852
4853 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4854 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4855 info_ptr->may_skip_backward = false; // elapsed time not wall time
4856 info_ptr->may_skip_forward = false; // elapsed time not wall time
4857 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4858 }
4859
4860 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4861 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4862 info_ptr->may_skip_backward = false; // elapsed time not wall time
4863 info_ptr->may_skip_forward = false; // elapsed time not wall time
4864 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4865 }
4866
4867 bool os::is_thread_cpu_time_supported() {
4868 return true;
4869 }
4870
4871 // System loadavg support. Returns -1 if load average cannot be obtained.
4872 // Linux doesn't yet have a (official) notion of processor sets,
4873 // so just return the system wide load average.
4874 int os::loadavg(double loadavg[], int nelem) {
4875 return ::getloadavg(loadavg, nelem);
4876 }
4877
4878 void os::pause() {
4879 char filename[MAX_PATH];
4880 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4881 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4882 } else {
4883 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4884 }
4885
4886 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4887 if (fd != -1) {
4888 struct stat buf;
4889 ::close(fd);
4890 while (::stat(filename, &buf) == 0) {
4891 (void)::poll(NULL, 0, 100);
4892 }
4893 } else {
4894 jio_fprintf(stderr,
4895 "Could not open pause file '%s', continuing immediately.\n", filename);
4896 }
4897 }
4898
4899
4900 // Refer to the comments in os_solaris.cpp park-unpark.
4901 //
4902 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4903 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4904 // For specifics regarding the bug see GLIBC BUGID 261237 :
4905 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4906 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4907 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4908 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4909 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4910 // and monitorenter when we're using 1-0 locking. All those operations may result in
4911 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4912 // of libpthread avoids the problem, but isn't practical.
4913 //
4914 // Possible remedies:
4915 //
4916 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4917 // This is palliative and probabilistic, however. If the thread is preempted
4918 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4919 // than the minimum period may have passed, and the abstime may be stale (in the
4920 // past) resultin in a hang. Using this technique reduces the odds of a hang
4921 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4922 //
4923 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4924 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4925 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4926 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4927 // thread.
4928 //
4929 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4930 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4931 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4932 // This also works well. In fact it avoids kernel-level scalability impediments
4933 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4934 // timers in a graceful fashion.
4935 //
4936 // 4. When the abstime value is in the past it appears that control returns
4937 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4938 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4939 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4940 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4941 // It may be possible to avoid reinitialization by checking the return
4942 // value from pthread_cond_timedwait(). In addition to reinitializing the
4943 // condvar we must establish the invariant that cond_signal() is only called
4944 // within critical sections protected by the adjunct mutex. This prevents
4945 // cond_signal() from "seeing" a condvar that's in the midst of being
4946 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4947 // desirable signal-after-unlock optimization that avoids futile context switching.
4948 //
4949 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4950 // structure when a condvar is used or initialized. cond_destroy() would
4951 // release the helper structure. Our reinitialize-after-timedwait fix
4952 // put excessive stress on malloc/free and locks protecting the c-heap.
4953 //
4954 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4955 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4956 // and only enabling the work-around for vulnerable environments.
4957
4958 // utility to compute the abstime argument to timedwait:
4959 // millis is the relative timeout time
4960 // abstime will be the absolute timeout time
4961 // TODO: replace compute_abstime() with unpackTime()
4962
4963 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4964 if (millis < 0) millis = 0;
4965 struct timeval now;
4966 int status = gettimeofday(&now, NULL);
4967 assert(status == 0, "gettimeofday");
4968 jlong seconds = millis / 1000;
4969 millis %= 1000;
4970 if (seconds > 50000000) { // see man cond_timedwait(3T)
4971 seconds = 50000000;
4972 }
4973 abstime->tv_sec = now.tv_sec + seconds;
4974 long usec = now.tv_usec + millis * 1000;
4975 if (usec >= 1000000) {
4976 abstime->tv_sec += 1;
4977 usec -= 1000000;
4978 }
4979 abstime->tv_nsec = usec * 1000;
4980 return abstime;
4981 }
4982
4983
4984 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4985 // Conceptually TryPark() should be equivalent to park(0).
4986
4987 int os::PlatformEvent::TryPark() {
4988 for (;;) {
4989 const int v = _Event ;
4990 guarantee ((v == 0) || (v == 1), "invariant") ;
4991 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
4992 }
4993 }
4994
4995 void os::PlatformEvent::park() { // AKA "down()"
4996 // Invariant: Only the thread associated with the Event/PlatformEvent
4997 // may call park().
4998 // TODO: assert that _Assoc != NULL or _Assoc == Self
4999 int v ;
5000 for (;;) {
5001 v = _Event ;
5002 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5003 }
5004 guarantee (v >= 0, "invariant") ;
5005 if (v == 0) {
5006 // Do this the hard way by blocking ...
5007 int status = pthread_mutex_lock(_mutex);
5008 assert_status(status == 0, status, "mutex_lock");
5009 guarantee (_nParked == 0, "invariant") ;
5010 ++ _nParked ;
5011 while (_Event < 0) {
5012 status = pthread_cond_wait(_cond, _mutex);
5013 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5014 // Treat this the same as if the wait was interrupted
5015 if (status == ETIME) { status = EINTR; }
5016 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5017 }
5018 -- _nParked ;
5019
5020 // In theory we could move the ST of 0 into _Event past the unlock(),
5021 // but then we'd need a MEMBAR after the ST.
5022 _Event = 0 ;
5023 status = pthread_mutex_unlock(_mutex);
5024 assert_status(status == 0, status, "mutex_unlock");
5025 }
5026 guarantee (_Event >= 0, "invariant") ;
5027 }
5028
5029 int os::PlatformEvent::park(jlong millis) {
5030 guarantee (_nParked == 0, "invariant") ;
5031
5032 int v ;
5033 for (;;) {
5034 v = _Event ;
5035 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5036 }
5037 guarantee (v >= 0, "invariant") ;
5038 if (v != 0) return OS_OK ;
5039
5040 // We do this the hard way, by blocking the thread.
5041 // Consider enforcing a minimum timeout value.
5042 struct timespec abst;
5043 compute_abstime(&abst, millis);
5044
5045 int ret = OS_TIMEOUT;
5046 int status = pthread_mutex_lock(_mutex);
5047 assert_status(status == 0, status, "mutex_lock");
5048 guarantee (_nParked == 0, "invariant") ;
5049 ++_nParked ;
5050
5051 // Object.wait(timo) will return because of
5052 // (a) notification
5053 // (b) timeout
5054 // (c) thread.interrupt
5055 //
5056 // Thread.interrupt and object.notify{All} both call Event::set.
5057 // That is, we treat thread.interrupt as a special case of notification.
5058 // The underlying Solaris implementation, cond_timedwait, admits
5059 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5060 // JVM from making those visible to Java code. As such, we must
5061 // filter out spurious wakeups. We assume all ETIME returns are valid.
5062 //
5063 // TODO: properly differentiate simultaneous notify+interrupt.
5064 // In that case, we should propagate the notify to another waiter.
5065
5066 while (_Event < 0) {
5067 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5068 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5069 pthread_cond_destroy (_cond);
5070 pthread_cond_init (_cond, NULL) ;
5071 }
5072 assert_status(status == 0 || status == EINTR ||
5073 status == ETIME || status == ETIMEDOUT,
5074 status, "cond_timedwait");
5075 if (!FilterSpuriousWakeups) break ; // previous semantics
5076 if (status == ETIME || status == ETIMEDOUT) break ;
5077 // We consume and ignore EINTR and spurious wakeups.
5078 }
5079 --_nParked ;
5080 if (_Event >= 0) {
5081 ret = OS_OK;
5082 }
5083 _Event = 0 ;
5084 status = pthread_mutex_unlock(_mutex);
5085 assert_status(status == 0, status, "mutex_unlock");
5086 assert (_nParked == 0, "invariant") ;
5087 return ret;
5088 }
5089
5090 void os::PlatformEvent::unpark() {
5091 int v, AnyWaiters ;
5092 for (;;) {
5093 v = _Event ;
5094 if (v > 0) {
5095 // The LD of _Event could have reordered or be satisfied
5096 // by a read-aside from this processor's write buffer.
5097 // To avoid problems execute a barrier and then
5098 // ratify the value.
5099 OrderAccess::fence() ;
5100 if (_Event == v) return ;
5101 continue ;
5102 }
5103 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5104 }
5105 if (v < 0) {
5106 // Wait for the thread associated with the event to vacate
5107 int status = pthread_mutex_lock(_mutex);
5108 assert_status(status == 0, status, "mutex_lock");
5109 AnyWaiters = _nParked ;
5110 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5111 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5112 AnyWaiters = 0 ;
5113 pthread_cond_signal (_cond);
5114 }
5115 status = pthread_mutex_unlock(_mutex);
5116 assert_status(status == 0, status, "mutex_unlock");
5117 if (AnyWaiters != 0) {
5118 status = pthread_cond_signal(_cond);
5119 assert_status(status == 0, status, "cond_signal");
5120 }
5121 }
5122
5123 // Note that we signal() _after dropping the lock for "immortal" Events.
5124 // This is safe and avoids a common class of futile wakeups. In rare
5125 // circumstances this can cause a thread to return prematurely from
5126 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5127 // simply re-test the condition and re-park itself.
5128 }
5129
5130
5131 // JSR166
5132 // -------------------------------------------------------
5133
5134 /*
5135 * The solaris and linux implementations of park/unpark are fairly
5136 * conservative for now, but can be improved. They currently use a
5137 * mutex/condvar pair, plus a a count.
5138 * Park decrements count if > 0, else does a condvar wait. Unpark
5139 * sets count to 1 and signals condvar. Only one thread ever waits
5140 * on the condvar. Contention seen when trying to park implies that someone
5141 * is unparking you, so don't wait. And spurious returns are fine, so there
5142 * is no need to track notifications.
5143 */
5144
5145
5146 #define NANOSECS_PER_SEC 1000000000
5147 #define NANOSECS_PER_MILLISEC 1000000
5148 #define MAX_SECS 100000000
5149 /*
5150 * This code is common to linux and solaris and will be moved to a
5151 * common place in dolphin.
5152 *
5153 * The passed in time value is either a relative time in nanoseconds
5154 * or an absolute time in milliseconds. Either way it has to be unpacked
5155 * into suitable seconds and nanoseconds components and stored in the
5156 * given timespec structure.
5157 * Given time is a 64-bit value and the time_t used in the timespec is only
5158 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5159 * overflow if times way in the future are given. Further on Solaris versions
5160 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5161 * number of seconds, in abstime, is less than current_time + 100,000,000.
5162 * As it will be 28 years before "now + 100000000" will overflow we can
5163 * ignore overflow and just impose a hard-limit on seconds using the value
5164 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5165 * years from "now".
5166 */
5167
5168 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5169 assert (time > 0, "convertTime");
5170
5171 struct timeval now;
5172 int status = gettimeofday(&now, NULL);
5173 assert(status == 0, "gettimeofday");
5174
5175 time_t max_secs = now.tv_sec + MAX_SECS;
5176
5177 if (isAbsolute) {
5178 jlong secs = time / 1000;
5179 if (secs > max_secs) {
5180 absTime->tv_sec = max_secs;
5181 }
5182 else {
5183 absTime->tv_sec = secs;
5184 }
5185 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5186 }
5187 else {
5188 jlong secs = time / NANOSECS_PER_SEC;
5189 if (secs >= MAX_SECS) {
5190 absTime->tv_sec = max_secs;
5191 absTime->tv_nsec = 0;
5192 }
5193 else {
5194 absTime->tv_sec = now.tv_sec + secs;
5195 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5196 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5197 absTime->tv_nsec -= NANOSECS_PER_SEC;
5198 ++absTime->tv_sec; // note: this must be <= max_secs
5199 }
5200 }
5201 }
5202 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5203 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5204 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5205 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5206 }
5207
5208 void Parker::park(bool isAbsolute, jlong time) {
5209 // Optional fast-path check:
5210 // Return immediately if a permit is available.
5211 if (_counter > 0) {
5212 _counter = 0 ;
5213 OrderAccess::fence();
5214 return ;
5215 }
5216
5217 Thread* thread = Thread::current();
5218 assert(thread->is_Java_thread(), "Must be JavaThread");
5219 JavaThread *jt = (JavaThread *)thread;
5220
5221 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5222 // Check interrupt before trying to wait
5223 if (Thread::is_interrupted(thread, false)) {
5224 return;
5225 }
5226
5227 // Next, demultiplex/decode time arguments
5228 timespec absTime;
5229 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5230 return;
5231 }
5232 if (time > 0) {
5233 unpackTime(&absTime, isAbsolute, time);
5234 }
5235
5236
5237 // Enter safepoint region
5238 // Beware of deadlocks such as 6317397.
5239 // The per-thread Parker:: mutex is a classic leaf-lock.
5240 // In particular a thread must never block on the Threads_lock while
5241 // holding the Parker:: mutex. If safepoints are pending both the
5242 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5243 ThreadBlockInVM tbivm(jt);
5244
5245 // Don't wait if cannot get lock since interference arises from
5246 // unblocking. Also. check interrupt before trying wait
5247 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5248 return;
5249 }
5250
5251 int status ;
5252 if (_counter > 0) { // no wait needed
5253 _counter = 0;
5254 status = pthread_mutex_unlock(_mutex);
5255 assert (status == 0, "invariant") ;
5256 OrderAccess::fence();
5257 return;
5258 }
5259
5260 #ifdef ASSERT
5261 // Don't catch signals while blocked; let the running threads have the signals.
5262 // (This allows a debugger to break into the running thread.)
5263 sigset_t oldsigs;
5264 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5265 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5266 #endif
5267
5268 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5269 jt->set_suspend_equivalent();
5270 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5271
5272 if (time == 0) {
5273 status = pthread_cond_wait (_cond, _mutex) ;
5274 } else {
5275 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5276 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5277 pthread_cond_destroy (_cond) ;
5278 pthread_cond_init (_cond, NULL);
5279 }
5280 }
5281 assert_status(status == 0 || status == EINTR ||
5282 status == ETIME || status == ETIMEDOUT,
5283 status, "cond_timedwait");
5284
5285 #ifdef ASSERT
5286 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5287 #endif
5288
5289 _counter = 0 ;
5290 status = pthread_mutex_unlock(_mutex) ;
5291 assert_status(status == 0, status, "invariant") ;
5292 // If externally suspended while waiting, re-suspend
5293 if (jt->handle_special_suspend_equivalent_condition()) {
5294 jt->java_suspend_self();
5295 }
5296
5297 OrderAccess::fence();
5298 }
5299
5300 void Parker::unpark() {
5301 int s, status ;
5302 status = pthread_mutex_lock(_mutex);
5303 assert (status == 0, "invariant") ;
5304 s = _counter;
5305 _counter = 1;
5306 if (s < 1) {
5307 if (WorkAroundNPTLTimedWaitHang) {
5308 status = pthread_cond_signal (_cond) ;
5309 assert (status == 0, "invariant") ;
5310 status = pthread_mutex_unlock(_mutex);
5311 assert (status == 0, "invariant") ;
5312 } else {
5313 status = pthread_mutex_unlock(_mutex);
5314 assert (status == 0, "invariant") ;
5315 status = pthread_cond_signal (_cond) ;
5316 assert (status == 0, "invariant") ;
5317 }
5318 } else {
5319 pthread_mutex_unlock(_mutex);
5320 assert (status == 0, "invariant") ;
5321 }
5322 }
5323
5324
5325 extern char** environ;
5326
5327 #ifndef __NR_fork
5328 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5329 #endif
5330
5331 #ifndef __NR_execve
5332 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5333 #endif
5334
5335 // Run the specified command in a separate process. Return its exit value,
5336 // or -1 on failure (e.g. can't fork a new process).
5337 // Unlike system(), this function can be called from signal handler. It
5338 // doesn't block SIGINT et al.
5339 int os::fork_and_exec(char* cmd) {
5340 const char * argv[4] = {"sh", "-c", cmd, NULL};
5341
5342 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5343 // pthread_atfork handlers and reset pthread library. All we need is a
5344 // separate process to execve. Make a direct syscall to fork process.
5345 // On IA64 there's no fork syscall, we have to use fork() and hope for
5346 // the best...
5347 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5348 IA64_ONLY(fork();)
5349
5350 if (pid < 0) {
5351 // fork failed
5352 return -1;
5353
5354 } else if (pid == 0) {
5355 // child process
5356
5357 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5358 // first to kill every thread on the thread list. Because this list is
5359 // not reset by fork() (see notes above), execve() will instead kill
5360 // every thread in the parent process. We know this is the only thread
5361 // in the new process, so make a system call directly.
5362 // IA64 should use normal execve() from glibc to match the glibc fork()
5363 // above.
5364 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5365 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5366
5367 // execve failed
5368 _exit(-1);
5369
5370 } else {
5371 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5372 // care about the actual exit code, for now.
5373
5374 int status;
5375
5376 // Wait for the child process to exit. This returns immediately if
5377 // the child has already exited. */
5378 while (waitpid(pid, &status, 0) < 0) {
5379 switch (errno) {
5380 case ECHILD: return 0;
5381 case EINTR: break;
5382 default: return -1;
5383 }
5384 }
5385
5386 if (WIFEXITED(status)) {
5387 // The child exited normally; get its exit code.
5388 return WEXITSTATUS(status);
5389 } else if (WIFSIGNALED(status)) {
5390 // The child exited because of a signal
5391 // The best value to return is 0x80 + signal number,
5392 // because that is what all Unix shells do, and because
5393 // it allows callers to distinguish between process exit and
5394 // process death by signal.
5395 return 0x80 + WTERMSIG(status);
5396 } else {
5397 // Unknown exit code; pass it through
5398 return status;
5399 }
5400 }
5401 }
5402
5403 // is_headless_jre()
5404 //
5405 // Test for the existence of libmawt in motif21 or xawt directories
5406 // in order to report if we are running in a headless jre
5407 //
5408 bool os::is_headless_jre() {
5409 struct stat statbuf;
5410 char buf[MAXPATHLEN];
5411 char libmawtpath[MAXPATHLEN];
5412 const char *xawtstr = "/xawt/libmawt.so";
5413 const char *motifstr = "/motif21/libmawt.so";
5414 char *p;
5415
5416 // Get path to libjvm.so
5417 os::jvm_path(buf, sizeof(buf));
5418
5419 // Get rid of libjvm.so
5420 p = strrchr(buf, '/');
5421 if (p == NULL) return false;
5422 else *p = '\0';
5423
5424 // Get rid of client or server
5425 p = strrchr(buf, '/');
5426 if (p == NULL) return false;
5427 else *p = '\0';
5428
5429 // check xawt/libmawt.so
5430 strcpy(libmawtpath, buf);
5431 strcat(libmawtpath, xawtstr);
5432 if (::stat(libmawtpath, &statbuf) == 0) return false;
5433
5434 // check motif21/libmawt.so
5435 strcpy(libmawtpath, buf);
5436 strcat(libmawtpath, motifstr);
5437 if (::stat(libmawtpath, &statbuf) == 0) return false;
5438
5439 return true;
5440 }
5441
5442
5443 #ifdef JAVASE_EMBEDDED
5444 //
5445 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5446 //
5447 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5448
5449 // ctor
5450 //
5451 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5452 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5453 _fd = fd;
5454
5455 if (os::create_thread(this, os::os_thread)) {
5456 _memnotify_thread = this;
5457 os::set_priority(this, NearMaxPriority);
5458 os::start_thread(this);
5459 }
5460 }
5461
5462 // Where all the work gets done
5463 //
5464 void MemNotifyThread::run() {
5465 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5466
5467 // Set up the select arguments
5468 fd_set rfds;
5469 if (_fd != -1) {
5470 FD_ZERO(&rfds);
5471 FD_SET(_fd, &rfds);
5472 }
5473
5474 // Now wait for the mem_notify device to wake up
5475 while (1) {
5476 // Wait for the mem_notify device to signal us..
5477 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5478 if (rc == -1) {
5479 perror("select!\n");
5480 break;
5481 } else if (rc) {
5482 //ssize_t free_before = os::available_memory();
5483 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5484
5485 // The kernel is telling us there is not much memory left...
5486 // try to do something about that
5487
5488 // If we are not already in a GC, try one.
5489 if (!Universe::heap()->is_gc_active()) {
5490 Universe::heap()->collect(GCCause::_allocation_failure);
5491
5492 //ssize_t free_after = os::available_memory();
5493 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5494 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5495 }
5496 // We might want to do something like the following if we find the GC's are not helping...
5497 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5498 }
5499 }
5500 }
5501
5502 //
5503 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5504 //
5505 void MemNotifyThread::start() {
5506 int fd;
5507 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5508 if (fd < 0) {
5509 return;
5510 }
5511
5512 if (memnotify_thread() == NULL) {
5513 new MemNotifyThread(fd);
5514 }
5515 }
5516 #endif // JAVASE_EMBEDDED