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 // no precompiled headers 26 #include "classfile/classLoader.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "code/vtableStubs.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "interpreter/interpreter.hpp" 33 #include "jvm_linux.h" 34 #include "memory/allocation.inline.hpp" 35 #include "memory/filemap.hpp" 36 #include "mutex_linux.inline.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "os_share_linux.hpp" 39 #include "prims/jniFastGetField.hpp" 40 #include "prims/jvm.h" 41 #include "prims/jvm_misc.hpp" 42 #include "runtime/arguments.hpp" 43 #include "runtime/extendedPC.hpp" 44 #include "runtime/globals.hpp" 45 #include "runtime/interfaceSupport.hpp" 46 #include "runtime/java.hpp" 47 #include "runtime/javaCalls.hpp" 48 #include "runtime/mutexLocker.hpp" 49 #include "runtime/objectMonitor.hpp" 50 #include "runtime/osThread.hpp" 51 #include "runtime/perfMemory.hpp" 52 #include "runtime/sharedRuntime.hpp" 53 #include "runtime/statSampler.hpp" 54 #include "runtime/stubRoutines.hpp" 55 #include "runtime/threadCritical.hpp" 56 #include "runtime/timer.hpp" 57 #include "services/attachListener.hpp" 58 #include "services/runtimeService.hpp" 59 #include "thread_linux.inline.hpp" 60 #include "utilities/decoder.hpp" 61 #include "utilities/defaultStream.hpp" 62 #include "utilities/events.hpp" 63 #include "utilities/growableArray.hpp" 64 #include "utilities/vmError.hpp" 65 #ifdef TARGET_ARCH_x86 66 # include "assembler_x86.inline.hpp" 67 # include "nativeInst_x86.hpp" 68 #endif 69 #ifdef TARGET_ARCH_sparc 70 # include "assembler_sparc.inline.hpp" 71 # include "nativeInst_sparc.hpp" 72 #endif 73 #ifdef TARGET_ARCH_zero 74 # include "assembler_zero.inline.hpp" 75 # include "nativeInst_zero.hpp" 76 #endif 77 #ifdef TARGET_ARCH_arm 78 # include "assembler_arm.inline.hpp" 79 # include "nativeInst_arm.hpp" 80 #endif 81 #ifdef TARGET_ARCH_ppc 82 # include "assembler_ppc.inline.hpp" 83 # include "nativeInst_ppc.hpp" 84 #endif 85 #ifdef COMPILER1 86 #include "c1/c1_Runtime1.hpp" 87 #endif 88 #ifdef COMPILER2 89 #include "opto/runtime.hpp" 90 #endif 91 92 // put OS-includes here 93 # include <sys/types.h> 94 # include <sys/mman.h> 95 # include <sys/stat.h> 96 # include <sys/select.h> 97 # include <pthread.h> 98 # include <signal.h> 99 # include <errno.h> 100 # include <dlfcn.h> 101 # include <stdio.h> 102 # include <unistd.h> 103 # include <sys/resource.h> 104 # include <pthread.h> 105 # include <sys/stat.h> 106 # include <sys/time.h> 107 # include <sys/times.h> 108 # include <sys/utsname.h> 109 # include <sys/socket.h> 110 # include <sys/wait.h> 111 # include <pwd.h> 112 # include <poll.h> 113 # include <semaphore.h> 114 # include <fcntl.h> 115 # include <string.h> 116 # include <syscall.h> 117 # include <sys/sysinfo.h> 118 # include <gnu/libc-version.h> 119 # include <sys/ipc.h> 120 # include <sys/shm.h> 121 # include <link.h> 122 # include <stdint.h> 123 # include <inttypes.h> 124 # include <sys/ioctl.h> 125 126 #define MAX_PATH (2 * K) 127 128 // for timer info max values which include all bits 129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 130 131 #define LARGEPAGES_BIT (1 << 6) 132 //////////////////////////////////////////////////////////////////////////////// 133 // global variables 134 julong os::Linux::_physical_memory = 0; 135 136 address os::Linux::_initial_thread_stack_bottom = NULL; 137 uintptr_t os::Linux::_initial_thread_stack_size = 0; 138 139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 141 Mutex* os::Linux::_createThread_lock = NULL; 142 pthread_t os::Linux::_main_thread; 143 int os::Linux::_page_size = -1; 144 bool os::Linux::_is_floating_stack = false; 145 bool os::Linux::_is_NPTL = false; 146 bool os::Linux::_supports_fast_thread_cpu_time = false; 147 const char * os::Linux::_glibc_version = NULL; 148 const char * os::Linux::_libpthread_version = NULL; 149 150 static jlong initial_time_count=0; 151 152 static int clock_tics_per_sec = 100; 153 154 // For diagnostics to print a message once. see run_periodic_checks 155 static sigset_t check_signal_done; 156 static bool check_signals = true;; 157 158 static pid_t _initial_pid = 0; 159 160 /* Signal number used to suspend/resume a thread */ 161 162 /* do not use any signal number less than SIGSEGV, see 4355769 */ 163 static int SR_signum = SIGUSR2; 164 sigset_t SR_sigset; 165 166 /* Used to protect dlsym() calls */ 167 static pthread_mutex_t dl_mutex; 168 169 #ifdef JAVASE_EMBEDDED 170 class MemNotifyThread: public Thread { 171 friend class VMStructs; 172 public: 173 virtual void run(); 174 175 private: 176 static MemNotifyThread* _memnotify_thread; 177 int _fd; 178 179 public: 180 181 // Constructor 182 MemNotifyThread(int fd); 183 184 // Tester 185 bool is_memnotify_thread() const { return true; } 186 187 // Printing 188 char* name() const { return (char*)"Linux MemNotify Thread"; } 189 190 // Returns the single instance of the MemNotifyThread 191 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; } 192 193 // Create and start the single instance of MemNotifyThread 194 static void start(); 195 }; 196 #endif // JAVASE_EMBEDDED 197 198 // utility functions 199 200 static int SR_initialize(); 201 static int SR_finalize(); 202 203 julong os::available_memory() { 204 return Linux::available_memory(); 205 } 206 207 julong os::Linux::available_memory() { 208 // values in struct sysinfo are "unsigned long" 209 struct sysinfo si; 210 sysinfo(&si); 211 212 return (julong)si.freeram * si.mem_unit; 213 } 214 215 julong os::physical_memory() { 216 return Linux::physical_memory(); 217 } 218 219 julong os::allocatable_physical_memory(julong size) { 220 #ifdef _LP64 221 return size; 222 #else 223 julong result = MIN2(size, (julong)3800*M); 224 if (!is_allocatable(result)) { 225 // See comments under solaris for alignment considerations 226 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 227 result = MIN2(size, reasonable_size); 228 } 229 return result; 230 #endif // _LP64 231 } 232 233 //////////////////////////////////////////////////////////////////////////////// 234 // environment support 235 236 bool os::getenv(const char* name, char* buf, int len) { 237 const char* val = ::getenv(name); 238 if (val != NULL && strlen(val) < (size_t)len) { 239 strcpy(buf, val); 240 return true; 241 } 242 if (len > 0) buf[0] = 0; // return a null string 243 return false; 244 } 245 246 247 // Return true if user is running as root. 248 249 bool os::have_special_privileges() { 250 static bool init = false; 251 static bool privileges = false; 252 if (!init) { 253 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 254 init = true; 255 } 256 return privileges; 257 } 258 259 260 #ifndef SYS_gettid 261 // i386: 224, ia64: 1105, amd64: 186, sparc 143 262 #ifdef __ia64__ 263 #define SYS_gettid 1105 264 #elif __i386__ 265 #define SYS_gettid 224 266 #elif __amd64__ 267 #define SYS_gettid 186 268 #elif __sparc__ 269 #define SYS_gettid 143 270 #else 271 #error define gettid for the arch 272 #endif 273 #endif 274 275 // Cpu architecture string 276 #if defined(ZERO) 277 static char cpu_arch[] = ZERO_LIBARCH; 278 #elif defined(IA64) 279 static char cpu_arch[] = "ia64"; 280 #elif defined(IA32) 281 static char cpu_arch[] = "i386"; 282 #elif defined(AMD64) 283 static char cpu_arch[] = "amd64"; 284 #elif defined(ARM) 285 static char cpu_arch[] = "arm"; 286 #elif defined(PPC) 287 static char cpu_arch[] = "ppc"; 288 #elif defined(SPARC) 289 # ifdef _LP64 290 static char cpu_arch[] = "sparcv9"; 291 # else 292 static char cpu_arch[] = "sparc"; 293 # endif 294 #else 295 #error Add appropriate cpu_arch setting 296 #endif 297 298 299 // pid_t gettid() 300 // 301 // Returns the kernel thread id of the currently running thread. Kernel 302 // thread id is used to access /proc. 303 // 304 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 305 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 306 // 307 pid_t os::Linux::gettid() { 308 int rslt = syscall(SYS_gettid); 309 if (rslt == -1) { 310 // old kernel, no NPTL support 311 return getpid(); 312 } else { 313 return (pid_t)rslt; 314 } 315 } 316 317 // Most versions of linux have a bug where the number of processors are 318 // determined by looking at the /proc file system. In a chroot environment, 319 // the system call returns 1. This causes the VM to act as if it is 320 // a single processor and elide locking (see is_MP() call). 321 static bool unsafe_chroot_detected = false; 322 static const char *unstable_chroot_error = "/proc file system not found.\n" 323 "Java may be unstable running multithreaded in a chroot " 324 "environment on Linux when /proc filesystem is not mounted."; 325 326 void os::Linux::initialize_system_info() { 327 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 328 if (processor_count() == 1) { 329 pid_t pid = os::Linux::gettid(); 330 char fname[32]; 331 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 332 FILE *fp = fopen(fname, "r"); 333 if (fp == NULL) { 334 unsafe_chroot_detected = true; 335 } else { 336 fclose(fp); 337 } 338 } 339 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 340 assert(processor_count() > 0, "linux error"); 341 } 342 343 void os::init_system_properties_values() { 344 // char arch[12]; 345 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 346 347 // The next steps are taken in the product version: 348 // 349 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 350 // This library should be located at: 351 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 352 // 353 // If "/jre/lib/" appears at the right place in the path, then we 354 // assume libjvm[_g].so is installed in a JDK and we use this path. 355 // 356 // Otherwise exit with message: "Could not create the Java virtual machine." 357 // 358 // The following extra steps are taken in the debugging version: 359 // 360 // If "/jre/lib/" does NOT appear at the right place in the path 361 // instead of exit check for $JAVA_HOME environment variable. 362 // 363 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 364 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 365 // it looks like libjvm[_g].so is installed there 366 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 367 // 368 // Otherwise exit. 369 // 370 // Important note: if the location of libjvm.so changes this 371 // code needs to be changed accordingly. 372 373 // The next few definitions allow the code to be verbatim: 374 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 375 #define getenv(n) ::getenv(n) 376 377 /* 378 * See ld(1): 379 * The linker uses the following search paths to locate required 380 * shared libraries: 381 * 1: ... 382 * ... 383 * 7: The default directories, normally /lib and /usr/lib. 384 */ 385 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 386 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 387 #else 388 #define DEFAULT_LIBPATH "/lib:/usr/lib" 389 #endif 390 391 #define EXTENSIONS_DIR "/lib/ext" 392 #define ENDORSED_DIR "/lib/endorsed" 393 #define REG_DIR "/usr/java/packages" 394 395 { 396 /* sysclasspath, java_home, dll_dir */ 397 { 398 char *home_path; 399 char *dll_path; 400 char *pslash; 401 char buf[MAXPATHLEN]; 402 os::jvm_path(buf, sizeof(buf)); 403 404 // Found the full path to libjvm.so. 405 // Now cut the path to <java_home>/jre if we can. 406 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 407 pslash = strrchr(buf, '/'); 408 if (pslash != NULL) 409 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 410 dll_path = malloc(strlen(buf) + 1); 411 if (dll_path == NULL) 412 return; 413 strcpy(dll_path, buf); 414 Arguments::set_dll_dir(dll_path); 415 416 if (pslash != NULL) { 417 pslash = strrchr(buf, '/'); 418 if (pslash != NULL) { 419 *pslash = '\0'; /* get rid of /<arch> */ 420 pslash = strrchr(buf, '/'); 421 if (pslash != NULL) 422 *pslash = '\0'; /* get rid of /lib */ 423 } 424 } 425 426 home_path = malloc(strlen(buf) + 1); 427 if (home_path == NULL) 428 return; 429 strcpy(home_path, buf); 430 Arguments::set_java_home(home_path); 431 432 if (!set_boot_path('/', ':')) 433 return; 434 } 435 436 /* 437 * Where to look for native libraries 438 * 439 * Note: Due to a legacy implementation, most of the library path 440 * is set in the launcher. This was to accomodate linking restrictions 441 * on legacy Linux implementations (which are no longer supported). 442 * Eventually, all the library path setting will be done here. 443 * 444 * However, to prevent the proliferation of improperly built native 445 * libraries, the new path component /usr/java/packages is added here. 446 * Eventually, all the library path setting will be done here. 447 */ 448 { 449 char *ld_library_path; 450 451 /* 452 * Construct the invariant part of ld_library_path. Note that the 453 * space for the colon and the trailing null are provided by the 454 * nulls included by the sizeof operator (so actually we allocate 455 * a byte more than necessary). 456 */ 457 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 458 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 459 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 460 461 /* 462 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 463 * should always exist (until the legacy problem cited above is 464 * addressed). 465 */ 466 char *v = getenv("LD_LIBRARY_PATH"); 467 if (v != NULL) { 468 char *t = ld_library_path; 469 /* That's +1 for the colon and +1 for the trailing '\0' */ 470 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 471 sprintf(ld_library_path, "%s:%s", v, t); 472 } 473 Arguments::set_library_path(ld_library_path); 474 } 475 476 /* 477 * Extensions directories. 478 * 479 * Note that the space for the colon and the trailing null are provided 480 * by the nulls included by the sizeof operator (so actually one byte more 481 * than necessary is allocated). 482 */ 483 { 484 char *buf = malloc(strlen(Arguments::get_java_home()) + 485 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 486 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 487 Arguments::get_java_home()); 488 Arguments::set_ext_dirs(buf); 489 } 490 491 /* Endorsed standards default directory. */ 492 { 493 char * buf; 494 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 495 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 496 Arguments::set_endorsed_dirs(buf); 497 } 498 } 499 500 #undef malloc 501 #undef getenv 502 #undef EXTENSIONS_DIR 503 #undef ENDORSED_DIR 504 505 // Done 506 return; 507 } 508 509 //////////////////////////////////////////////////////////////////////////////// 510 // breakpoint support 511 512 void os::breakpoint() { 513 BREAKPOINT; 514 } 515 516 extern "C" void breakpoint() { 517 // use debugger to set breakpoint here 518 } 519 520 //////////////////////////////////////////////////////////////////////////////// 521 // signal support 522 523 debug_only(static bool signal_sets_initialized = false); 524 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 525 526 bool os::Linux::is_sig_ignored(int sig) { 527 struct sigaction oact; 528 sigaction(sig, (struct sigaction*)NULL, &oact); 529 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 530 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 531 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 532 return true; 533 else 534 return false; 535 } 536 537 void os::Linux::signal_sets_init() { 538 // Should also have an assertion stating we are still single-threaded. 539 assert(!signal_sets_initialized, "Already initialized"); 540 // Fill in signals that are necessarily unblocked for all threads in 541 // the VM. Currently, we unblock the following signals: 542 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 543 // by -Xrs (=ReduceSignalUsage)); 544 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 545 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 546 // the dispositions or masks wrt these signals. 547 // Programs embedding the VM that want to use the above signals for their 548 // own purposes must, at this time, use the "-Xrs" option to prevent 549 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 550 // (See bug 4345157, and other related bugs). 551 // In reality, though, unblocking these signals is really a nop, since 552 // these signals are not blocked by default. 553 sigemptyset(&unblocked_sigs); 554 sigemptyset(&allowdebug_blocked_sigs); 555 sigaddset(&unblocked_sigs, SIGILL); 556 sigaddset(&unblocked_sigs, SIGSEGV); 557 sigaddset(&unblocked_sigs, SIGBUS); 558 sigaddset(&unblocked_sigs, SIGFPE); 559 sigaddset(&unblocked_sigs, SR_signum); 560 561 if (!ReduceSignalUsage) { 562 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 563 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 564 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 565 } 566 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 567 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 568 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 569 } 570 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 571 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 572 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 573 } 574 } 575 // Fill in signals that are blocked by all but the VM thread. 576 sigemptyset(&vm_sigs); 577 if (!ReduceSignalUsage) 578 sigaddset(&vm_sigs, BREAK_SIGNAL); 579 debug_only(signal_sets_initialized = true); 580 581 } 582 583 // These are signals that are unblocked while a thread is running Java. 584 // (For some reason, they get blocked by default.) 585 sigset_t* os::Linux::unblocked_signals() { 586 assert(signal_sets_initialized, "Not initialized"); 587 return &unblocked_sigs; 588 } 589 590 // These are the signals that are blocked while a (non-VM) thread is 591 // running Java. Only the VM thread handles these signals. 592 sigset_t* os::Linux::vm_signals() { 593 assert(signal_sets_initialized, "Not initialized"); 594 return &vm_sigs; 595 } 596 597 // These are signals that are blocked during cond_wait to allow debugger in 598 sigset_t* os::Linux::allowdebug_blocked_signals() { 599 assert(signal_sets_initialized, "Not initialized"); 600 return &allowdebug_blocked_sigs; 601 } 602 603 void os::Linux::hotspot_sigmask(Thread* thread) { 604 605 //Save caller's signal mask before setting VM signal mask 606 sigset_t caller_sigmask; 607 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 608 609 OSThread* osthread = thread->osthread(); 610 osthread->set_caller_sigmask(caller_sigmask); 611 612 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 613 614 if (!ReduceSignalUsage) { 615 if (thread->is_VM_thread()) { 616 // Only the VM thread handles BREAK_SIGNAL ... 617 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 618 } else { 619 // ... all other threads block BREAK_SIGNAL 620 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 621 } 622 } 623 } 624 625 ////////////////////////////////////////////////////////////////////////////// 626 // detecting pthread library 627 628 void os::Linux::libpthread_init() { 629 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 630 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 631 // generic name for earlier versions. 632 // Define macros here so we can build HotSpot on old systems. 633 # ifndef _CS_GNU_LIBC_VERSION 634 # define _CS_GNU_LIBC_VERSION 2 635 # endif 636 # ifndef _CS_GNU_LIBPTHREAD_VERSION 637 # define _CS_GNU_LIBPTHREAD_VERSION 3 638 # endif 639 640 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 641 if (n > 0) { 642 char *str = (char *)malloc(n); 643 confstr(_CS_GNU_LIBC_VERSION, str, n); 644 os::Linux::set_glibc_version(str); 645 } else { 646 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 647 static char _gnu_libc_version[32]; 648 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 649 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 650 os::Linux::set_glibc_version(_gnu_libc_version); 651 } 652 653 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 654 if (n > 0) { 655 char *str = (char *)malloc(n); 656 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 657 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 658 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 659 // is the case. LinuxThreads has a hard limit on max number of threads. 660 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 661 // On the other hand, NPTL does not have such a limit, sysconf() 662 // will return -1 and errno is not changed. Check if it is really NPTL. 663 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 664 strstr(str, "NPTL") && 665 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 666 free(str); 667 os::Linux::set_libpthread_version("linuxthreads"); 668 } else { 669 os::Linux::set_libpthread_version(str); 670 } 671 } else { 672 // glibc before 2.3.2 only has LinuxThreads. 673 os::Linux::set_libpthread_version("linuxthreads"); 674 } 675 676 if (strstr(libpthread_version(), "NPTL")) { 677 os::Linux::set_is_NPTL(); 678 } else { 679 os::Linux::set_is_LinuxThreads(); 680 } 681 682 // LinuxThreads have two flavors: floating-stack mode, which allows variable 683 // stack size; and fixed-stack mode. NPTL is always floating-stack. 684 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 685 os::Linux::set_is_floating_stack(); 686 } 687 } 688 689 ///////////////////////////////////////////////////////////////////////////// 690 // thread stack 691 692 // Force Linux kernel to expand current thread stack. If "bottom" is close 693 // to the stack guard, caller should block all signals. 694 // 695 // MAP_GROWSDOWN: 696 // A special mmap() flag that is used to implement thread stacks. It tells 697 // kernel that the memory region should extend downwards when needed. This 698 // allows early versions of LinuxThreads to only mmap the first few pages 699 // when creating a new thread. Linux kernel will automatically expand thread 700 // stack as needed (on page faults). 701 // 702 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 703 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 704 // region, it's hard to tell if the fault is due to a legitimate stack 705 // access or because of reading/writing non-exist memory (e.g. buffer 706 // overrun). As a rule, if the fault happens below current stack pointer, 707 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 708 // application (see Linux kernel fault.c). 709 // 710 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 711 // stack overflow detection. 712 // 713 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 714 // not use this flag. However, the stack of initial thread is not created 715 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 716 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 717 // and then attach the thread to JVM. 718 // 719 // To get around the problem and allow stack banging on Linux, we need to 720 // manually expand thread stack after receiving the SIGSEGV. 721 // 722 // There are two ways to expand thread stack to address "bottom", we used 723 // both of them in JVM before 1.5: 724 // 1. adjust stack pointer first so that it is below "bottom", and then 725 // touch "bottom" 726 // 2. mmap() the page in question 727 // 728 // Now alternate signal stack is gone, it's harder to use 2. For instance, 729 // if current sp is already near the lower end of page 101, and we need to 730 // call mmap() to map page 100, it is possible that part of the mmap() frame 731 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 732 // That will destroy the mmap() frame and cause VM to crash. 733 // 734 // The following code works by adjusting sp first, then accessing the "bottom" 735 // page to force a page fault. Linux kernel will then automatically expand the 736 // stack mapping. 737 // 738 // _expand_stack_to() assumes its frame size is less than page size, which 739 // should always be true if the function is not inlined. 740 741 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 742 #define NOINLINE 743 #else 744 #define NOINLINE __attribute__ ((noinline)) 745 #endif 746 747 static void _expand_stack_to(address bottom) NOINLINE; 748 749 static void _expand_stack_to(address bottom) { 750 address sp; 751 size_t size; 752 volatile char *p; 753 754 // Adjust bottom to point to the largest address within the same page, it 755 // gives us a one-page buffer if alloca() allocates slightly more memory. 756 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 757 bottom += os::Linux::page_size() - 1; 758 759 // sp might be slightly above current stack pointer; if that's the case, we 760 // will alloca() a little more space than necessary, which is OK. Don't use 761 // os::current_stack_pointer(), as its result can be slightly below current 762 // stack pointer, causing us to not alloca enough to reach "bottom". 763 sp = (address)&sp; 764 765 if (sp > bottom) { 766 size = sp - bottom; 767 p = (volatile char *)alloca(size); 768 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 769 p[0] = '\0'; 770 } 771 } 772 773 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 774 assert(t!=NULL, "just checking"); 775 assert(t->osthread()->expanding_stack(), "expand should be set"); 776 assert(t->stack_base() != NULL, "stack_base was not initialized"); 777 778 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 779 sigset_t mask_all, old_sigset; 780 sigfillset(&mask_all); 781 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 782 _expand_stack_to(addr); 783 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 784 return true; 785 } 786 return false; 787 } 788 789 ////////////////////////////////////////////////////////////////////////////// 790 // create new thread 791 792 static address highest_vm_reserved_address(); 793 794 // check if it's safe to start a new thread 795 static bool _thread_safety_check(Thread* thread) { 796 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 797 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 798 // Heap is mmap'ed at lower end of memory space. Thread stacks are 799 // allocated (MAP_FIXED) from high address space. Every thread stack 800 // occupies a fixed size slot (usually 2Mbytes, but user can change 801 // it to other values if they rebuild LinuxThreads). 802 // 803 // Problem with MAP_FIXED is that mmap() can still succeed even part of 804 // the memory region has already been mmap'ed. That means if we have too 805 // many threads and/or very large heap, eventually thread stack will 806 // collide with heap. 807 // 808 // Here we try to prevent heap/stack collision by comparing current 809 // stack bottom with the highest address that has been mmap'ed by JVM 810 // plus a safety margin for memory maps created by native code. 811 // 812 // This feature can be disabled by setting ThreadSafetyMargin to 0 813 // 814 if (ThreadSafetyMargin > 0) { 815 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 816 817 // not safe if our stack extends below the safety margin 818 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 819 } else { 820 return true; 821 } 822 } else { 823 // Floating stack LinuxThreads or NPTL: 824 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 825 // there's not enough space left, pthread_create() will fail. If we come 826 // here, that means enough space has been reserved for stack. 827 return true; 828 } 829 } 830 831 // Thread start routine for all newly created threads 832 static void *java_start(Thread *thread) { 833 // Try to randomize the cache line index of hot stack frames. 834 // This helps when threads of the same stack traces evict each other's 835 // cache lines. The threads can be either from the same JVM instance, or 836 // from different JVM instances. The benefit is especially true for 837 // processors with hyperthreading technology. 838 static int counter = 0; 839 int pid = os::current_process_id(); 840 alloca(((pid ^ counter++) & 7) * 128); 841 842 ThreadLocalStorage::set_thread(thread); 843 844 OSThread* osthread = thread->osthread(); 845 Monitor* sync = osthread->startThread_lock(); 846 847 // non floating stack LinuxThreads needs extra check, see above 848 if (!_thread_safety_check(thread)) { 849 // notify parent thread 850 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 851 osthread->set_state(ZOMBIE); 852 sync->notify_all(); 853 return NULL; 854 } 855 856 // thread_id is kernel thread id (similar to Solaris LWP id) 857 osthread->set_thread_id(os::Linux::gettid()); 858 859 if (UseNUMA) { 860 int lgrp_id = os::numa_get_group_id(); 861 if (lgrp_id != -1) { 862 thread->set_lgrp_id(lgrp_id); 863 } 864 } 865 // initialize signal mask for this thread 866 os::Linux::hotspot_sigmask(thread); 867 868 // initialize floating point control register 869 os::Linux::init_thread_fpu_state(); 870 871 // handshaking with parent thread 872 { 873 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 874 875 // notify parent thread 876 osthread->set_state(INITIALIZED); 877 sync->notify_all(); 878 879 // wait until os::start_thread() 880 while (osthread->get_state() == INITIALIZED) { 881 sync->wait(Mutex::_no_safepoint_check_flag); 882 } 883 } 884 885 // call one more level start routine 886 thread->run(); 887 888 return 0; 889 } 890 891 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 892 assert(thread->osthread() == NULL, "caller responsible"); 893 894 // Allocate the OSThread object 895 OSThread* osthread = new OSThread(NULL, NULL); 896 if (osthread == NULL) { 897 return false; 898 } 899 900 // set the correct thread state 901 osthread->set_thread_type(thr_type); 902 903 // Initial state is ALLOCATED but not INITIALIZED 904 osthread->set_state(ALLOCATED); 905 906 thread->set_osthread(osthread); 907 908 // init thread attributes 909 pthread_attr_t attr; 910 pthread_attr_init(&attr); 911 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 912 913 // stack size 914 if (os::Linux::supports_variable_stack_size()) { 915 // calculate stack size if it's not specified by caller 916 if (stack_size == 0) { 917 stack_size = os::Linux::default_stack_size(thr_type); 918 919 switch (thr_type) { 920 case os::java_thread: 921 // Java threads use ThreadStackSize which default value can be 922 // changed with the flag -Xss 923 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 924 stack_size = JavaThread::stack_size_at_create(); 925 break; 926 case os::compiler_thread: 927 if (CompilerThreadStackSize > 0) { 928 stack_size = (size_t)(CompilerThreadStackSize * K); 929 break; 930 } // else fall through: 931 // use VMThreadStackSize if CompilerThreadStackSize is not defined 932 case os::vm_thread: 933 case os::pgc_thread: 934 case os::cgc_thread: 935 case os::watcher_thread: 936 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 937 break; 938 } 939 } 940 941 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 942 pthread_attr_setstacksize(&attr, stack_size); 943 } else { 944 // let pthread_create() pick the default value. 945 } 946 947 // glibc guard page 948 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 949 950 ThreadState state; 951 952 { 953 // Serialize thread creation if we are running with fixed stack LinuxThreads 954 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 955 if (lock) { 956 os::Linux::createThread_lock()->lock_without_safepoint_check(); 957 } 958 959 pthread_t tid; 960 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 961 962 pthread_attr_destroy(&attr); 963 964 if (ret != 0) { 965 if (PrintMiscellaneous && (Verbose || WizardMode)) { 966 perror("pthread_create()"); 967 } 968 // Need to clean up stuff we've allocated so far 969 thread->set_osthread(NULL); 970 delete osthread; 971 if (lock) os::Linux::createThread_lock()->unlock(); 972 return false; 973 } 974 975 // Store pthread info into the OSThread 976 osthread->set_pthread_id(tid); 977 978 // Wait until child thread is either initialized or aborted 979 { 980 Monitor* sync_with_child = osthread->startThread_lock(); 981 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 982 while ((state = osthread->get_state()) == ALLOCATED) { 983 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 984 } 985 } 986 987 if (lock) { 988 os::Linux::createThread_lock()->unlock(); 989 } 990 } 991 992 // Aborted due to thread limit being reached 993 if (state == ZOMBIE) { 994 thread->set_osthread(NULL); 995 delete osthread; 996 return false; 997 } 998 999 // The thread is returned suspended (in state INITIALIZED), 1000 // and is started higher up in the call chain 1001 assert(state == INITIALIZED, "race condition"); 1002 return true; 1003 } 1004 1005 ///////////////////////////////////////////////////////////////////////////// 1006 // attach existing thread 1007 1008 // bootstrap the main thread 1009 bool os::create_main_thread(JavaThread* thread) { 1010 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 1011 return create_attached_thread(thread); 1012 } 1013 1014 bool os::create_attached_thread(JavaThread* thread) { 1015 #ifdef ASSERT 1016 thread->verify_not_published(); 1017 #endif 1018 1019 // Allocate the OSThread object 1020 OSThread* osthread = new OSThread(NULL, NULL); 1021 1022 if (osthread == NULL) { 1023 return false; 1024 } 1025 1026 // Store pthread info into the OSThread 1027 osthread->set_thread_id(os::Linux::gettid()); 1028 osthread->set_pthread_id(::pthread_self()); 1029 1030 // initialize floating point control register 1031 os::Linux::init_thread_fpu_state(); 1032 1033 // Initial thread state is RUNNABLE 1034 osthread->set_state(RUNNABLE); 1035 1036 thread->set_osthread(osthread); 1037 1038 if (UseNUMA) { 1039 int lgrp_id = os::numa_get_group_id(); 1040 if (lgrp_id != -1) { 1041 thread->set_lgrp_id(lgrp_id); 1042 } 1043 } 1044 1045 if (os::Linux::is_initial_thread()) { 1046 // If current thread is initial thread, its stack is mapped on demand, 1047 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1048 // the entire stack region to avoid SEGV in stack banging. 1049 // It is also useful to get around the heap-stack-gap problem on SuSE 1050 // kernel (see 4821821 for details). We first expand stack to the top 1051 // of yellow zone, then enable stack yellow zone (order is significant, 1052 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1053 // is no gap between the last two virtual memory regions. 1054 1055 JavaThread *jt = (JavaThread *)thread; 1056 address addr = jt->stack_yellow_zone_base(); 1057 assert(addr != NULL, "initialization problem?"); 1058 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1059 1060 osthread->set_expanding_stack(); 1061 os::Linux::manually_expand_stack(jt, addr); 1062 osthread->clear_expanding_stack(); 1063 } 1064 1065 // initialize signal mask for this thread 1066 // and save the caller's signal mask 1067 os::Linux::hotspot_sigmask(thread); 1068 1069 return true; 1070 } 1071 1072 void os::pd_start_thread(Thread* thread) { 1073 OSThread * osthread = thread->osthread(); 1074 assert(osthread->get_state() != INITIALIZED, "just checking"); 1075 Monitor* sync_with_child = osthread->startThread_lock(); 1076 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1077 sync_with_child->notify(); 1078 } 1079 1080 // Free Linux resources related to the OSThread 1081 void os::free_thread(OSThread* osthread) { 1082 assert(osthread != NULL, "osthread not set"); 1083 1084 if (Thread::current()->osthread() == osthread) { 1085 // Restore caller's signal mask 1086 sigset_t sigmask = osthread->caller_sigmask(); 1087 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1088 } 1089 1090 delete osthread; 1091 } 1092 1093 ////////////////////////////////////////////////////////////////////////////// 1094 // thread local storage 1095 1096 int os::allocate_thread_local_storage() { 1097 pthread_key_t key; 1098 int rslt = pthread_key_create(&key, NULL); 1099 assert(rslt == 0, "cannot allocate thread local storage"); 1100 return (int)key; 1101 } 1102 1103 // Note: This is currently not used by VM, as we don't destroy TLS key 1104 // on VM exit. 1105 void os::free_thread_local_storage(int index) { 1106 int rslt = pthread_key_delete((pthread_key_t)index); 1107 assert(rslt == 0, "invalid index"); 1108 } 1109 1110 void os::thread_local_storage_at_put(int index, void* value) { 1111 int rslt = pthread_setspecific((pthread_key_t)index, value); 1112 assert(rslt == 0, "pthread_setspecific failed"); 1113 } 1114 1115 extern "C" Thread* get_thread() { 1116 return ThreadLocalStorage::thread(); 1117 } 1118 1119 ////////////////////////////////////////////////////////////////////////////// 1120 // initial thread 1121 1122 // Check if current thread is the initial thread, similar to Solaris thr_main. 1123 bool os::Linux::is_initial_thread(void) { 1124 char dummy; 1125 // If called before init complete, thread stack bottom will be null. 1126 // Can be called if fatal error occurs before initialization. 1127 if (initial_thread_stack_bottom() == NULL) return false; 1128 assert(initial_thread_stack_bottom() != NULL && 1129 initial_thread_stack_size() != 0, 1130 "os::init did not locate initial thread's stack region"); 1131 if ((address)&dummy >= initial_thread_stack_bottom() && 1132 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1133 return true; 1134 else return false; 1135 } 1136 1137 // Find the virtual memory area that contains addr 1138 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1139 FILE *fp = fopen("/proc/self/maps", "r"); 1140 if (fp) { 1141 address low, high; 1142 while (!feof(fp)) { 1143 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1144 if (low <= addr && addr < high) { 1145 if (vma_low) *vma_low = low; 1146 if (vma_high) *vma_high = high; 1147 fclose (fp); 1148 return true; 1149 } 1150 } 1151 for (;;) { 1152 int ch = fgetc(fp); 1153 if (ch == EOF || ch == (int)'\n') break; 1154 } 1155 } 1156 fclose(fp); 1157 } 1158 return false; 1159 } 1160 1161 // Locate initial thread stack. This special handling of initial thread stack 1162 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1163 // bogus value for initial thread. 1164 void os::Linux::capture_initial_stack(size_t max_size) { 1165 // stack size is the easy part, get it from RLIMIT_STACK 1166 size_t stack_size; 1167 struct rlimit rlim; 1168 getrlimit(RLIMIT_STACK, &rlim); 1169 stack_size = rlim.rlim_cur; 1170 1171 // 6308388: a bug in ld.so will relocate its own .data section to the 1172 // lower end of primordial stack; reduce ulimit -s value a little bit 1173 // so we won't install guard page on ld.so's data section. 1174 stack_size -= 2 * page_size(); 1175 1176 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1177 // 7.1, in both cases we will get 2G in return value. 1178 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1179 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1180 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1181 // in case other parts in glibc still assumes 2M max stack size. 1182 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1183 #ifndef IA64 1184 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1185 #else 1186 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1187 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1188 #endif 1189 1190 // Try to figure out where the stack base (top) is. This is harder. 1191 // 1192 // When an application is started, glibc saves the initial stack pointer in 1193 // a global variable "__libc_stack_end", which is then used by system 1194 // libraries. __libc_stack_end should be pretty close to stack top. The 1195 // variable is available since the very early days. However, because it is 1196 // a private interface, it could disappear in the future. 1197 // 1198 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1199 // to __libc_stack_end, it is very close to stack top, but isn't the real 1200 // stack top. Note that /proc may not exist if VM is running as a chroot 1201 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1202 // /proc/<pid>/stat could change in the future (though unlikely). 1203 // 1204 // We try __libc_stack_end first. If that doesn't work, look for 1205 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1206 // as a hint, which should work well in most cases. 1207 1208 uintptr_t stack_start; 1209 1210 // try __libc_stack_end first 1211 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1212 if (p && *p) { 1213 stack_start = *p; 1214 } else { 1215 // see if we can get the start_stack field from /proc/self/stat 1216 FILE *fp; 1217 int pid; 1218 char state; 1219 int ppid; 1220 int pgrp; 1221 int session; 1222 int nr; 1223 int tpgrp; 1224 unsigned long flags; 1225 unsigned long minflt; 1226 unsigned long cminflt; 1227 unsigned long majflt; 1228 unsigned long cmajflt; 1229 unsigned long utime; 1230 unsigned long stime; 1231 long cutime; 1232 long cstime; 1233 long prio; 1234 long nice; 1235 long junk; 1236 long it_real; 1237 uintptr_t start; 1238 uintptr_t vsize; 1239 intptr_t rss; 1240 uintptr_t rsslim; 1241 uintptr_t scodes; 1242 uintptr_t ecode; 1243 int i; 1244 1245 // Figure what the primordial thread stack base is. Code is inspired 1246 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1247 // followed by command name surrounded by parentheses, state, etc. 1248 char stat[2048]; 1249 int statlen; 1250 1251 fp = fopen("/proc/self/stat", "r"); 1252 if (fp) { 1253 statlen = fread(stat, 1, 2047, fp); 1254 stat[statlen] = '\0'; 1255 fclose(fp); 1256 1257 // Skip pid and the command string. Note that we could be dealing with 1258 // weird command names, e.g. user could decide to rename java launcher 1259 // to "java 1.4.2 :)", then the stat file would look like 1260 // 1234 (java 1.4.2 :)) R ... ... 1261 // We don't really need to know the command string, just find the last 1262 // occurrence of ")" and then start parsing from there. See bug 4726580. 1263 char * s = strrchr(stat, ')'); 1264 1265 i = 0; 1266 if (s) { 1267 // Skip blank chars 1268 do s++; while (isspace(*s)); 1269 1270 #define _UFM UINTX_FORMAT 1271 #define _DFM INTX_FORMAT 1272 1273 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1274 /* 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 */ 1275 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, 1276 &state, /* 3 %c */ 1277 &ppid, /* 4 %d */ 1278 &pgrp, /* 5 %d */ 1279 &session, /* 6 %d */ 1280 &nr, /* 7 %d */ 1281 &tpgrp, /* 8 %d */ 1282 &flags, /* 9 %lu */ 1283 &minflt, /* 10 %lu */ 1284 &cminflt, /* 11 %lu */ 1285 &majflt, /* 12 %lu */ 1286 &cmajflt, /* 13 %lu */ 1287 &utime, /* 14 %lu */ 1288 &stime, /* 15 %lu */ 1289 &cutime, /* 16 %ld */ 1290 &cstime, /* 17 %ld */ 1291 &prio, /* 18 %ld */ 1292 &nice, /* 19 %ld */ 1293 &junk, /* 20 %ld */ 1294 &it_real, /* 21 %ld */ 1295 &start, /* 22 UINTX_FORMAT */ 1296 &vsize, /* 23 UINTX_FORMAT */ 1297 &rss, /* 24 INTX_FORMAT */ 1298 &rsslim, /* 25 UINTX_FORMAT */ 1299 &scodes, /* 26 UINTX_FORMAT */ 1300 &ecode, /* 27 UINTX_FORMAT */ 1301 &stack_start); /* 28 UINTX_FORMAT */ 1302 } 1303 1304 #undef _UFM 1305 #undef _DFM 1306 1307 if (i != 28 - 2) { 1308 assert(false, "Bad conversion from /proc/self/stat"); 1309 // product mode - assume we are the initial thread, good luck in the 1310 // embedded case. 1311 warning("Can't detect initial thread stack location - bad conversion"); 1312 stack_start = (uintptr_t) &rlim; 1313 } 1314 } else { 1315 // For some reason we can't open /proc/self/stat (for example, running on 1316 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1317 // most cases, so don't abort: 1318 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1319 stack_start = (uintptr_t) &rlim; 1320 } 1321 } 1322 1323 // Now we have a pointer (stack_start) very close to the stack top, the 1324 // next thing to do is to figure out the exact location of stack top. We 1325 // can find out the virtual memory area that contains stack_start by 1326 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1327 // and its upper limit is the real stack top. (again, this would fail if 1328 // running inside chroot, because /proc may not exist.) 1329 1330 uintptr_t stack_top; 1331 address low, high; 1332 if (find_vma((address)stack_start, &low, &high)) { 1333 // success, "high" is the true stack top. (ignore "low", because initial 1334 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1335 stack_top = (uintptr_t)high; 1336 } else { 1337 // failed, likely because /proc/self/maps does not exist 1338 warning("Can't detect initial thread stack location - find_vma failed"); 1339 // best effort: stack_start is normally within a few pages below the real 1340 // stack top, use it as stack top, and reduce stack size so we won't put 1341 // guard page outside stack. 1342 stack_top = stack_start; 1343 stack_size -= 16 * page_size(); 1344 } 1345 1346 // stack_top could be partially down the page so align it 1347 stack_top = align_size_up(stack_top, page_size()); 1348 1349 if (max_size && stack_size > max_size) { 1350 _initial_thread_stack_size = max_size; 1351 } else { 1352 _initial_thread_stack_size = stack_size; 1353 } 1354 1355 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1356 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1357 } 1358 1359 //////////////////////////////////////////////////////////////////////////////// 1360 // time support 1361 1362 // Time since start-up in seconds to a fine granularity. 1363 // Used by VMSelfDestructTimer and the MemProfiler. 1364 double os::elapsedTime() { 1365 1366 return (double)(os::elapsed_counter()) * 0.000001; 1367 } 1368 1369 jlong os::elapsed_counter() { 1370 timeval time; 1371 int status = gettimeofday(&time, NULL); 1372 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1373 } 1374 1375 jlong os::elapsed_frequency() { 1376 return (1000 * 1000); 1377 } 1378 1379 // For now, we say that linux does not support vtime. I have no idea 1380 // whether it can actually be made to (DLD, 9/13/05). 1381 1382 bool os::supports_vtime() { return false; } 1383 bool os::enable_vtime() { return false; } 1384 bool os::vtime_enabled() { return false; } 1385 double os::elapsedVTime() { 1386 // better than nothing, but not much 1387 return elapsedTime(); 1388 } 1389 1390 jlong os::javaTimeMillis() { 1391 timeval time; 1392 int status = gettimeofday(&time, NULL); 1393 assert(status != -1, "linux error"); 1394 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1395 } 1396 1397 #ifndef CLOCK_MONOTONIC 1398 #define CLOCK_MONOTONIC (1) 1399 #endif 1400 1401 void os::Linux::clock_init() { 1402 // we do dlopen's in this particular order due to bug in linux 1403 // dynamical loader (see 6348968) leading to crash on exit 1404 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1405 if (handle == NULL) { 1406 handle = dlopen("librt.so", RTLD_LAZY); 1407 } 1408 1409 if (handle) { 1410 int (*clock_getres_func)(clockid_t, struct timespec*) = 1411 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1412 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1413 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1414 if (clock_getres_func && clock_gettime_func) { 1415 // See if monotonic clock is supported by the kernel. Note that some 1416 // early implementations simply return kernel jiffies (updated every 1417 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1418 // for nano time (though the monotonic property is still nice to have). 1419 // It's fixed in newer kernels, however clock_getres() still returns 1420 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1421 // resolution for now. Hopefully as people move to new kernels, this 1422 // won't be a problem. 1423 struct timespec res; 1424 struct timespec tp; 1425 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1426 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1427 // yes, monotonic clock is supported 1428 _clock_gettime = clock_gettime_func; 1429 } else { 1430 // close librt if there is no monotonic clock 1431 dlclose(handle); 1432 } 1433 } 1434 } 1435 } 1436 1437 #ifndef SYS_clock_getres 1438 1439 #if defined(IA32) || defined(AMD64) 1440 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1441 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1442 #else 1443 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1444 #define sys_clock_getres(x,y) -1 1445 #endif 1446 1447 #else 1448 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1449 #endif 1450 1451 void os::Linux::fast_thread_clock_init() { 1452 if (!UseLinuxPosixThreadCPUClocks) { 1453 return; 1454 } 1455 clockid_t clockid; 1456 struct timespec tp; 1457 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1458 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1459 1460 // Switch to using fast clocks for thread cpu time if 1461 // the sys_clock_getres() returns 0 error code. 1462 // Note, that some kernels may support the current thread 1463 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1464 // returned by the pthread_getcpuclockid(). 1465 // If the fast Posix clocks are supported then the sys_clock_getres() 1466 // must return at least tp.tv_sec == 0 which means a resolution 1467 // better than 1 sec. This is extra check for reliability. 1468 1469 if(pthread_getcpuclockid_func && 1470 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1471 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1472 1473 _supports_fast_thread_cpu_time = true; 1474 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1475 } 1476 } 1477 1478 jlong os::javaTimeNanos() { 1479 if (Linux::supports_monotonic_clock()) { 1480 struct timespec tp; 1481 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1482 assert(status == 0, "gettime error"); 1483 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1484 return result; 1485 } else { 1486 timeval time; 1487 int status = gettimeofday(&time, NULL); 1488 assert(status != -1, "linux error"); 1489 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1490 return 1000 * usecs; 1491 } 1492 } 1493 1494 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1495 if (Linux::supports_monotonic_clock()) { 1496 info_ptr->max_value = ALL_64_BITS; 1497 1498 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1499 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1500 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1501 } else { 1502 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1503 info_ptr->max_value = ALL_64_BITS; 1504 1505 // gettimeofday is a real time clock so it skips 1506 info_ptr->may_skip_backward = true; 1507 info_ptr->may_skip_forward = true; 1508 } 1509 1510 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1511 } 1512 1513 // Return the real, user, and system times in seconds from an 1514 // arbitrary fixed point in the past. 1515 bool os::getTimesSecs(double* process_real_time, 1516 double* process_user_time, 1517 double* process_system_time) { 1518 struct tms ticks; 1519 clock_t real_ticks = times(&ticks); 1520 1521 if (real_ticks == (clock_t) (-1)) { 1522 return false; 1523 } else { 1524 double ticks_per_second = (double) clock_tics_per_sec; 1525 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1526 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1527 *process_real_time = ((double) real_ticks) / ticks_per_second; 1528 1529 return true; 1530 } 1531 } 1532 1533 1534 char * os::local_time_string(char *buf, size_t buflen) { 1535 struct tm t; 1536 time_t long_time; 1537 time(&long_time); 1538 localtime_r(&long_time, &t); 1539 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1540 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1541 t.tm_hour, t.tm_min, t.tm_sec); 1542 return buf; 1543 } 1544 1545 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1546 return localtime_r(clock, res); 1547 } 1548 1549 //////////////////////////////////////////////////////////////////////////////// 1550 // runtime exit support 1551 1552 // Note: os::shutdown() might be called very early during initialization, or 1553 // called from signal handler. Before adding something to os::shutdown(), make 1554 // sure it is async-safe and can handle partially initialized VM. 1555 void os::shutdown() { 1556 1557 // allow PerfMemory to attempt cleanup of any persistent resources 1558 perfMemory_exit(); 1559 1560 // needs to remove object in file system 1561 AttachListener::abort(); 1562 1563 // flush buffered output, finish log files 1564 ostream_abort(); 1565 1566 // Check for abort hook 1567 abort_hook_t abort_hook = Arguments::abort_hook(); 1568 if (abort_hook != NULL) { 1569 abort_hook(); 1570 } 1571 1572 } 1573 1574 // Note: os::abort() might be called very early during initialization, or 1575 // called from signal handler. Before adding something to os::abort(), make 1576 // sure it is async-safe and can handle partially initialized VM. 1577 void os::abort(bool dump_core) { 1578 os::shutdown(); 1579 if (dump_core) { 1580 #ifndef PRODUCT 1581 fdStream out(defaultStream::output_fd()); 1582 out.print_raw("Current thread is "); 1583 char buf[16]; 1584 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1585 out.print_raw_cr(buf); 1586 out.print_raw_cr("Dumping core ..."); 1587 #endif 1588 ::abort(); // dump core 1589 } 1590 1591 ::exit(1); 1592 } 1593 1594 // Die immediately, no exit hook, no abort hook, no cleanup. 1595 void os::die() { 1596 // _exit() on LinuxThreads only kills current thread 1597 ::abort(); 1598 } 1599 1600 // unused on linux for now. 1601 void os::set_error_file(const char *logfile) {} 1602 1603 1604 // This method is a copy of JDK's sysGetLastErrorString 1605 // from src/solaris/hpi/src/system_md.c 1606 1607 size_t os::lasterror(char *buf, size_t len) { 1608 1609 if (errno == 0) return 0; 1610 1611 const char *s = ::strerror(errno); 1612 size_t n = ::strlen(s); 1613 if (n >= len) { 1614 n = len - 1; 1615 } 1616 ::strncpy(buf, s, n); 1617 buf[n] = '\0'; 1618 return n; 1619 } 1620 1621 intx os::current_thread_id() { return (intx)pthread_self(); } 1622 int os::current_process_id() { 1623 1624 // Under the old linux thread library, linux gives each thread 1625 // its own process id. Because of this each thread will return 1626 // a different pid if this method were to return the result 1627 // of getpid(2). Linux provides no api that returns the pid 1628 // of the launcher thread for the vm. This implementation 1629 // returns a unique pid, the pid of the launcher thread 1630 // that starts the vm 'process'. 1631 1632 // Under the NPTL, getpid() returns the same pid as the 1633 // launcher thread rather than a unique pid per thread. 1634 // Use gettid() if you want the old pre NPTL behaviour. 1635 1636 // if you are looking for the result of a call to getpid() that 1637 // returns a unique pid for the calling thread, then look at the 1638 // OSThread::thread_id() method in osThread_linux.hpp file 1639 1640 return (int)(_initial_pid ? _initial_pid : getpid()); 1641 } 1642 1643 // DLL functions 1644 1645 const char* os::dll_file_extension() { return ".so"; } 1646 1647 // This must be hard coded because it's the system's temporary 1648 // directory not the java application's temp directory, ala java.io.tmpdir. 1649 const char* os::get_temp_directory() { return "/tmp"; } 1650 1651 static bool file_exists(const char* filename) { 1652 struct stat statbuf; 1653 if (filename == NULL || strlen(filename) == 0) { 1654 return false; 1655 } 1656 return os::stat(filename, &statbuf) == 0; 1657 } 1658 1659 void os::dll_build_name(char* buffer, size_t buflen, 1660 const char* pname, const char* fname) { 1661 // Copied from libhpi 1662 const size_t pnamelen = pname ? strlen(pname) : 0; 1663 1664 // Quietly truncate on buffer overflow. Should be an error. 1665 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1666 *buffer = '\0'; 1667 return; 1668 } 1669 1670 if (pnamelen == 0) { 1671 snprintf(buffer, buflen, "lib%s.so", fname); 1672 } else if (strchr(pname, *os::path_separator()) != NULL) { 1673 int n; 1674 char** pelements = split_path(pname, &n); 1675 for (int i = 0 ; i < n ; i++) { 1676 // Really shouldn't be NULL, but check can't hurt 1677 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1678 continue; // skip the empty path values 1679 } 1680 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1681 if (file_exists(buffer)) { 1682 break; 1683 } 1684 } 1685 // release the storage 1686 for (int i = 0 ; i < n ; i++) { 1687 if (pelements[i] != NULL) { 1688 FREE_C_HEAP_ARRAY(char, pelements[i]); 1689 } 1690 } 1691 if (pelements != NULL) { 1692 FREE_C_HEAP_ARRAY(char*, pelements); 1693 } 1694 } else { 1695 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1696 } 1697 } 1698 1699 const char* os::get_current_directory(char *buf, int buflen) { 1700 return getcwd(buf, buflen); 1701 } 1702 1703 // check if addr is inside libjvm[_g].so 1704 bool os::address_is_in_vm(address addr) { 1705 static address libjvm_base_addr; 1706 Dl_info dlinfo; 1707 1708 if (libjvm_base_addr == NULL) { 1709 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1710 libjvm_base_addr = (address)dlinfo.dli_fbase; 1711 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1712 } 1713 1714 if (dladdr((void *)addr, &dlinfo)) { 1715 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1716 } 1717 1718 return false; 1719 } 1720 1721 bool os::dll_address_to_function_name(address addr, char *buf, 1722 int buflen, int *offset) { 1723 Dl_info dlinfo; 1724 1725 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1726 if (buf != NULL) { 1727 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1728 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1729 } 1730 } 1731 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1732 return true; 1733 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1734 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1735 buf, buflen, offset, dlinfo.dli_fname)) { 1736 return true; 1737 } 1738 } 1739 1740 if (buf != NULL) buf[0] = '\0'; 1741 if (offset != NULL) *offset = -1; 1742 return false; 1743 } 1744 1745 struct _address_to_library_name { 1746 address addr; // input : memory address 1747 size_t buflen; // size of fname 1748 char* fname; // output: library name 1749 address base; // library base addr 1750 }; 1751 1752 static int address_to_library_name_callback(struct dl_phdr_info *info, 1753 size_t size, void *data) { 1754 int i; 1755 bool found = false; 1756 address libbase = NULL; 1757 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1758 1759 // iterate through all loadable segments 1760 for (i = 0; i < info->dlpi_phnum; i++) { 1761 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1762 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1763 // base address of a library is the lowest address of its loaded 1764 // segments. 1765 if (libbase == NULL || libbase > segbase) { 1766 libbase = segbase; 1767 } 1768 // see if 'addr' is within current segment 1769 if (segbase <= d->addr && 1770 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1771 found = true; 1772 } 1773 } 1774 } 1775 1776 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1777 // so dll_address_to_library_name() can fall through to use dladdr() which 1778 // can figure out executable name from argv[0]. 1779 if (found && info->dlpi_name && info->dlpi_name[0]) { 1780 d->base = libbase; 1781 if (d->fname) { 1782 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1783 } 1784 return 1; 1785 } 1786 return 0; 1787 } 1788 1789 bool os::dll_address_to_library_name(address addr, char* buf, 1790 int buflen, int* offset) { 1791 Dl_info dlinfo; 1792 struct _address_to_library_name data; 1793 1794 // There is a bug in old glibc dladdr() implementation that it could resolve 1795 // to wrong library name if the .so file has a base address != NULL. Here 1796 // we iterate through the program headers of all loaded libraries to find 1797 // out which library 'addr' really belongs to. This workaround can be 1798 // removed once the minimum requirement for glibc is moved to 2.3.x. 1799 data.addr = addr; 1800 data.fname = buf; 1801 data.buflen = buflen; 1802 data.base = NULL; 1803 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1804 1805 if (rslt) { 1806 // buf already contains library name 1807 if (offset) *offset = addr - data.base; 1808 return true; 1809 } else if (dladdr((void*)addr, &dlinfo)){ 1810 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1811 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1812 return true; 1813 } else { 1814 if (buf) buf[0] = '\0'; 1815 if (offset) *offset = -1; 1816 return false; 1817 } 1818 } 1819 1820 // Loads .dll/.so and 1821 // in case of error it checks if .dll/.so was built for the 1822 // same architecture as Hotspot is running on 1823 1824 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1825 { 1826 void * result= ::dlopen(filename, RTLD_LAZY); 1827 if (result != NULL) { 1828 // Successful loading 1829 return result; 1830 } 1831 1832 Elf32_Ehdr elf_head; 1833 1834 // Read system error message into ebuf 1835 // It may or may not be overwritten below 1836 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1837 ebuf[ebuflen-1]='\0'; 1838 int diag_msg_max_length=ebuflen-strlen(ebuf); 1839 char* diag_msg_buf=ebuf+strlen(ebuf); 1840 1841 if (diag_msg_max_length==0) { 1842 // No more space in ebuf for additional diagnostics message 1843 return NULL; 1844 } 1845 1846 1847 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1848 1849 if (file_descriptor < 0) { 1850 // Can't open library, report dlerror() message 1851 return NULL; 1852 } 1853 1854 bool failed_to_read_elf_head= 1855 (sizeof(elf_head)!= 1856 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1857 1858 ::close(file_descriptor); 1859 if (failed_to_read_elf_head) { 1860 // file i/o error - report dlerror() msg 1861 return NULL; 1862 } 1863 1864 typedef struct { 1865 Elf32_Half code; // Actual value as defined in elf.h 1866 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1867 char elf_class; // 32 or 64 bit 1868 char endianess; // MSB or LSB 1869 char* name; // String representation 1870 } arch_t; 1871 1872 #ifndef EM_486 1873 #define EM_486 6 /* Intel 80486 */ 1874 #endif 1875 1876 static const arch_t arch_array[]={ 1877 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1878 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1879 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1880 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1881 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1882 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1883 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1884 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1885 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1886 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1887 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1888 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1889 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1890 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1891 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1892 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1893 }; 1894 1895 #if (defined IA32) 1896 static Elf32_Half running_arch_code=EM_386; 1897 #elif (defined AMD64) 1898 static Elf32_Half running_arch_code=EM_X86_64; 1899 #elif (defined IA64) 1900 static Elf32_Half running_arch_code=EM_IA_64; 1901 #elif (defined __sparc) && (defined _LP64) 1902 static Elf32_Half running_arch_code=EM_SPARCV9; 1903 #elif (defined __sparc) && (!defined _LP64) 1904 static Elf32_Half running_arch_code=EM_SPARC; 1905 #elif (defined __powerpc64__) 1906 static Elf32_Half running_arch_code=EM_PPC64; 1907 #elif (defined __powerpc__) 1908 static Elf32_Half running_arch_code=EM_PPC; 1909 #elif (defined ARM) 1910 static Elf32_Half running_arch_code=EM_ARM; 1911 #elif (defined S390) 1912 static Elf32_Half running_arch_code=EM_S390; 1913 #elif (defined ALPHA) 1914 static Elf32_Half running_arch_code=EM_ALPHA; 1915 #elif (defined MIPSEL) 1916 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1917 #elif (defined PARISC) 1918 static Elf32_Half running_arch_code=EM_PARISC; 1919 #elif (defined MIPS) 1920 static Elf32_Half running_arch_code=EM_MIPS; 1921 #elif (defined M68K) 1922 static Elf32_Half running_arch_code=EM_68K; 1923 #else 1924 #error Method os::dll_load requires that one of following is defined:\ 1925 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1926 #endif 1927 1928 // Identify compatability class for VM's architecture and library's architecture 1929 // Obtain string descriptions for architectures 1930 1931 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1932 int running_arch_index=-1; 1933 1934 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1935 if (running_arch_code == arch_array[i].code) { 1936 running_arch_index = i; 1937 } 1938 if (lib_arch.code == arch_array[i].code) { 1939 lib_arch.compat_class = arch_array[i].compat_class; 1940 lib_arch.name = arch_array[i].name; 1941 } 1942 } 1943 1944 assert(running_arch_index != -1, 1945 "Didn't find running architecture code (running_arch_code) in arch_array"); 1946 if (running_arch_index == -1) { 1947 // Even though running architecture detection failed 1948 // we may still continue with reporting dlerror() message 1949 return NULL; 1950 } 1951 1952 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1954 return NULL; 1955 } 1956 1957 #ifndef S390 1958 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1960 return NULL; 1961 } 1962 #endif // !S390 1963 1964 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1965 if ( lib_arch.name!=NULL ) { 1966 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1967 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1968 lib_arch.name, arch_array[running_arch_index].name); 1969 } else { 1970 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1971 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1972 lib_arch.code, 1973 arch_array[running_arch_index].name); 1974 } 1975 } 1976 1977 return NULL; 1978 } 1979 1980 /* 1981 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1982 * chances are you might want to run the generated bits against glibc-2.0 1983 * libdl.so, so always use locking for any version of glibc. 1984 */ 1985 void* os::dll_lookup(void* handle, const char* name) { 1986 pthread_mutex_lock(&dl_mutex); 1987 void* res = dlsym(handle, name); 1988 pthread_mutex_unlock(&dl_mutex); 1989 return res; 1990 } 1991 1992 1993 static bool _print_ascii_file(const char* filename, outputStream* st) { 1994 int fd = ::open(filename, O_RDONLY); 1995 if (fd == -1) { 1996 return false; 1997 } 1998 1999 char buf[32]; 2000 int bytes; 2001 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 2002 st->print_raw(buf, bytes); 2003 } 2004 2005 ::close(fd); 2006 2007 return true; 2008 } 2009 2010 void os::print_dll_info(outputStream *st) { 2011 st->print_cr("Dynamic libraries:"); 2012 2013 char fname[32]; 2014 pid_t pid = os::Linux::gettid(); 2015 2016 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2017 2018 if (!_print_ascii_file(fname, st)) { 2019 st->print("Can not get library information for pid = %d\n", pid); 2020 } 2021 } 2022 2023 2024 void os::print_os_info(outputStream* st) { 2025 st->print("OS:"); 2026 2027 // Try to identify popular distros. 2028 // Most Linux distributions have /etc/XXX-release file, which contains 2029 // the OS version string. Some have more than one /etc/XXX-release file 2030 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 2031 // so the order is important. 2032 if (!_print_ascii_file("/etc/mandrake-release", st) && 2033 !_print_ascii_file("/etc/sun-release", st) && 2034 !_print_ascii_file("/etc/redhat-release", st) && 2035 !_print_ascii_file("/etc/SuSE-release", st) && 2036 !_print_ascii_file("/etc/turbolinux-release", st) && 2037 !_print_ascii_file("/etc/gentoo-release", st) && 2038 !_print_ascii_file("/etc/debian_version", st) && 2039 !_print_ascii_file("/etc/ltib-release", st) && 2040 !_print_ascii_file("/etc/angstrom-version", st)) { 2041 st->print("Linux"); 2042 } 2043 st->cr(); 2044 2045 // kernel 2046 st->print("uname:"); 2047 struct utsname name; 2048 uname(&name); 2049 st->print(name.sysname); st->print(" "); 2050 st->print(name.release); st->print(" "); 2051 st->print(name.version); st->print(" "); 2052 st->print(name.machine); 2053 st->cr(); 2054 2055 // Print warning if unsafe chroot environment detected 2056 if (unsafe_chroot_detected) { 2057 st->print("WARNING!! "); 2058 st->print_cr(unstable_chroot_error); 2059 } 2060 2061 // libc, pthread 2062 st->print("libc:"); 2063 st->print(os::Linux::glibc_version()); st->print(" "); 2064 st->print(os::Linux::libpthread_version()); st->print(" "); 2065 if (os::Linux::is_LinuxThreads()) { 2066 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2067 } 2068 st->cr(); 2069 2070 // rlimit 2071 st->print("rlimit:"); 2072 struct rlimit rlim; 2073 2074 st->print(" STACK "); 2075 getrlimit(RLIMIT_STACK, &rlim); 2076 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2077 else st->print("%uk", rlim.rlim_cur >> 10); 2078 2079 st->print(", CORE "); 2080 getrlimit(RLIMIT_CORE, &rlim); 2081 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2082 else st->print("%uk", rlim.rlim_cur >> 10); 2083 2084 st->print(", NPROC "); 2085 getrlimit(RLIMIT_NPROC, &rlim); 2086 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2087 else st->print("%d", rlim.rlim_cur); 2088 2089 st->print(", NOFILE "); 2090 getrlimit(RLIMIT_NOFILE, &rlim); 2091 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2092 else st->print("%d", rlim.rlim_cur); 2093 2094 st->print(", AS "); 2095 getrlimit(RLIMIT_AS, &rlim); 2096 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2097 else st->print("%uk", rlim.rlim_cur >> 10); 2098 st->cr(); 2099 2100 // load average 2101 st->print("load average:"); 2102 double loadavg[3]; 2103 os::loadavg(loadavg, 3); 2104 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 2105 st->cr(); 2106 2107 // meminfo 2108 st->print("\n/proc/meminfo:\n"); 2109 _print_ascii_file("/proc/meminfo", st); 2110 st->cr(); 2111 } 2112 2113 void os::pd_print_cpu_info(outputStream* st) { 2114 st->print("\n/proc/cpuinfo:\n"); 2115 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2116 st->print(" <Not Available>"); 2117 } 2118 st->cr(); 2119 } 2120 2121 void os::print_memory_info(outputStream* st) { 2122 2123 st->print("Memory:"); 2124 st->print(" %dk page", os::vm_page_size()>>10); 2125 2126 // values in struct sysinfo are "unsigned long" 2127 struct sysinfo si; 2128 sysinfo(&si); 2129 2130 st->print(", physical " UINT64_FORMAT "k", 2131 os::physical_memory() >> 10); 2132 st->print("(" UINT64_FORMAT "k free)", 2133 os::available_memory() >> 10); 2134 st->print(", swap " UINT64_FORMAT "k", 2135 ((jlong)si.totalswap * si.mem_unit) >> 10); 2136 st->print("(" UINT64_FORMAT "k free)", 2137 ((jlong)si.freeswap * si.mem_unit) >> 10); 2138 st->cr(); 2139 } 2140 2141 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2142 // but they're the same for all the linux arch that we support 2143 // and they're the same for solaris but there's no common place to put this. 2144 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2145 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2146 "ILL_COPROC", "ILL_BADSTK" }; 2147 2148 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2149 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2150 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2151 2152 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2153 2154 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2155 2156 void os::print_siginfo(outputStream* st, void* siginfo) { 2157 st->print("siginfo:"); 2158 2159 const int buflen = 100; 2160 char buf[buflen]; 2161 siginfo_t *si = (siginfo_t*)siginfo; 2162 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2163 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2164 st->print("si_errno=%s", buf); 2165 } else { 2166 st->print("si_errno=%d", si->si_errno); 2167 } 2168 const int c = si->si_code; 2169 assert(c > 0, "unexpected si_code"); 2170 switch (si->si_signo) { 2171 case SIGILL: 2172 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2173 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2174 break; 2175 case SIGFPE: 2176 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2177 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2178 break; 2179 case SIGSEGV: 2180 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2181 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2182 break; 2183 case SIGBUS: 2184 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2185 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2186 break; 2187 default: 2188 st->print(", si_code=%d", si->si_code); 2189 // no si_addr 2190 } 2191 2192 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2193 UseSharedSpaces) { 2194 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2195 if (mapinfo->is_in_shared_space(si->si_addr)) { 2196 st->print("\n\nError accessing class data sharing archive." \ 2197 " Mapped file inaccessible during execution, " \ 2198 " possible disk/network problem."); 2199 } 2200 } 2201 st->cr(); 2202 } 2203 2204 2205 static void print_signal_handler(outputStream* st, int sig, 2206 char* buf, size_t buflen); 2207 2208 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2209 st->print_cr("Signal Handlers:"); 2210 print_signal_handler(st, SIGSEGV, buf, buflen); 2211 print_signal_handler(st, SIGBUS , buf, buflen); 2212 print_signal_handler(st, SIGFPE , buf, buflen); 2213 print_signal_handler(st, SIGPIPE, buf, buflen); 2214 print_signal_handler(st, SIGXFSZ, buf, buflen); 2215 print_signal_handler(st, SIGILL , buf, buflen); 2216 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2217 print_signal_handler(st, SR_signum, buf, buflen); 2218 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2219 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2220 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2221 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2222 } 2223 2224 static char saved_jvm_path[MAXPATHLEN] = {0}; 2225 2226 // Find the full path to the current module, libjvm.so or libjvm_g.so 2227 void os::jvm_path(char *buf, jint buflen) { 2228 // Error checking. 2229 if (buflen < MAXPATHLEN) { 2230 assert(false, "must use a large-enough buffer"); 2231 buf[0] = '\0'; 2232 return; 2233 } 2234 // Lazy resolve the path to current module. 2235 if (saved_jvm_path[0] != 0) { 2236 strcpy(buf, saved_jvm_path); 2237 return; 2238 } 2239 2240 char dli_fname[MAXPATHLEN]; 2241 bool ret = dll_address_to_library_name( 2242 CAST_FROM_FN_PTR(address, os::jvm_path), 2243 dli_fname, sizeof(dli_fname), NULL); 2244 assert(ret != 0, "cannot locate libjvm"); 2245 char *rp = realpath(dli_fname, buf); 2246 if (rp == NULL) 2247 return; 2248 2249 if (Arguments::created_by_gamma_launcher()) { 2250 // Support for the gamma launcher. Typical value for buf is 2251 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2252 // the right place in the string, then assume we are installed in a JDK and 2253 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2254 // up the path so it looks like libjvm.so is installed there (append a 2255 // fake suffix hotspot/libjvm.so). 2256 const char *p = buf + strlen(buf) - 1; 2257 for (int count = 0; p > buf && count < 5; ++count) { 2258 for (--p; p > buf && *p != '/'; --p) 2259 /* empty */ ; 2260 } 2261 2262 if (strncmp(p, "/jre/lib/", 9) != 0) { 2263 // Look for JAVA_HOME in the environment. 2264 char* java_home_var = ::getenv("JAVA_HOME"); 2265 if (java_home_var != NULL && java_home_var[0] != 0) { 2266 char* jrelib_p; 2267 int len; 2268 2269 // Check the current module name "libjvm.so" or "libjvm_g.so". 2270 p = strrchr(buf, '/'); 2271 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2272 p = strstr(p, "_g") ? "_g" : ""; 2273 2274 rp = realpath(java_home_var, buf); 2275 if (rp == NULL) 2276 return; 2277 2278 // determine if this is a legacy image or modules image 2279 // modules image doesn't have "jre" subdirectory 2280 len = strlen(buf); 2281 jrelib_p = buf + len; 2282 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2283 if (0 != access(buf, F_OK)) { 2284 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2285 } 2286 2287 if (0 == access(buf, F_OK)) { 2288 // Use current module name "libjvm[_g].so" instead of 2289 // "libjvm"debug_only("_g")".so" since for fastdebug version 2290 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2291 len = strlen(buf); 2292 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p); 2293 } else { 2294 // Go back to path of .so 2295 rp = realpath(dli_fname, buf); 2296 if (rp == NULL) 2297 return; 2298 } 2299 } 2300 } 2301 } 2302 2303 strcpy(saved_jvm_path, buf); 2304 } 2305 2306 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2307 // no prefix required, not even "_" 2308 } 2309 2310 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2311 // no suffix required 2312 } 2313 2314 //////////////////////////////////////////////////////////////////////////////// 2315 // sun.misc.Signal support 2316 2317 static volatile jint sigint_count = 0; 2318 2319 static void 2320 UserHandler(int sig, void *siginfo, void *context) { 2321 // 4511530 - sem_post is serialized and handled by the manager thread. When 2322 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2323 // don't want to flood the manager thread with sem_post requests. 2324 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2325 return; 2326 2327 // Ctrl-C is pressed during error reporting, likely because the error 2328 // handler fails to abort. Let VM die immediately. 2329 if (sig == SIGINT && is_error_reported()) { 2330 os::die(); 2331 } 2332 2333 os::signal_notify(sig); 2334 } 2335 2336 void* os::user_handler() { 2337 return CAST_FROM_FN_PTR(void*, UserHandler); 2338 } 2339 2340 extern "C" { 2341 typedef void (*sa_handler_t)(int); 2342 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2343 } 2344 2345 void* os::signal(int signal_number, void* handler) { 2346 struct sigaction sigAct, oldSigAct; 2347 2348 sigfillset(&(sigAct.sa_mask)); 2349 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2350 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2351 2352 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2353 // -1 means registration failed 2354 return (void *)-1; 2355 } 2356 2357 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2358 } 2359 2360 void os::signal_raise(int signal_number) { 2361 ::raise(signal_number); 2362 } 2363 2364 /* 2365 * The following code is moved from os.cpp for making this 2366 * code platform specific, which it is by its very nature. 2367 */ 2368 2369 // Will be modified when max signal is changed to be dynamic 2370 int os::sigexitnum_pd() { 2371 return NSIG; 2372 } 2373 2374 // a counter for each possible signal value 2375 static volatile jint pending_signals[NSIG+1] = { 0 }; 2376 2377 // Linux(POSIX) specific hand shaking semaphore. 2378 static sem_t sig_sem; 2379 2380 void os::signal_init_pd() { 2381 // Initialize signal structures 2382 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2383 2384 // Initialize signal semaphore 2385 ::sem_init(&sig_sem, 0, 0); 2386 } 2387 2388 void os::signal_notify(int sig) { 2389 Atomic::inc(&pending_signals[sig]); 2390 ::sem_post(&sig_sem); 2391 } 2392 2393 static int check_pending_signals(bool wait) { 2394 Atomic::store(0, &sigint_count); 2395 for (;;) { 2396 for (int i = 0; i < NSIG + 1; i++) { 2397 jint n = pending_signals[i]; 2398 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2399 return i; 2400 } 2401 } 2402 if (!wait) { 2403 return -1; 2404 } 2405 JavaThread *thread = JavaThread::current(); 2406 ThreadBlockInVM tbivm(thread); 2407 2408 bool threadIsSuspended; 2409 do { 2410 thread->set_suspend_equivalent(); 2411 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2412 ::sem_wait(&sig_sem); 2413 2414 // were we externally suspended while we were waiting? 2415 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2416 if (threadIsSuspended) { 2417 // 2418 // The semaphore has been incremented, but while we were waiting 2419 // another thread suspended us. We don't want to continue running 2420 // while suspended because that would surprise the thread that 2421 // suspended us. 2422 // 2423 ::sem_post(&sig_sem); 2424 2425 thread->java_suspend_self(); 2426 } 2427 } while (threadIsSuspended); 2428 } 2429 } 2430 2431 int os::signal_lookup() { 2432 return check_pending_signals(false); 2433 } 2434 2435 int os::signal_wait() { 2436 return check_pending_signals(true); 2437 } 2438 2439 //////////////////////////////////////////////////////////////////////////////// 2440 // Virtual Memory 2441 2442 int os::vm_page_size() { 2443 // Seems redundant as all get out 2444 assert(os::Linux::page_size() != -1, "must call os::init"); 2445 return os::Linux::page_size(); 2446 } 2447 2448 // Solaris allocates memory by pages. 2449 int os::vm_allocation_granularity() { 2450 assert(os::Linux::page_size() != -1, "must call os::init"); 2451 return os::Linux::page_size(); 2452 } 2453 2454 // Rationale behind this function: 2455 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2456 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2457 // samples for JITted code. Here we create private executable mapping over the code cache 2458 // and then we can use standard (well, almost, as mapping can change) way to provide 2459 // info for the reporting script by storing timestamp and location of symbol 2460 void linux_wrap_code(char* base, size_t size) { 2461 static volatile jint cnt = 0; 2462 2463 if (!UseOprofile) { 2464 return; 2465 } 2466 2467 char buf[PATH_MAX+1]; 2468 int num = Atomic::add(1, &cnt); 2469 2470 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2471 os::get_temp_directory(), os::current_process_id(), num); 2472 unlink(buf); 2473 2474 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2475 2476 if (fd != -1) { 2477 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2478 if (rv != (off_t)-1) { 2479 if (::write(fd, "", 1) == 1) { 2480 mmap(base, size, 2481 PROT_READ|PROT_WRITE|PROT_EXEC, 2482 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2483 } 2484 } 2485 ::close(fd); 2486 unlink(buf); 2487 } 2488 } 2489 2490 // NOTE: Linux kernel does not really reserve the pages for us. 2491 // All it does is to check if there are enough free pages 2492 // left at the time of mmap(). This could be a potential 2493 // problem. 2494 bool os::commit_memory(char* addr, size_t size, bool exec) { 2495 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2496 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2497 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2498 if (res != (uintptr_t) MAP_FAILED) { 2499 if (UseNUMAInterleaving) { 2500 numa_make_global(addr, size); 2501 } 2502 return true; 2503 } 2504 return false; 2505 } 2506 2507 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2508 #ifndef MAP_HUGETLB 2509 #define MAP_HUGETLB 0x40000 2510 #endif 2511 2512 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2513 #ifndef MADV_HUGEPAGE 2514 #define MADV_HUGEPAGE 14 2515 #endif 2516 2517 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2518 bool exec) { 2519 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2520 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2521 uintptr_t res = 2522 (uintptr_t) ::mmap(addr, size, prot, 2523 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB, 2524 -1, 0); 2525 if (res != (uintptr_t) MAP_FAILED) { 2526 if (UseNUMAInterleaving) { 2527 numa_make_global(addr, size); 2528 } 2529 return true; 2530 } 2531 // Fall through and try to use small pages 2532 } 2533 2534 if (commit_memory(addr, size, exec)) { 2535 realign_memory(addr, size, alignment_hint); 2536 return true; 2537 } 2538 return false; 2539 } 2540 2541 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2542 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2543 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2544 // be supported or the memory may already be backed by huge pages. 2545 ::madvise(addr, bytes, MADV_HUGEPAGE); 2546 } 2547 } 2548 2549 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2550 commit_memory(addr, bytes, alignment_hint, false); 2551 } 2552 2553 void os::numa_make_global(char *addr, size_t bytes) { 2554 Linux::numa_interleave_memory(addr, bytes); 2555 } 2556 2557 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2558 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2559 } 2560 2561 bool os::numa_topology_changed() { return false; } 2562 2563 size_t os::numa_get_groups_num() { 2564 int max_node = Linux::numa_max_node(); 2565 return max_node > 0 ? max_node + 1 : 1; 2566 } 2567 2568 int os::numa_get_group_id() { 2569 int cpu_id = Linux::sched_getcpu(); 2570 if (cpu_id != -1) { 2571 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2572 if (lgrp_id != -1) { 2573 return lgrp_id; 2574 } 2575 } 2576 return 0; 2577 } 2578 2579 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2580 for (size_t i = 0; i < size; i++) { 2581 ids[i] = i; 2582 } 2583 return size; 2584 } 2585 2586 bool os::get_page_info(char *start, page_info* info) { 2587 return false; 2588 } 2589 2590 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2591 return end; 2592 } 2593 2594 2595 int os::Linux::sched_getcpu_syscall(void) { 2596 unsigned int cpu; 2597 int retval = -1; 2598 2599 #if defined(IA32) 2600 # ifndef SYS_getcpu 2601 # define SYS_getcpu 318 2602 # endif 2603 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2604 #elif defined(AMD64) 2605 // Unfortunately we have to bring all these macros here from vsyscall.h 2606 // to be able to compile on old linuxes. 2607 # define __NR_vgetcpu 2 2608 # define VSYSCALL_START (-10UL << 20) 2609 # define VSYSCALL_SIZE 1024 2610 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2611 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2612 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2613 retval = vgetcpu(&cpu, NULL, NULL); 2614 #endif 2615 2616 return (retval == -1) ? retval : cpu; 2617 } 2618 2619 // Something to do with the numa-aware allocator needs these symbols 2620 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2621 extern "C" JNIEXPORT void numa_error(char *where) { } 2622 extern "C" JNIEXPORT int fork1() { return fork(); } 2623 2624 2625 // If we are running with libnuma version > 2, then we should 2626 // be trying to use symbols with versions 1.1 2627 // If we are running with earlier version, which did not have symbol versions, 2628 // we should use the base version. 2629 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2630 void *f = dlvsym(handle, name, "libnuma_1.1"); 2631 if (f == NULL) { 2632 f = dlsym(handle, name); 2633 } 2634 return f; 2635 } 2636 2637 bool os::Linux::libnuma_init() { 2638 // sched_getcpu() should be in libc. 2639 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2640 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2641 2642 // If it's not, try a direct syscall. 2643 if (sched_getcpu() == -1) 2644 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall)); 2645 2646 if (sched_getcpu() != -1) { // Does it work? 2647 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2648 if (handle != NULL) { 2649 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2650 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2651 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2652 libnuma_dlsym(handle, "numa_max_node"))); 2653 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2654 libnuma_dlsym(handle, "numa_available"))); 2655 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2656 libnuma_dlsym(handle, "numa_tonode_memory"))); 2657 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2658 libnuma_dlsym(handle, "numa_interleave_memory"))); 2659 2660 2661 if (numa_available() != -1) { 2662 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2663 // Create a cpu -> node mapping 2664 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2665 rebuild_cpu_to_node_map(); 2666 return true; 2667 } 2668 } 2669 } 2670 return false; 2671 } 2672 2673 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2674 // The table is later used in get_node_by_cpu(). 2675 void os::Linux::rebuild_cpu_to_node_map() { 2676 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2677 // in libnuma (possible values are starting from 16, 2678 // and continuing up with every other power of 2, but less 2679 // than the maximum number of CPUs supported by kernel), and 2680 // is a subject to change (in libnuma version 2 the requirements 2681 // are more reasonable) we'll just hardcode the number they use 2682 // in the library. 2683 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2684 2685 size_t cpu_num = os::active_processor_count(); 2686 size_t cpu_map_size = NCPUS / BitsPerCLong; 2687 size_t cpu_map_valid_size = 2688 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2689 2690 cpu_to_node()->clear(); 2691 cpu_to_node()->at_grow(cpu_num - 1); 2692 size_t node_num = numa_get_groups_num(); 2693 2694 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2695 for (size_t i = 0; i < node_num; i++) { 2696 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2697 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2698 if (cpu_map[j] != 0) { 2699 for (size_t k = 0; k < BitsPerCLong; k++) { 2700 if (cpu_map[j] & (1UL << k)) { 2701 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2702 } 2703 } 2704 } 2705 } 2706 } 2707 } 2708 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2709 } 2710 2711 int os::Linux::get_node_by_cpu(int cpu_id) { 2712 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2713 return cpu_to_node()->at(cpu_id); 2714 } 2715 return -1; 2716 } 2717 2718 GrowableArray<int>* os::Linux::_cpu_to_node; 2719 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2720 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2721 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2722 os::Linux::numa_available_func_t os::Linux::_numa_available; 2723 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2724 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2725 unsigned long* os::Linux::_numa_all_nodes; 2726 2727 bool os::uncommit_memory(char* addr, size_t size) { 2728 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2729 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2730 return res != (uintptr_t) MAP_FAILED; 2731 } 2732 2733 // Linux uses a growable mapping for the stack, and if the mapping for 2734 // the stack guard pages is not removed when we detach a thread the 2735 // stack cannot grow beyond the pages where the stack guard was 2736 // mapped. If at some point later in the process the stack expands to 2737 // that point, the Linux kernel cannot expand the stack any further 2738 // because the guard pages are in the way, and a segfault occurs. 2739 // 2740 // However, it's essential not to split the stack region by unmapping 2741 // a region (leaving a hole) that's already part of the stack mapping, 2742 // so if the stack mapping has already grown beyond the guard pages at 2743 // the time we create them, we have to truncate the stack mapping. 2744 // So, we need to know the extent of the stack mapping when 2745 // create_stack_guard_pages() is called. 2746 2747 // Find the bounds of the stack mapping. Return true for success. 2748 // 2749 // We only need this for stacks that are growable: at the time of 2750 // writing thread stacks don't use growable mappings (i.e. those 2751 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2752 // only applies to the main thread. 2753 2754 static 2755 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) { 2756 2757 char buf[128]; 2758 int fd, sz; 2759 2760 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) { 2761 return false; 2762 } 2763 2764 const char kw[] = "[stack]"; 2765 const int kwlen = sizeof(kw)-1; 2766 2767 // Address part of /proc/self/maps couldn't be more than 128 bytes 2768 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) { 2769 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) { 2770 // Extract addresses 2771 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2772 uintptr_t sp = (uintptr_t) __builtin_frame_address(0); 2773 if (sp >= *bottom && sp <= *top) { 2774 ::close(fd); 2775 return true; 2776 } 2777 } 2778 } 2779 } 2780 2781 ::close(fd); 2782 return false; 2783 } 2784 2785 2786 // If the (growable) stack mapping already extends beyond the point 2787 // where we're going to put our guard pages, truncate the mapping at 2788 // that point by munmap()ping it. This ensures that when we later 2789 // munmap() the guard pages we don't leave a hole in the stack 2790 // mapping. This only affects the main/initial thread, but guard 2791 // against future OS changes 2792 bool os::create_stack_guard_pages(char* addr, size_t size) { 2793 uintptr_t stack_extent, stack_base; 2794 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2795 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2796 assert(os::Linux::is_initial_thread(), 2797 "growable stack in non-initial thread"); 2798 if (stack_extent < (uintptr_t)addr) 2799 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2800 } 2801 2802 return os::commit_memory(addr, size); 2803 } 2804 2805 // If this is a growable mapping, remove the guard pages entirely by 2806 // munmap()ping them. If not, just call uncommit_memory(). This only 2807 // affects the main/initial thread, but guard against future OS changes 2808 bool os::remove_stack_guard_pages(char* addr, size_t size) { 2809 uintptr_t stack_extent, stack_base; 2810 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2811 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2812 assert(os::Linux::is_initial_thread(), 2813 "growable stack in non-initial thread"); 2814 2815 return ::munmap(addr, size) == 0; 2816 } 2817 2818 return os::uncommit_memory(addr, size); 2819 } 2820 2821 static address _highest_vm_reserved_address = NULL; 2822 2823 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2824 // at 'requested_addr'. If there are existing memory mappings at the same 2825 // location, however, they will be overwritten. If 'fixed' is false, 2826 // 'requested_addr' is only treated as a hint, the return value may or 2827 // may not start from the requested address. Unlike Linux mmap(), this 2828 // function returns NULL to indicate failure. 2829 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2830 char * addr; 2831 int flags; 2832 2833 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2834 if (fixed) { 2835 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2836 flags |= MAP_FIXED; 2837 } 2838 2839 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2840 // to PROT_EXEC if executable when we commit the page. 2841 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2842 flags, -1, 0); 2843 2844 if (addr != MAP_FAILED) { 2845 // anon_mmap() should only get called during VM initialization, 2846 // don't need lock (actually we can skip locking even it can be called 2847 // from multiple threads, because _highest_vm_reserved_address is just a 2848 // hint about the upper limit of non-stack memory regions.) 2849 if ((address)addr + bytes > _highest_vm_reserved_address) { 2850 _highest_vm_reserved_address = (address)addr + bytes; 2851 } 2852 } 2853 2854 return addr == MAP_FAILED ? NULL : addr; 2855 } 2856 2857 // Don't update _highest_vm_reserved_address, because there might be memory 2858 // regions above addr + size. If so, releasing a memory region only creates 2859 // a hole in the address space, it doesn't help prevent heap-stack collision. 2860 // 2861 static int anon_munmap(char * addr, size_t size) { 2862 return ::munmap(addr, size) == 0; 2863 } 2864 2865 char* os::reserve_memory(size_t bytes, char* requested_addr, 2866 size_t alignment_hint) { 2867 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2868 } 2869 2870 bool os::release_memory(char* addr, size_t size) { 2871 return anon_munmap(addr, size); 2872 } 2873 2874 static address highest_vm_reserved_address() { 2875 return _highest_vm_reserved_address; 2876 } 2877 2878 static bool linux_mprotect(char* addr, size_t size, int prot) { 2879 // Linux wants the mprotect address argument to be page aligned. 2880 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2881 2882 // According to SUSv3, mprotect() should only be used with mappings 2883 // established by mmap(), and mmap() always maps whole pages. Unaligned 2884 // 'addr' likely indicates problem in the VM (e.g. trying to change 2885 // protection of malloc'ed or statically allocated memory). Check the 2886 // caller if you hit this assert. 2887 assert(addr == bottom, "sanity check"); 2888 2889 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2890 return ::mprotect(bottom, size, prot) == 0; 2891 } 2892 2893 // Set protections specified 2894 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2895 bool is_committed) { 2896 unsigned int p = 0; 2897 switch (prot) { 2898 case MEM_PROT_NONE: p = PROT_NONE; break; 2899 case MEM_PROT_READ: p = PROT_READ; break; 2900 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2901 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2902 default: 2903 ShouldNotReachHere(); 2904 } 2905 // is_committed is unused. 2906 return linux_mprotect(addr, bytes, p); 2907 } 2908 2909 bool os::guard_memory(char* addr, size_t size) { 2910 return linux_mprotect(addr, size, PROT_NONE); 2911 } 2912 2913 bool os::unguard_memory(char* addr, size_t size) { 2914 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2915 } 2916 2917 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 2918 bool result = false; 2919 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE, 2920 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 2921 -1, 0); 2922 2923 if (p != (void *) -1) { 2924 // We don't know if this really is a huge page or not. 2925 FILE *fp = fopen("/proc/self/maps", "r"); 2926 if (fp) { 2927 while (!feof(fp)) { 2928 char chars[257]; 2929 long x = 0; 2930 if (fgets(chars, sizeof(chars), fp)) { 2931 if (sscanf(chars, "%lx-%*x", &x) == 1 2932 && x == (long)p) { 2933 if (strstr (chars, "hugepage")) { 2934 result = true; 2935 break; 2936 } 2937 } 2938 } 2939 } 2940 fclose(fp); 2941 } 2942 munmap (p, page_size); 2943 if (result) 2944 return true; 2945 } 2946 2947 if (warn) { 2948 warning("HugeTLBFS is not supported by the operating system."); 2949 } 2950 2951 return result; 2952 } 2953 2954 /* 2955 * Set the coredump_filter bits to include largepages in core dump (bit 6) 2956 * 2957 * From the coredump_filter documentation: 2958 * 2959 * - (bit 0) anonymous private memory 2960 * - (bit 1) anonymous shared memory 2961 * - (bit 2) file-backed private memory 2962 * - (bit 3) file-backed shared memory 2963 * - (bit 4) ELF header pages in file-backed private memory areas (it is 2964 * effective only if the bit 2 is cleared) 2965 * - (bit 5) hugetlb private memory 2966 * - (bit 6) hugetlb shared memory 2967 */ 2968 static void set_coredump_filter(void) { 2969 FILE *f; 2970 long cdm; 2971 2972 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 2973 return; 2974 } 2975 2976 if (fscanf(f, "%lx", &cdm) != 1) { 2977 fclose(f); 2978 return; 2979 } 2980 2981 rewind(f); 2982 2983 if ((cdm & LARGEPAGES_BIT) == 0) { 2984 cdm |= LARGEPAGES_BIT; 2985 fprintf(f, "%#lx", cdm); 2986 } 2987 2988 fclose(f); 2989 } 2990 2991 // Large page support 2992 2993 static size_t _large_page_size = 0; 2994 2995 void os::large_page_init() { 2996 if (!UseLargePages) { 2997 UseHugeTLBFS = false; 2998 UseSHM = false; 2999 return; 3000 } 3001 3002 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) { 3003 // If UseLargePages is specified on the command line try both methods, 3004 // if it's default, then try only HugeTLBFS. 3005 if (FLAG_IS_DEFAULT(UseLargePages)) { 3006 UseHugeTLBFS = true; 3007 } else { 3008 UseHugeTLBFS = UseSHM = true; 3009 } 3010 } 3011 3012 if (LargePageSizeInBytes) { 3013 _large_page_size = LargePageSizeInBytes; 3014 } else { 3015 // large_page_size on Linux is used to round up heap size. x86 uses either 3016 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3017 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3018 // page as large as 256M. 3019 // 3020 // Here we try to figure out page size by parsing /proc/meminfo and looking 3021 // for a line with the following format: 3022 // Hugepagesize: 2048 kB 3023 // 3024 // If we can't determine the value (e.g. /proc is not mounted, or the text 3025 // format has been changed), we'll use the largest page size supported by 3026 // the processor. 3027 3028 #ifndef ZERO 3029 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3030 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 3031 #endif // ZERO 3032 3033 FILE *fp = fopen("/proc/meminfo", "r"); 3034 if (fp) { 3035 while (!feof(fp)) { 3036 int x = 0; 3037 char buf[16]; 3038 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3039 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3040 _large_page_size = x * K; 3041 break; 3042 } 3043 } else { 3044 // skip to next line 3045 for (;;) { 3046 int ch = fgetc(fp); 3047 if (ch == EOF || ch == (int)'\n') break; 3048 } 3049 } 3050 } 3051 fclose(fp); 3052 } 3053 } 3054 3055 // print a warning if any large page related flag is specified on command line 3056 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3057 3058 const size_t default_page_size = (size_t)Linux::page_size(); 3059 if (_large_page_size > default_page_size) { 3060 _page_sizes[0] = _large_page_size; 3061 _page_sizes[1] = default_page_size; 3062 _page_sizes[2] = 0; 3063 } 3064 UseHugeTLBFS = UseHugeTLBFS && 3065 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size); 3066 3067 if (UseHugeTLBFS) 3068 UseSHM = false; 3069 3070 UseLargePages = UseHugeTLBFS || UseSHM; 3071 3072 set_coredump_filter(); 3073 } 3074 3075 #ifndef SHM_HUGETLB 3076 #define SHM_HUGETLB 04000 3077 #endif 3078 3079 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 3080 // "exec" is passed in but not used. Creating the shared image for 3081 // the code cache doesn't have an SHM_X executable permission to check. 3082 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3083 3084 key_t key = IPC_PRIVATE; 3085 char *addr; 3086 3087 bool warn_on_failure = UseLargePages && 3088 (!FLAG_IS_DEFAULT(UseLargePages) || 3089 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 3090 ); 3091 char msg[128]; 3092 3093 // Create a large shared memory region to attach to based on size. 3094 // Currently, size is the total size of the heap 3095 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3096 if (shmid == -1) { 3097 // Possible reasons for shmget failure: 3098 // 1. shmmax is too small for Java heap. 3099 // > check shmmax value: cat /proc/sys/kernel/shmmax 3100 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3101 // 2. not enough large page memory. 3102 // > check available large pages: cat /proc/meminfo 3103 // > increase amount of large pages: 3104 // echo new_value > /proc/sys/vm/nr_hugepages 3105 // Note 1: different Linux may use different name for this property, 3106 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3107 // Note 2: it's possible there's enough physical memory available but 3108 // they are so fragmented after a long run that they can't 3109 // coalesce into large pages. Try to reserve large pages when 3110 // the system is still "fresh". 3111 if (warn_on_failure) { 3112 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3113 warning(msg); 3114 } 3115 return NULL; 3116 } 3117 3118 // attach to the region 3119 addr = (char*)shmat(shmid, req_addr, 0); 3120 int err = errno; 3121 3122 // Remove shmid. If shmat() is successful, the actual shared memory segment 3123 // will be deleted when it's detached by shmdt() or when the process 3124 // terminates. If shmat() is not successful this will remove the shared 3125 // segment immediately. 3126 shmctl(shmid, IPC_RMID, NULL); 3127 3128 if ((intptr_t)addr == -1) { 3129 if (warn_on_failure) { 3130 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3131 warning(msg); 3132 } 3133 return NULL; 3134 } 3135 3136 if ((addr != NULL) && UseNUMAInterleaving) { 3137 numa_make_global(addr, bytes); 3138 } 3139 3140 return addr; 3141 } 3142 3143 bool os::release_memory_special(char* base, size_t bytes) { 3144 // detaching the SHM segment will also delete it, see reserve_memory_special() 3145 int rslt = shmdt(base); 3146 return rslt == 0; 3147 } 3148 3149 size_t os::large_page_size() { 3150 return _large_page_size; 3151 } 3152 3153 // HugeTLBFS allows application to commit large page memory on demand; 3154 // with SysV SHM the entire memory region must be allocated as shared 3155 // memory. 3156 bool os::can_commit_large_page_memory() { 3157 return UseHugeTLBFS; 3158 } 3159 3160 bool os::can_execute_large_page_memory() { 3161 return UseHugeTLBFS; 3162 } 3163 3164 // Reserve memory at an arbitrary address, only if that area is 3165 // available (and not reserved for something else). 3166 3167 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3168 const int max_tries = 10; 3169 char* base[max_tries]; 3170 size_t size[max_tries]; 3171 const size_t gap = 0x000000; 3172 3173 // Assert only that the size is a multiple of the page size, since 3174 // that's all that mmap requires, and since that's all we really know 3175 // about at this low abstraction level. If we need higher alignment, 3176 // we can either pass an alignment to this method or verify alignment 3177 // in one of the methods further up the call chain. See bug 5044738. 3178 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3179 3180 // Repeatedly allocate blocks until the block is allocated at the 3181 // right spot. Give up after max_tries. Note that reserve_memory() will 3182 // automatically update _highest_vm_reserved_address if the call is 3183 // successful. The variable tracks the highest memory address every reserved 3184 // by JVM. It is used to detect heap-stack collision if running with 3185 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3186 // space than needed, it could confuse the collision detecting code. To 3187 // solve the problem, save current _highest_vm_reserved_address and 3188 // calculate the correct value before return. 3189 address old_highest = _highest_vm_reserved_address; 3190 3191 // Linux mmap allows caller to pass an address as hint; give it a try first, 3192 // if kernel honors the hint then we can return immediately. 3193 char * addr = anon_mmap(requested_addr, bytes, false); 3194 if (addr == requested_addr) { 3195 return requested_addr; 3196 } 3197 3198 if (addr != NULL) { 3199 // mmap() is successful but it fails to reserve at the requested address 3200 anon_munmap(addr, bytes); 3201 } 3202 3203 int i; 3204 for (i = 0; i < max_tries; ++i) { 3205 base[i] = reserve_memory(bytes); 3206 3207 if (base[i] != NULL) { 3208 // Is this the block we wanted? 3209 if (base[i] == requested_addr) { 3210 size[i] = bytes; 3211 break; 3212 } 3213 3214 // Does this overlap the block we wanted? Give back the overlapped 3215 // parts and try again. 3216 3217 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3218 if (top_overlap >= 0 && top_overlap < bytes) { 3219 unmap_memory(base[i], top_overlap); 3220 base[i] += top_overlap; 3221 size[i] = bytes - top_overlap; 3222 } else { 3223 size_t bottom_overlap = base[i] + bytes - requested_addr; 3224 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3225 unmap_memory(requested_addr, bottom_overlap); 3226 size[i] = bytes - bottom_overlap; 3227 } else { 3228 size[i] = bytes; 3229 } 3230 } 3231 } 3232 } 3233 3234 // Give back the unused reserved pieces. 3235 3236 for (int j = 0; j < i; ++j) { 3237 if (base[j] != NULL) { 3238 unmap_memory(base[j], size[j]); 3239 } 3240 } 3241 3242 if (i < max_tries) { 3243 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3244 return requested_addr; 3245 } else { 3246 _highest_vm_reserved_address = old_highest; 3247 return NULL; 3248 } 3249 } 3250 3251 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3252 return ::read(fd, buf, nBytes); 3253 } 3254 3255 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3256 // Solaris uses poll(), linux uses park(). 3257 // Poll() is likely a better choice, assuming that Thread.interrupt() 3258 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3259 // SIGSEGV, see 4355769. 3260 3261 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3262 assert(thread == Thread::current(), "thread consistency check"); 3263 3264 ParkEvent * const slp = thread->_SleepEvent ; 3265 slp->reset() ; 3266 OrderAccess::fence() ; 3267 3268 if (interruptible) { 3269 jlong prevtime = javaTimeNanos(); 3270 3271 for (;;) { 3272 if (os::is_interrupted(thread, true)) { 3273 return OS_INTRPT; 3274 } 3275 3276 jlong newtime = javaTimeNanos(); 3277 3278 if (newtime - prevtime < 0) { 3279 // time moving backwards, should only happen if no monotonic clock 3280 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3281 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3282 } else { 3283 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3284 } 3285 3286 if(millis <= 0) { 3287 return OS_OK; 3288 } 3289 3290 prevtime = newtime; 3291 3292 { 3293 assert(thread->is_Java_thread(), "sanity check"); 3294 JavaThread *jt = (JavaThread *) thread; 3295 ThreadBlockInVM tbivm(jt); 3296 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3297 3298 jt->set_suspend_equivalent(); 3299 // cleared by handle_special_suspend_equivalent_condition() or 3300 // java_suspend_self() via check_and_wait_while_suspended() 3301 3302 slp->park(millis); 3303 3304 // were we externally suspended while we were waiting? 3305 jt->check_and_wait_while_suspended(); 3306 } 3307 } 3308 } else { 3309 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3310 jlong prevtime = javaTimeNanos(); 3311 3312 for (;;) { 3313 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3314 // the 1st iteration ... 3315 jlong newtime = javaTimeNanos(); 3316 3317 if (newtime - prevtime < 0) { 3318 // time moving backwards, should only happen if no monotonic clock 3319 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3320 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3321 } else { 3322 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3323 } 3324 3325 if(millis <= 0) break ; 3326 3327 prevtime = newtime; 3328 slp->park(millis); 3329 } 3330 return OS_OK ; 3331 } 3332 } 3333 3334 int os::naked_sleep() { 3335 // %% make the sleep time an integer flag. for now use 1 millisec. 3336 return os::sleep(Thread::current(), 1, false); 3337 } 3338 3339 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3340 void os::infinite_sleep() { 3341 while (true) { // sleep forever ... 3342 ::sleep(100); // ... 100 seconds at a time 3343 } 3344 } 3345 3346 // Used to convert frequent JVM_Yield() to nops 3347 bool os::dont_yield() { 3348 return DontYieldALot; 3349 } 3350 3351 void os::yield() { 3352 sched_yield(); 3353 } 3354 3355 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3356 3357 void os::yield_all(int attempts) { 3358 // Yields to all threads, including threads with lower priorities 3359 // Threads on Linux are all with same priority. The Solaris style 3360 // os::yield_all() with nanosleep(1ms) is not necessary. 3361 sched_yield(); 3362 } 3363 3364 // Called from the tight loops to possibly influence time-sharing heuristics 3365 void os::loop_breaker(int attempts) { 3366 os::yield_all(attempts); 3367 } 3368 3369 //////////////////////////////////////////////////////////////////////////////// 3370 // thread priority support 3371 3372 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3373 // only supports dynamic priority, static priority must be zero. For real-time 3374 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3375 // However, for large multi-threaded applications, SCHED_RR is not only slower 3376 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3377 // of 5 runs - Sep 2005). 3378 // 3379 // The following code actually changes the niceness of kernel-thread/LWP. It 3380 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3381 // not the entire user process, and user level threads are 1:1 mapped to kernel 3382 // threads. It has always been the case, but could change in the future. For 3383 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3384 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3385 3386 int os::java_to_os_priority[CriticalPriority + 1] = { 3387 19, // 0 Entry should never be used 3388 3389 4, // 1 MinPriority 3390 3, // 2 3391 2, // 3 3392 3393 1, // 4 3394 0, // 5 NormPriority 3395 -1, // 6 3396 3397 -2, // 7 3398 -3, // 8 3399 -4, // 9 NearMaxPriority 3400 3401 -5, // 10 MaxPriority 3402 3403 -5 // 11 CriticalPriority 3404 }; 3405 3406 static int prio_init() { 3407 if (ThreadPriorityPolicy == 1) { 3408 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3409 // if effective uid is not root. Perhaps, a more elegant way of doing 3410 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3411 if (geteuid() != 0) { 3412 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3413 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3414 } 3415 ThreadPriorityPolicy = 0; 3416 } 3417 } 3418 return 0; 3419 } 3420 3421 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3422 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3423 3424 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3425 return (ret == 0) ? OS_OK : OS_ERR; 3426 } 3427 3428 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3429 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3430 *priority_ptr = java_to_os_priority[NormPriority]; 3431 return OS_OK; 3432 } 3433 3434 errno = 0; 3435 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3436 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3437 } 3438 3439 // Hint to the underlying OS that a task switch would not be good. 3440 // Void return because it's a hint and can fail. 3441 void os::hint_no_preempt() {} 3442 3443 //////////////////////////////////////////////////////////////////////////////// 3444 // suspend/resume support 3445 3446 // the low-level signal-based suspend/resume support is a remnant from the 3447 // old VM-suspension that used to be for java-suspension, safepoints etc, 3448 // within hotspot. Now there is a single use-case for this: 3449 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3450 // that runs in the watcher thread. 3451 // The remaining code is greatly simplified from the more general suspension 3452 // code that used to be used. 3453 // 3454 // The protocol is quite simple: 3455 // - suspend: 3456 // - sends a signal to the target thread 3457 // - polls the suspend state of the osthread using a yield loop 3458 // - target thread signal handler (SR_handler) sets suspend state 3459 // and blocks in sigsuspend until continued 3460 // - resume: 3461 // - sets target osthread state to continue 3462 // - sends signal to end the sigsuspend loop in the SR_handler 3463 // 3464 // Note that the SR_lock plays no role in this suspend/resume protocol. 3465 // 3466 3467 static void resume_clear_context(OSThread *osthread) { 3468 osthread->set_ucontext(NULL); 3469 osthread->set_siginfo(NULL); 3470 3471 // notify the suspend action is completed, we have now resumed 3472 osthread->sr.clear_suspended(); 3473 } 3474 3475 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3476 osthread->set_ucontext(context); 3477 osthread->set_siginfo(siginfo); 3478 } 3479 3480 // 3481 // Handler function invoked when a thread's execution is suspended or 3482 // resumed. We have to be careful that only async-safe functions are 3483 // called here (Note: most pthread functions are not async safe and 3484 // should be avoided.) 3485 // 3486 // Note: sigwait() is a more natural fit than sigsuspend() from an 3487 // interface point of view, but sigwait() prevents the signal hander 3488 // from being run. libpthread would get very confused by not having 3489 // its signal handlers run and prevents sigwait()'s use with the 3490 // mutex granting granting signal. 3491 // 3492 // Currently only ever called on the VMThread 3493 // 3494 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3495 // Save and restore errno to avoid confusing native code with EINTR 3496 // after sigsuspend. 3497 int old_errno = errno; 3498 3499 Thread* thread = Thread::current(); 3500 OSThread* osthread = thread->osthread(); 3501 assert(thread->is_VM_thread(), "Must be VMThread"); 3502 // read current suspend action 3503 int action = osthread->sr.suspend_action(); 3504 if (action == SR_SUSPEND) { 3505 suspend_save_context(osthread, siginfo, context); 3506 3507 // Notify the suspend action is about to be completed. do_suspend() 3508 // waits until SR_SUSPENDED is set and then returns. We will wait 3509 // here for a resume signal and that completes the suspend-other 3510 // action. do_suspend/do_resume is always called as a pair from 3511 // the same thread - so there are no races 3512 3513 // notify the caller 3514 osthread->sr.set_suspended(); 3515 3516 sigset_t suspend_set; // signals for sigsuspend() 3517 3518 // get current set of blocked signals and unblock resume signal 3519 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3520 sigdelset(&suspend_set, SR_signum); 3521 3522 // wait here until we are resumed 3523 do { 3524 sigsuspend(&suspend_set); 3525 // ignore all returns until we get a resume signal 3526 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3527 3528 resume_clear_context(osthread); 3529 3530 } else { 3531 assert(action == SR_CONTINUE, "unexpected sr action"); 3532 // nothing special to do - just leave the handler 3533 } 3534 3535 errno = old_errno; 3536 } 3537 3538 3539 static int SR_initialize() { 3540 struct sigaction act; 3541 char *s; 3542 /* Get signal number to use for suspend/resume */ 3543 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3544 int sig = ::strtol(s, 0, 10); 3545 if (sig > 0 || sig < _NSIG) { 3546 SR_signum = sig; 3547 } 3548 } 3549 3550 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3551 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3552 3553 sigemptyset(&SR_sigset); 3554 sigaddset(&SR_sigset, SR_signum); 3555 3556 /* Set up signal handler for suspend/resume */ 3557 act.sa_flags = SA_RESTART|SA_SIGINFO; 3558 act.sa_handler = (void (*)(int)) SR_handler; 3559 3560 // SR_signum is blocked by default. 3561 // 4528190 - We also need to block pthread restart signal (32 on all 3562 // supported Linux platforms). Note that LinuxThreads need to block 3563 // this signal for all threads to work properly. So we don't have 3564 // to use hard-coded signal number when setting up the mask. 3565 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3566 3567 if (sigaction(SR_signum, &act, 0) == -1) { 3568 return -1; 3569 } 3570 3571 // Save signal flag 3572 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3573 return 0; 3574 } 3575 3576 static int SR_finalize() { 3577 return 0; 3578 } 3579 3580 3581 // returns true on success and false on error - really an error is fatal 3582 // but this seems the normal response to library errors 3583 static bool do_suspend(OSThread* osthread) { 3584 // mark as suspended and send signal 3585 osthread->sr.set_suspend_action(SR_SUSPEND); 3586 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3587 assert_status(status == 0, status, "pthread_kill"); 3588 3589 // check status and wait until notified of suspension 3590 if (status == 0) { 3591 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3592 os::yield_all(i); 3593 } 3594 osthread->sr.set_suspend_action(SR_NONE); 3595 return true; 3596 } 3597 else { 3598 osthread->sr.set_suspend_action(SR_NONE); 3599 return false; 3600 } 3601 } 3602 3603 static void do_resume(OSThread* osthread) { 3604 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3605 osthread->sr.set_suspend_action(SR_CONTINUE); 3606 3607 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3608 assert_status(status == 0, status, "pthread_kill"); 3609 // check status and wait unit notified of resumption 3610 if (status == 0) { 3611 for (int i = 0; osthread->sr.is_suspended(); i++) { 3612 os::yield_all(i); 3613 } 3614 } 3615 osthread->sr.set_suspend_action(SR_NONE); 3616 } 3617 3618 //////////////////////////////////////////////////////////////////////////////// 3619 // interrupt support 3620 3621 void os::interrupt(Thread* thread) { 3622 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3623 "possibility of dangling Thread pointer"); 3624 3625 OSThread* osthread = thread->osthread(); 3626 3627 if (!osthread->interrupted()) { 3628 osthread->set_interrupted(true); 3629 // More than one thread can get here with the same value of osthread, 3630 // resulting in multiple notifications. We do, however, want the store 3631 // to interrupted() to be visible to other threads before we execute unpark(). 3632 OrderAccess::fence(); 3633 ParkEvent * const slp = thread->_SleepEvent ; 3634 if (slp != NULL) slp->unpark() ; 3635 } 3636 3637 // For JSR166. Unpark even if interrupt status already was set 3638 if (thread->is_Java_thread()) 3639 ((JavaThread*)thread)->parker()->unpark(); 3640 3641 ParkEvent * ev = thread->_ParkEvent ; 3642 if (ev != NULL) ev->unpark() ; 3643 3644 } 3645 3646 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3647 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3648 "possibility of dangling Thread pointer"); 3649 3650 OSThread* osthread = thread->osthread(); 3651 3652 bool interrupted = osthread->interrupted(); 3653 3654 if (interrupted && clear_interrupted) { 3655 osthread->set_interrupted(false); 3656 // consider thread->_SleepEvent->reset() ... optional optimization 3657 } 3658 3659 return interrupted; 3660 } 3661 3662 /////////////////////////////////////////////////////////////////////////////////// 3663 // signal handling (except suspend/resume) 3664 3665 // This routine may be used by user applications as a "hook" to catch signals. 3666 // The user-defined signal handler must pass unrecognized signals to this 3667 // routine, and if it returns true (non-zero), then the signal handler must 3668 // return immediately. If the flag "abort_if_unrecognized" is true, then this 3669 // routine will never retun false (zero), but instead will execute a VM panic 3670 // routine kill the process. 3671 // 3672 // If this routine returns false, it is OK to call it again. This allows 3673 // the user-defined signal handler to perform checks either before or after 3674 // the VM performs its own checks. Naturally, the user code would be making 3675 // a serious error if it tried to handle an exception (such as a null check 3676 // or breakpoint) that the VM was generating for its own correct operation. 3677 // 3678 // This routine may recognize any of the following kinds of signals: 3679 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3680 // It should be consulted by handlers for any of those signals. 3681 // 3682 // The caller of this routine must pass in the three arguments supplied 3683 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 3684 // field of the structure passed to sigaction(). This routine assumes that 3685 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3686 // 3687 // Note that the VM will print warnings if it detects conflicting signal 3688 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3689 // 3690 extern "C" JNIEXPORT int 3691 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3692 void* ucontext, int abort_if_unrecognized); 3693 3694 void signalHandler(int sig, siginfo_t* info, void* uc) { 3695 assert(info != NULL && uc != NULL, "it must be old kernel"); 3696 JVM_handle_linux_signal(sig, info, uc, true); 3697 } 3698 3699 3700 // This boolean allows users to forward their own non-matching signals 3701 // to JVM_handle_linux_signal, harmlessly. 3702 bool os::Linux::signal_handlers_are_installed = false; 3703 3704 // For signal-chaining 3705 struct sigaction os::Linux::sigact[MAXSIGNUM]; 3706 unsigned int os::Linux::sigs = 0; 3707 bool os::Linux::libjsig_is_loaded = false; 3708 typedef struct sigaction *(*get_signal_t)(int); 3709 get_signal_t os::Linux::get_signal_action = NULL; 3710 3711 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3712 struct sigaction *actp = NULL; 3713 3714 if (libjsig_is_loaded) { 3715 // Retrieve the old signal handler from libjsig 3716 actp = (*get_signal_action)(sig); 3717 } 3718 if (actp == NULL) { 3719 // Retrieve the preinstalled signal handler from jvm 3720 actp = get_preinstalled_handler(sig); 3721 } 3722 3723 return actp; 3724 } 3725 3726 static bool call_chained_handler(struct sigaction *actp, int sig, 3727 siginfo_t *siginfo, void *context) { 3728 // Call the old signal handler 3729 if (actp->sa_handler == SIG_DFL) { 3730 // It's more reasonable to let jvm treat it as an unexpected exception 3731 // instead of taking the default action. 3732 return false; 3733 } else if (actp->sa_handler != SIG_IGN) { 3734 if ((actp->sa_flags & SA_NODEFER) == 0) { 3735 // automaticlly block the signal 3736 sigaddset(&(actp->sa_mask), sig); 3737 } 3738 3739 sa_handler_t hand; 3740 sa_sigaction_t sa; 3741 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3742 // retrieve the chained handler 3743 if (siginfo_flag_set) { 3744 sa = actp->sa_sigaction; 3745 } else { 3746 hand = actp->sa_handler; 3747 } 3748 3749 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3750 actp->sa_handler = SIG_DFL; 3751 } 3752 3753 // try to honor the signal mask 3754 sigset_t oset; 3755 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3756 3757 // call into the chained handler 3758 if (siginfo_flag_set) { 3759 (*sa)(sig, siginfo, context); 3760 } else { 3761 (*hand)(sig); 3762 } 3763 3764 // restore the signal mask 3765 pthread_sigmask(SIG_SETMASK, &oset, 0); 3766 } 3767 // Tell jvm's signal handler the signal is taken care of. 3768 return true; 3769 } 3770 3771 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3772 bool chained = false; 3773 // signal-chaining 3774 if (UseSignalChaining) { 3775 struct sigaction *actp = get_chained_signal_action(sig); 3776 if (actp != NULL) { 3777 chained = call_chained_handler(actp, sig, siginfo, context); 3778 } 3779 } 3780 return chained; 3781 } 3782 3783 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3784 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3785 return &sigact[sig]; 3786 } 3787 return NULL; 3788 } 3789 3790 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3791 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3792 sigact[sig] = oldAct; 3793 sigs |= (unsigned int)1 << sig; 3794 } 3795 3796 // for diagnostic 3797 int os::Linux::sigflags[MAXSIGNUM]; 3798 3799 int os::Linux::get_our_sigflags(int sig) { 3800 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3801 return sigflags[sig]; 3802 } 3803 3804 void os::Linux::set_our_sigflags(int sig, int flags) { 3805 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3806 sigflags[sig] = flags; 3807 } 3808 3809 void os::Linux::set_signal_handler(int sig, bool set_installed) { 3810 // Check for overwrite. 3811 struct sigaction oldAct; 3812 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3813 3814 void* oldhand = oldAct.sa_sigaction 3815 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3816 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3817 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3818 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3819 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3820 if (AllowUserSignalHandlers || !set_installed) { 3821 // Do not overwrite; user takes responsibility to forward to us. 3822 return; 3823 } else if (UseSignalChaining) { 3824 // save the old handler in jvm 3825 save_preinstalled_handler(sig, oldAct); 3826 // libjsig also interposes the sigaction() call below and saves the 3827 // old sigaction on it own. 3828 } else { 3829 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3830 "%#lx for signal %d.", (long)oldhand, sig)); 3831 } 3832 } 3833 3834 struct sigaction sigAct; 3835 sigfillset(&(sigAct.sa_mask)); 3836 sigAct.sa_handler = SIG_DFL; 3837 if (!set_installed) { 3838 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3839 } else { 3840 sigAct.sa_sigaction = signalHandler; 3841 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3842 } 3843 // Save flags, which are set by ours 3844 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3845 sigflags[sig] = sigAct.sa_flags; 3846 3847 int ret = sigaction(sig, &sigAct, &oldAct); 3848 assert(ret == 0, "check"); 3849 3850 void* oldhand2 = oldAct.sa_sigaction 3851 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3852 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3853 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3854 } 3855 3856 // install signal handlers for signals that HotSpot needs to 3857 // handle in order to support Java-level exception handling. 3858 3859 void os::Linux::install_signal_handlers() { 3860 if (!signal_handlers_are_installed) { 3861 signal_handlers_are_installed = true; 3862 3863 // signal-chaining 3864 typedef void (*signal_setting_t)(); 3865 signal_setting_t begin_signal_setting = NULL; 3866 signal_setting_t end_signal_setting = NULL; 3867 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3868 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3869 if (begin_signal_setting != NULL) { 3870 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3871 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3872 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3873 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3874 libjsig_is_loaded = true; 3875 assert(UseSignalChaining, "should enable signal-chaining"); 3876 } 3877 if (libjsig_is_loaded) { 3878 // Tell libjsig jvm is setting signal handlers 3879 (*begin_signal_setting)(); 3880 } 3881 3882 set_signal_handler(SIGSEGV, true); 3883 set_signal_handler(SIGPIPE, true); 3884 set_signal_handler(SIGBUS, true); 3885 set_signal_handler(SIGILL, true); 3886 set_signal_handler(SIGFPE, true); 3887 set_signal_handler(SIGXFSZ, true); 3888 3889 if (libjsig_is_loaded) { 3890 // Tell libjsig jvm finishes setting signal handlers 3891 (*end_signal_setting)(); 3892 } 3893 3894 // We don't activate signal checker if libjsig is in place, we trust ourselves 3895 // and if UserSignalHandler is installed all bets are off. 3896 // Log that signal checking is off only if -verbose:jni is specified. 3897 if (CheckJNICalls) { 3898 if (libjsig_is_loaded) { 3899 if (PrintJNIResolving) { 3900 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3901 } 3902 check_signals = false; 3903 } 3904 if (AllowUserSignalHandlers) { 3905 if (PrintJNIResolving) { 3906 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3907 } 3908 check_signals = false; 3909 } 3910 } 3911 } 3912 } 3913 3914 // This is the fastest way to get thread cpu time on Linux. 3915 // Returns cpu time (user+sys) for any thread, not only for current. 3916 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 3917 // It might work on 2.6.10+ with a special kernel/glibc patch. 3918 // For reference, please, see IEEE Std 1003.1-2004: 3919 // http://www.unix.org/single_unix_specification 3920 3921 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3922 struct timespec tp; 3923 int rc = os::Linux::clock_gettime(clockid, &tp); 3924 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3925 3926 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 3927 } 3928 3929 ///// 3930 // glibc on Linux platform uses non-documented flag 3931 // to indicate, that some special sort of signal 3932 // trampoline is used. 3933 // We will never set this flag, and we should 3934 // ignore this flag in our diagnostic 3935 #ifdef SIGNIFICANT_SIGNAL_MASK 3936 #undef SIGNIFICANT_SIGNAL_MASK 3937 #endif 3938 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3939 3940 static const char* get_signal_handler_name(address handler, 3941 char* buf, int buflen) { 3942 int offset; 3943 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3944 if (found) { 3945 // skip directory names 3946 const char *p1, *p2; 3947 p1 = buf; 3948 size_t len = strlen(os::file_separator()); 3949 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3950 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3951 } else { 3952 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3953 } 3954 return buf; 3955 } 3956 3957 static void print_signal_handler(outputStream* st, int sig, 3958 char* buf, size_t buflen) { 3959 struct sigaction sa; 3960 3961 sigaction(sig, NULL, &sa); 3962 3963 // See comment for SIGNIFICANT_SIGNAL_MASK define 3964 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3965 3966 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3967 3968 address handler = (sa.sa_flags & SA_SIGINFO) 3969 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3970 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3971 3972 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3973 st->print("SIG_DFL"); 3974 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3975 st->print("SIG_IGN"); 3976 } else { 3977 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3978 } 3979 3980 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3981 3982 address rh = VMError::get_resetted_sighandler(sig); 3983 // May be, handler was resetted by VMError? 3984 if(rh != NULL) { 3985 handler = rh; 3986 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3987 } 3988 3989 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3990 3991 // Check: is it our handler? 3992 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3993 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3994 // It is our signal handler 3995 // check for flags, reset system-used one! 3996 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3997 st->print( 3998 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 3999 os::Linux::get_our_sigflags(sig)); 4000 } 4001 } 4002 st->cr(); 4003 } 4004 4005 4006 #define DO_SIGNAL_CHECK(sig) \ 4007 if (!sigismember(&check_signal_done, sig)) \ 4008 os::Linux::check_signal_handler(sig) 4009 4010 // This method is a periodic task to check for misbehaving JNI applications 4011 // under CheckJNI, we can add any periodic checks here 4012 4013 void os::run_periodic_checks() { 4014 4015 if (check_signals == false) return; 4016 4017 // SEGV and BUS if overridden could potentially prevent 4018 // generation of hs*.log in the event of a crash, debugging 4019 // such a case can be very challenging, so we absolutely 4020 // check the following for a good measure: 4021 DO_SIGNAL_CHECK(SIGSEGV); 4022 DO_SIGNAL_CHECK(SIGILL); 4023 DO_SIGNAL_CHECK(SIGFPE); 4024 DO_SIGNAL_CHECK(SIGBUS); 4025 DO_SIGNAL_CHECK(SIGPIPE); 4026 DO_SIGNAL_CHECK(SIGXFSZ); 4027 4028 4029 // ReduceSignalUsage allows the user to override these handlers 4030 // see comments at the very top and jvm_solaris.h 4031 if (!ReduceSignalUsage) { 4032 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4033 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4034 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4035 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4036 } 4037 4038 DO_SIGNAL_CHECK(SR_signum); 4039 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4040 } 4041 4042 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4043 4044 static os_sigaction_t os_sigaction = NULL; 4045 4046 void os::Linux::check_signal_handler(int sig) { 4047 char buf[O_BUFLEN]; 4048 address jvmHandler = NULL; 4049 4050 4051 struct sigaction act; 4052 if (os_sigaction == NULL) { 4053 // only trust the default sigaction, in case it has been interposed 4054 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4055 if (os_sigaction == NULL) return; 4056 } 4057 4058 os_sigaction(sig, (struct sigaction*)NULL, &act); 4059 4060 4061 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4062 4063 address thisHandler = (act.sa_flags & SA_SIGINFO) 4064 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4065 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 4066 4067 4068 switch(sig) { 4069 case SIGSEGV: 4070 case SIGBUS: 4071 case SIGFPE: 4072 case SIGPIPE: 4073 case SIGILL: 4074 case SIGXFSZ: 4075 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4076 break; 4077 4078 case SHUTDOWN1_SIGNAL: 4079 case SHUTDOWN2_SIGNAL: 4080 case SHUTDOWN3_SIGNAL: 4081 case BREAK_SIGNAL: 4082 jvmHandler = (address)user_handler(); 4083 break; 4084 4085 case INTERRUPT_SIGNAL: 4086 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4087 break; 4088 4089 default: 4090 if (sig == SR_signum) { 4091 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4092 } else { 4093 return; 4094 } 4095 break; 4096 } 4097 4098 if (thisHandler != jvmHandler) { 4099 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4100 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4101 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4102 // No need to check this sig any longer 4103 sigaddset(&check_signal_done, sig); 4104 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4105 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4106 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4107 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4108 // No need to check this sig any longer 4109 sigaddset(&check_signal_done, sig); 4110 } 4111 4112 // Dump all the signal 4113 if (sigismember(&check_signal_done, sig)) { 4114 print_signal_handlers(tty, buf, O_BUFLEN); 4115 } 4116 } 4117 4118 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 4119 4120 extern bool signal_name(int signo, char* buf, size_t len); 4121 4122 const char* os::exception_name(int exception_code, char* buf, size_t size) { 4123 if (0 < exception_code && exception_code <= SIGRTMAX) { 4124 // signal 4125 if (!signal_name(exception_code, buf, size)) { 4126 jio_snprintf(buf, size, "SIG%d", exception_code); 4127 } 4128 return buf; 4129 } else { 4130 return NULL; 4131 } 4132 } 4133 4134 // this is called _before_ the most of global arguments have been parsed 4135 void os::init(void) { 4136 char dummy; /* used to get a guess on initial stack address */ 4137 // first_hrtime = gethrtime(); 4138 4139 // With LinuxThreads the JavaMain thread pid (primordial thread) 4140 // is different than the pid of the java launcher thread. 4141 // So, on Linux, the launcher thread pid is passed to the VM 4142 // via the sun.java.launcher.pid property. 4143 // Use this property instead of getpid() if it was correctly passed. 4144 // See bug 6351349. 4145 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4146 4147 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4148 4149 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4150 4151 init_random(1234567); 4152 4153 ThreadCritical::initialize(); 4154 4155 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4156 if (Linux::page_size() == -1) { 4157 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4158 strerror(errno))); 4159 } 4160 init_page_sizes((size_t) Linux::page_size()); 4161 4162 Linux::initialize_system_info(); 4163 4164 // main_thread points to the aboriginal thread 4165 Linux::_main_thread = pthread_self(); 4166 4167 Linux::clock_init(); 4168 initial_time_count = os::elapsed_counter(); 4169 pthread_mutex_init(&dl_mutex, NULL); 4170 } 4171 4172 // To install functions for atexit system call 4173 extern "C" { 4174 static void perfMemory_exit_helper() { 4175 perfMemory_exit(); 4176 } 4177 } 4178 4179 // this is called _after_ the global arguments have been parsed 4180 jint os::init_2(void) 4181 { 4182 Linux::fast_thread_clock_init(); 4183 4184 // Allocate a single page and mark it as readable for safepoint polling 4185 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4186 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4187 4188 os::set_polling_page( polling_page ); 4189 4190 #ifndef PRODUCT 4191 if(Verbose && PrintMiscellaneous) 4192 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4193 #endif 4194 4195 if (!UseMembar) { 4196 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4197 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 4198 os::set_memory_serialize_page( mem_serialize_page ); 4199 4200 #ifndef PRODUCT 4201 if(Verbose && PrintMiscellaneous) 4202 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4203 #endif 4204 } 4205 4206 os::large_page_init(); 4207 4208 // initialize suspend/resume support - must do this before signal_sets_init() 4209 if (SR_initialize() != 0) { 4210 perror("SR_initialize failed"); 4211 return JNI_ERR; 4212 } 4213 4214 Linux::signal_sets_init(); 4215 Linux::install_signal_handlers(); 4216 4217 // Check minimum allowable stack size for thread creation and to initialize 4218 // the java system classes, including StackOverflowError - depends on page 4219 // size. Add a page for compiler2 recursion in main thread. 4220 // Add in 2*BytesPerWord times page size to account for VM stack during 4221 // class initialization depending on 32 or 64 bit VM. 4222 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4223 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+ 4224 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size()); 4225 4226 size_t threadStackSizeInBytes = ThreadStackSize * K; 4227 if (threadStackSizeInBytes != 0 && 4228 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4229 tty->print_cr("\nThe stack size specified is too small, " 4230 "Specify at least %dk", 4231 os::Linux::min_stack_allowed/ K); 4232 return JNI_ERR; 4233 } 4234 4235 // Make the stack size a multiple of the page size so that 4236 // the yellow/red zones can be guarded. 4237 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4238 vm_page_size())); 4239 4240 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4241 4242 Linux::libpthread_init(); 4243 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4244 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4245 Linux::glibc_version(), Linux::libpthread_version(), 4246 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4247 } 4248 4249 if (UseNUMA) { 4250 if (!Linux::libnuma_init()) { 4251 UseNUMA = false; 4252 } else { 4253 if ((Linux::numa_max_node() < 1)) { 4254 // There's only one node(they start from 0), disable NUMA. 4255 UseNUMA = false; 4256 } 4257 } 4258 // With SHM large pages we cannot uncommit a page, so there's not way 4259 // we can make the adaptive lgrp chunk resizing work. If the user specified 4260 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and 4261 // disable adaptive resizing. 4262 if (UseNUMA && UseLargePages && UseSHM) { 4263 if (!FLAG_IS_DEFAULT(UseNUMA)) { 4264 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) { 4265 UseLargePages = false; 4266 } else { 4267 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing"); 4268 UseAdaptiveSizePolicy = false; 4269 UseAdaptiveNUMAChunkSizing = false; 4270 } 4271 } else { 4272 UseNUMA = false; 4273 } 4274 } 4275 if (!UseNUMA && ForceNUMA) { 4276 UseNUMA = true; 4277 } 4278 } 4279 4280 if (MaxFDLimit) { 4281 // set the number of file descriptors to max. print out error 4282 // if getrlimit/setrlimit fails but continue regardless. 4283 struct rlimit nbr_files; 4284 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4285 if (status != 0) { 4286 if (PrintMiscellaneous && (Verbose || WizardMode)) 4287 perror("os::init_2 getrlimit failed"); 4288 } else { 4289 nbr_files.rlim_cur = nbr_files.rlim_max; 4290 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4291 if (status != 0) { 4292 if (PrintMiscellaneous && (Verbose || WizardMode)) 4293 perror("os::init_2 setrlimit failed"); 4294 } 4295 } 4296 } 4297 4298 // Initialize lock used to serialize thread creation (see os::create_thread) 4299 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4300 4301 // at-exit methods are called in the reverse order of their registration. 4302 // atexit functions are called on return from main or as a result of a 4303 // call to exit(3C). There can be only 32 of these functions registered 4304 // and atexit() does not set errno. 4305 4306 if (PerfAllowAtExitRegistration) { 4307 // only register atexit functions if PerfAllowAtExitRegistration is set. 4308 // atexit functions can be delayed until process exit time, which 4309 // can be problematic for embedded VM situations. Embedded VMs should 4310 // call DestroyJavaVM() to assure that VM resources are released. 4311 4312 // note: perfMemory_exit_helper atexit function may be removed in 4313 // the future if the appropriate cleanup code can be added to the 4314 // VM_Exit VMOperation's doit method. 4315 if (atexit(perfMemory_exit_helper) != 0) { 4316 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4317 } 4318 } 4319 4320 // initialize thread priority policy 4321 prio_init(); 4322 4323 return JNI_OK; 4324 } 4325 4326 // this is called at the end of vm_initialization 4327 void os::init_3(void) 4328 { 4329 #ifdef JAVASE_EMBEDDED 4330 // Start the MemNotifyThread 4331 if (LowMemoryProtection) { 4332 MemNotifyThread::start(); 4333 } 4334 return; 4335 #endif 4336 } 4337 4338 // Mark the polling page as unreadable 4339 void os::make_polling_page_unreadable(void) { 4340 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4341 fatal("Could not disable polling page"); 4342 }; 4343 4344 // Mark the polling page as readable 4345 void os::make_polling_page_readable(void) { 4346 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4347 fatal("Could not enable polling page"); 4348 } 4349 }; 4350 4351 int os::active_processor_count() { 4352 // Linux doesn't yet have a (official) notion of processor sets, 4353 // so just return the number of online processors. 4354 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4355 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4356 return online_cpus; 4357 } 4358 4359 void os::set_native_thread_name(const char *name) { 4360 // Not yet implemented. 4361 return; 4362 } 4363 4364 bool os::distribute_processes(uint length, uint* distribution) { 4365 // Not yet implemented. 4366 return false; 4367 } 4368 4369 bool os::bind_to_processor(uint processor_id) { 4370 // Not yet implemented. 4371 return false; 4372 } 4373 4374 /// 4375 4376 // Suspends the target using the signal mechanism and then grabs the PC before 4377 // resuming the target. Used by the flat-profiler only 4378 ExtendedPC os::get_thread_pc(Thread* thread) { 4379 // Make sure that it is called by the watcher for the VMThread 4380 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4381 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4382 4383 ExtendedPC epc; 4384 4385 OSThread* osthread = thread->osthread(); 4386 if (do_suspend(osthread)) { 4387 if (osthread->ucontext() != NULL) { 4388 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4389 } else { 4390 // NULL context is unexpected, double-check this is the VMThread 4391 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4392 } 4393 do_resume(osthread); 4394 } 4395 // failure means pthread_kill failed for some reason - arguably this is 4396 // a fatal problem, but such problems are ignored elsewhere 4397 4398 return epc; 4399 } 4400 4401 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4402 { 4403 if (is_NPTL()) { 4404 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4405 } else { 4406 #ifndef IA64 4407 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4408 // word back to default 64bit precision if condvar is signaled. Java 4409 // wants 53bit precision. Save and restore current value. 4410 int fpu = get_fpu_control_word(); 4411 #endif // IA64 4412 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4413 #ifndef IA64 4414 set_fpu_control_word(fpu); 4415 #endif // IA64 4416 return status; 4417 } 4418 } 4419 4420 //////////////////////////////////////////////////////////////////////////////// 4421 // debug support 4422 4423 static address same_page(address x, address y) { 4424 int page_bits = -os::vm_page_size(); 4425 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4426 return x; 4427 else if (x > y) 4428 return (address)(intptr_t(y) | ~page_bits) + 1; 4429 else 4430 return (address)(intptr_t(y) & page_bits); 4431 } 4432 4433 bool os::find(address addr, outputStream* st) { 4434 Dl_info dlinfo; 4435 memset(&dlinfo, 0, sizeof(dlinfo)); 4436 if (dladdr(addr, &dlinfo)) { 4437 st->print(PTR_FORMAT ": ", addr); 4438 if (dlinfo.dli_sname != NULL) { 4439 st->print("%s+%#x", dlinfo.dli_sname, 4440 addr - (intptr_t)dlinfo.dli_saddr); 4441 } else if (dlinfo.dli_fname) { 4442 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4443 } else { 4444 st->print("<absolute address>"); 4445 } 4446 if (dlinfo.dli_fname) { 4447 st->print(" in %s", dlinfo.dli_fname); 4448 } 4449 if (dlinfo.dli_fbase) { 4450 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4451 } 4452 st->cr(); 4453 4454 if (Verbose) { 4455 // decode some bytes around the PC 4456 address begin = same_page(addr-40, addr); 4457 address end = same_page(addr+40, addr); 4458 address lowest = (address) dlinfo.dli_sname; 4459 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4460 if (begin < lowest) begin = lowest; 4461 Dl_info dlinfo2; 4462 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4463 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4464 end = (address) dlinfo2.dli_saddr; 4465 Disassembler::decode(begin, end, st); 4466 } 4467 return true; 4468 } 4469 return false; 4470 } 4471 4472 //////////////////////////////////////////////////////////////////////////////// 4473 // misc 4474 4475 // This does not do anything on Linux. This is basically a hook for being 4476 // able to use structured exception handling (thread-local exception filters) 4477 // on, e.g., Win32. 4478 void 4479 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4480 JavaCallArguments* args, Thread* thread) { 4481 f(value, method, args, thread); 4482 } 4483 4484 void os::print_statistics() { 4485 } 4486 4487 int os::message_box(const char* title, const char* message) { 4488 int i; 4489 fdStream err(defaultStream::error_fd()); 4490 for (i = 0; i < 78; i++) err.print_raw("="); 4491 err.cr(); 4492 err.print_raw_cr(title); 4493 for (i = 0; i < 78; i++) err.print_raw("-"); 4494 err.cr(); 4495 err.print_raw_cr(message); 4496 for (i = 0; i < 78; i++) err.print_raw("="); 4497 err.cr(); 4498 4499 char buf[16]; 4500 // Prevent process from exiting upon "read error" without consuming all CPU 4501 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4502 4503 return buf[0] == 'y' || buf[0] == 'Y'; 4504 } 4505 4506 int os::stat(const char *path, struct stat *sbuf) { 4507 char pathbuf[MAX_PATH]; 4508 if (strlen(path) > MAX_PATH - 1) { 4509 errno = ENAMETOOLONG; 4510 return -1; 4511 } 4512 os::native_path(strcpy(pathbuf, path)); 4513 return ::stat(pathbuf, sbuf); 4514 } 4515 4516 bool os::check_heap(bool force) { 4517 return true; 4518 } 4519 4520 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4521 return ::vsnprintf(buf, count, format, args); 4522 } 4523 4524 // Is a (classpath) directory empty? 4525 bool os::dir_is_empty(const char* path) { 4526 DIR *dir = NULL; 4527 struct dirent *ptr; 4528 4529 dir = opendir(path); 4530 if (dir == NULL) return true; 4531 4532 /* Scan the directory */ 4533 bool result = true; 4534 char buf[sizeof(struct dirent) + MAX_PATH]; 4535 while (result && (ptr = ::readdir(dir)) != NULL) { 4536 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4537 result = false; 4538 } 4539 } 4540 closedir(dir); 4541 return result; 4542 } 4543 4544 // This code originates from JDK's sysOpen and open64_w 4545 // from src/solaris/hpi/src/system_md.c 4546 4547 #ifndef O_DELETE 4548 #define O_DELETE 0x10000 4549 #endif 4550 4551 // Open a file. Unlink the file immediately after open returns 4552 // if the specified oflag has the O_DELETE flag set. 4553 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4554 4555 int os::open(const char *path, int oflag, int mode) { 4556 4557 if (strlen(path) > MAX_PATH - 1) { 4558 errno = ENAMETOOLONG; 4559 return -1; 4560 } 4561 int fd; 4562 int o_delete = (oflag & O_DELETE); 4563 oflag = oflag & ~O_DELETE; 4564 4565 fd = ::open64(path, oflag, mode); 4566 if (fd == -1) return -1; 4567 4568 //If the open succeeded, the file might still be a directory 4569 { 4570 struct stat64 buf64; 4571 int ret = ::fstat64(fd, &buf64); 4572 int st_mode = buf64.st_mode; 4573 4574 if (ret != -1) { 4575 if ((st_mode & S_IFMT) == S_IFDIR) { 4576 errno = EISDIR; 4577 ::close(fd); 4578 return -1; 4579 } 4580 } else { 4581 ::close(fd); 4582 return -1; 4583 } 4584 } 4585 4586 /* 4587 * All file descriptors that are opened in the JVM and not 4588 * specifically destined for a subprocess should have the 4589 * close-on-exec flag set. If we don't set it, then careless 3rd 4590 * party native code might fork and exec without closing all 4591 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4592 * UNIXProcess.c), and this in turn might: 4593 * 4594 * - cause end-of-file to fail to be detected on some file 4595 * descriptors, resulting in mysterious hangs, or 4596 * 4597 * - might cause an fopen in the subprocess to fail on a system 4598 * suffering from bug 1085341. 4599 * 4600 * (Yes, the default setting of the close-on-exec flag is a Unix 4601 * design flaw) 4602 * 4603 * See: 4604 * 1085341: 32-bit stdio routines should support file descriptors >255 4605 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4606 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4607 */ 4608 #ifdef FD_CLOEXEC 4609 { 4610 int flags = ::fcntl(fd, F_GETFD); 4611 if (flags != -1) 4612 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4613 } 4614 #endif 4615 4616 if (o_delete != 0) { 4617 ::unlink(path); 4618 } 4619 return fd; 4620 } 4621 4622 4623 // create binary file, rewriting existing file if required 4624 int os::create_binary_file(const char* path, bool rewrite_existing) { 4625 int oflags = O_WRONLY | O_CREAT; 4626 if (!rewrite_existing) { 4627 oflags |= O_EXCL; 4628 } 4629 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4630 } 4631 4632 // return current position of file pointer 4633 jlong os::current_file_offset(int fd) { 4634 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4635 } 4636 4637 // move file pointer to the specified offset 4638 jlong os::seek_to_file_offset(int fd, jlong offset) { 4639 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4640 } 4641 4642 // This code originates from JDK's sysAvailable 4643 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4644 4645 int os::available(int fd, jlong *bytes) { 4646 jlong cur, end; 4647 int mode; 4648 struct stat64 buf64; 4649 4650 if (::fstat64(fd, &buf64) >= 0) { 4651 mode = buf64.st_mode; 4652 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4653 /* 4654 * XXX: is the following call interruptible? If so, this might 4655 * need to go through the INTERRUPT_IO() wrapper as for other 4656 * blocking, interruptible calls in this file. 4657 */ 4658 int n; 4659 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4660 *bytes = n; 4661 return 1; 4662 } 4663 } 4664 } 4665 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4666 return 0; 4667 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4668 return 0; 4669 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4670 return 0; 4671 } 4672 *bytes = end - cur; 4673 return 1; 4674 } 4675 4676 int os::socket_available(int fd, jint *pbytes) { 4677 // Linux doc says EINTR not returned, unlike Solaris 4678 int ret = ::ioctl(fd, FIONREAD, pbytes); 4679 4680 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 4681 // is expected to return 0 on failure and 1 on success to the jdk. 4682 return (ret < 0) ? 0 : 1; 4683 } 4684 4685 // Map a block of memory. 4686 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4687 char *addr, size_t bytes, bool read_only, 4688 bool allow_exec) { 4689 int prot; 4690 int flags; 4691 4692 if (read_only) { 4693 prot = PROT_READ; 4694 flags = MAP_SHARED; 4695 } else { 4696 prot = PROT_READ | PROT_WRITE; 4697 flags = MAP_PRIVATE; 4698 } 4699 4700 if (allow_exec) { 4701 prot |= PROT_EXEC; 4702 } 4703 4704 if (addr != NULL) { 4705 flags |= MAP_FIXED; 4706 } 4707 4708 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4709 fd, file_offset); 4710 if (mapped_address == MAP_FAILED) { 4711 return NULL; 4712 } 4713 return mapped_address; 4714 } 4715 4716 4717 // Remap a block of memory. 4718 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4719 char *addr, size_t bytes, bool read_only, 4720 bool allow_exec) { 4721 // same as map_memory() on this OS 4722 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4723 allow_exec); 4724 } 4725 4726 4727 // Unmap a block of memory. 4728 bool os::unmap_memory(char* addr, size_t bytes) { 4729 return munmap(addr, bytes) == 0; 4730 } 4731 4732 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4733 4734 static clockid_t thread_cpu_clockid(Thread* thread) { 4735 pthread_t tid = thread->osthread()->pthread_id(); 4736 clockid_t clockid; 4737 4738 // Get thread clockid 4739 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4740 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4741 return clockid; 4742 } 4743 4744 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4745 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 4746 // of a thread. 4747 // 4748 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4749 // the fast estimate available on the platform. 4750 4751 jlong os::current_thread_cpu_time() { 4752 if (os::Linux::supports_fast_thread_cpu_time()) { 4753 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4754 } else { 4755 // return user + sys since the cost is the same 4756 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4757 } 4758 } 4759 4760 jlong os::thread_cpu_time(Thread* thread) { 4761 // consistent with what current_thread_cpu_time() returns 4762 if (os::Linux::supports_fast_thread_cpu_time()) { 4763 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4764 } else { 4765 return slow_thread_cpu_time(thread, true /* user + sys */); 4766 } 4767 } 4768 4769 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4770 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4771 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4772 } else { 4773 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4774 } 4775 } 4776 4777 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4778 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4779 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4780 } else { 4781 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4782 } 4783 } 4784 4785 // 4786 // -1 on error. 4787 // 4788 4789 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4790 static bool proc_pid_cpu_avail = true; 4791 static bool proc_task_unchecked = true; 4792 static const char *proc_stat_path = "/proc/%d/stat"; 4793 pid_t tid = thread->osthread()->thread_id(); 4794 int i; 4795 char *s; 4796 char stat[2048]; 4797 int statlen; 4798 char proc_name[64]; 4799 int count; 4800 long sys_time, user_time; 4801 char string[64]; 4802 char cdummy; 4803 int idummy; 4804 long ldummy; 4805 FILE *fp; 4806 4807 // We first try accessing /proc/<pid>/cpu since this is faster to 4808 // process. If this file is not present (linux kernels 2.5 and above) 4809 // then we open /proc/<pid>/stat. 4810 if ( proc_pid_cpu_avail ) { 4811 sprintf(proc_name, "/proc/%d/cpu", tid); 4812 fp = fopen(proc_name, "r"); 4813 if ( fp != NULL ) { 4814 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4815 fclose(fp); 4816 if ( count != 3 ) return -1; 4817 4818 if (user_sys_cpu_time) { 4819 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4820 } else { 4821 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4822 } 4823 } 4824 else proc_pid_cpu_avail = false; 4825 } 4826 4827 // The /proc/<tid>/stat aggregates per-process usage on 4828 // new Linux kernels 2.6+ where NPTL is supported. 4829 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4830 // See bug 6328462. 4831 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4832 // and possibly in some other cases, so we check its availability. 4833 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4834 // This is executed only once 4835 proc_task_unchecked = false; 4836 fp = fopen("/proc/self/task", "r"); 4837 if (fp != NULL) { 4838 proc_stat_path = "/proc/self/task/%d/stat"; 4839 fclose(fp); 4840 } 4841 } 4842 4843 sprintf(proc_name, proc_stat_path, tid); 4844 fp = fopen(proc_name, "r"); 4845 if ( fp == NULL ) return -1; 4846 statlen = fread(stat, 1, 2047, fp); 4847 stat[statlen] = '\0'; 4848 fclose(fp); 4849 4850 // Skip pid and the command string. Note that we could be dealing with 4851 // weird command names, e.g. user could decide to rename java launcher 4852 // to "java 1.4.2 :)", then the stat file would look like 4853 // 1234 (java 1.4.2 :)) R ... ... 4854 // We don't really need to know the command string, just find the last 4855 // occurrence of ")" and then start parsing from there. See bug 4726580. 4856 s = strrchr(stat, ')'); 4857 i = 0; 4858 if (s == NULL ) return -1; 4859 4860 // Skip blank chars 4861 do s++; while (isspace(*s)); 4862 4863 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4864 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4865 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4866 &user_time, &sys_time); 4867 if ( count != 13 ) return -1; 4868 if (user_sys_cpu_time) { 4869 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4870 } else { 4871 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4872 } 4873 } 4874 4875 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4876 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4877 info_ptr->may_skip_backward = false; // elapsed time not wall time 4878 info_ptr->may_skip_forward = false; // elapsed time not wall time 4879 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4880 } 4881 4882 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4883 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4884 info_ptr->may_skip_backward = false; // elapsed time not wall time 4885 info_ptr->may_skip_forward = false; // elapsed time not wall time 4886 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4887 } 4888 4889 bool os::is_thread_cpu_time_supported() { 4890 return true; 4891 } 4892 4893 // System loadavg support. Returns -1 if load average cannot be obtained. 4894 // Linux doesn't yet have a (official) notion of processor sets, 4895 // so just return the system wide load average. 4896 int os::loadavg(double loadavg[], int nelem) { 4897 return ::getloadavg(loadavg, nelem); 4898 } 4899 4900 void os::pause() { 4901 char filename[MAX_PATH]; 4902 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4903 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4904 } else { 4905 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4906 } 4907 4908 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4909 if (fd != -1) { 4910 struct stat buf; 4911 ::close(fd); 4912 while (::stat(filename, &buf) == 0) { 4913 (void)::poll(NULL, 0, 100); 4914 } 4915 } else { 4916 jio_fprintf(stderr, 4917 "Could not open pause file '%s', continuing immediately.\n", filename); 4918 } 4919 } 4920 4921 4922 // Refer to the comments in os_solaris.cpp park-unpark. 4923 // 4924 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4925 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4926 // For specifics regarding the bug see GLIBC BUGID 261237 : 4927 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4928 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4929 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4930 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 4931 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4932 // and monitorenter when we're using 1-0 locking. All those operations may result in 4933 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4934 // of libpthread avoids the problem, but isn't practical. 4935 // 4936 // Possible remedies: 4937 // 4938 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4939 // This is palliative and probabilistic, however. If the thread is preempted 4940 // between the call to compute_abstime() and pthread_cond_timedwait(), more 4941 // than the minimum period may have passed, and the abstime may be stale (in the 4942 // past) resultin in a hang. Using this technique reduces the odds of a hang 4943 // but the JVM is still vulnerable, particularly on heavily loaded systems. 4944 // 4945 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4946 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4947 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4948 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4949 // thread. 4950 // 4951 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4952 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4953 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4954 // This also works well. In fact it avoids kernel-level scalability impediments 4955 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 4956 // timers in a graceful fashion. 4957 // 4958 // 4. When the abstime value is in the past it appears that control returns 4959 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4960 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4961 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 4962 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4963 // It may be possible to avoid reinitialization by checking the return 4964 // value from pthread_cond_timedwait(). In addition to reinitializing the 4965 // condvar we must establish the invariant that cond_signal() is only called 4966 // within critical sections protected by the adjunct mutex. This prevents 4967 // cond_signal() from "seeing" a condvar that's in the midst of being 4968 // reinitialized or that is corrupt. Sadly, this invariant obviates the 4969 // desirable signal-after-unlock optimization that avoids futile context switching. 4970 // 4971 // I'm also concerned that some versions of NTPL might allocate an auxilliary 4972 // structure when a condvar is used or initialized. cond_destroy() would 4973 // release the helper structure. Our reinitialize-after-timedwait fix 4974 // put excessive stress on malloc/free and locks protecting the c-heap. 4975 // 4976 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4977 // It may be possible to refine (4) by checking the kernel and NTPL verisons 4978 // and only enabling the work-around for vulnerable environments. 4979 4980 // utility to compute the abstime argument to timedwait: 4981 // millis is the relative timeout time 4982 // abstime will be the absolute timeout time 4983 // TODO: replace compute_abstime() with unpackTime() 4984 4985 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4986 if (millis < 0) millis = 0; 4987 struct timeval now; 4988 int status = gettimeofday(&now, NULL); 4989 assert(status == 0, "gettimeofday"); 4990 jlong seconds = millis / 1000; 4991 millis %= 1000; 4992 if (seconds > 50000000) { // see man cond_timedwait(3T) 4993 seconds = 50000000; 4994 } 4995 abstime->tv_sec = now.tv_sec + seconds; 4996 long usec = now.tv_usec + millis * 1000; 4997 if (usec >= 1000000) { 4998 abstime->tv_sec += 1; 4999 usec -= 1000000; 5000 } 5001 abstime->tv_nsec = usec * 1000; 5002 return abstime; 5003 } 5004 5005 5006 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 5007 // Conceptually TryPark() should be equivalent to park(0). 5008 5009 int os::PlatformEvent::TryPark() { 5010 for (;;) { 5011 const int v = _Event ; 5012 guarantee ((v == 0) || (v == 1), "invariant") ; 5013 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 5014 } 5015 } 5016 5017 void os::PlatformEvent::park() { // AKA "down()" 5018 // Invariant: Only the thread associated with the Event/PlatformEvent 5019 // may call park(). 5020 // TODO: assert that _Assoc != NULL or _Assoc == Self 5021 int v ; 5022 for (;;) { 5023 v = _Event ; 5024 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5025 } 5026 guarantee (v >= 0, "invariant") ; 5027 if (v == 0) { 5028 // Do this the hard way by blocking ... 5029 int status = pthread_mutex_lock(_mutex); 5030 assert_status(status == 0, status, "mutex_lock"); 5031 guarantee (_nParked == 0, "invariant") ; 5032 ++ _nParked ; 5033 while (_Event < 0) { 5034 status = pthread_cond_wait(_cond, _mutex); 5035 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5036 // Treat this the same as if the wait was interrupted 5037 if (status == ETIME) { status = EINTR; } 5038 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5039 } 5040 -- _nParked ; 5041 5042 // In theory we could move the ST of 0 into _Event past the unlock(), 5043 // but then we'd need a MEMBAR after the ST. 5044 _Event = 0 ; 5045 status = pthread_mutex_unlock(_mutex); 5046 assert_status(status == 0, status, "mutex_unlock"); 5047 } 5048 guarantee (_Event >= 0, "invariant") ; 5049 } 5050 5051 int os::PlatformEvent::park(jlong millis) { 5052 guarantee (_nParked == 0, "invariant") ; 5053 5054 int v ; 5055 for (;;) { 5056 v = _Event ; 5057 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5058 } 5059 guarantee (v >= 0, "invariant") ; 5060 if (v != 0) return OS_OK ; 5061 5062 // We do this the hard way, by blocking the thread. 5063 // Consider enforcing a minimum timeout value. 5064 struct timespec abst; 5065 compute_abstime(&abst, millis); 5066 5067 int ret = OS_TIMEOUT; 5068 int status = pthread_mutex_lock(_mutex); 5069 assert_status(status == 0, status, "mutex_lock"); 5070 guarantee (_nParked == 0, "invariant") ; 5071 ++_nParked ; 5072 5073 // Object.wait(timo) will return because of 5074 // (a) notification 5075 // (b) timeout 5076 // (c) thread.interrupt 5077 // 5078 // Thread.interrupt and object.notify{All} both call Event::set. 5079 // That is, we treat thread.interrupt as a special case of notification. 5080 // The underlying Solaris implementation, cond_timedwait, admits 5081 // spurious/premature wakeups, but the JLS/JVM spec prevents the 5082 // JVM from making those visible to Java code. As such, we must 5083 // filter out spurious wakeups. We assume all ETIME returns are valid. 5084 // 5085 // TODO: properly differentiate simultaneous notify+interrupt. 5086 // In that case, we should propagate the notify to another waiter. 5087 5088 while (_Event < 0) { 5089 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 5090 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5091 pthread_cond_destroy (_cond); 5092 pthread_cond_init (_cond, NULL) ; 5093 } 5094 assert_status(status == 0 || status == EINTR || 5095 status == ETIME || status == ETIMEDOUT, 5096 status, "cond_timedwait"); 5097 if (!FilterSpuriousWakeups) break ; // previous semantics 5098 if (status == ETIME || status == ETIMEDOUT) break ; 5099 // We consume and ignore EINTR and spurious wakeups. 5100 } 5101 --_nParked ; 5102 if (_Event >= 0) { 5103 ret = OS_OK; 5104 } 5105 _Event = 0 ; 5106 status = pthread_mutex_unlock(_mutex); 5107 assert_status(status == 0, status, "mutex_unlock"); 5108 assert (_nParked == 0, "invariant") ; 5109 return ret; 5110 } 5111 5112 void os::PlatformEvent::unpark() { 5113 int v, AnyWaiters ; 5114 for (;;) { 5115 v = _Event ; 5116 if (v > 0) { 5117 // The LD of _Event could have reordered or be satisfied 5118 // by a read-aside from this processor's write buffer. 5119 // To avoid problems execute a barrier and then 5120 // ratify the value. 5121 OrderAccess::fence() ; 5122 if (_Event == v) return ; 5123 continue ; 5124 } 5125 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 5126 } 5127 if (v < 0) { 5128 // Wait for the thread associated with the event to vacate 5129 int status = pthread_mutex_lock(_mutex); 5130 assert_status(status == 0, status, "mutex_lock"); 5131 AnyWaiters = _nParked ; 5132 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 5133 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5134 AnyWaiters = 0 ; 5135 pthread_cond_signal (_cond); 5136 } 5137 status = pthread_mutex_unlock(_mutex); 5138 assert_status(status == 0, status, "mutex_unlock"); 5139 if (AnyWaiters != 0) { 5140 status = pthread_cond_signal(_cond); 5141 assert_status(status == 0, status, "cond_signal"); 5142 } 5143 } 5144 5145 // Note that we signal() _after dropping the lock for "immortal" Events. 5146 // This is safe and avoids a common class of futile wakeups. In rare 5147 // circumstances this can cause a thread to return prematurely from 5148 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 5149 // simply re-test the condition and re-park itself. 5150 } 5151 5152 5153 // JSR166 5154 // ------------------------------------------------------- 5155 5156 /* 5157 * The solaris and linux implementations of park/unpark are fairly 5158 * conservative for now, but can be improved. They currently use a 5159 * mutex/condvar pair, plus a a count. 5160 * Park decrements count if > 0, else does a condvar wait. Unpark 5161 * sets count to 1 and signals condvar. Only one thread ever waits 5162 * on the condvar. Contention seen when trying to park implies that someone 5163 * is unparking you, so don't wait. And spurious returns are fine, so there 5164 * is no need to track notifications. 5165 */ 5166 5167 #define MAX_SECS 100000000 5168 /* 5169 * This code is common to linux and solaris and will be moved to a 5170 * common place in dolphin. 5171 * 5172 * The passed in time value is either a relative time in nanoseconds 5173 * or an absolute time in milliseconds. Either way it has to be unpacked 5174 * into suitable seconds and nanoseconds components and stored in the 5175 * given timespec structure. 5176 * Given time is a 64-bit value and the time_t used in the timespec is only 5177 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 5178 * overflow if times way in the future are given. Further on Solaris versions 5179 * prior to 10 there is a restriction (see cond_timedwait) that the specified 5180 * number of seconds, in abstime, is less than current_time + 100,000,000. 5181 * As it will be 28 years before "now + 100000000" will overflow we can 5182 * ignore overflow and just impose a hard-limit on seconds using the value 5183 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 5184 * years from "now". 5185 */ 5186 5187 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5188 assert (time > 0, "convertTime"); 5189 5190 struct timeval now; 5191 int status = gettimeofday(&now, NULL); 5192 assert(status == 0, "gettimeofday"); 5193 5194 time_t max_secs = now.tv_sec + MAX_SECS; 5195 5196 if (isAbsolute) { 5197 jlong secs = time / 1000; 5198 if (secs > max_secs) { 5199 absTime->tv_sec = max_secs; 5200 } 5201 else { 5202 absTime->tv_sec = secs; 5203 } 5204 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5205 } 5206 else { 5207 jlong secs = time / NANOSECS_PER_SEC; 5208 if (secs >= MAX_SECS) { 5209 absTime->tv_sec = max_secs; 5210 absTime->tv_nsec = 0; 5211 } 5212 else { 5213 absTime->tv_sec = now.tv_sec + secs; 5214 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5215 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5216 absTime->tv_nsec -= NANOSECS_PER_SEC; 5217 ++absTime->tv_sec; // note: this must be <= max_secs 5218 } 5219 } 5220 } 5221 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5222 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5223 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5224 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5225 } 5226 5227 void Parker::park(bool isAbsolute, jlong time) { 5228 // Optional fast-path check: 5229 // Return immediately if a permit is available. 5230 if (_counter > 0) { 5231 _counter = 0 ; 5232 OrderAccess::fence(); 5233 return ; 5234 } 5235 5236 Thread* thread = Thread::current(); 5237 assert(thread->is_Java_thread(), "Must be JavaThread"); 5238 JavaThread *jt = (JavaThread *)thread; 5239 5240 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5241 // Check interrupt before trying to wait 5242 if (Thread::is_interrupted(thread, false)) { 5243 return; 5244 } 5245 5246 // Next, demultiplex/decode time arguments 5247 timespec absTime; 5248 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5249 return; 5250 } 5251 if (time > 0) { 5252 unpackTime(&absTime, isAbsolute, time); 5253 } 5254 5255 5256 // Enter safepoint region 5257 // Beware of deadlocks such as 6317397. 5258 // The per-thread Parker:: mutex is a classic leaf-lock. 5259 // In particular a thread must never block on the Threads_lock while 5260 // holding the Parker:: mutex. If safepoints are pending both the 5261 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5262 ThreadBlockInVM tbivm(jt); 5263 5264 // Don't wait if cannot get lock since interference arises from 5265 // unblocking. Also. check interrupt before trying wait 5266 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5267 return; 5268 } 5269 5270 int status ; 5271 if (_counter > 0) { // no wait needed 5272 _counter = 0; 5273 status = pthread_mutex_unlock(_mutex); 5274 assert (status == 0, "invariant") ; 5275 OrderAccess::fence(); 5276 return; 5277 } 5278 5279 #ifdef ASSERT 5280 // Don't catch signals while blocked; let the running threads have the signals. 5281 // (This allows a debugger to break into the running thread.) 5282 sigset_t oldsigs; 5283 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5284 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5285 #endif 5286 5287 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5288 jt->set_suspend_equivalent(); 5289 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5290 5291 if (time == 0) { 5292 status = pthread_cond_wait (_cond, _mutex) ; 5293 } else { 5294 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5295 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5296 pthread_cond_destroy (_cond) ; 5297 pthread_cond_init (_cond, NULL); 5298 } 5299 } 5300 assert_status(status == 0 || status == EINTR || 5301 status == ETIME || status == ETIMEDOUT, 5302 status, "cond_timedwait"); 5303 5304 #ifdef ASSERT 5305 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5306 #endif 5307 5308 _counter = 0 ; 5309 status = pthread_mutex_unlock(_mutex) ; 5310 assert_status(status == 0, status, "invariant") ; 5311 // If externally suspended while waiting, re-suspend 5312 if (jt->handle_special_suspend_equivalent_condition()) { 5313 jt->java_suspend_self(); 5314 } 5315 5316 OrderAccess::fence(); 5317 } 5318 5319 void Parker::unpark() { 5320 int s, status ; 5321 status = pthread_mutex_lock(_mutex); 5322 assert (status == 0, "invariant") ; 5323 s = _counter; 5324 _counter = 1; 5325 if (s < 1) { 5326 if (WorkAroundNPTLTimedWaitHang) { 5327 status = pthread_cond_signal (_cond) ; 5328 assert (status == 0, "invariant") ; 5329 status = pthread_mutex_unlock(_mutex); 5330 assert (status == 0, "invariant") ; 5331 } else { 5332 status = pthread_mutex_unlock(_mutex); 5333 assert (status == 0, "invariant") ; 5334 status = pthread_cond_signal (_cond) ; 5335 assert (status == 0, "invariant") ; 5336 } 5337 } else { 5338 pthread_mutex_unlock(_mutex); 5339 assert (status == 0, "invariant") ; 5340 } 5341 } 5342 5343 5344 extern char** environ; 5345 5346 #ifndef __NR_fork 5347 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5348 #endif 5349 5350 #ifndef __NR_execve 5351 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5352 #endif 5353 5354 // Run the specified command in a separate process. Return its exit value, 5355 // or -1 on failure (e.g. can't fork a new process). 5356 // Unlike system(), this function can be called from signal handler. It 5357 // doesn't block SIGINT et al. 5358 int os::fork_and_exec(char* cmd) { 5359 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5360 5361 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5362 // pthread_atfork handlers and reset pthread library. All we need is a 5363 // separate process to execve. Make a direct syscall to fork process. 5364 // On IA64 there's no fork syscall, we have to use fork() and hope for 5365 // the best... 5366 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5367 IA64_ONLY(fork();) 5368 5369 if (pid < 0) { 5370 // fork failed 5371 return -1; 5372 5373 } else if (pid == 0) { 5374 // child process 5375 5376 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5377 // first to kill every thread on the thread list. Because this list is 5378 // not reset by fork() (see notes above), execve() will instead kill 5379 // every thread in the parent process. We know this is the only thread 5380 // in the new process, so make a system call directly. 5381 // IA64 should use normal execve() from glibc to match the glibc fork() 5382 // above. 5383 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5384 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5385 5386 // execve failed 5387 _exit(-1); 5388 5389 } else { 5390 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5391 // care about the actual exit code, for now. 5392 5393 int status; 5394 5395 // Wait for the child process to exit. This returns immediately if 5396 // the child has already exited. */ 5397 while (waitpid(pid, &status, 0) < 0) { 5398 switch (errno) { 5399 case ECHILD: return 0; 5400 case EINTR: break; 5401 default: return -1; 5402 } 5403 } 5404 5405 if (WIFEXITED(status)) { 5406 // The child exited normally; get its exit code. 5407 return WEXITSTATUS(status); 5408 } else if (WIFSIGNALED(status)) { 5409 // The child exited because of a signal 5410 // The best value to return is 0x80 + signal number, 5411 // because that is what all Unix shells do, and because 5412 // it allows callers to distinguish between process exit and 5413 // process death by signal. 5414 return 0x80 + WTERMSIG(status); 5415 } else { 5416 // Unknown exit code; pass it through 5417 return status; 5418 } 5419 } 5420 } 5421 5422 // is_headless_jre() 5423 // 5424 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5425 // in order to report if we are running in a headless jre 5426 // 5427 // Since JDK8 xawt/libmawt.so was moved into the same directory 5428 // as libawt.so, and renamed libawt_xawt.so 5429 // 5430 bool os::is_headless_jre() { 5431 struct stat statbuf; 5432 char buf[MAXPATHLEN]; 5433 char libmawtpath[MAXPATHLEN]; 5434 const char *xawtstr = "/xawt/libmawt.so"; 5435 const char *new_xawtstr = "/libawt_xawt.so"; 5436 char *p; 5437 5438 // Get path to libjvm.so 5439 os::jvm_path(buf, sizeof(buf)); 5440 5441 // Get rid of libjvm.so 5442 p = strrchr(buf, '/'); 5443 if (p == NULL) return false; 5444 else *p = '\0'; 5445 5446 // Get rid of client or server 5447 p = strrchr(buf, '/'); 5448 if (p == NULL) return false; 5449 else *p = '\0'; 5450 5451 // check xawt/libmawt.so 5452 strcpy(libmawtpath, buf); 5453 strcat(libmawtpath, xawtstr); 5454 if (::stat(libmawtpath, &statbuf) == 0) return false; 5455 5456 // check libawt_xawt.so 5457 strcpy(libmawtpath, buf); 5458 strcat(libmawtpath, new_xawtstr); 5459 if (::stat(libmawtpath, &statbuf) == 0) return false; 5460 5461 return true; 5462 } 5463 5464 5465 #ifdef JAVASE_EMBEDDED 5466 // 5467 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory. 5468 // 5469 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL; 5470 5471 // ctor 5472 // 5473 MemNotifyThread::MemNotifyThread(int fd): Thread() { 5474 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread"); 5475 _fd = fd; 5476 5477 if (os::create_thread(this, os::os_thread)) { 5478 _memnotify_thread = this; 5479 os::set_priority(this, NearMaxPriority); 5480 os::start_thread(this); 5481 } 5482 } 5483 5484 // Where all the work gets done 5485 // 5486 void MemNotifyThread::run() { 5487 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread"); 5488 5489 // Set up the select arguments 5490 fd_set rfds; 5491 if (_fd != -1) { 5492 FD_ZERO(&rfds); 5493 FD_SET(_fd, &rfds); 5494 } 5495 5496 // Now wait for the mem_notify device to wake up 5497 while (1) { 5498 // Wait for the mem_notify device to signal us.. 5499 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL); 5500 if (rc == -1) { 5501 perror("select!\n"); 5502 break; 5503 } else if (rc) { 5504 //ssize_t free_before = os::available_memory(); 5505 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024); 5506 5507 // The kernel is telling us there is not much memory left... 5508 // try to do something about that 5509 5510 // If we are not already in a GC, try one. 5511 if (!Universe::heap()->is_gc_active()) { 5512 Universe::heap()->collect(GCCause::_allocation_failure); 5513 5514 //ssize_t free_after = os::available_memory(); 5515 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024); 5516 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024); 5517 } 5518 // We might want to do something like the following if we find the GC's are not helping... 5519 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true); 5520 } 5521 } 5522 } 5523 5524 // 5525 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it. 5526 // 5527 void MemNotifyThread::start() { 5528 int fd; 5529 fd = open ("/dev/mem_notify", O_RDONLY, 0); 5530 if (fd < 0) { 5531 return; 5532 } 5533 5534 if (memnotify_thread() == NULL) { 5535 new MemNotifyThread(fd); 5536 } 5537 } 5538 #endif // JAVASE_EMBEDDED