1 /* 2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "classfile/classLoader.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "code/vtableStubs.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "compiler/disassembler.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "jvm_linux.h" 35 #include "logging/log.hpp" 36 #include "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "mutex_linux.inline.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "os_linux.inline.hpp" 41 #include "os_share_linux.hpp" 42 #include "prims/jniFastGetField.hpp" 43 #include "prims/jvm.h" 44 #include "prims/jvm_misc.hpp" 45 #include "runtime/arguments.hpp" 46 #include "runtime/atomic.inline.hpp" 47 #include "runtime/extendedPC.hpp" 48 #include "runtime/globals.hpp" 49 #include "runtime/interfaceSupport.hpp" 50 #include "runtime/init.hpp" 51 #include "runtime/java.hpp" 52 #include "runtime/javaCalls.hpp" 53 #include "runtime/mutexLocker.hpp" 54 #include "runtime/objectMonitor.hpp" 55 #include "runtime/orderAccess.inline.hpp" 56 #include "runtime/osThread.hpp" 57 #include "runtime/perfMemory.hpp" 58 #include "runtime/sharedRuntime.hpp" 59 #include "runtime/statSampler.hpp" 60 #include "runtime/stubRoutines.hpp" 61 #include "runtime/thread.inline.hpp" 62 #include "runtime/threadCritical.hpp" 63 #include "runtime/timer.hpp" 64 #include "semaphore_posix.hpp" 65 #include "services/attachListener.hpp" 66 #include "services/memTracker.hpp" 67 #include "services/runtimeService.hpp" 68 #include "utilities/decoder.hpp" 69 #include "utilities/defaultStream.hpp" 70 #include "utilities/events.hpp" 71 #include "utilities/elfFile.hpp" 72 #include "utilities/growableArray.hpp" 73 #include "utilities/macros.hpp" 74 #include "utilities/vmError.hpp" 75 76 // put OS-includes here 77 # include <sys/types.h> 78 # include <sys/mman.h> 79 # include <sys/stat.h> 80 # include <sys/select.h> 81 # include <pthread.h> 82 # include <signal.h> 83 # include <errno.h> 84 # include <dlfcn.h> 85 # include <stdio.h> 86 # include <unistd.h> 87 # include <sys/resource.h> 88 # include <pthread.h> 89 # include <sys/stat.h> 90 # include <sys/time.h> 91 # include <sys/times.h> 92 # include <sys/utsname.h> 93 # include <sys/socket.h> 94 # include <sys/wait.h> 95 # include <pwd.h> 96 # include <poll.h> 97 # include <semaphore.h> 98 # include <fcntl.h> 99 # include <string.h> 100 # include <syscall.h> 101 # include <sys/sysinfo.h> 102 # include <gnu/libc-version.h> 103 # include <sys/ipc.h> 104 # include <sys/shm.h> 105 # include <link.h> 106 # include <stdint.h> 107 # include <inttypes.h> 108 # include <sys/ioctl.h> 109 110 #ifndef _GNU_SOURCE 111 #define _GNU_SOURCE 112 #include <sched.h> 113 #undef _GNU_SOURCE 114 #else 115 #include <sched.h> 116 #endif 117 118 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 119 // getrusage() is prepared to handle the associated failure. 120 #ifndef RUSAGE_THREAD 121 #define RUSAGE_THREAD (1) /* only the calling thread */ 122 #endif 123 124 #define MAX_PATH (2 * K) 125 126 #define MAX_SECS 100000000 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 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 142 Mutex* os::Linux::_createThread_lock = NULL; 143 pthread_t os::Linux::_main_thread; 144 int os::Linux::_page_size = -1; 145 const int os::Linux::_vm_default_page_size = (8 * K); 146 bool os::Linux::_supports_fast_thread_cpu_time = false; 147 uint32_t os::Linux::_os_version = 0; 148 const char * os::Linux::_glibc_version = NULL; 149 const char * os::Linux::_libpthread_version = NULL; 150 pthread_condattr_t os::Linux::_condattr[1]; 151 152 static jlong initial_time_count=0; 153 154 static int clock_tics_per_sec = 100; 155 156 // For diagnostics to print a message once. see run_periodic_checks 157 static sigset_t check_signal_done; 158 static bool check_signals = true; 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 // Declarations 167 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 168 169 // utility functions 170 171 static int SR_initialize(); 172 173 julong os::available_memory() { 174 return Linux::available_memory(); 175 } 176 177 julong os::Linux::available_memory() { 178 // values in struct sysinfo are "unsigned long" 179 struct sysinfo si; 180 sysinfo(&si); 181 182 return (julong)si.freeram * si.mem_unit; 183 } 184 185 julong os::physical_memory() { 186 return Linux::physical_memory(); 187 } 188 189 // Return true if user is running as root. 190 191 bool os::have_special_privileges() { 192 static bool init = false; 193 static bool privileges = false; 194 if (!init) { 195 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 196 init = true; 197 } 198 return privileges; 199 } 200 201 202 #ifndef SYS_gettid 203 // i386: 224, ia64: 1105, amd64: 186, sparc 143 204 #ifdef __ia64__ 205 #define SYS_gettid 1105 206 #else 207 #ifdef __i386__ 208 #define SYS_gettid 224 209 #else 210 #ifdef __amd64__ 211 #define SYS_gettid 186 212 #else 213 #ifdef __sparc__ 214 #define SYS_gettid 143 215 #else 216 #error define gettid for the arch 217 #endif 218 #endif 219 #endif 220 #endif 221 #endif 222 223 // Cpu architecture string 224 static char cpu_arch[] = HOTSPOT_LIB_ARCH; 225 226 227 // pid_t gettid() 228 // 229 // Returns the kernel thread id of the currently running thread. Kernel 230 // thread id is used to access /proc. 231 pid_t os::Linux::gettid() { 232 int rslt = syscall(SYS_gettid); 233 assert(rslt != -1, "must be."); // old linuxthreads implementation? 234 return (pid_t)rslt; 235 } 236 237 // Most versions of linux have a bug where the number of processors are 238 // determined by looking at the /proc file system. In a chroot environment, 239 // the system call returns 1. This causes the VM to act as if it is 240 // a single processor and elide locking (see is_MP() call). 241 static bool unsafe_chroot_detected = false; 242 static const char *unstable_chroot_error = "/proc file system not found.\n" 243 "Java may be unstable running multithreaded in a chroot " 244 "environment on Linux when /proc filesystem is not mounted."; 245 246 void os::Linux::initialize_system_info() { 247 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 248 if (processor_count() == 1) { 249 pid_t pid = os::Linux::gettid(); 250 char fname[32]; 251 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 252 FILE *fp = fopen(fname, "r"); 253 if (fp == NULL) { 254 unsafe_chroot_detected = true; 255 } else { 256 fclose(fp); 257 } 258 } 259 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 260 assert(processor_count() > 0, "linux error"); 261 } 262 263 void os::init_system_properties_values() { 264 // The next steps are taken in the product version: 265 // 266 // Obtain the JAVA_HOME value from the location of libjvm.so. 267 // This library should be located at: 268 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 269 // 270 // If "/jre/lib/" appears at the right place in the path, then we 271 // assume libjvm.so is installed in a JDK and we use this path. 272 // 273 // Otherwise exit with message: "Could not create the Java virtual machine." 274 // 275 // The following extra steps are taken in the debugging version: 276 // 277 // If "/jre/lib/" does NOT appear at the right place in the path 278 // instead of exit check for $JAVA_HOME environment variable. 279 // 280 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 281 // then we append a fake suffix "hotspot/libjvm.so" to this path so 282 // it looks like libjvm.so is installed there 283 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 284 // 285 // Otherwise exit. 286 // 287 // Important note: if the location of libjvm.so changes this 288 // code needs to be changed accordingly. 289 290 // See ld(1): 291 // The linker uses the following search paths to locate required 292 // shared libraries: 293 // 1: ... 294 // ... 295 // 7: The default directories, normally /lib and /usr/lib. 296 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 297 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 298 #else 299 #define DEFAULT_LIBPATH "/lib:/usr/lib" 300 #endif 301 302 // Base path of extensions installed on the system. 303 #define SYS_EXT_DIR "/usr/java/packages" 304 #define EXTENSIONS_DIR "/lib/ext" 305 306 // Buffer that fits several sprintfs. 307 // Note that the space for the colon and the trailing null are provided 308 // by the nulls included by the sizeof operator. 309 const size_t bufsize = 310 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 311 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 312 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 313 314 // sysclasspath, java_home, dll_dir 315 { 316 char *pslash; 317 os::jvm_path(buf, bufsize); 318 319 // Found the full path to libjvm.so. 320 // Now cut the path to <java_home>/jre if we can. 321 pslash = strrchr(buf, '/'); 322 if (pslash != NULL) { 323 *pslash = '\0'; // Get rid of /libjvm.so. 324 } 325 pslash = strrchr(buf, '/'); 326 if (pslash != NULL) { 327 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 328 } 329 Arguments::set_dll_dir(buf); 330 331 if (pslash != NULL) { 332 pslash = strrchr(buf, '/'); 333 if (pslash != NULL) { 334 *pslash = '\0'; // Get rid of /<arch>. 335 pslash = strrchr(buf, '/'); 336 if (pslash != NULL) { 337 *pslash = '\0'; // Get rid of /lib. 338 } 339 } 340 } 341 Arguments::set_java_home(buf); 342 set_boot_path('/', ':'); 343 } 344 345 // Where to look for native libraries. 346 // 347 // Note: Due to a legacy implementation, most of the library path 348 // is set in the launcher. This was to accomodate linking restrictions 349 // on legacy Linux implementations (which are no longer supported). 350 // Eventually, all the library path setting will be done here. 351 // 352 // However, to prevent the proliferation of improperly built native 353 // libraries, the new path component /usr/java/packages is added here. 354 // Eventually, all the library path setting will be done here. 355 { 356 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 357 // should always exist (until the legacy problem cited above is 358 // addressed). 359 const char *v = ::getenv("LD_LIBRARY_PATH"); 360 const char *v_colon = ":"; 361 if (v == NULL) { v = ""; v_colon = ""; } 362 // That's +1 for the colon and +1 for the trailing '\0'. 363 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 364 strlen(v) + 1 + 365 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 366 mtInternal); 367 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 368 Arguments::set_library_path(ld_library_path); 369 FREE_C_HEAP_ARRAY(char, ld_library_path); 370 } 371 372 // Extensions directories. 373 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 374 Arguments::set_ext_dirs(buf); 375 376 FREE_C_HEAP_ARRAY(char, buf); 377 378 #undef DEFAULT_LIBPATH 379 #undef SYS_EXT_DIR 380 #undef EXTENSIONS_DIR 381 } 382 383 //////////////////////////////////////////////////////////////////////////////// 384 // breakpoint support 385 386 void os::breakpoint() { 387 BREAKPOINT; 388 } 389 390 extern "C" void breakpoint() { 391 // use debugger to set breakpoint here 392 } 393 394 //////////////////////////////////////////////////////////////////////////////// 395 // signal support 396 397 debug_only(static bool signal_sets_initialized = false); 398 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 399 400 bool os::Linux::is_sig_ignored(int sig) { 401 struct sigaction oact; 402 sigaction(sig, (struct sigaction*)NULL, &oact); 403 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 404 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 405 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 406 return true; 407 } else { 408 return false; 409 } 410 } 411 412 void os::Linux::signal_sets_init() { 413 // Should also have an assertion stating we are still single-threaded. 414 assert(!signal_sets_initialized, "Already initialized"); 415 // Fill in signals that are necessarily unblocked for all threads in 416 // the VM. Currently, we unblock the following signals: 417 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 418 // by -Xrs (=ReduceSignalUsage)); 419 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 420 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 421 // the dispositions or masks wrt these signals. 422 // Programs embedding the VM that want to use the above signals for their 423 // own purposes must, at this time, use the "-Xrs" option to prevent 424 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 425 // (See bug 4345157, and other related bugs). 426 // In reality, though, unblocking these signals is really a nop, since 427 // these signals are not blocked by default. 428 sigemptyset(&unblocked_sigs); 429 sigemptyset(&allowdebug_blocked_sigs); 430 sigaddset(&unblocked_sigs, SIGILL); 431 sigaddset(&unblocked_sigs, SIGSEGV); 432 sigaddset(&unblocked_sigs, SIGBUS); 433 sigaddset(&unblocked_sigs, SIGFPE); 434 #if defined(PPC64) 435 sigaddset(&unblocked_sigs, SIGTRAP); 436 #endif 437 sigaddset(&unblocked_sigs, SR_signum); 438 439 if (!ReduceSignalUsage) { 440 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 441 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 442 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 443 } 444 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 445 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 446 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 447 } 448 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 449 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 450 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 451 } 452 } 453 // Fill in signals that are blocked by all but the VM thread. 454 sigemptyset(&vm_sigs); 455 if (!ReduceSignalUsage) { 456 sigaddset(&vm_sigs, BREAK_SIGNAL); 457 } 458 debug_only(signal_sets_initialized = true); 459 460 } 461 462 // These are signals that are unblocked while a thread is running Java. 463 // (For some reason, they get blocked by default.) 464 sigset_t* os::Linux::unblocked_signals() { 465 assert(signal_sets_initialized, "Not initialized"); 466 return &unblocked_sigs; 467 } 468 469 // These are the signals that are blocked while a (non-VM) thread is 470 // running Java. Only the VM thread handles these signals. 471 sigset_t* os::Linux::vm_signals() { 472 assert(signal_sets_initialized, "Not initialized"); 473 return &vm_sigs; 474 } 475 476 // These are signals that are blocked during cond_wait to allow debugger in 477 sigset_t* os::Linux::allowdebug_blocked_signals() { 478 assert(signal_sets_initialized, "Not initialized"); 479 return &allowdebug_blocked_sigs; 480 } 481 482 void os::Linux::hotspot_sigmask(Thread* thread) { 483 484 //Save caller's signal mask before setting VM signal mask 485 sigset_t caller_sigmask; 486 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 487 488 OSThread* osthread = thread->osthread(); 489 osthread->set_caller_sigmask(caller_sigmask); 490 491 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 492 493 if (!ReduceSignalUsage) { 494 if (thread->is_VM_thread()) { 495 // Only the VM thread handles BREAK_SIGNAL ... 496 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 497 } else { 498 // ... all other threads block BREAK_SIGNAL 499 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 500 } 501 } 502 } 503 504 ////////////////////////////////////////////////////////////////////////////// 505 // detecting pthread library 506 507 void os::Linux::libpthread_init() { 508 // Save glibc and pthread version strings. 509 #if !defined(_CS_GNU_LIBC_VERSION) || \ 510 !defined(_CS_GNU_LIBPTHREAD_VERSION) 511 #error "glibc too old (< 2.3.2)" 512 #endif 513 514 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 515 assert(n > 0, "cannot retrieve glibc version"); 516 char *str = (char *)malloc(n, mtInternal); 517 confstr(_CS_GNU_LIBC_VERSION, str, n); 518 os::Linux::set_glibc_version(str); 519 520 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 521 assert(n > 0, "cannot retrieve pthread version"); 522 str = (char *)malloc(n, mtInternal); 523 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 524 os::Linux::set_libpthread_version(str); 525 } 526 527 ///////////////////////////////////////////////////////////////////////////// 528 // thread stack expansion 529 530 // os::Linux::manually_expand_stack() takes care of expanding the thread 531 // stack. Note that this is normally not needed: pthread stacks allocate 532 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 533 // committed. Therefore it is not necessary to expand the stack manually. 534 // 535 // Manually expanding the stack was historically needed on LinuxThreads 536 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 537 // it is kept to deal with very rare corner cases: 538 // 539 // For one, user may run the VM on an own implementation of threads 540 // whose stacks are - like the old LinuxThreads - implemented using 541 // mmap(MAP_GROWSDOWN). 542 // 543 // Also, this coding may be needed if the VM is running on the primordial 544 // thread. Normally we avoid running on the primordial thread; however, 545 // user may still invoke the VM on the primordial thread. 546 // 547 // The following historical comment describes the details about running 548 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 549 550 551 // Force Linux kernel to expand current thread stack. If "bottom" is close 552 // to the stack guard, caller should block all signals. 553 // 554 // MAP_GROWSDOWN: 555 // A special mmap() flag that is used to implement thread stacks. It tells 556 // kernel that the memory region should extend downwards when needed. This 557 // allows early versions of LinuxThreads to only mmap the first few pages 558 // when creating a new thread. Linux kernel will automatically expand thread 559 // stack as needed (on page faults). 560 // 561 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 562 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 563 // region, it's hard to tell if the fault is due to a legitimate stack 564 // access or because of reading/writing non-exist memory (e.g. buffer 565 // overrun). As a rule, if the fault happens below current stack pointer, 566 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 567 // application (see Linux kernel fault.c). 568 // 569 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 570 // stack overflow detection. 571 // 572 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 573 // not use MAP_GROWSDOWN. 574 // 575 // To get around the problem and allow stack banging on Linux, we need to 576 // manually expand thread stack after receiving the SIGSEGV. 577 // 578 // There are two ways to expand thread stack to address "bottom", we used 579 // both of them in JVM before 1.5: 580 // 1. adjust stack pointer first so that it is below "bottom", and then 581 // touch "bottom" 582 // 2. mmap() the page in question 583 // 584 // Now alternate signal stack is gone, it's harder to use 2. For instance, 585 // if current sp is already near the lower end of page 101, and we need to 586 // call mmap() to map page 100, it is possible that part of the mmap() frame 587 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 588 // That will destroy the mmap() frame and cause VM to crash. 589 // 590 // The following code works by adjusting sp first, then accessing the "bottom" 591 // page to force a page fault. Linux kernel will then automatically expand the 592 // stack mapping. 593 // 594 // _expand_stack_to() assumes its frame size is less than page size, which 595 // should always be true if the function is not inlined. 596 597 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 598 #define NOINLINE 599 #else 600 #define NOINLINE __attribute__ ((noinline)) 601 #endif 602 603 static void _expand_stack_to(address bottom) NOINLINE; 604 605 static void _expand_stack_to(address bottom) { 606 address sp; 607 size_t size; 608 volatile char *p; 609 610 // Adjust bottom to point to the largest address within the same page, it 611 // gives us a one-page buffer if alloca() allocates slightly more memory. 612 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 613 bottom += os::Linux::page_size() - 1; 614 615 // sp might be slightly above current stack pointer; if that's the case, we 616 // will alloca() a little more space than necessary, which is OK. Don't use 617 // os::current_stack_pointer(), as its result can be slightly below current 618 // stack pointer, causing us to not alloca enough to reach "bottom". 619 sp = (address)&sp; 620 621 if (sp > bottom) { 622 size = sp - bottom; 623 p = (volatile char *)alloca(size); 624 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 625 p[0] = '\0'; 626 } 627 } 628 629 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 630 assert(t!=NULL, "just checking"); 631 assert(t->osthread()->expanding_stack(), "expand should be set"); 632 assert(t->stack_base() != NULL, "stack_base was not initialized"); 633 634 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 635 sigset_t mask_all, old_sigset; 636 sigfillset(&mask_all); 637 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 638 _expand_stack_to(addr); 639 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 640 return true; 641 } 642 return false; 643 } 644 645 ////////////////////////////////////////////////////////////////////////////// 646 // create new thread 647 648 // Thread start routine for all newly created threads 649 static void *java_start(Thread *thread) { 650 // Try to randomize the cache line index of hot stack frames. 651 // This helps when threads of the same stack traces evict each other's 652 // cache lines. The threads can be either from the same JVM instance, or 653 // from different JVM instances. The benefit is especially true for 654 // processors with hyperthreading technology. 655 static int counter = 0; 656 int pid = os::current_process_id(); 657 alloca(((pid ^ counter++) & 7) * 128); 658 659 thread->initialize_thread_current(); 660 661 OSThread* osthread = thread->osthread(); 662 Monitor* sync = osthread->startThread_lock(); 663 664 osthread->set_thread_id(os::current_thread_id()); 665 666 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 667 os::current_thread_id(), (uintx) pthread_self()); 668 669 if (UseNUMA) { 670 int lgrp_id = os::numa_get_group_id(); 671 if (lgrp_id != -1) { 672 thread->set_lgrp_id(lgrp_id); 673 } 674 } 675 // initialize signal mask for this thread 676 os::Linux::hotspot_sigmask(thread); 677 678 // initialize floating point control register 679 os::Linux::init_thread_fpu_state(); 680 681 // handshaking with parent thread 682 { 683 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 684 685 // notify parent thread 686 osthread->set_state(INITIALIZED); 687 sync->notify_all(); 688 689 // wait until os::start_thread() 690 while (osthread->get_state() == INITIALIZED) { 691 sync->wait(Mutex::_no_safepoint_check_flag); 692 } 693 } 694 695 // call one more level start routine 696 thread->run(); 697 698 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 699 os::current_thread_id(), (uintx) pthread_self()); 700 701 return 0; 702 } 703 704 bool os::create_thread(Thread* thread, ThreadType thr_type, 705 size_t stack_size) { 706 assert(thread->osthread() == NULL, "caller responsible"); 707 708 // Allocate the OSThread object 709 OSThread* osthread = new OSThread(NULL, NULL); 710 if (osthread == NULL) { 711 return false; 712 } 713 714 // set the correct thread state 715 osthread->set_thread_type(thr_type); 716 717 // Initial state is ALLOCATED but not INITIALIZED 718 osthread->set_state(ALLOCATED); 719 720 thread->set_osthread(osthread); 721 722 // init thread attributes 723 pthread_attr_t attr; 724 pthread_attr_init(&attr); 725 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 726 727 // stack size 728 // calculate stack size if it's not specified by caller 729 if (stack_size == 0) { 730 stack_size = os::Linux::default_stack_size(thr_type); 731 732 switch (thr_type) { 733 case os::java_thread: 734 // Java threads use ThreadStackSize which default value can be 735 // changed with the flag -Xss 736 assert(JavaThread::stack_size_at_create() > 0, "this should be set"); 737 stack_size = JavaThread::stack_size_at_create(); 738 break; 739 case os::compiler_thread: 740 if (CompilerThreadStackSize > 0) { 741 stack_size = (size_t)(CompilerThreadStackSize * K); 742 break; 743 } // else fall through: 744 // use VMThreadStackSize if CompilerThreadStackSize is not defined 745 case os::vm_thread: 746 case os::pgc_thread: 747 case os::cgc_thread: 748 case os::watcher_thread: 749 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 750 break; 751 } 752 } 753 754 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 755 pthread_attr_setstacksize(&attr, stack_size); 756 757 // glibc guard page 758 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 759 760 ThreadState state; 761 762 { 763 pthread_t tid; 764 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 765 766 char buf[64]; 767 if (ret == 0) { 768 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 769 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 770 } else { 771 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 772 strerror(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 773 } 774 775 pthread_attr_destroy(&attr); 776 777 if (ret != 0) { 778 // Need to clean up stuff we've allocated so far 779 thread->set_osthread(NULL); 780 delete osthread; 781 return false; 782 } 783 784 // Store pthread info into the OSThread 785 osthread->set_pthread_id(tid); 786 787 // Wait until child thread is either initialized or aborted 788 { 789 Monitor* sync_with_child = osthread->startThread_lock(); 790 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 791 while ((state = osthread->get_state()) == ALLOCATED) { 792 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 793 } 794 } 795 } 796 797 // Aborted due to thread limit being reached 798 if (state == ZOMBIE) { 799 thread->set_osthread(NULL); 800 delete osthread; 801 return false; 802 } 803 804 // The thread is returned suspended (in state INITIALIZED), 805 // and is started higher up in the call chain 806 assert(state == INITIALIZED, "race condition"); 807 return true; 808 } 809 810 ///////////////////////////////////////////////////////////////////////////// 811 // attach existing thread 812 813 // bootstrap the main thread 814 bool os::create_main_thread(JavaThread* thread) { 815 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 816 return create_attached_thread(thread); 817 } 818 819 bool os::create_attached_thread(JavaThread* thread) { 820 #ifdef ASSERT 821 thread->verify_not_published(); 822 #endif 823 824 // Allocate the OSThread object 825 OSThread* osthread = new OSThread(NULL, NULL); 826 827 if (osthread == NULL) { 828 return false; 829 } 830 831 // Store pthread info into the OSThread 832 osthread->set_thread_id(os::Linux::gettid()); 833 osthread->set_pthread_id(::pthread_self()); 834 835 // initialize floating point control register 836 os::Linux::init_thread_fpu_state(); 837 838 // Initial thread state is RUNNABLE 839 osthread->set_state(RUNNABLE); 840 841 thread->set_osthread(osthread); 842 843 if (UseNUMA) { 844 int lgrp_id = os::numa_get_group_id(); 845 if (lgrp_id != -1) { 846 thread->set_lgrp_id(lgrp_id); 847 } 848 } 849 850 if (os::Linux::is_initial_thread()) { 851 // If current thread is initial thread, its stack is mapped on demand, 852 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 853 // the entire stack region to avoid SEGV in stack banging. 854 // It is also useful to get around the heap-stack-gap problem on SuSE 855 // kernel (see 4821821 for details). We first expand stack to the top 856 // of yellow zone, then enable stack yellow zone (order is significant, 857 // enabling yellow zone first will crash JVM on SuSE Linux), so there 858 // is no gap between the last two virtual memory regions. 859 860 JavaThread *jt = (JavaThread *)thread; 861 address addr = jt->stack_reserved_zone_base(); 862 assert(addr != NULL, "initialization problem?"); 863 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 864 865 osthread->set_expanding_stack(); 866 os::Linux::manually_expand_stack(jt, addr); 867 osthread->clear_expanding_stack(); 868 } 869 870 // initialize signal mask for this thread 871 // and save the caller's signal mask 872 os::Linux::hotspot_sigmask(thread); 873 874 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 875 os::current_thread_id(), (uintx) pthread_self()); 876 877 return true; 878 } 879 880 void os::pd_start_thread(Thread* thread) { 881 OSThread * osthread = thread->osthread(); 882 assert(osthread->get_state() != INITIALIZED, "just checking"); 883 Monitor* sync_with_child = osthread->startThread_lock(); 884 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 885 sync_with_child->notify(); 886 } 887 888 // Free Linux resources related to the OSThread 889 void os::free_thread(OSThread* osthread) { 890 assert(osthread != NULL, "osthread not set"); 891 892 if (Thread::current()->osthread() == osthread) { 893 // Restore caller's signal mask 894 sigset_t sigmask = osthread->caller_sigmask(); 895 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 896 } 897 898 delete osthread; 899 } 900 901 ////////////////////////////////////////////////////////////////////////////// 902 // initial thread 903 904 // Check if current thread is the initial thread, similar to Solaris thr_main. 905 bool os::Linux::is_initial_thread(void) { 906 char dummy; 907 // If called before init complete, thread stack bottom will be null. 908 // Can be called if fatal error occurs before initialization. 909 if (initial_thread_stack_bottom() == NULL) return false; 910 assert(initial_thread_stack_bottom() != NULL && 911 initial_thread_stack_size() != 0, 912 "os::init did not locate initial thread's stack region"); 913 if ((address)&dummy >= initial_thread_stack_bottom() && 914 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 915 return true; 916 } else { 917 return false; 918 } 919 } 920 921 // Find the virtual memory area that contains addr 922 static bool find_vma(address addr, address* vma_low, address* vma_high) { 923 FILE *fp = fopen("/proc/self/maps", "r"); 924 if (fp) { 925 address low, high; 926 while (!feof(fp)) { 927 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 928 if (low <= addr && addr < high) { 929 if (vma_low) *vma_low = low; 930 if (vma_high) *vma_high = high; 931 fclose(fp); 932 return true; 933 } 934 } 935 for (;;) { 936 int ch = fgetc(fp); 937 if (ch == EOF || ch == (int)'\n') break; 938 } 939 } 940 fclose(fp); 941 } 942 return false; 943 } 944 945 // Locate initial thread stack. This special handling of initial thread stack 946 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 947 // bogus value for initial thread. 948 void os::Linux::capture_initial_stack(size_t max_size) { 949 // stack size is the easy part, get it from RLIMIT_STACK 950 size_t stack_size; 951 struct rlimit rlim; 952 getrlimit(RLIMIT_STACK, &rlim); 953 stack_size = rlim.rlim_cur; 954 955 // 6308388: a bug in ld.so will relocate its own .data section to the 956 // lower end of primordial stack; reduce ulimit -s value a little bit 957 // so we won't install guard page on ld.so's data section. 958 stack_size -= 2 * page_size(); 959 960 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 961 // 7.1, in both cases we will get 2G in return value. 962 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 963 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 964 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 965 // in case other parts in glibc still assumes 2M max stack size. 966 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 967 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 968 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 969 stack_size = 2 * K * K IA64_ONLY(*2); 970 } 971 // Try to figure out where the stack base (top) is. This is harder. 972 // 973 // When an application is started, glibc saves the initial stack pointer in 974 // a global variable "__libc_stack_end", which is then used by system 975 // libraries. __libc_stack_end should be pretty close to stack top. The 976 // variable is available since the very early days. However, because it is 977 // a private interface, it could disappear in the future. 978 // 979 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 980 // to __libc_stack_end, it is very close to stack top, but isn't the real 981 // stack top. Note that /proc may not exist if VM is running as a chroot 982 // program, so reading /proc/<pid>/stat could fail. Also the contents of 983 // /proc/<pid>/stat could change in the future (though unlikely). 984 // 985 // We try __libc_stack_end first. If that doesn't work, look for 986 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 987 // as a hint, which should work well in most cases. 988 989 uintptr_t stack_start; 990 991 // try __libc_stack_end first 992 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 993 if (p && *p) { 994 stack_start = *p; 995 } else { 996 // see if we can get the start_stack field from /proc/self/stat 997 FILE *fp; 998 int pid; 999 char state; 1000 int ppid; 1001 int pgrp; 1002 int session; 1003 int nr; 1004 int tpgrp; 1005 unsigned long flags; 1006 unsigned long minflt; 1007 unsigned long cminflt; 1008 unsigned long majflt; 1009 unsigned long cmajflt; 1010 unsigned long utime; 1011 unsigned long stime; 1012 long cutime; 1013 long cstime; 1014 long prio; 1015 long nice; 1016 long junk; 1017 long it_real; 1018 uintptr_t start; 1019 uintptr_t vsize; 1020 intptr_t rss; 1021 uintptr_t rsslim; 1022 uintptr_t scodes; 1023 uintptr_t ecode; 1024 int i; 1025 1026 // Figure what the primordial thread stack base is. Code is inspired 1027 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1028 // followed by command name surrounded by parentheses, state, etc. 1029 char stat[2048]; 1030 int statlen; 1031 1032 fp = fopen("/proc/self/stat", "r"); 1033 if (fp) { 1034 statlen = fread(stat, 1, 2047, fp); 1035 stat[statlen] = '\0'; 1036 fclose(fp); 1037 1038 // Skip pid and the command string. Note that we could be dealing with 1039 // weird command names, e.g. user could decide to rename java launcher 1040 // to "java 1.4.2 :)", then the stat file would look like 1041 // 1234 (java 1.4.2 :)) R ... ... 1042 // We don't really need to know the command string, just find the last 1043 // occurrence of ")" and then start parsing from there. See bug 4726580. 1044 char * s = strrchr(stat, ')'); 1045 1046 i = 0; 1047 if (s) { 1048 // Skip blank chars 1049 do { s++; } while (s && isspace(*s)); 1050 1051 #define _UFM UINTX_FORMAT 1052 #define _DFM INTX_FORMAT 1053 1054 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1055 // 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 1056 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, 1057 &state, // 3 %c 1058 &ppid, // 4 %d 1059 &pgrp, // 5 %d 1060 &session, // 6 %d 1061 &nr, // 7 %d 1062 &tpgrp, // 8 %d 1063 &flags, // 9 %lu 1064 &minflt, // 10 %lu 1065 &cminflt, // 11 %lu 1066 &majflt, // 12 %lu 1067 &cmajflt, // 13 %lu 1068 &utime, // 14 %lu 1069 &stime, // 15 %lu 1070 &cutime, // 16 %ld 1071 &cstime, // 17 %ld 1072 &prio, // 18 %ld 1073 &nice, // 19 %ld 1074 &junk, // 20 %ld 1075 &it_real, // 21 %ld 1076 &start, // 22 UINTX_FORMAT 1077 &vsize, // 23 UINTX_FORMAT 1078 &rss, // 24 INTX_FORMAT 1079 &rsslim, // 25 UINTX_FORMAT 1080 &scodes, // 26 UINTX_FORMAT 1081 &ecode, // 27 UINTX_FORMAT 1082 &stack_start); // 28 UINTX_FORMAT 1083 } 1084 1085 #undef _UFM 1086 #undef _DFM 1087 1088 if (i != 28 - 2) { 1089 assert(false, "Bad conversion from /proc/self/stat"); 1090 // product mode - assume we are the initial thread, good luck in the 1091 // embedded case. 1092 warning("Can't detect initial thread stack location - bad conversion"); 1093 stack_start = (uintptr_t) &rlim; 1094 } 1095 } else { 1096 // For some reason we can't open /proc/self/stat (for example, running on 1097 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1098 // most cases, so don't abort: 1099 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1100 stack_start = (uintptr_t) &rlim; 1101 } 1102 } 1103 1104 // Now we have a pointer (stack_start) very close to the stack top, the 1105 // next thing to do is to figure out the exact location of stack top. We 1106 // can find out the virtual memory area that contains stack_start by 1107 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1108 // and its upper limit is the real stack top. (again, this would fail if 1109 // running inside chroot, because /proc may not exist.) 1110 1111 uintptr_t stack_top; 1112 address low, high; 1113 if (find_vma((address)stack_start, &low, &high)) { 1114 // success, "high" is the true stack top. (ignore "low", because initial 1115 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1116 stack_top = (uintptr_t)high; 1117 } else { 1118 // failed, likely because /proc/self/maps does not exist 1119 warning("Can't detect initial thread stack location - find_vma failed"); 1120 // best effort: stack_start is normally within a few pages below the real 1121 // stack top, use it as stack top, and reduce stack size so we won't put 1122 // guard page outside stack. 1123 stack_top = stack_start; 1124 stack_size -= 16 * page_size(); 1125 } 1126 1127 // stack_top could be partially down the page so align it 1128 stack_top = align_size_up(stack_top, page_size()); 1129 1130 if (max_size && stack_size > max_size) { 1131 _initial_thread_stack_size = max_size; 1132 } else { 1133 _initial_thread_stack_size = stack_size; 1134 } 1135 1136 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1137 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1138 } 1139 1140 //////////////////////////////////////////////////////////////////////////////// 1141 // time support 1142 1143 // Time since start-up in seconds to a fine granularity. 1144 // Used by VMSelfDestructTimer and the MemProfiler. 1145 double os::elapsedTime() { 1146 1147 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1148 } 1149 1150 jlong os::elapsed_counter() { 1151 return javaTimeNanos() - initial_time_count; 1152 } 1153 1154 jlong os::elapsed_frequency() { 1155 return NANOSECS_PER_SEC; // nanosecond resolution 1156 } 1157 1158 bool os::supports_vtime() { return true; } 1159 bool os::enable_vtime() { return false; } 1160 bool os::vtime_enabled() { return false; } 1161 1162 double os::elapsedVTime() { 1163 struct rusage usage; 1164 int retval = getrusage(RUSAGE_THREAD, &usage); 1165 if (retval == 0) { 1166 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1167 } else { 1168 // better than nothing, but not much 1169 return elapsedTime(); 1170 } 1171 } 1172 1173 jlong os::javaTimeMillis() { 1174 timeval time; 1175 int status = gettimeofday(&time, NULL); 1176 assert(status != -1, "linux error"); 1177 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1178 } 1179 1180 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1181 timeval time; 1182 int status = gettimeofday(&time, NULL); 1183 assert(status != -1, "linux error"); 1184 seconds = jlong(time.tv_sec); 1185 nanos = jlong(time.tv_usec) * 1000; 1186 } 1187 1188 1189 #ifndef CLOCK_MONOTONIC 1190 #define CLOCK_MONOTONIC (1) 1191 #endif 1192 1193 void os::Linux::clock_init() { 1194 // we do dlopen's in this particular order due to bug in linux 1195 // dynamical loader (see 6348968) leading to crash on exit 1196 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1197 if (handle == NULL) { 1198 handle = dlopen("librt.so", RTLD_LAZY); 1199 } 1200 1201 if (handle) { 1202 int (*clock_getres_func)(clockid_t, struct timespec*) = 1203 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1204 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1205 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1206 if (clock_getres_func && clock_gettime_func) { 1207 // See if monotonic clock is supported by the kernel. Note that some 1208 // early implementations simply return kernel jiffies (updated every 1209 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1210 // for nano time (though the monotonic property is still nice to have). 1211 // It's fixed in newer kernels, however clock_getres() still returns 1212 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1213 // resolution for now. Hopefully as people move to new kernels, this 1214 // won't be a problem. 1215 struct timespec res; 1216 struct timespec tp; 1217 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1218 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1219 // yes, monotonic clock is supported 1220 _clock_gettime = clock_gettime_func; 1221 return; 1222 } else { 1223 // close librt if there is no monotonic clock 1224 dlclose(handle); 1225 } 1226 } 1227 } 1228 warning("No monotonic clock was available - timed services may " \ 1229 "be adversely affected if the time-of-day clock changes"); 1230 } 1231 1232 #ifndef SYS_clock_getres 1233 #if defined(IA32) || defined(AMD64) 1234 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1235 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1236 #else 1237 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1238 #define sys_clock_getres(x,y) -1 1239 #endif 1240 #else 1241 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1242 #endif 1243 1244 void os::Linux::fast_thread_clock_init() { 1245 if (!UseLinuxPosixThreadCPUClocks) { 1246 return; 1247 } 1248 clockid_t clockid; 1249 struct timespec tp; 1250 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1251 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1252 1253 // Switch to using fast clocks for thread cpu time if 1254 // the sys_clock_getres() returns 0 error code. 1255 // Note, that some kernels may support the current thread 1256 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1257 // returned by the pthread_getcpuclockid(). 1258 // If the fast Posix clocks are supported then the sys_clock_getres() 1259 // must return at least tp.tv_sec == 0 which means a resolution 1260 // better than 1 sec. This is extra check for reliability. 1261 1262 if (pthread_getcpuclockid_func && 1263 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1264 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1265 _supports_fast_thread_cpu_time = true; 1266 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1267 } 1268 } 1269 1270 jlong os::javaTimeNanos() { 1271 if (os::supports_monotonic_clock()) { 1272 struct timespec tp; 1273 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1274 assert(status == 0, "gettime error"); 1275 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1276 return result; 1277 } else { 1278 timeval time; 1279 int status = gettimeofday(&time, NULL); 1280 assert(status != -1, "linux error"); 1281 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1282 return 1000 * usecs; 1283 } 1284 } 1285 1286 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1287 if (os::supports_monotonic_clock()) { 1288 info_ptr->max_value = ALL_64_BITS; 1289 1290 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1291 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1292 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1293 } else { 1294 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1295 info_ptr->max_value = ALL_64_BITS; 1296 1297 // gettimeofday is a real time clock so it skips 1298 info_ptr->may_skip_backward = true; 1299 info_ptr->may_skip_forward = true; 1300 } 1301 1302 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1303 } 1304 1305 // Return the real, user, and system times in seconds from an 1306 // arbitrary fixed point in the past. 1307 bool os::getTimesSecs(double* process_real_time, 1308 double* process_user_time, 1309 double* process_system_time) { 1310 struct tms ticks; 1311 clock_t real_ticks = times(&ticks); 1312 1313 if (real_ticks == (clock_t) (-1)) { 1314 return false; 1315 } else { 1316 double ticks_per_second = (double) clock_tics_per_sec; 1317 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1318 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1319 *process_real_time = ((double) real_ticks) / ticks_per_second; 1320 1321 return true; 1322 } 1323 } 1324 1325 1326 char * os::local_time_string(char *buf, size_t buflen) { 1327 struct tm t; 1328 time_t long_time; 1329 time(&long_time); 1330 localtime_r(&long_time, &t); 1331 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1332 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1333 t.tm_hour, t.tm_min, t.tm_sec); 1334 return buf; 1335 } 1336 1337 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1338 return localtime_r(clock, res); 1339 } 1340 1341 //////////////////////////////////////////////////////////////////////////////// 1342 // runtime exit support 1343 1344 // Note: os::shutdown() might be called very early during initialization, or 1345 // called from signal handler. Before adding something to os::shutdown(), make 1346 // sure it is async-safe and can handle partially initialized VM. 1347 void os::shutdown() { 1348 1349 // allow PerfMemory to attempt cleanup of any persistent resources 1350 perfMemory_exit(); 1351 1352 // needs to remove object in file system 1353 AttachListener::abort(); 1354 1355 // flush buffered output, finish log files 1356 ostream_abort(); 1357 1358 // Check for abort hook 1359 abort_hook_t abort_hook = Arguments::abort_hook(); 1360 if (abort_hook != NULL) { 1361 abort_hook(); 1362 } 1363 1364 } 1365 1366 // Note: os::abort() might be called very early during initialization, or 1367 // called from signal handler. Before adding something to os::abort(), make 1368 // sure it is async-safe and can handle partially initialized VM. 1369 void os::abort(bool dump_core, void* siginfo, const void* context) { 1370 os::shutdown(); 1371 if (dump_core) { 1372 #ifndef PRODUCT 1373 fdStream out(defaultStream::output_fd()); 1374 out.print_raw("Current thread is "); 1375 char buf[16]; 1376 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1377 out.print_raw_cr(buf); 1378 out.print_raw_cr("Dumping core ..."); 1379 #endif 1380 ::abort(); // dump core 1381 } 1382 1383 ::exit(1); 1384 } 1385 1386 // Die immediately, no exit hook, no abort hook, no cleanup. 1387 void os::die() { 1388 ::abort(); 1389 } 1390 1391 1392 // This method is a copy of JDK's sysGetLastErrorString 1393 // from src/solaris/hpi/src/system_md.c 1394 1395 size_t os::lasterror(char *buf, size_t len) { 1396 if (errno == 0) return 0; 1397 1398 const char *s = ::strerror(errno); 1399 size_t n = ::strlen(s); 1400 if (n >= len) { 1401 n = len - 1; 1402 } 1403 ::strncpy(buf, s, n); 1404 buf[n] = '\0'; 1405 return n; 1406 } 1407 1408 // thread_id is kernel thread id (similar to Solaris LWP id) 1409 intx os::current_thread_id() { return os::Linux::gettid(); } 1410 int os::current_process_id() { 1411 return ::getpid(); 1412 } 1413 1414 // DLL functions 1415 1416 const char* os::dll_file_extension() { return ".so"; } 1417 1418 // This must be hard coded because it's the system's temporary 1419 // directory not the java application's temp directory, ala java.io.tmpdir. 1420 const char* os::get_temp_directory() { return "/tmp"; } 1421 1422 static bool file_exists(const char* filename) { 1423 struct stat statbuf; 1424 if (filename == NULL || strlen(filename) == 0) { 1425 return false; 1426 } 1427 return os::stat(filename, &statbuf) == 0; 1428 } 1429 1430 bool os::dll_build_name(char* buffer, size_t buflen, 1431 const char* pname, const char* fname) { 1432 bool retval = false; 1433 // Copied from libhpi 1434 const size_t pnamelen = pname ? strlen(pname) : 0; 1435 1436 // Return error on buffer overflow. 1437 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1438 return retval; 1439 } 1440 1441 if (pnamelen == 0) { 1442 snprintf(buffer, buflen, "lib%s.so", fname); 1443 retval = true; 1444 } else if (strchr(pname, *os::path_separator()) != NULL) { 1445 int n; 1446 char** pelements = split_path(pname, &n); 1447 if (pelements == NULL) { 1448 return false; 1449 } 1450 for (int i = 0; i < n; i++) { 1451 // Really shouldn't be NULL, but check can't hurt 1452 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1453 continue; // skip the empty path values 1454 } 1455 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1456 if (file_exists(buffer)) { 1457 retval = true; 1458 break; 1459 } 1460 } 1461 // release the storage 1462 for (int i = 0; i < n; i++) { 1463 if (pelements[i] != NULL) { 1464 FREE_C_HEAP_ARRAY(char, pelements[i]); 1465 } 1466 } 1467 if (pelements != NULL) { 1468 FREE_C_HEAP_ARRAY(char*, pelements); 1469 } 1470 } else { 1471 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1472 retval = true; 1473 } 1474 return retval; 1475 } 1476 1477 // check if addr is inside libjvm.so 1478 bool os::address_is_in_vm(address addr) { 1479 static address libjvm_base_addr; 1480 Dl_info dlinfo; 1481 1482 if (libjvm_base_addr == NULL) { 1483 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1484 libjvm_base_addr = (address)dlinfo.dli_fbase; 1485 } 1486 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1487 } 1488 1489 if (dladdr((void *)addr, &dlinfo) != 0) { 1490 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1491 } 1492 1493 return false; 1494 } 1495 1496 bool os::dll_address_to_function_name(address addr, char *buf, 1497 int buflen, int *offset, 1498 bool demangle) { 1499 // buf is not optional, but offset is optional 1500 assert(buf != NULL, "sanity check"); 1501 1502 Dl_info dlinfo; 1503 1504 if (dladdr((void*)addr, &dlinfo) != 0) { 1505 // see if we have a matching symbol 1506 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1507 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1508 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1509 } 1510 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1511 return true; 1512 } 1513 // no matching symbol so try for just file info 1514 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1515 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1516 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1517 return true; 1518 } 1519 } 1520 } 1521 1522 buf[0] = '\0'; 1523 if (offset != NULL) *offset = -1; 1524 return false; 1525 } 1526 1527 struct _address_to_library_name { 1528 address addr; // input : memory address 1529 size_t buflen; // size of fname 1530 char* fname; // output: library name 1531 address base; // library base addr 1532 }; 1533 1534 static int address_to_library_name_callback(struct dl_phdr_info *info, 1535 size_t size, void *data) { 1536 int i; 1537 bool found = false; 1538 address libbase = NULL; 1539 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1540 1541 // iterate through all loadable segments 1542 for (i = 0; i < info->dlpi_phnum; i++) { 1543 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1544 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1545 // base address of a library is the lowest address of its loaded 1546 // segments. 1547 if (libbase == NULL || libbase > segbase) { 1548 libbase = segbase; 1549 } 1550 // see if 'addr' is within current segment 1551 if (segbase <= d->addr && 1552 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1553 found = true; 1554 } 1555 } 1556 } 1557 1558 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1559 // so dll_address_to_library_name() can fall through to use dladdr() which 1560 // can figure out executable name from argv[0]. 1561 if (found && info->dlpi_name && info->dlpi_name[0]) { 1562 d->base = libbase; 1563 if (d->fname) { 1564 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1565 } 1566 return 1; 1567 } 1568 return 0; 1569 } 1570 1571 bool os::dll_address_to_library_name(address addr, char* buf, 1572 int buflen, int* offset) { 1573 // buf is not optional, but offset is optional 1574 assert(buf != NULL, "sanity check"); 1575 1576 Dl_info dlinfo; 1577 struct _address_to_library_name data; 1578 1579 // There is a bug in old glibc dladdr() implementation that it could resolve 1580 // to wrong library name if the .so file has a base address != NULL. Here 1581 // we iterate through the program headers of all loaded libraries to find 1582 // out which library 'addr' really belongs to. This workaround can be 1583 // removed once the minimum requirement for glibc is moved to 2.3.x. 1584 data.addr = addr; 1585 data.fname = buf; 1586 data.buflen = buflen; 1587 data.base = NULL; 1588 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1589 1590 if (rslt) { 1591 // buf already contains library name 1592 if (offset) *offset = addr - data.base; 1593 return true; 1594 } 1595 if (dladdr((void*)addr, &dlinfo) != 0) { 1596 if (dlinfo.dli_fname != NULL) { 1597 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1598 } 1599 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1600 *offset = addr - (address)dlinfo.dli_fbase; 1601 } 1602 return true; 1603 } 1604 1605 buf[0] = '\0'; 1606 if (offset) *offset = -1; 1607 return false; 1608 } 1609 1610 // Loads .dll/.so and 1611 // in case of error it checks if .dll/.so was built for the 1612 // same architecture as Hotspot is running on 1613 1614 1615 // Remember the stack's state. The Linux dynamic linker will change 1616 // the stack to 'executable' at most once, so we must safepoint only once. 1617 bool os::Linux::_stack_is_executable = false; 1618 1619 // VM operation that loads a library. This is necessary if stack protection 1620 // of the Java stacks can be lost during loading the library. If we 1621 // do not stop the Java threads, they can stack overflow before the stacks 1622 // are protected again. 1623 class VM_LinuxDllLoad: public VM_Operation { 1624 private: 1625 const char *_filename; 1626 char *_ebuf; 1627 int _ebuflen; 1628 void *_lib; 1629 public: 1630 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1631 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1632 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1633 void doit() { 1634 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1635 os::Linux::_stack_is_executable = true; 1636 } 1637 void* loaded_library() { return _lib; } 1638 }; 1639 1640 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1641 void * result = NULL; 1642 bool load_attempted = false; 1643 1644 // Check whether the library to load might change execution rights 1645 // of the stack. If they are changed, the protection of the stack 1646 // guard pages will be lost. We need a safepoint to fix this. 1647 // 1648 // See Linux man page execstack(8) for more info. 1649 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1650 ElfFile ef(filename); 1651 if (!ef.specifies_noexecstack()) { 1652 if (!is_init_completed()) { 1653 os::Linux::_stack_is_executable = true; 1654 // This is OK - No Java threads have been created yet, and hence no 1655 // stack guard pages to fix. 1656 // 1657 // This should happen only when you are building JDK7 using a very 1658 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1659 // 1660 // Dynamic loader will make all stacks executable after 1661 // this function returns, and will not do that again. 1662 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1663 } else { 1664 warning("You have loaded library %s which might have disabled stack guard. " 1665 "The VM will try to fix the stack guard now.\n" 1666 "It's highly recommended that you fix the library with " 1667 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1668 filename); 1669 1670 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1671 JavaThread *jt = JavaThread::current(); 1672 if (jt->thread_state() != _thread_in_native) { 1673 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1674 // that requires ExecStack. Cannot enter safe point. Let's give up. 1675 warning("Unable to fix stack guard. Giving up."); 1676 } else { 1677 if (!LoadExecStackDllInVMThread) { 1678 // This is for the case where the DLL has an static 1679 // constructor function that executes JNI code. We cannot 1680 // load such DLLs in the VMThread. 1681 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1682 } 1683 1684 ThreadInVMfromNative tiv(jt); 1685 debug_only(VMNativeEntryWrapper vew;) 1686 1687 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1688 VMThread::execute(&op); 1689 if (LoadExecStackDllInVMThread) { 1690 result = op.loaded_library(); 1691 } 1692 load_attempted = true; 1693 } 1694 } 1695 } 1696 } 1697 1698 if (!load_attempted) { 1699 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1700 } 1701 1702 if (result != NULL) { 1703 // Successful loading 1704 return result; 1705 } 1706 1707 Elf32_Ehdr elf_head; 1708 int diag_msg_max_length=ebuflen-strlen(ebuf); 1709 char* diag_msg_buf=ebuf+strlen(ebuf); 1710 1711 if (diag_msg_max_length==0) { 1712 // No more space in ebuf for additional diagnostics message 1713 return NULL; 1714 } 1715 1716 1717 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1718 1719 if (file_descriptor < 0) { 1720 // Can't open library, report dlerror() message 1721 return NULL; 1722 } 1723 1724 bool failed_to_read_elf_head= 1725 (sizeof(elf_head)!= 1726 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1727 1728 ::close(file_descriptor); 1729 if (failed_to_read_elf_head) { 1730 // file i/o error - report dlerror() msg 1731 return NULL; 1732 } 1733 1734 typedef struct { 1735 Elf32_Half code; // Actual value as defined in elf.h 1736 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1737 char elf_class; // 32 or 64 bit 1738 char endianess; // MSB or LSB 1739 char* name; // String representation 1740 } arch_t; 1741 1742 #ifndef EM_486 1743 #define EM_486 6 /* Intel 80486 */ 1744 #endif 1745 #ifndef EM_AARCH64 1746 #define EM_AARCH64 183 /* ARM AARCH64 */ 1747 #endif 1748 1749 static const arch_t arch_array[]={ 1750 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1751 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1752 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1753 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1754 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1755 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1756 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1757 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1758 #if defined(VM_LITTLE_ENDIAN) 1759 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1760 #else 1761 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"}, 1762 #endif 1763 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1764 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1765 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1766 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1767 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1768 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1769 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1770 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1771 }; 1772 1773 #if (defined IA32) 1774 static Elf32_Half running_arch_code=EM_386; 1775 #elif (defined AMD64) 1776 static Elf32_Half running_arch_code=EM_X86_64; 1777 #elif (defined IA64) 1778 static Elf32_Half running_arch_code=EM_IA_64; 1779 #elif (defined __sparc) && (defined _LP64) 1780 static Elf32_Half running_arch_code=EM_SPARCV9; 1781 #elif (defined __sparc) && (!defined _LP64) 1782 static Elf32_Half running_arch_code=EM_SPARC; 1783 #elif (defined __powerpc64__) 1784 static Elf32_Half running_arch_code=EM_PPC64; 1785 #elif (defined __powerpc__) 1786 static Elf32_Half running_arch_code=EM_PPC; 1787 #elif (defined ARM) 1788 static Elf32_Half running_arch_code=EM_ARM; 1789 #elif (defined S390) 1790 static Elf32_Half running_arch_code=EM_S390; 1791 #elif (defined ALPHA) 1792 static Elf32_Half running_arch_code=EM_ALPHA; 1793 #elif (defined MIPSEL) 1794 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1795 #elif (defined PARISC) 1796 static Elf32_Half running_arch_code=EM_PARISC; 1797 #elif (defined MIPS) 1798 static Elf32_Half running_arch_code=EM_MIPS; 1799 #elif (defined M68K) 1800 static Elf32_Half running_arch_code=EM_68K; 1801 #elif (defined AARCH64) 1802 static Elf32_Half running_arch_code=EM_AARCH64; 1803 #else 1804 #error Method os::dll_load requires that one of following is defined:\ 1805 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64 1806 #endif 1807 1808 // Identify compatability class for VM's architecture and library's architecture 1809 // Obtain string descriptions for architectures 1810 1811 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1812 int running_arch_index=-1; 1813 1814 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1815 if (running_arch_code == arch_array[i].code) { 1816 running_arch_index = i; 1817 } 1818 if (lib_arch.code == arch_array[i].code) { 1819 lib_arch.compat_class = arch_array[i].compat_class; 1820 lib_arch.name = arch_array[i].name; 1821 } 1822 } 1823 1824 assert(running_arch_index != -1, 1825 "Didn't find running architecture code (running_arch_code) in arch_array"); 1826 if (running_arch_index == -1) { 1827 // Even though running architecture detection failed 1828 // we may still continue with reporting dlerror() message 1829 return NULL; 1830 } 1831 1832 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1833 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1834 return NULL; 1835 } 1836 1837 #ifndef S390 1838 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1839 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1840 return NULL; 1841 } 1842 #endif // !S390 1843 1844 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1845 if (lib_arch.name!=NULL) { 1846 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1847 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1848 lib_arch.name, arch_array[running_arch_index].name); 1849 } else { 1850 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1851 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1852 lib_arch.code, 1853 arch_array[running_arch_index].name); 1854 } 1855 } 1856 1857 return NULL; 1858 } 1859 1860 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1861 int ebuflen) { 1862 void * result = ::dlopen(filename, RTLD_LAZY); 1863 if (result == NULL) { 1864 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1865 ebuf[ebuflen-1] = '\0'; 1866 } 1867 return result; 1868 } 1869 1870 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1871 int ebuflen) { 1872 void * result = NULL; 1873 if (LoadExecStackDllInVMThread) { 1874 result = dlopen_helper(filename, ebuf, ebuflen); 1875 } 1876 1877 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1878 // library that requires an executable stack, or which does not have this 1879 // stack attribute set, dlopen changes the stack attribute to executable. The 1880 // read protection of the guard pages gets lost. 1881 // 1882 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1883 // may have been queued at the same time. 1884 1885 if (!_stack_is_executable) { 1886 JavaThread *jt = Threads::first(); 1887 1888 while (jt) { 1889 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1890 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1891 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1892 warning("Attempt to reguard stack yellow zone failed."); 1893 } 1894 } 1895 jt = jt->next(); 1896 } 1897 } 1898 1899 return result; 1900 } 1901 1902 void* os::dll_lookup(void* handle, const char* name) { 1903 void* res = dlsym(handle, name); 1904 return res; 1905 } 1906 1907 void* os::get_default_process_handle() { 1908 return (void*)::dlopen(NULL, RTLD_LAZY); 1909 } 1910 1911 static bool _print_ascii_file(const char* filename, outputStream* st) { 1912 int fd = ::open(filename, O_RDONLY); 1913 if (fd == -1) { 1914 return false; 1915 } 1916 1917 char buf[32]; 1918 int bytes; 1919 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1920 st->print_raw(buf, bytes); 1921 } 1922 1923 ::close(fd); 1924 1925 return true; 1926 } 1927 1928 void os::print_dll_info(outputStream *st) { 1929 st->print_cr("Dynamic libraries:"); 1930 1931 char fname[32]; 1932 pid_t pid = os::Linux::gettid(); 1933 1934 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1935 1936 if (!_print_ascii_file(fname, st)) { 1937 st->print("Can not get library information for pid = %d\n", pid); 1938 } 1939 } 1940 1941 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1942 FILE *procmapsFile = NULL; 1943 1944 // Open the procfs maps file for the current process 1945 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1946 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1947 char line[PATH_MAX + 100]; 1948 1949 // Read line by line from 'file' 1950 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1951 u8 base, top, offset, inode; 1952 char permissions[5]; 1953 char device[6]; 1954 char name[PATH_MAX + 1]; 1955 1956 // Parse fields from line 1957 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1958 &base, &top, permissions, &offset, device, &inode, name); 1959 1960 // Filter by device id '00:00' so that we only get file system mapped files. 1961 if (strcmp(device, "00:00") != 0) { 1962 1963 // Call callback with the fields of interest 1964 if(callback(name, (address)base, (address)top, param)) { 1965 // Oops abort, callback aborted 1966 fclose(procmapsFile); 1967 return 1; 1968 } 1969 } 1970 } 1971 fclose(procmapsFile); 1972 } 1973 return 0; 1974 } 1975 1976 void os::print_os_info_brief(outputStream* st) { 1977 os::Linux::print_distro_info(st); 1978 1979 os::Posix::print_uname_info(st); 1980 1981 os::Linux::print_libversion_info(st); 1982 1983 } 1984 1985 void os::print_os_info(outputStream* st) { 1986 st->print("OS:"); 1987 1988 os::Linux::print_distro_info(st); 1989 1990 os::Posix::print_uname_info(st); 1991 1992 // Print warning if unsafe chroot environment detected 1993 if (unsafe_chroot_detected) { 1994 st->print("WARNING!! "); 1995 st->print_cr("%s", unstable_chroot_error); 1996 } 1997 1998 os::Linux::print_libversion_info(st); 1999 2000 os::Posix::print_rlimit_info(st); 2001 2002 os::Posix::print_load_average(st); 2003 2004 os::Linux::print_full_memory_info(st); 2005 } 2006 2007 // Try to identify popular distros. 2008 // Most Linux distributions have a /etc/XXX-release file, which contains 2009 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2010 // file that also contains the OS version string. Some have more than one 2011 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2012 // /etc/redhat-release.), so the order is important. 2013 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2014 // their own specific XXX-release file as well as a redhat-release file. 2015 // Because of this the XXX-release file needs to be searched for before the 2016 // redhat-release file. 2017 // Since Red Hat has a lsb-release file that is not very descriptive the 2018 // search for redhat-release needs to be before lsb-release. 2019 // Since the lsb-release file is the new standard it needs to be searched 2020 // before the older style release files. 2021 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2022 // next to last resort. The os-release file is a new standard that contains 2023 // distribution information and the system-release file seems to be an old 2024 // standard that has been replaced by the lsb-release and os-release files. 2025 // Searching for the debian_version file is the last resort. It contains 2026 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2027 // "Debian " is printed before the contents of the debian_version file. 2028 2029 const char* distro_files[] = { 2030 "/etc/oracle-release", 2031 "/etc/mandriva-release", 2032 "/etc/mandrake-release", 2033 "/etc/sun-release", 2034 "/etc/redhat-release", 2035 "/etc/lsb-release", 2036 "/etc/SuSE-release", 2037 "/etc/turbolinux-release", 2038 "/etc/gentoo-release", 2039 "/etc/ltib-release", 2040 "/etc/angstrom-version", 2041 "/etc/system-release", 2042 "/etc/os-release", 2043 NULL }; 2044 2045 void os::Linux::print_distro_info(outputStream* st) { 2046 for (int i = 0;; i++) { 2047 const char* file = distro_files[i]; 2048 if (file == NULL) { 2049 break; // done 2050 } 2051 // If file prints, we found it. 2052 if (_print_ascii_file(file, st)) { 2053 return; 2054 } 2055 } 2056 2057 if (file_exists("/etc/debian_version")) { 2058 st->print("Debian "); 2059 _print_ascii_file("/etc/debian_version", st); 2060 } else { 2061 st->print("Linux"); 2062 } 2063 st->cr(); 2064 } 2065 2066 static void parse_os_info(char* distro, size_t length, const char* file) { 2067 FILE* fp = fopen(file, "r"); 2068 if (fp != NULL) { 2069 char buf[256]; 2070 // get last line of the file. 2071 while (fgets(buf, sizeof(buf), fp)) { } 2072 // Edit out extra stuff in expected ubuntu format 2073 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL) { 2074 char* ptr = strstr(buf, "\""); // the name is in quotes 2075 if (ptr != NULL) { 2076 ptr++; // go beyond first quote 2077 char* nl = strchr(ptr, '\"'); 2078 if (nl != NULL) *nl = '\0'; 2079 strncpy(distro, ptr, length); 2080 } else { 2081 ptr = strstr(buf, "="); 2082 ptr++; // go beyond equals then 2083 char* nl = strchr(ptr, '\n'); 2084 if (nl != NULL) *nl = '\0'; 2085 strncpy(distro, ptr, length); 2086 } 2087 } else { 2088 // if not in expected Ubuntu format, print out whole line minus \n 2089 char* nl = strchr(buf, '\n'); 2090 if (nl != NULL) *nl = '\0'; 2091 strncpy(distro, buf, length); 2092 } 2093 // close distro file 2094 fclose(fp); 2095 } 2096 } 2097 2098 void os::get_summary_os_info(char* buf, size_t buflen) { 2099 for (int i = 0;; i++) { 2100 const char* file = distro_files[i]; 2101 if (file == NULL) { 2102 break; // ran out of distro_files 2103 } 2104 if (file_exists(file)) { 2105 parse_os_info(buf, buflen, file); 2106 return; 2107 } 2108 } 2109 // special case for debian 2110 if (file_exists("/etc/debian_version")) { 2111 strncpy(buf, "Debian ", buflen); 2112 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2113 } else { 2114 strncpy(buf, "Linux", buflen); 2115 } 2116 } 2117 2118 void os::Linux::print_libversion_info(outputStream* st) { 2119 // libc, pthread 2120 st->print("libc:"); 2121 st->print("%s ", os::Linux::glibc_version()); 2122 st->print("%s ", os::Linux::libpthread_version()); 2123 st->cr(); 2124 } 2125 2126 void os::Linux::print_full_memory_info(outputStream* st) { 2127 st->print("\n/proc/meminfo:\n"); 2128 _print_ascii_file("/proc/meminfo", st); 2129 st->cr(); 2130 } 2131 2132 void os::print_memory_info(outputStream* st) { 2133 2134 st->print("Memory:"); 2135 st->print(" %dk page", os::vm_page_size()>>10); 2136 2137 // values in struct sysinfo are "unsigned long" 2138 struct sysinfo si; 2139 sysinfo(&si); 2140 2141 st->print(", physical " UINT64_FORMAT "k", 2142 os::physical_memory() >> 10); 2143 st->print("(" UINT64_FORMAT "k free)", 2144 os::available_memory() >> 10); 2145 st->print(", swap " UINT64_FORMAT "k", 2146 ((jlong)si.totalswap * si.mem_unit) >> 10); 2147 st->print("(" UINT64_FORMAT "k free)", 2148 ((jlong)si.freeswap * si.mem_unit) >> 10); 2149 st->cr(); 2150 } 2151 2152 // Print the first "model name" line and the first "flags" line 2153 // that we find and nothing more. We assume "model name" comes 2154 // before "flags" so if we find a second "model name", then the 2155 // "flags" field is considered missing. 2156 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2157 #if defined(IA32) || defined(AMD64) 2158 // Other platforms have less repetitive cpuinfo files 2159 FILE *fp = fopen("/proc/cpuinfo", "r"); 2160 if (fp) { 2161 while (!feof(fp)) { 2162 if (fgets(buf, buflen, fp)) { 2163 // Assume model name comes before flags 2164 bool model_name_printed = false; 2165 if (strstr(buf, "model name") != NULL) { 2166 if (!model_name_printed) { 2167 st->print_raw("\nCPU Model and flags from /proc/cpuinfo:\n"); 2168 st->print_raw(buf); 2169 model_name_printed = true; 2170 } else { 2171 // model name printed but not flags? Odd, just return 2172 fclose(fp); 2173 return true; 2174 } 2175 } 2176 // print the flags line too 2177 if (strstr(buf, "flags") != NULL) { 2178 st->print_raw(buf); 2179 fclose(fp); 2180 return true; 2181 } 2182 } 2183 } 2184 fclose(fp); 2185 } 2186 #endif // x86 platforms 2187 return false; 2188 } 2189 2190 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2191 // Only print the model name if the platform provides this as a summary 2192 if (!print_model_name_and_flags(st, buf, buflen)) { 2193 st->print("\n/proc/cpuinfo:\n"); 2194 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2195 st->print_cr(" <Not Available>"); 2196 } 2197 } 2198 } 2199 2200 #if defined(AMD64) || defined(IA32) || defined(X32) 2201 const char* search_string = "model name"; 2202 #elif defined(SPARC) 2203 const char* search_string = "cpu"; 2204 #elif defined(PPC64) 2205 const char* search_string = "cpu"; 2206 #else 2207 const char* search_string = "Processor"; 2208 #endif 2209 2210 // Parses the cpuinfo file for string representing the model name. 2211 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2212 FILE* fp = fopen("/proc/cpuinfo", "r"); 2213 if (fp != NULL) { 2214 while (!feof(fp)) { 2215 char buf[256]; 2216 if (fgets(buf, sizeof(buf), fp)) { 2217 char* start = strstr(buf, search_string); 2218 if (start != NULL) { 2219 char *ptr = start + strlen(search_string); 2220 char *end = buf + strlen(buf); 2221 while (ptr != end) { 2222 // skip whitespace and colon for the rest of the name. 2223 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2224 break; 2225 } 2226 ptr++; 2227 } 2228 if (ptr != end) { 2229 // reasonable string, get rid of newline and keep the rest 2230 char* nl = strchr(buf, '\n'); 2231 if (nl != NULL) *nl = '\0'; 2232 strncpy(cpuinfo, ptr, length); 2233 fclose(fp); 2234 return; 2235 } 2236 } 2237 } 2238 } 2239 fclose(fp); 2240 } 2241 // cpuinfo not found or parsing failed, just print generic string. The entire 2242 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2243 #if defined(AMD64) 2244 strncpy(cpuinfo, "x86_64", length); 2245 #elif defined(IA32) 2246 strncpy(cpuinfo, "x86_32", length); 2247 #elif defined(IA64) 2248 strncpy(cpuinfo, "IA64", length); 2249 #elif defined(SPARC) 2250 strncpy(cpuinfo, "sparcv9", length); 2251 #elif defined(AARCH64) 2252 strncpy(cpuinfo, "AArch64", length); 2253 #elif defined(ARM) 2254 strncpy(cpuinfo, "ARM", length); 2255 #elif defined(PPC) 2256 strncpy(cpuinfo, "PPC64", length); 2257 #elif defined(ZERO_LIBARCH) 2258 strncpy(cpuinfo, ZERO_LIBARCH, length); 2259 #else 2260 strncpy(cpuinfo, "unknown", length); 2261 #endif 2262 } 2263 2264 static void print_signal_handler(outputStream* st, int sig, 2265 char* buf, size_t buflen); 2266 2267 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2268 st->print_cr("Signal Handlers:"); 2269 print_signal_handler(st, SIGSEGV, buf, buflen); 2270 print_signal_handler(st, SIGBUS , buf, buflen); 2271 print_signal_handler(st, SIGFPE , buf, buflen); 2272 print_signal_handler(st, SIGPIPE, buf, buflen); 2273 print_signal_handler(st, SIGXFSZ, buf, buflen); 2274 print_signal_handler(st, SIGILL , buf, buflen); 2275 print_signal_handler(st, SR_signum, buf, buflen); 2276 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2277 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2278 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2279 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2280 #if defined(PPC64) 2281 print_signal_handler(st, SIGTRAP, buf, buflen); 2282 #endif 2283 } 2284 2285 static char saved_jvm_path[MAXPATHLEN] = {0}; 2286 2287 // Find the full path to the current module, libjvm.so 2288 void os::jvm_path(char *buf, jint buflen) { 2289 // Error checking. 2290 if (buflen < MAXPATHLEN) { 2291 assert(false, "must use a large-enough buffer"); 2292 buf[0] = '\0'; 2293 return; 2294 } 2295 // Lazy resolve the path to current module. 2296 if (saved_jvm_path[0] != 0) { 2297 strcpy(buf, saved_jvm_path); 2298 return; 2299 } 2300 2301 char dli_fname[MAXPATHLEN]; 2302 bool ret = dll_address_to_library_name( 2303 CAST_FROM_FN_PTR(address, os::jvm_path), 2304 dli_fname, sizeof(dli_fname), NULL); 2305 assert(ret, "cannot locate libjvm"); 2306 char *rp = NULL; 2307 if (ret && dli_fname[0] != '\0') { 2308 rp = realpath(dli_fname, buf); 2309 } 2310 if (rp == NULL) { 2311 return; 2312 } 2313 2314 if (Arguments::sun_java_launcher_is_altjvm()) { 2315 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2316 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2317 // If "/jre/lib/" appears at the right place in the string, then 2318 // assume we are installed in a JDK and we're done. Otherwise, check 2319 // for a JAVA_HOME environment variable and fix up the path so it 2320 // looks like libjvm.so is installed there (append a fake suffix 2321 // hotspot/libjvm.so). 2322 const char *p = buf + strlen(buf) - 1; 2323 for (int count = 0; p > buf && count < 5; ++count) { 2324 for (--p; p > buf && *p != '/'; --p) 2325 /* empty */ ; 2326 } 2327 2328 if (strncmp(p, "/jre/lib/", 9) != 0) { 2329 // Look for JAVA_HOME in the environment. 2330 char* java_home_var = ::getenv("JAVA_HOME"); 2331 if (java_home_var != NULL && java_home_var[0] != 0) { 2332 char* jrelib_p; 2333 int len; 2334 2335 // Check the current module name "libjvm.so". 2336 p = strrchr(buf, '/'); 2337 if (p == NULL) { 2338 return; 2339 } 2340 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2341 2342 rp = realpath(java_home_var, buf); 2343 if (rp == NULL) { 2344 return; 2345 } 2346 2347 // determine if this is a legacy image or modules image 2348 // modules image doesn't have "jre" subdirectory 2349 len = strlen(buf); 2350 assert(len < buflen, "Ran out of buffer room"); 2351 jrelib_p = buf + len; 2352 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2353 if (0 != access(buf, F_OK)) { 2354 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2355 } 2356 2357 if (0 == access(buf, F_OK)) { 2358 // Use current module name "libjvm.so" 2359 len = strlen(buf); 2360 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2361 } else { 2362 // Go back to path of .so 2363 rp = realpath(dli_fname, buf); 2364 if (rp == NULL) { 2365 return; 2366 } 2367 } 2368 } 2369 } 2370 } 2371 2372 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2373 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2374 } 2375 2376 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2377 // no prefix required, not even "_" 2378 } 2379 2380 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2381 // no suffix required 2382 } 2383 2384 //////////////////////////////////////////////////////////////////////////////// 2385 // sun.misc.Signal support 2386 2387 static volatile jint sigint_count = 0; 2388 2389 static void UserHandler(int sig, void *siginfo, void *context) { 2390 // 4511530 - sem_post is serialized and handled by the manager thread. When 2391 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2392 // don't want to flood the manager thread with sem_post requests. 2393 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2394 return; 2395 } 2396 2397 // Ctrl-C is pressed during error reporting, likely because the error 2398 // handler fails to abort. Let VM die immediately. 2399 if (sig == SIGINT && is_error_reported()) { 2400 os::die(); 2401 } 2402 2403 os::signal_notify(sig); 2404 } 2405 2406 void* os::user_handler() { 2407 return CAST_FROM_FN_PTR(void*, UserHandler); 2408 } 2409 2410 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2411 struct timespec ts; 2412 // Semaphore's are always associated with CLOCK_REALTIME 2413 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2414 // see unpackTime for discussion on overflow checking 2415 if (sec >= MAX_SECS) { 2416 ts.tv_sec += MAX_SECS; 2417 ts.tv_nsec = 0; 2418 } else { 2419 ts.tv_sec += sec; 2420 ts.tv_nsec += nsec; 2421 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2422 ts.tv_nsec -= NANOSECS_PER_SEC; 2423 ++ts.tv_sec; // note: this must be <= max_secs 2424 } 2425 } 2426 2427 return ts; 2428 } 2429 2430 extern "C" { 2431 typedef void (*sa_handler_t)(int); 2432 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2433 } 2434 2435 void* os::signal(int signal_number, void* handler) { 2436 struct sigaction sigAct, oldSigAct; 2437 2438 sigfillset(&(sigAct.sa_mask)); 2439 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2440 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2441 2442 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2443 // -1 means registration failed 2444 return (void *)-1; 2445 } 2446 2447 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2448 } 2449 2450 void os::signal_raise(int signal_number) { 2451 ::raise(signal_number); 2452 } 2453 2454 // The following code is moved from os.cpp for making this 2455 // code platform specific, which it is by its very nature. 2456 2457 // Will be modified when max signal is changed to be dynamic 2458 int os::sigexitnum_pd() { 2459 return NSIG; 2460 } 2461 2462 // a counter for each possible signal value 2463 static volatile jint pending_signals[NSIG+1] = { 0 }; 2464 2465 // Linux(POSIX) specific hand shaking semaphore. 2466 static sem_t sig_sem; 2467 static PosixSemaphore sr_semaphore; 2468 2469 void os::signal_init_pd() { 2470 // Initialize signal structures 2471 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2472 2473 // Initialize signal semaphore 2474 ::sem_init(&sig_sem, 0, 0); 2475 } 2476 2477 void os::signal_notify(int sig) { 2478 Atomic::inc(&pending_signals[sig]); 2479 ::sem_post(&sig_sem); 2480 } 2481 2482 static int check_pending_signals(bool wait) { 2483 Atomic::store(0, &sigint_count); 2484 for (;;) { 2485 for (int i = 0; i < NSIG + 1; i++) { 2486 jint n = pending_signals[i]; 2487 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2488 return i; 2489 } 2490 } 2491 if (!wait) { 2492 return -1; 2493 } 2494 JavaThread *thread = JavaThread::current(); 2495 ThreadBlockInVM tbivm(thread); 2496 2497 bool threadIsSuspended; 2498 do { 2499 thread->set_suspend_equivalent(); 2500 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2501 ::sem_wait(&sig_sem); 2502 2503 // were we externally suspended while we were waiting? 2504 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2505 if (threadIsSuspended) { 2506 // The semaphore has been incremented, but while we were waiting 2507 // another thread suspended us. We don't want to continue running 2508 // while suspended because that would surprise the thread that 2509 // suspended us. 2510 ::sem_post(&sig_sem); 2511 2512 thread->java_suspend_self(); 2513 } 2514 } while (threadIsSuspended); 2515 } 2516 } 2517 2518 int os::signal_lookup() { 2519 return check_pending_signals(false); 2520 } 2521 2522 int os::signal_wait() { 2523 return check_pending_signals(true); 2524 } 2525 2526 //////////////////////////////////////////////////////////////////////////////// 2527 // Virtual Memory 2528 2529 int os::vm_page_size() { 2530 // Seems redundant as all get out 2531 assert(os::Linux::page_size() != -1, "must call os::init"); 2532 return os::Linux::page_size(); 2533 } 2534 2535 // Solaris allocates memory by pages. 2536 int os::vm_allocation_granularity() { 2537 assert(os::Linux::page_size() != -1, "must call os::init"); 2538 return os::Linux::page_size(); 2539 } 2540 2541 // Rationale behind this function: 2542 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2543 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2544 // samples for JITted code. Here we create private executable mapping over the code cache 2545 // and then we can use standard (well, almost, as mapping can change) way to provide 2546 // info for the reporting script by storing timestamp and location of symbol 2547 void linux_wrap_code(char* base, size_t size) { 2548 static volatile jint cnt = 0; 2549 2550 if (!UseOprofile) { 2551 return; 2552 } 2553 2554 char buf[PATH_MAX+1]; 2555 int num = Atomic::add(1, &cnt); 2556 2557 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2558 os::get_temp_directory(), os::current_process_id(), num); 2559 unlink(buf); 2560 2561 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2562 2563 if (fd != -1) { 2564 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2565 if (rv != (off_t)-1) { 2566 if (::write(fd, "", 1) == 1) { 2567 mmap(base, size, 2568 PROT_READ|PROT_WRITE|PROT_EXEC, 2569 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2570 } 2571 } 2572 ::close(fd); 2573 unlink(buf); 2574 } 2575 } 2576 2577 static bool recoverable_mmap_error(int err) { 2578 // See if the error is one we can let the caller handle. This 2579 // list of errno values comes from JBS-6843484. I can't find a 2580 // Linux man page that documents this specific set of errno 2581 // values so while this list currently matches Solaris, it may 2582 // change as we gain experience with this failure mode. 2583 switch (err) { 2584 case EBADF: 2585 case EINVAL: 2586 case ENOTSUP: 2587 // let the caller deal with these errors 2588 return true; 2589 2590 default: 2591 // Any remaining errors on this OS can cause our reserved mapping 2592 // to be lost. That can cause confusion where different data 2593 // structures think they have the same memory mapped. The worst 2594 // scenario is if both the VM and a library think they have the 2595 // same memory mapped. 2596 return false; 2597 } 2598 } 2599 2600 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2601 int err) { 2602 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2603 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2604 strerror(err), err); 2605 } 2606 2607 static void warn_fail_commit_memory(char* addr, size_t size, 2608 size_t alignment_hint, bool exec, 2609 int err) { 2610 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2611 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2612 alignment_hint, exec, strerror(err), err); 2613 } 2614 2615 // NOTE: Linux kernel does not really reserve the pages for us. 2616 // All it does is to check if there are enough free pages 2617 // left at the time of mmap(). This could be a potential 2618 // problem. 2619 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2620 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2621 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2622 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2623 if (res != (uintptr_t) MAP_FAILED) { 2624 if (UseNUMAInterleaving) { 2625 numa_make_global(addr, size); 2626 } 2627 return 0; 2628 } 2629 2630 int err = errno; // save errno from mmap() call above 2631 2632 if (!recoverable_mmap_error(err)) { 2633 warn_fail_commit_memory(addr, size, exec, err); 2634 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2635 } 2636 2637 return err; 2638 } 2639 2640 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2641 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2642 } 2643 2644 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2645 const char* mesg) { 2646 assert(mesg != NULL, "mesg must be specified"); 2647 int err = os::Linux::commit_memory_impl(addr, size, exec); 2648 if (err != 0) { 2649 // the caller wants all commit errors to exit with the specified mesg: 2650 warn_fail_commit_memory(addr, size, exec, err); 2651 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2652 } 2653 } 2654 2655 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2656 #ifndef MAP_HUGETLB 2657 #define MAP_HUGETLB 0x40000 2658 #endif 2659 2660 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2661 #ifndef MADV_HUGEPAGE 2662 #define MADV_HUGEPAGE 14 2663 #endif 2664 2665 int os::Linux::commit_memory_impl(char* addr, size_t size, 2666 size_t alignment_hint, bool exec) { 2667 int err = os::Linux::commit_memory_impl(addr, size, exec); 2668 if (err == 0) { 2669 realign_memory(addr, size, alignment_hint); 2670 } 2671 return err; 2672 } 2673 2674 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2675 bool exec) { 2676 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2677 } 2678 2679 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2680 size_t alignment_hint, bool exec, 2681 const char* mesg) { 2682 assert(mesg != NULL, "mesg must be specified"); 2683 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2684 if (err != 0) { 2685 // the caller wants all commit errors to exit with the specified mesg: 2686 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2687 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2688 } 2689 } 2690 2691 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2692 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2693 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2694 // be supported or the memory may already be backed by huge pages. 2695 ::madvise(addr, bytes, MADV_HUGEPAGE); 2696 } 2697 } 2698 2699 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2700 // This method works by doing an mmap over an existing mmaping and effectively discarding 2701 // the existing pages. However it won't work for SHM-based large pages that cannot be 2702 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2703 // small pages on top of the SHM segment. This method always works for small pages, so we 2704 // allow that in any case. 2705 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2706 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2707 } 2708 } 2709 2710 void os::numa_make_global(char *addr, size_t bytes) { 2711 Linux::numa_interleave_memory(addr, bytes); 2712 } 2713 2714 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2715 // bind policy to MPOL_PREFERRED for the current thread. 2716 #define USE_MPOL_PREFERRED 0 2717 2718 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2719 // To make NUMA and large pages more robust when both enabled, we need to ease 2720 // the requirements on where the memory should be allocated. MPOL_BIND is the 2721 // default policy and it will force memory to be allocated on the specified 2722 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2723 // the specified node, but will not force it. Using this policy will prevent 2724 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2725 // free large pages. 2726 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2727 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2728 } 2729 2730 bool os::numa_topology_changed() { return false; } 2731 2732 size_t os::numa_get_groups_num() { 2733 int max_node = Linux::numa_max_node(); 2734 return max_node > 0 ? max_node + 1 : 1; 2735 } 2736 2737 int os::numa_get_group_id() { 2738 int cpu_id = Linux::sched_getcpu(); 2739 if (cpu_id != -1) { 2740 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2741 if (lgrp_id != -1) { 2742 return lgrp_id; 2743 } 2744 } 2745 return 0; 2746 } 2747 2748 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2749 for (size_t i = 0; i < size; i++) { 2750 ids[i] = i; 2751 } 2752 return size; 2753 } 2754 2755 bool os::get_page_info(char *start, page_info* info) { 2756 return false; 2757 } 2758 2759 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2760 page_info* page_found) { 2761 return end; 2762 } 2763 2764 2765 int os::Linux::sched_getcpu_syscall(void) { 2766 unsigned int cpu = 0; 2767 int retval = -1; 2768 2769 #if defined(IA32) 2770 #ifndef SYS_getcpu 2771 #define SYS_getcpu 318 2772 #endif 2773 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2774 #elif defined(AMD64) 2775 // Unfortunately we have to bring all these macros here from vsyscall.h 2776 // to be able to compile on old linuxes. 2777 #define __NR_vgetcpu 2 2778 #define VSYSCALL_START (-10UL << 20) 2779 #define VSYSCALL_SIZE 1024 2780 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2781 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2782 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2783 retval = vgetcpu(&cpu, NULL, NULL); 2784 #endif 2785 2786 return (retval == -1) ? retval : cpu; 2787 } 2788 2789 // Something to do with the numa-aware allocator needs these symbols 2790 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2791 extern "C" JNIEXPORT void numa_error(char *where) { } 2792 2793 2794 // If we are running with libnuma version > 2, then we should 2795 // be trying to use symbols with versions 1.1 2796 // If we are running with earlier version, which did not have symbol versions, 2797 // we should use the base version. 2798 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2799 void *f = dlvsym(handle, name, "libnuma_1.1"); 2800 if (f == NULL) { 2801 f = dlsym(handle, name); 2802 } 2803 return f; 2804 } 2805 2806 bool os::Linux::libnuma_init() { 2807 // sched_getcpu() should be in libc. 2808 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2809 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2810 2811 // If it's not, try a direct syscall. 2812 if (sched_getcpu() == -1) { 2813 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2814 (void*)&sched_getcpu_syscall)); 2815 } 2816 2817 if (sched_getcpu() != -1) { // Does it work? 2818 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2819 if (handle != NULL) { 2820 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2821 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2822 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2823 libnuma_dlsym(handle, "numa_max_node"))); 2824 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2825 libnuma_dlsym(handle, "numa_available"))); 2826 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2827 libnuma_dlsym(handle, "numa_tonode_memory"))); 2828 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2829 libnuma_dlsym(handle, "numa_interleave_memory"))); 2830 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2831 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2832 2833 2834 if (numa_available() != -1) { 2835 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2836 // Create a cpu -> node mapping 2837 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2838 rebuild_cpu_to_node_map(); 2839 return true; 2840 } 2841 } 2842 } 2843 return false; 2844 } 2845 2846 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2847 // The table is later used in get_node_by_cpu(). 2848 void os::Linux::rebuild_cpu_to_node_map() { 2849 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2850 // in libnuma (possible values are starting from 16, 2851 // and continuing up with every other power of 2, but less 2852 // than the maximum number of CPUs supported by kernel), and 2853 // is a subject to change (in libnuma version 2 the requirements 2854 // are more reasonable) we'll just hardcode the number they use 2855 // in the library. 2856 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2857 2858 size_t cpu_num = os::active_processor_count(); 2859 size_t cpu_map_size = NCPUS / BitsPerCLong; 2860 size_t cpu_map_valid_size = 2861 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2862 2863 cpu_to_node()->clear(); 2864 cpu_to_node()->at_grow(cpu_num - 1); 2865 size_t node_num = numa_get_groups_num(); 2866 2867 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2868 for (size_t i = 0; i < node_num; i++) { 2869 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2870 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2871 if (cpu_map[j] != 0) { 2872 for (size_t k = 0; k < BitsPerCLong; k++) { 2873 if (cpu_map[j] & (1UL << k)) { 2874 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2875 } 2876 } 2877 } 2878 } 2879 } 2880 } 2881 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2882 } 2883 2884 int os::Linux::get_node_by_cpu(int cpu_id) { 2885 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2886 return cpu_to_node()->at(cpu_id); 2887 } 2888 return -1; 2889 } 2890 2891 GrowableArray<int>* os::Linux::_cpu_to_node; 2892 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2893 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2894 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2895 os::Linux::numa_available_func_t os::Linux::_numa_available; 2896 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2897 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2898 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2899 unsigned long* os::Linux::_numa_all_nodes; 2900 2901 bool os::pd_uncommit_memory(char* addr, size_t size) { 2902 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2903 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2904 return res != (uintptr_t) MAP_FAILED; 2905 } 2906 2907 static address get_stack_commited_bottom(address bottom, size_t size) { 2908 address nbot = bottom; 2909 address ntop = bottom + size; 2910 2911 size_t page_sz = os::vm_page_size(); 2912 unsigned pages = size / page_sz; 2913 2914 unsigned char vec[1]; 2915 unsigned imin = 1, imax = pages + 1, imid; 2916 int mincore_return_value = 0; 2917 2918 assert(imin <= imax, "Unexpected page size"); 2919 2920 while (imin < imax) { 2921 imid = (imax + imin) / 2; 2922 nbot = ntop - (imid * page_sz); 2923 2924 // Use a trick with mincore to check whether the page is mapped or not. 2925 // mincore sets vec to 1 if page resides in memory and to 0 if page 2926 // is swapped output but if page we are asking for is unmapped 2927 // it returns -1,ENOMEM 2928 mincore_return_value = mincore(nbot, page_sz, vec); 2929 2930 if (mincore_return_value == -1) { 2931 // Page is not mapped go up 2932 // to find first mapped page 2933 if (errno != EAGAIN) { 2934 assert(errno == ENOMEM, "Unexpected mincore errno"); 2935 imax = imid; 2936 } 2937 } else { 2938 // Page is mapped go down 2939 // to find first not mapped page 2940 imin = imid + 1; 2941 } 2942 } 2943 2944 nbot = nbot + page_sz; 2945 2946 // Adjust stack bottom one page up if last checked page is not mapped 2947 if (mincore_return_value == -1) { 2948 nbot = nbot + page_sz; 2949 } 2950 2951 return nbot; 2952 } 2953 2954 2955 // Linux uses a growable mapping for the stack, and if the mapping for 2956 // the stack guard pages is not removed when we detach a thread the 2957 // stack cannot grow beyond the pages where the stack guard was 2958 // mapped. If at some point later in the process the stack expands to 2959 // that point, the Linux kernel cannot expand the stack any further 2960 // because the guard pages are in the way, and a segfault occurs. 2961 // 2962 // However, it's essential not to split the stack region by unmapping 2963 // a region (leaving a hole) that's already part of the stack mapping, 2964 // so if the stack mapping has already grown beyond the guard pages at 2965 // the time we create them, we have to truncate the stack mapping. 2966 // So, we need to know the extent of the stack mapping when 2967 // create_stack_guard_pages() is called. 2968 2969 // We only need this for stacks that are growable: at the time of 2970 // writing thread stacks don't use growable mappings (i.e. those 2971 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2972 // only applies to the main thread. 2973 2974 // If the (growable) stack mapping already extends beyond the point 2975 // where we're going to put our guard pages, truncate the mapping at 2976 // that point by munmap()ping it. This ensures that when we later 2977 // munmap() the guard pages we don't leave a hole in the stack 2978 // mapping. This only affects the main/initial thread 2979 2980 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 2981 if (os::Linux::is_initial_thread()) { 2982 // As we manually grow stack up to bottom inside create_attached_thread(), 2983 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 2984 // we don't need to do anything special. 2985 // Check it first, before calling heavy function. 2986 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 2987 unsigned char vec[1]; 2988 2989 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 2990 // Fallback to slow path on all errors, including EAGAIN 2991 stack_extent = (uintptr_t) get_stack_commited_bottom( 2992 os::Linux::initial_thread_stack_bottom(), 2993 (size_t)addr - stack_extent); 2994 } 2995 2996 if (stack_extent < (uintptr_t)addr) { 2997 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 2998 } 2999 } 3000 3001 return os::commit_memory(addr, size, !ExecMem); 3002 } 3003 3004 // If this is a growable mapping, remove the guard pages entirely by 3005 // munmap()ping them. If not, just call uncommit_memory(). This only 3006 // affects the main/initial thread, but guard against future OS changes 3007 // It's safe to always unmap guard pages for initial thread because we 3008 // always place it right after end of the mapped region 3009 3010 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3011 uintptr_t stack_extent, stack_base; 3012 3013 if (os::Linux::is_initial_thread()) { 3014 return ::munmap(addr, size) == 0; 3015 } 3016 3017 return os::uncommit_memory(addr, size); 3018 } 3019 3020 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3021 // at 'requested_addr'. If there are existing memory mappings at the same 3022 // location, however, they will be overwritten. If 'fixed' is false, 3023 // 'requested_addr' is only treated as a hint, the return value may or 3024 // may not start from the requested address. Unlike Linux mmap(), this 3025 // function returns NULL to indicate failure. 3026 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3027 char * addr; 3028 int flags; 3029 3030 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3031 if (fixed) { 3032 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3033 flags |= MAP_FIXED; 3034 } 3035 3036 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3037 // touch an uncommitted page. Otherwise, the read/write might 3038 // succeed if we have enough swap space to back the physical page. 3039 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3040 flags, -1, 0); 3041 3042 return addr == MAP_FAILED ? NULL : addr; 3043 } 3044 3045 static int anon_munmap(char * addr, size_t size) { 3046 return ::munmap(addr, size) == 0; 3047 } 3048 3049 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3050 size_t alignment_hint) { 3051 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3052 } 3053 3054 bool os::pd_release_memory(char* addr, size_t size) { 3055 return anon_munmap(addr, size); 3056 } 3057 3058 static bool linux_mprotect(char* addr, size_t size, int prot) { 3059 // Linux wants the mprotect address argument to be page aligned. 3060 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3061 3062 // According to SUSv3, mprotect() should only be used with mappings 3063 // established by mmap(), and mmap() always maps whole pages. Unaligned 3064 // 'addr' likely indicates problem in the VM (e.g. trying to change 3065 // protection of malloc'ed or statically allocated memory). Check the 3066 // caller if you hit this assert. 3067 assert(addr == bottom, "sanity check"); 3068 3069 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3070 return ::mprotect(bottom, size, prot) == 0; 3071 } 3072 3073 // Set protections specified 3074 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3075 bool is_committed) { 3076 unsigned int p = 0; 3077 switch (prot) { 3078 case MEM_PROT_NONE: p = PROT_NONE; break; 3079 case MEM_PROT_READ: p = PROT_READ; break; 3080 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3081 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3082 default: 3083 ShouldNotReachHere(); 3084 } 3085 // is_committed is unused. 3086 return linux_mprotect(addr, bytes, p); 3087 } 3088 3089 bool os::guard_memory(char* addr, size_t size) { 3090 return linux_mprotect(addr, size, PROT_NONE); 3091 } 3092 3093 bool os::unguard_memory(char* addr, size_t size) { 3094 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3095 } 3096 3097 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3098 size_t page_size) { 3099 bool result = false; 3100 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3101 MAP_ANONYMOUS|MAP_PRIVATE, 3102 -1, 0); 3103 if (p != MAP_FAILED) { 3104 void *aligned_p = align_ptr_up(p, page_size); 3105 3106 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3107 3108 munmap(p, page_size * 2); 3109 } 3110 3111 if (warn && !result) { 3112 warning("TransparentHugePages is not supported by the operating system."); 3113 } 3114 3115 return result; 3116 } 3117 3118 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3119 bool result = false; 3120 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3121 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3122 -1, 0); 3123 3124 if (p != MAP_FAILED) { 3125 // We don't know if this really is a huge page or not. 3126 FILE *fp = fopen("/proc/self/maps", "r"); 3127 if (fp) { 3128 while (!feof(fp)) { 3129 char chars[257]; 3130 long x = 0; 3131 if (fgets(chars, sizeof(chars), fp)) { 3132 if (sscanf(chars, "%lx-%*x", &x) == 1 3133 && x == (long)p) { 3134 if (strstr (chars, "hugepage")) { 3135 result = true; 3136 break; 3137 } 3138 } 3139 } 3140 } 3141 fclose(fp); 3142 } 3143 munmap(p, page_size); 3144 } 3145 3146 if (warn && !result) { 3147 warning("HugeTLBFS is not supported by the operating system."); 3148 } 3149 3150 return result; 3151 } 3152 3153 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3154 // 3155 // From the coredump_filter documentation: 3156 // 3157 // - (bit 0) anonymous private memory 3158 // - (bit 1) anonymous shared memory 3159 // - (bit 2) file-backed private memory 3160 // - (bit 3) file-backed shared memory 3161 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3162 // effective only if the bit 2 is cleared) 3163 // - (bit 5) hugetlb private memory 3164 // - (bit 6) hugetlb shared memory 3165 // 3166 static void set_coredump_filter(void) { 3167 FILE *f; 3168 long cdm; 3169 3170 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3171 return; 3172 } 3173 3174 if (fscanf(f, "%lx", &cdm) != 1) { 3175 fclose(f); 3176 return; 3177 } 3178 3179 rewind(f); 3180 3181 if ((cdm & LARGEPAGES_BIT) == 0) { 3182 cdm |= LARGEPAGES_BIT; 3183 fprintf(f, "%#lx", cdm); 3184 } 3185 3186 fclose(f); 3187 } 3188 3189 // Large page support 3190 3191 static size_t _large_page_size = 0; 3192 3193 size_t os::Linux::find_large_page_size() { 3194 size_t large_page_size = 0; 3195 3196 // large_page_size on Linux is used to round up heap size. x86 uses either 3197 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3198 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3199 // page as large as 256M. 3200 // 3201 // Here we try to figure out page size by parsing /proc/meminfo and looking 3202 // for a line with the following format: 3203 // Hugepagesize: 2048 kB 3204 // 3205 // If we can't determine the value (e.g. /proc is not mounted, or the text 3206 // format has been changed), we'll use the largest page size supported by 3207 // the processor. 3208 3209 #ifndef ZERO 3210 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3211 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M); 3212 #endif // ZERO 3213 3214 FILE *fp = fopen("/proc/meminfo", "r"); 3215 if (fp) { 3216 while (!feof(fp)) { 3217 int x = 0; 3218 char buf[16]; 3219 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3220 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3221 large_page_size = x * K; 3222 break; 3223 } 3224 } else { 3225 // skip to next line 3226 for (;;) { 3227 int ch = fgetc(fp); 3228 if (ch == EOF || ch == (int)'\n') break; 3229 } 3230 } 3231 } 3232 fclose(fp); 3233 } 3234 3235 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3236 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3237 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3238 proper_unit_for_byte_size(large_page_size)); 3239 } 3240 3241 return large_page_size; 3242 } 3243 3244 size_t os::Linux::setup_large_page_size() { 3245 _large_page_size = Linux::find_large_page_size(); 3246 const size_t default_page_size = (size_t)Linux::page_size(); 3247 if (_large_page_size > default_page_size) { 3248 _page_sizes[0] = _large_page_size; 3249 _page_sizes[1] = default_page_size; 3250 _page_sizes[2] = 0; 3251 } 3252 3253 return _large_page_size; 3254 } 3255 3256 bool os::Linux::setup_large_page_type(size_t page_size) { 3257 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3258 FLAG_IS_DEFAULT(UseSHM) && 3259 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3260 3261 // The type of large pages has not been specified by the user. 3262 3263 // Try UseHugeTLBFS and then UseSHM. 3264 UseHugeTLBFS = UseSHM = true; 3265 3266 // Don't try UseTransparentHugePages since there are known 3267 // performance issues with it turned on. This might change in the future. 3268 UseTransparentHugePages = false; 3269 } 3270 3271 if (UseTransparentHugePages) { 3272 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3273 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3274 UseHugeTLBFS = false; 3275 UseSHM = false; 3276 return true; 3277 } 3278 UseTransparentHugePages = false; 3279 } 3280 3281 if (UseHugeTLBFS) { 3282 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3283 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3284 UseSHM = false; 3285 return true; 3286 } 3287 UseHugeTLBFS = false; 3288 } 3289 3290 return UseSHM; 3291 } 3292 3293 void os::large_page_init() { 3294 if (!UseLargePages && 3295 !UseTransparentHugePages && 3296 !UseHugeTLBFS && 3297 !UseSHM) { 3298 // Not using large pages. 3299 return; 3300 } 3301 3302 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3303 // The user explicitly turned off large pages. 3304 // Ignore the rest of the large pages flags. 3305 UseTransparentHugePages = false; 3306 UseHugeTLBFS = false; 3307 UseSHM = false; 3308 return; 3309 } 3310 3311 size_t large_page_size = Linux::setup_large_page_size(); 3312 UseLargePages = Linux::setup_large_page_type(large_page_size); 3313 3314 set_coredump_filter(); 3315 } 3316 3317 #ifndef SHM_HUGETLB 3318 #define SHM_HUGETLB 04000 3319 #endif 3320 3321 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3322 char* req_addr, bool exec) { 3323 // "exec" is passed in but not used. Creating the shared image for 3324 // the code cache doesn't have an SHM_X executable permission to check. 3325 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3326 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3327 3328 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) { 3329 return NULL; // Fallback to small pages. 3330 } 3331 3332 key_t key = IPC_PRIVATE; 3333 char *addr; 3334 3335 bool warn_on_failure = UseLargePages && 3336 (!FLAG_IS_DEFAULT(UseLargePages) || 3337 !FLAG_IS_DEFAULT(UseSHM) || 3338 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3339 char msg[128]; 3340 3341 // Create a large shared memory region to attach to based on size. 3342 // Currently, size is the total size of the heap 3343 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3344 if (shmid == -1) { 3345 // Possible reasons for shmget failure: 3346 // 1. shmmax is too small for Java heap. 3347 // > check shmmax value: cat /proc/sys/kernel/shmmax 3348 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3349 // 2. not enough large page memory. 3350 // > check available large pages: cat /proc/meminfo 3351 // > increase amount of large pages: 3352 // echo new_value > /proc/sys/vm/nr_hugepages 3353 // Note 1: different Linux may use different name for this property, 3354 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3355 // Note 2: it's possible there's enough physical memory available but 3356 // they are so fragmented after a long run that they can't 3357 // coalesce into large pages. Try to reserve large pages when 3358 // the system is still "fresh". 3359 if (warn_on_failure) { 3360 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3361 warning("%s", msg); 3362 } 3363 return NULL; 3364 } 3365 3366 // attach to the region 3367 addr = (char*)shmat(shmid, req_addr, 0); 3368 int err = errno; 3369 3370 // Remove shmid. If shmat() is successful, the actual shared memory segment 3371 // will be deleted when it's detached by shmdt() or when the process 3372 // terminates. If shmat() is not successful this will remove the shared 3373 // segment immediately. 3374 shmctl(shmid, IPC_RMID, NULL); 3375 3376 if ((intptr_t)addr == -1) { 3377 if (warn_on_failure) { 3378 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3379 warning("%s", msg); 3380 } 3381 return NULL; 3382 } 3383 3384 return addr; 3385 } 3386 3387 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3388 int error) { 3389 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3390 3391 bool warn_on_failure = UseLargePages && 3392 (!FLAG_IS_DEFAULT(UseLargePages) || 3393 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3394 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3395 3396 if (warn_on_failure) { 3397 char msg[128]; 3398 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3399 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3400 warning("%s", msg); 3401 } 3402 } 3403 3404 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3405 char* req_addr, 3406 bool exec) { 3407 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3408 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3409 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3410 3411 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3412 char* addr = (char*)::mmap(req_addr, bytes, prot, 3413 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3414 -1, 0); 3415 3416 if (addr == MAP_FAILED) { 3417 warn_on_large_pages_failure(req_addr, bytes, errno); 3418 return NULL; 3419 } 3420 3421 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3422 3423 return addr; 3424 } 3425 3426 // Helper for os::Linux::reserve_memory_special_huge_tlbfs_mixed(). 3427 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3428 // (req_addr != NULL) or with a given alignment. 3429 // - bytes shall be a multiple of alignment. 3430 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3431 // - alignment sets the alignment at which memory shall be allocated. 3432 // It must be a multiple of allocation granularity. 3433 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3434 // req_addr or NULL. 3435 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3436 3437 size_t extra_size = bytes; 3438 if (req_addr == NULL && alignment > 0) { 3439 extra_size += alignment; 3440 } 3441 3442 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3443 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3444 -1, 0); 3445 if (start == MAP_FAILED) { 3446 start = NULL; 3447 } else { 3448 if (req_addr != NULL) { 3449 if (start != req_addr) { 3450 ::munmap(start, extra_size); 3451 start = NULL; 3452 } 3453 } else { 3454 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3455 char* const end_aligned = start_aligned + bytes; 3456 char* const end = start + extra_size; 3457 if (start_aligned > start) { 3458 ::munmap(start, start_aligned - start); 3459 } 3460 if (end_aligned < end) { 3461 ::munmap(end_aligned, end - end_aligned); 3462 } 3463 start = start_aligned; 3464 } 3465 } 3466 return start; 3467 3468 } 3469 3470 // Reserve memory using mmap(MAP_HUGETLB). 3471 // - bytes shall be a multiple of alignment. 3472 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3473 // - alignment sets the alignment at which memory shall be allocated. 3474 // It must be a multiple of allocation granularity. 3475 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3476 // req_addr or NULL. 3477 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3478 size_t alignment, 3479 char* req_addr, 3480 bool exec) { 3481 size_t large_page_size = os::large_page_size(); 3482 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3483 3484 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3485 assert(is_size_aligned(bytes, alignment), "Must be"); 3486 3487 // First reserve - but not commit - the address range in small pages. 3488 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3489 3490 if (start == NULL) { 3491 return NULL; 3492 } 3493 3494 assert(is_ptr_aligned(start, alignment), "Must be"); 3495 3496 char* end = start + bytes; 3497 3498 // Find the regions of the allocated chunk that can be promoted to large pages. 3499 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3500 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3501 3502 size_t lp_bytes = lp_end - lp_start; 3503 3504 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3505 3506 if (lp_bytes == 0) { 3507 // The mapped region doesn't even span the start and the end of a large page. 3508 // Fall back to allocate a non-special area. 3509 ::munmap(start, end - start); 3510 return NULL; 3511 } 3512 3513 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3514 3515 void* result; 3516 3517 // Commit small-paged leading area. 3518 if (start != lp_start) { 3519 result = ::mmap(start, lp_start - start, prot, 3520 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3521 -1, 0); 3522 if (result == MAP_FAILED) { 3523 ::munmap(lp_start, end - lp_start); 3524 return NULL; 3525 } 3526 } 3527 3528 // Commit large-paged area. 3529 result = ::mmap(lp_start, lp_bytes, prot, 3530 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3531 -1, 0); 3532 if (result == MAP_FAILED) { 3533 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3534 // If the mmap above fails, the large pages region will be unmapped and we 3535 // have regions before and after with small pages. Release these regions. 3536 // 3537 // | mapped | unmapped | mapped | 3538 // ^ ^ ^ ^ 3539 // start lp_start lp_end end 3540 // 3541 ::munmap(start, lp_start - start); 3542 ::munmap(lp_end, end - lp_end); 3543 return NULL; 3544 } 3545 3546 // Commit small-paged trailing area. 3547 if (lp_end != end) { 3548 result = ::mmap(lp_end, end - lp_end, prot, 3549 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3550 -1, 0); 3551 if (result == MAP_FAILED) { 3552 ::munmap(start, lp_end - start); 3553 return NULL; 3554 } 3555 } 3556 3557 return start; 3558 } 3559 3560 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3561 size_t alignment, 3562 char* req_addr, 3563 bool exec) { 3564 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3565 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3566 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3567 assert(is_power_of_2(os::large_page_size()), "Must be"); 3568 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3569 3570 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3571 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3572 } else { 3573 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3574 } 3575 } 3576 3577 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3578 char* req_addr, bool exec) { 3579 assert(UseLargePages, "only for large pages"); 3580 3581 char* addr; 3582 if (UseSHM) { 3583 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3584 } else { 3585 assert(UseHugeTLBFS, "must be"); 3586 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3587 } 3588 3589 if (addr != NULL) { 3590 if (UseNUMAInterleaving) { 3591 numa_make_global(addr, bytes); 3592 } 3593 3594 // The memory is committed 3595 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3596 } 3597 3598 return addr; 3599 } 3600 3601 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3602 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3603 return shmdt(base) == 0; 3604 } 3605 3606 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3607 return pd_release_memory(base, bytes); 3608 } 3609 3610 bool os::release_memory_special(char* base, size_t bytes) { 3611 bool res; 3612 if (MemTracker::tracking_level() > NMT_minimal) { 3613 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3614 res = os::Linux::release_memory_special_impl(base, bytes); 3615 if (res) { 3616 tkr.record((address)base, bytes); 3617 } 3618 3619 } else { 3620 res = os::Linux::release_memory_special_impl(base, bytes); 3621 } 3622 return res; 3623 } 3624 3625 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3626 assert(UseLargePages, "only for large pages"); 3627 bool res; 3628 3629 if (UseSHM) { 3630 res = os::Linux::release_memory_special_shm(base, bytes); 3631 } else { 3632 assert(UseHugeTLBFS, "must be"); 3633 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3634 } 3635 return res; 3636 } 3637 3638 size_t os::large_page_size() { 3639 return _large_page_size; 3640 } 3641 3642 // With SysV SHM the entire memory region must be allocated as shared 3643 // memory. 3644 // HugeTLBFS allows application to commit large page memory on demand. 3645 // However, when committing memory with HugeTLBFS fails, the region 3646 // that was supposed to be committed will lose the old reservation 3647 // and allow other threads to steal that memory region. Because of this 3648 // behavior we can't commit HugeTLBFS memory. 3649 bool os::can_commit_large_page_memory() { 3650 return UseTransparentHugePages; 3651 } 3652 3653 bool os::can_execute_large_page_memory() { 3654 return UseTransparentHugePages || UseHugeTLBFS; 3655 } 3656 3657 // Reserve memory at an arbitrary address, only if that area is 3658 // available (and not reserved for something else). 3659 3660 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3661 const int max_tries = 10; 3662 char* base[max_tries]; 3663 size_t size[max_tries]; 3664 const size_t gap = 0x000000; 3665 3666 // Assert only that the size is a multiple of the page size, since 3667 // that's all that mmap requires, and since that's all we really know 3668 // about at this low abstraction level. If we need higher alignment, 3669 // we can either pass an alignment to this method or verify alignment 3670 // in one of the methods further up the call chain. See bug 5044738. 3671 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3672 3673 // Repeatedly allocate blocks until the block is allocated at the 3674 // right spot. 3675 3676 // Linux mmap allows caller to pass an address as hint; give it a try first, 3677 // if kernel honors the hint then we can return immediately. 3678 char * addr = anon_mmap(requested_addr, bytes, false); 3679 if (addr == requested_addr) { 3680 return requested_addr; 3681 } 3682 3683 if (addr != NULL) { 3684 // mmap() is successful but it fails to reserve at the requested address 3685 anon_munmap(addr, bytes); 3686 } 3687 3688 int i; 3689 for (i = 0; i < max_tries; ++i) { 3690 base[i] = reserve_memory(bytes); 3691 3692 if (base[i] != NULL) { 3693 // Is this the block we wanted? 3694 if (base[i] == requested_addr) { 3695 size[i] = bytes; 3696 break; 3697 } 3698 3699 // Does this overlap the block we wanted? Give back the overlapped 3700 // parts and try again. 3701 3702 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3703 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3704 unmap_memory(base[i], top_overlap); 3705 base[i] += top_overlap; 3706 size[i] = bytes - top_overlap; 3707 } else { 3708 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3709 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3710 unmap_memory(requested_addr, bottom_overlap); 3711 size[i] = bytes - bottom_overlap; 3712 } else { 3713 size[i] = bytes; 3714 } 3715 } 3716 } 3717 } 3718 3719 // Give back the unused reserved pieces. 3720 3721 for (int j = 0; j < i; ++j) { 3722 if (base[j] != NULL) { 3723 unmap_memory(base[j], size[j]); 3724 } 3725 } 3726 3727 if (i < max_tries) { 3728 return requested_addr; 3729 } else { 3730 return NULL; 3731 } 3732 } 3733 3734 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3735 return ::read(fd, buf, nBytes); 3736 } 3737 3738 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3739 return ::pread(fd, buf, nBytes, offset); 3740 } 3741 3742 // Short sleep, direct OS call. 3743 // 3744 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3745 // sched_yield(2) will actually give up the CPU: 3746 // 3747 // * Alone on this pariticular CPU, keeps running. 3748 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3749 // (pre 2.6.39). 3750 // 3751 // So calling this with 0 is an alternative. 3752 // 3753 void os::naked_short_sleep(jlong ms) { 3754 struct timespec req; 3755 3756 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3757 req.tv_sec = 0; 3758 if (ms > 0) { 3759 req.tv_nsec = (ms % 1000) * 1000000; 3760 } else { 3761 req.tv_nsec = 1; 3762 } 3763 3764 nanosleep(&req, NULL); 3765 3766 return; 3767 } 3768 3769 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3770 void os::infinite_sleep() { 3771 while (true) { // sleep forever ... 3772 ::sleep(100); // ... 100 seconds at a time 3773 } 3774 } 3775 3776 // Used to convert frequent JVM_Yield() to nops 3777 bool os::dont_yield() { 3778 return DontYieldALot; 3779 } 3780 3781 void os::naked_yield() { 3782 sched_yield(); 3783 } 3784 3785 //////////////////////////////////////////////////////////////////////////////// 3786 // thread priority support 3787 3788 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3789 // only supports dynamic priority, static priority must be zero. For real-time 3790 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3791 // However, for large multi-threaded applications, SCHED_RR is not only slower 3792 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3793 // of 5 runs - Sep 2005). 3794 // 3795 // The following code actually changes the niceness of kernel-thread/LWP. It 3796 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3797 // not the entire user process, and user level threads are 1:1 mapped to kernel 3798 // threads. It has always been the case, but could change in the future. For 3799 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3800 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3801 3802 int os::java_to_os_priority[CriticalPriority + 1] = { 3803 19, // 0 Entry should never be used 3804 3805 4, // 1 MinPriority 3806 3, // 2 3807 2, // 3 3808 3809 1, // 4 3810 0, // 5 NormPriority 3811 -1, // 6 3812 3813 -2, // 7 3814 -3, // 8 3815 -4, // 9 NearMaxPriority 3816 3817 -5, // 10 MaxPriority 3818 3819 -5 // 11 CriticalPriority 3820 }; 3821 3822 static int prio_init() { 3823 if (ThreadPriorityPolicy == 1) { 3824 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3825 // if effective uid is not root. Perhaps, a more elegant way of doing 3826 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3827 if (geteuid() != 0) { 3828 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3829 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3830 } 3831 ThreadPriorityPolicy = 0; 3832 } 3833 } 3834 if (UseCriticalJavaThreadPriority) { 3835 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3836 } 3837 return 0; 3838 } 3839 3840 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3841 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3842 3843 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3844 return (ret == 0) ? OS_OK : OS_ERR; 3845 } 3846 3847 OSReturn os::get_native_priority(const Thread* const thread, 3848 int *priority_ptr) { 3849 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3850 *priority_ptr = java_to_os_priority[NormPriority]; 3851 return OS_OK; 3852 } 3853 3854 errno = 0; 3855 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3856 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3857 } 3858 3859 // Hint to the underlying OS that a task switch would not be good. 3860 // Void return because it's a hint and can fail. 3861 void os::hint_no_preempt() {} 3862 3863 //////////////////////////////////////////////////////////////////////////////// 3864 // suspend/resume support 3865 3866 // the low-level signal-based suspend/resume support is a remnant from the 3867 // old VM-suspension that used to be for java-suspension, safepoints etc, 3868 // within hotspot. Now there is a single use-case for this: 3869 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3870 // that runs in the watcher thread. 3871 // The remaining code is greatly simplified from the more general suspension 3872 // code that used to be used. 3873 // 3874 // The protocol is quite simple: 3875 // - suspend: 3876 // - sends a signal to the target thread 3877 // - polls the suspend state of the osthread using a yield loop 3878 // - target thread signal handler (SR_handler) sets suspend state 3879 // and blocks in sigsuspend until continued 3880 // - resume: 3881 // - sets target osthread state to continue 3882 // - sends signal to end the sigsuspend loop in the SR_handler 3883 // 3884 // Note that the SR_lock plays no role in this suspend/resume protocol. 3885 3886 static void resume_clear_context(OSThread *osthread) { 3887 osthread->set_ucontext(NULL); 3888 osthread->set_siginfo(NULL); 3889 } 3890 3891 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3892 ucontext_t* context) { 3893 osthread->set_ucontext(context); 3894 osthread->set_siginfo(siginfo); 3895 } 3896 3897 // Handler function invoked when a thread's execution is suspended or 3898 // resumed. We have to be careful that only async-safe functions are 3899 // called here (Note: most pthread functions are not async safe and 3900 // should be avoided.) 3901 // 3902 // Note: sigwait() is a more natural fit than sigsuspend() from an 3903 // interface point of view, but sigwait() prevents the signal hander 3904 // from being run. libpthread would get very confused by not having 3905 // its signal handlers run and prevents sigwait()'s use with the 3906 // mutex granting granting signal. 3907 // 3908 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3909 // 3910 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3911 // Save and restore errno to avoid confusing native code with EINTR 3912 // after sigsuspend. 3913 int old_errno = errno; 3914 3915 Thread* thread = Thread::current(); 3916 OSThread* osthread = thread->osthread(); 3917 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3918 3919 os::SuspendResume::State current = osthread->sr.state(); 3920 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 3921 suspend_save_context(osthread, siginfo, context); 3922 3923 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 3924 os::SuspendResume::State state = osthread->sr.suspended(); 3925 if (state == os::SuspendResume::SR_SUSPENDED) { 3926 sigset_t suspend_set; // signals for sigsuspend() 3927 3928 // get current set of blocked signals and unblock resume signal 3929 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3930 sigdelset(&suspend_set, SR_signum); 3931 3932 sr_semaphore.signal(); 3933 // wait here until we are resumed 3934 while (1) { 3935 sigsuspend(&suspend_set); 3936 3937 os::SuspendResume::State result = osthread->sr.running(); 3938 if (result == os::SuspendResume::SR_RUNNING) { 3939 sr_semaphore.signal(); 3940 break; 3941 } 3942 } 3943 3944 } else if (state == os::SuspendResume::SR_RUNNING) { 3945 // request was cancelled, continue 3946 } else { 3947 ShouldNotReachHere(); 3948 } 3949 3950 resume_clear_context(osthread); 3951 } else if (current == os::SuspendResume::SR_RUNNING) { 3952 // request was cancelled, continue 3953 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 3954 // ignore 3955 } else { 3956 // ignore 3957 } 3958 3959 errno = old_errno; 3960 } 3961 3962 static int SR_initialize() { 3963 struct sigaction act; 3964 char *s; 3965 3966 // Get signal number to use for suspend/resume 3967 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3968 int sig = ::strtol(s, 0, 10); 3969 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 3970 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 3971 SR_signum = sig; 3972 } else { 3973 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 3974 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 3975 } 3976 } 3977 3978 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3979 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3980 3981 sigemptyset(&SR_sigset); 3982 sigaddset(&SR_sigset, SR_signum); 3983 3984 // Set up signal handler for suspend/resume 3985 act.sa_flags = SA_RESTART|SA_SIGINFO; 3986 act.sa_handler = (void (*)(int)) SR_handler; 3987 3988 // SR_signum is blocked by default. 3989 // 4528190 - We also need to block pthread restart signal (32 on all 3990 // supported Linux platforms). Note that LinuxThreads need to block 3991 // this signal for all threads to work properly. So we don't have 3992 // to use hard-coded signal number when setting up the mask. 3993 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3994 3995 if (sigaction(SR_signum, &act, 0) == -1) { 3996 return -1; 3997 } 3998 3999 // Save signal flag 4000 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4001 return 0; 4002 } 4003 4004 static int sr_notify(OSThread* osthread) { 4005 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4006 assert_status(status == 0, status, "pthread_kill"); 4007 return status; 4008 } 4009 4010 // "Randomly" selected value for how long we want to spin 4011 // before bailing out on suspending a thread, also how often 4012 // we send a signal to a thread we want to resume 4013 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4014 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4015 4016 // returns true on success and false on error - really an error is fatal 4017 // but this seems the normal response to library errors 4018 static bool do_suspend(OSThread* osthread) { 4019 assert(osthread->sr.is_running(), "thread should be running"); 4020 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4021 4022 // mark as suspended and send signal 4023 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4024 // failed to switch, state wasn't running? 4025 ShouldNotReachHere(); 4026 return false; 4027 } 4028 4029 if (sr_notify(osthread) != 0) { 4030 ShouldNotReachHere(); 4031 } 4032 4033 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4034 while (true) { 4035 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4036 break; 4037 } else { 4038 // timeout 4039 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4040 if (cancelled == os::SuspendResume::SR_RUNNING) { 4041 return false; 4042 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4043 // make sure that we consume the signal on the semaphore as well 4044 sr_semaphore.wait(); 4045 break; 4046 } else { 4047 ShouldNotReachHere(); 4048 return false; 4049 } 4050 } 4051 } 4052 4053 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4054 return true; 4055 } 4056 4057 static void do_resume(OSThread* osthread) { 4058 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4059 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4060 4061 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4062 // failed to switch to WAKEUP_REQUEST 4063 ShouldNotReachHere(); 4064 return; 4065 } 4066 4067 while (true) { 4068 if (sr_notify(osthread) == 0) { 4069 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4070 if (osthread->sr.is_running()) { 4071 return; 4072 } 4073 } 4074 } else { 4075 ShouldNotReachHere(); 4076 } 4077 } 4078 4079 guarantee(osthread->sr.is_running(), "Must be running!"); 4080 } 4081 4082 /////////////////////////////////////////////////////////////////////////////////// 4083 // signal handling (except suspend/resume) 4084 4085 // This routine may be used by user applications as a "hook" to catch signals. 4086 // The user-defined signal handler must pass unrecognized signals to this 4087 // routine, and if it returns true (non-zero), then the signal handler must 4088 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4089 // routine will never retun false (zero), but instead will execute a VM panic 4090 // routine kill the process. 4091 // 4092 // If this routine returns false, it is OK to call it again. This allows 4093 // the user-defined signal handler to perform checks either before or after 4094 // the VM performs its own checks. Naturally, the user code would be making 4095 // a serious error if it tried to handle an exception (such as a null check 4096 // or breakpoint) that the VM was generating for its own correct operation. 4097 // 4098 // This routine may recognize any of the following kinds of signals: 4099 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4100 // It should be consulted by handlers for any of those signals. 4101 // 4102 // The caller of this routine must pass in the three arguments supplied 4103 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4104 // field of the structure passed to sigaction(). This routine assumes that 4105 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4106 // 4107 // Note that the VM will print warnings if it detects conflicting signal 4108 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4109 // 4110 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4111 siginfo_t* siginfo, 4112 void* ucontext, 4113 int abort_if_unrecognized); 4114 4115 void signalHandler(int sig, siginfo_t* info, void* uc) { 4116 assert(info != NULL && uc != NULL, "it must be old kernel"); 4117 int orig_errno = errno; // Preserve errno value over signal handler. 4118 JVM_handle_linux_signal(sig, info, uc, true); 4119 errno = orig_errno; 4120 } 4121 4122 4123 // This boolean allows users to forward their own non-matching signals 4124 // to JVM_handle_linux_signal, harmlessly. 4125 bool os::Linux::signal_handlers_are_installed = false; 4126 4127 // For signal-chaining 4128 struct sigaction sigact[NSIG]; 4129 uint64_t sigs = 0; 4130 #if (64 < NSIG-1) 4131 #error "Not all signals can be encoded in sigs. Adapt its type!" 4132 #endif 4133 bool os::Linux::libjsig_is_loaded = false; 4134 typedef struct sigaction *(*get_signal_t)(int); 4135 get_signal_t os::Linux::get_signal_action = NULL; 4136 4137 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4138 struct sigaction *actp = NULL; 4139 4140 if (libjsig_is_loaded) { 4141 // Retrieve the old signal handler from libjsig 4142 actp = (*get_signal_action)(sig); 4143 } 4144 if (actp == NULL) { 4145 // Retrieve the preinstalled signal handler from jvm 4146 actp = get_preinstalled_handler(sig); 4147 } 4148 4149 return actp; 4150 } 4151 4152 static bool call_chained_handler(struct sigaction *actp, int sig, 4153 siginfo_t *siginfo, void *context) { 4154 // Call the old signal handler 4155 if (actp->sa_handler == SIG_DFL) { 4156 // It's more reasonable to let jvm treat it as an unexpected exception 4157 // instead of taking the default action. 4158 return false; 4159 } else if (actp->sa_handler != SIG_IGN) { 4160 if ((actp->sa_flags & SA_NODEFER) == 0) { 4161 // automaticlly block the signal 4162 sigaddset(&(actp->sa_mask), sig); 4163 } 4164 4165 sa_handler_t hand = NULL; 4166 sa_sigaction_t sa = NULL; 4167 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4168 // retrieve the chained handler 4169 if (siginfo_flag_set) { 4170 sa = actp->sa_sigaction; 4171 } else { 4172 hand = actp->sa_handler; 4173 } 4174 4175 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4176 actp->sa_handler = SIG_DFL; 4177 } 4178 4179 // try to honor the signal mask 4180 sigset_t oset; 4181 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4182 4183 // call into the chained handler 4184 if (siginfo_flag_set) { 4185 (*sa)(sig, siginfo, context); 4186 } else { 4187 (*hand)(sig); 4188 } 4189 4190 // restore the signal mask 4191 pthread_sigmask(SIG_SETMASK, &oset, 0); 4192 } 4193 // Tell jvm's signal handler the signal is taken care of. 4194 return true; 4195 } 4196 4197 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4198 bool chained = false; 4199 // signal-chaining 4200 if (UseSignalChaining) { 4201 struct sigaction *actp = get_chained_signal_action(sig); 4202 if (actp != NULL) { 4203 chained = call_chained_handler(actp, sig, siginfo, context); 4204 } 4205 } 4206 return chained; 4207 } 4208 4209 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4210 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4211 return &sigact[sig]; 4212 } 4213 return NULL; 4214 } 4215 4216 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4217 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4218 sigact[sig] = oldAct; 4219 sigs |= (uint64_t)1 << (sig-1); 4220 } 4221 4222 // for diagnostic 4223 int sigflags[NSIG]; 4224 4225 int os::Linux::get_our_sigflags(int sig) { 4226 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4227 return sigflags[sig]; 4228 } 4229 4230 void os::Linux::set_our_sigflags(int sig, int flags) { 4231 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4232 if (sig > 0 && sig < NSIG) { 4233 sigflags[sig] = flags; 4234 } 4235 } 4236 4237 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4238 // Check for overwrite. 4239 struct sigaction oldAct; 4240 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4241 4242 void* oldhand = oldAct.sa_sigaction 4243 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4244 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4245 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4246 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4247 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4248 if (AllowUserSignalHandlers || !set_installed) { 4249 // Do not overwrite; user takes responsibility to forward to us. 4250 return; 4251 } else if (UseSignalChaining) { 4252 // save the old handler in jvm 4253 save_preinstalled_handler(sig, oldAct); 4254 // libjsig also interposes the sigaction() call below and saves the 4255 // old sigaction on it own. 4256 } else { 4257 fatal("Encountered unexpected pre-existing sigaction handler " 4258 "%#lx for signal %d.", (long)oldhand, sig); 4259 } 4260 } 4261 4262 struct sigaction sigAct; 4263 sigfillset(&(sigAct.sa_mask)); 4264 sigAct.sa_handler = SIG_DFL; 4265 if (!set_installed) { 4266 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4267 } else { 4268 sigAct.sa_sigaction = signalHandler; 4269 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4270 } 4271 // Save flags, which are set by ours 4272 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4273 sigflags[sig] = sigAct.sa_flags; 4274 4275 int ret = sigaction(sig, &sigAct, &oldAct); 4276 assert(ret == 0, "check"); 4277 4278 void* oldhand2 = oldAct.sa_sigaction 4279 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4280 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4281 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4282 } 4283 4284 // install signal handlers for signals that HotSpot needs to 4285 // handle in order to support Java-level exception handling. 4286 4287 void os::Linux::install_signal_handlers() { 4288 if (!signal_handlers_are_installed) { 4289 signal_handlers_are_installed = true; 4290 4291 // signal-chaining 4292 typedef void (*signal_setting_t)(); 4293 signal_setting_t begin_signal_setting = NULL; 4294 signal_setting_t end_signal_setting = NULL; 4295 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4296 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4297 if (begin_signal_setting != NULL) { 4298 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4299 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4300 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4301 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4302 libjsig_is_loaded = true; 4303 assert(UseSignalChaining, "should enable signal-chaining"); 4304 } 4305 if (libjsig_is_loaded) { 4306 // Tell libjsig jvm is setting signal handlers 4307 (*begin_signal_setting)(); 4308 } 4309 4310 set_signal_handler(SIGSEGV, true); 4311 set_signal_handler(SIGPIPE, true); 4312 set_signal_handler(SIGBUS, true); 4313 set_signal_handler(SIGILL, true); 4314 set_signal_handler(SIGFPE, true); 4315 #if defined(PPC64) 4316 set_signal_handler(SIGTRAP, true); 4317 #endif 4318 set_signal_handler(SIGXFSZ, true); 4319 4320 if (libjsig_is_loaded) { 4321 // Tell libjsig jvm finishes setting signal handlers 4322 (*end_signal_setting)(); 4323 } 4324 4325 // We don't activate signal checker if libjsig is in place, we trust ourselves 4326 // and if UserSignalHandler is installed all bets are off. 4327 // Log that signal checking is off only if -verbose:jni is specified. 4328 if (CheckJNICalls) { 4329 if (libjsig_is_loaded) { 4330 if (PrintJNIResolving) { 4331 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4332 } 4333 check_signals = false; 4334 } 4335 if (AllowUserSignalHandlers) { 4336 if (PrintJNIResolving) { 4337 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4338 } 4339 check_signals = false; 4340 } 4341 } 4342 } 4343 } 4344 4345 // This is the fastest way to get thread cpu time on Linux. 4346 // Returns cpu time (user+sys) for any thread, not only for current. 4347 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4348 // It might work on 2.6.10+ with a special kernel/glibc patch. 4349 // For reference, please, see IEEE Std 1003.1-2004: 4350 // http://www.unix.org/single_unix_specification 4351 4352 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4353 struct timespec tp; 4354 int rc = os::Linux::clock_gettime(clockid, &tp); 4355 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4356 4357 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4358 } 4359 4360 void os::Linux::initialize_os_info() { 4361 assert(_os_version == 0, "OS info already initialized"); 4362 4363 struct utsname _uname; 4364 4365 uint32_t major; 4366 uint32_t minor; 4367 uint32_t fix; 4368 4369 int rc; 4370 4371 // Kernel version is unknown if 4372 // verification below fails. 4373 _os_version = 0x01000000; 4374 4375 rc = uname(&_uname); 4376 if (rc != -1) { 4377 4378 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4379 if (rc == 3) { 4380 4381 if (major < 256 && minor < 256 && fix < 256) { 4382 // Kernel version format is as expected, 4383 // set it overriding unknown state. 4384 _os_version = (major << 16) | 4385 (minor << 8 ) | 4386 (fix << 0 ) ; 4387 } 4388 } 4389 } 4390 } 4391 4392 uint32_t os::Linux::os_version() { 4393 assert(_os_version != 0, "not initialized"); 4394 return _os_version & 0x00FFFFFF; 4395 } 4396 4397 bool os::Linux::os_version_is_known() { 4398 assert(_os_version != 0, "not initialized"); 4399 return _os_version & 0x01000000 ? false : true; 4400 } 4401 4402 ///// 4403 // glibc on Linux platform uses non-documented flag 4404 // to indicate, that some special sort of signal 4405 // trampoline is used. 4406 // We will never set this flag, and we should 4407 // ignore this flag in our diagnostic 4408 #ifdef SIGNIFICANT_SIGNAL_MASK 4409 #undef SIGNIFICANT_SIGNAL_MASK 4410 #endif 4411 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4412 4413 static const char* get_signal_handler_name(address handler, 4414 char* buf, int buflen) { 4415 int offset = 0; 4416 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4417 if (found) { 4418 // skip directory names 4419 const char *p1, *p2; 4420 p1 = buf; 4421 size_t len = strlen(os::file_separator()); 4422 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4423 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4424 } else { 4425 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4426 } 4427 return buf; 4428 } 4429 4430 static void print_signal_handler(outputStream* st, int sig, 4431 char* buf, size_t buflen) { 4432 struct sigaction sa; 4433 4434 sigaction(sig, NULL, &sa); 4435 4436 // See comment for SIGNIFICANT_SIGNAL_MASK define 4437 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4438 4439 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4440 4441 address handler = (sa.sa_flags & SA_SIGINFO) 4442 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4443 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4444 4445 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4446 st->print("SIG_DFL"); 4447 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4448 st->print("SIG_IGN"); 4449 } else { 4450 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4451 } 4452 4453 st->print(", sa_mask[0]="); 4454 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4455 4456 address rh = VMError::get_resetted_sighandler(sig); 4457 // May be, handler was resetted by VMError? 4458 if (rh != NULL) { 4459 handler = rh; 4460 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4461 } 4462 4463 st->print(", sa_flags="); 4464 os::Posix::print_sa_flags(st, sa.sa_flags); 4465 4466 // Check: is it our handler? 4467 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4468 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4469 // It is our signal handler 4470 // check for flags, reset system-used one! 4471 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4472 st->print( 4473 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4474 os::Linux::get_our_sigflags(sig)); 4475 } 4476 } 4477 st->cr(); 4478 } 4479 4480 4481 #define DO_SIGNAL_CHECK(sig) \ 4482 do { \ 4483 if (!sigismember(&check_signal_done, sig)) { \ 4484 os::Linux::check_signal_handler(sig); \ 4485 } \ 4486 } while (0) 4487 4488 // This method is a periodic task to check for misbehaving JNI applications 4489 // under CheckJNI, we can add any periodic checks here 4490 4491 void os::run_periodic_checks() { 4492 if (check_signals == false) return; 4493 4494 // SEGV and BUS if overridden could potentially prevent 4495 // generation of hs*.log in the event of a crash, debugging 4496 // such a case can be very challenging, so we absolutely 4497 // check the following for a good measure: 4498 DO_SIGNAL_CHECK(SIGSEGV); 4499 DO_SIGNAL_CHECK(SIGILL); 4500 DO_SIGNAL_CHECK(SIGFPE); 4501 DO_SIGNAL_CHECK(SIGBUS); 4502 DO_SIGNAL_CHECK(SIGPIPE); 4503 DO_SIGNAL_CHECK(SIGXFSZ); 4504 #if defined(PPC64) 4505 DO_SIGNAL_CHECK(SIGTRAP); 4506 #endif 4507 4508 // ReduceSignalUsage allows the user to override these handlers 4509 // see comments at the very top and jvm_solaris.h 4510 if (!ReduceSignalUsage) { 4511 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4512 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4513 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4514 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4515 } 4516 4517 DO_SIGNAL_CHECK(SR_signum); 4518 } 4519 4520 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4521 4522 static os_sigaction_t os_sigaction = NULL; 4523 4524 void os::Linux::check_signal_handler(int sig) { 4525 char buf[O_BUFLEN]; 4526 address jvmHandler = NULL; 4527 4528 4529 struct sigaction act; 4530 if (os_sigaction == NULL) { 4531 // only trust the default sigaction, in case it has been interposed 4532 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4533 if (os_sigaction == NULL) return; 4534 } 4535 4536 os_sigaction(sig, (struct sigaction*)NULL, &act); 4537 4538 4539 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4540 4541 address thisHandler = (act.sa_flags & SA_SIGINFO) 4542 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4543 : CAST_FROM_FN_PTR(address, act.sa_handler); 4544 4545 4546 switch (sig) { 4547 case SIGSEGV: 4548 case SIGBUS: 4549 case SIGFPE: 4550 case SIGPIPE: 4551 case SIGILL: 4552 case SIGXFSZ: 4553 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4554 break; 4555 4556 case SHUTDOWN1_SIGNAL: 4557 case SHUTDOWN2_SIGNAL: 4558 case SHUTDOWN3_SIGNAL: 4559 case BREAK_SIGNAL: 4560 jvmHandler = (address)user_handler(); 4561 break; 4562 4563 default: 4564 if (sig == SR_signum) { 4565 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4566 } else { 4567 return; 4568 } 4569 break; 4570 } 4571 4572 if (thisHandler != jvmHandler) { 4573 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4574 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4575 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4576 // No need to check this sig any longer 4577 sigaddset(&check_signal_done, sig); 4578 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4579 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4580 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4581 exception_name(sig, buf, O_BUFLEN)); 4582 } 4583 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4584 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4585 tty->print("expected:"); 4586 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4587 tty->cr(); 4588 tty->print(" found:"); 4589 os::Posix::print_sa_flags(tty, act.sa_flags); 4590 tty->cr(); 4591 // No need to check this sig any longer 4592 sigaddset(&check_signal_done, sig); 4593 } 4594 4595 // Dump all the signal 4596 if (sigismember(&check_signal_done, sig)) { 4597 print_signal_handlers(tty, buf, O_BUFLEN); 4598 } 4599 } 4600 4601 extern void report_error(char* file_name, int line_no, char* title, 4602 char* format, ...); 4603 4604 // this is called _before_ the most of global arguments have been parsed 4605 void os::init(void) { 4606 char dummy; // used to get a guess on initial stack address 4607 // first_hrtime = gethrtime(); 4608 4609 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4610 4611 init_random(1234567); 4612 4613 ThreadCritical::initialize(); 4614 4615 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4616 if (Linux::page_size() == -1) { 4617 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4618 strerror(errno)); 4619 } 4620 init_page_sizes((size_t) Linux::page_size()); 4621 4622 Linux::initialize_system_info(); 4623 4624 Linux::initialize_os_info(); 4625 4626 // main_thread points to the aboriginal thread 4627 Linux::_main_thread = pthread_self(); 4628 4629 Linux::clock_init(); 4630 initial_time_count = javaTimeNanos(); 4631 4632 // pthread_condattr initialization for monotonic clock 4633 int status; 4634 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4635 if ((status = pthread_condattr_init(_condattr)) != 0) { 4636 fatal("pthread_condattr_init: %s", strerror(status)); 4637 } 4638 // Only set the clock if CLOCK_MONOTONIC is available 4639 if (os::supports_monotonic_clock()) { 4640 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4641 if (status == EINVAL) { 4642 warning("Unable to use monotonic clock with relative timed-waits" \ 4643 " - changes to the time-of-day clock may have adverse affects"); 4644 } else { 4645 fatal("pthread_condattr_setclock: %s", strerror(status)); 4646 } 4647 } 4648 } 4649 // else it defaults to CLOCK_REALTIME 4650 4651 // retrieve entry point for pthread_setname_np 4652 Linux::_pthread_setname_np = 4653 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4654 4655 } 4656 4657 // To install functions for atexit system call 4658 extern "C" { 4659 static void perfMemory_exit_helper() { 4660 perfMemory_exit(); 4661 } 4662 } 4663 4664 // this is called _after_ the global arguments have been parsed 4665 jint os::init_2(void) { 4666 Linux::fast_thread_clock_init(); 4667 4668 // Allocate a single page and mark it as readable for safepoint polling 4669 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4670 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4671 4672 os::set_polling_page(polling_page); 4673 4674 #ifndef PRODUCT 4675 if (Verbose && PrintMiscellaneous) { 4676 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", 4677 (intptr_t)polling_page); 4678 } 4679 #endif 4680 4681 if (!UseMembar) { 4682 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4683 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4684 os::set_memory_serialize_page(mem_serialize_page); 4685 4686 #ifndef PRODUCT 4687 if (Verbose && PrintMiscellaneous) { 4688 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", 4689 (intptr_t)mem_serialize_page); 4690 } 4691 #endif 4692 } 4693 4694 // initialize suspend/resume support - must do this before signal_sets_init() 4695 if (SR_initialize() != 0) { 4696 perror("SR_initialize failed"); 4697 return JNI_ERR; 4698 } 4699 4700 Linux::signal_sets_init(); 4701 Linux::install_signal_handlers(); 4702 4703 // Check minimum allowable stack size for thread creation and to initialize 4704 // the java system classes, including StackOverflowError - depends on page 4705 // size. Add a page for compiler2 recursion in main thread. 4706 // Add in 2*BytesPerWord times page size to account for VM stack during 4707 // class initialization depending on 32 or 64 bit VM. 4708 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4709 JavaThread::stack_guard_zone_size() + 4710 JavaThread::stack_shadow_zone_size() + 4711 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4712 4713 size_t threadStackSizeInBytes = ThreadStackSize * K; 4714 if (threadStackSizeInBytes != 0 && 4715 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4716 tty->print_cr("\nThe stack size specified is too small, " 4717 "Specify at least " SIZE_FORMAT "k", 4718 os::Linux::min_stack_allowed/ K); 4719 return JNI_ERR; 4720 } 4721 4722 // Make the stack size a multiple of the page size so that 4723 // the yellow/red zones can be guarded. 4724 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4725 vm_page_size())); 4726 4727 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4728 4729 #if defined(IA32) 4730 workaround_expand_exec_shield_cs_limit(); 4731 #endif 4732 4733 Linux::libpthread_init(); 4734 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4735 tty->print_cr("[HotSpot is running with %s, %s]\n", 4736 Linux::glibc_version(), Linux::libpthread_version()); 4737 } 4738 4739 if (UseNUMA) { 4740 if (!Linux::libnuma_init()) { 4741 UseNUMA = false; 4742 } else { 4743 if ((Linux::numa_max_node() < 1)) { 4744 // There's only one node(they start from 0), disable NUMA. 4745 UseNUMA = false; 4746 } 4747 } 4748 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4749 // we can make the adaptive lgrp chunk resizing work. If the user specified 4750 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4751 // disable adaptive resizing. 4752 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4753 if (FLAG_IS_DEFAULT(UseNUMA)) { 4754 UseNUMA = false; 4755 } else { 4756 if (FLAG_IS_DEFAULT(UseLargePages) && 4757 FLAG_IS_DEFAULT(UseSHM) && 4758 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4759 UseLargePages = false; 4760 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4761 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4762 UseAdaptiveSizePolicy = false; 4763 UseAdaptiveNUMAChunkSizing = false; 4764 } 4765 } 4766 } 4767 if (!UseNUMA && ForceNUMA) { 4768 UseNUMA = true; 4769 } 4770 } 4771 4772 if (MaxFDLimit) { 4773 // set the number of file descriptors to max. print out error 4774 // if getrlimit/setrlimit fails but continue regardless. 4775 struct rlimit nbr_files; 4776 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4777 if (status != 0) { 4778 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4779 perror("os::init_2 getrlimit failed"); 4780 } 4781 } else { 4782 nbr_files.rlim_cur = nbr_files.rlim_max; 4783 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4784 if (status != 0) { 4785 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4786 perror("os::init_2 setrlimit failed"); 4787 } 4788 } 4789 } 4790 } 4791 4792 // Initialize lock used to serialize thread creation (see os::create_thread) 4793 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4794 4795 // at-exit methods are called in the reverse order of their registration. 4796 // atexit functions are called on return from main or as a result of a 4797 // call to exit(3C). There can be only 32 of these functions registered 4798 // and atexit() does not set errno. 4799 4800 if (PerfAllowAtExitRegistration) { 4801 // only register atexit functions if PerfAllowAtExitRegistration is set. 4802 // atexit functions can be delayed until process exit time, which 4803 // can be problematic for embedded VM situations. Embedded VMs should 4804 // call DestroyJavaVM() to assure that VM resources are released. 4805 4806 // note: perfMemory_exit_helper atexit function may be removed in 4807 // the future if the appropriate cleanup code can be added to the 4808 // VM_Exit VMOperation's doit method. 4809 if (atexit(perfMemory_exit_helper) != 0) { 4810 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4811 } 4812 } 4813 4814 // initialize thread priority policy 4815 prio_init(); 4816 4817 return JNI_OK; 4818 } 4819 4820 // Mark the polling page as unreadable 4821 void os::make_polling_page_unreadable(void) { 4822 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4823 fatal("Could not disable polling page"); 4824 } 4825 } 4826 4827 // Mark the polling page as readable 4828 void os::make_polling_page_readable(void) { 4829 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4830 fatal("Could not enable polling page"); 4831 } 4832 } 4833 4834 // older glibc versions don't have this macro (which expands to 4835 // an optimized bit-counting function) so we have to roll our own 4836 #ifndef CPU_COUNT 4837 4838 static int _cpu_count(const cpu_set_t* cpus) { 4839 int count = 0; 4840 // only look up to the number of configured processors 4841 for (int i = 0; i < os::processor_count(); i++) { 4842 if (CPU_ISSET(i, cpus)) { 4843 count++; 4844 } 4845 } 4846 return count; 4847 } 4848 4849 #define CPU_COUNT(cpus) _cpu_count(cpus) 4850 4851 #endif // CPU_COUNT 4852 4853 // Get the current number of available processors for this process. 4854 // This value can change at any time during a process's lifetime. 4855 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 4856 // If it appears there may be more than 1024 processors then we do a 4857 // dynamic check - see 6515172 for details. 4858 // If anything goes wrong we fallback to returning the number of online 4859 // processors - which can be greater than the number available to the process. 4860 int os::active_processor_count() { 4861 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 4862 cpu_set_t* cpus_p = &cpus; 4863 int cpus_size = sizeof(cpu_set_t); 4864 4865 int configured_cpus = processor_count(); // upper bound on available cpus 4866 int cpu_count = 0; 4867 4868 // old build platforms may not support dynamic cpu sets 4869 #ifdef CPU_ALLOC 4870 4871 // To enable easy testing of the dynamic path on different platforms we 4872 // introduce a diagnostic flag: UseCpuAllocPath 4873 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 4874 // kernel may use a mask bigger than cpu_set_t 4875 log_trace(os)("active_processor_count: using dynamic path %s" 4876 "- configured processors: %d", 4877 UseCpuAllocPath ? "(forced) " : "", 4878 configured_cpus); 4879 cpus_p = CPU_ALLOC(configured_cpus); 4880 if (cpus_p != NULL) { 4881 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 4882 // zero it just to be safe 4883 CPU_ZERO_S(cpus_size, cpus_p); 4884 } 4885 else { 4886 // failed to allocate so fallback to online cpus 4887 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4888 log_trace(os)("active_processor_count: " 4889 "CPU_ALLOC failed (%s) - using " 4890 "online processor count: %d", 4891 strerror(errno), online_cpus); 4892 return online_cpus; 4893 } 4894 } 4895 else { 4896 log_trace(os)("active_processor_count: using static path - configured processors: %d", 4897 configured_cpus); 4898 } 4899 #else // CPU_ALLOC 4900 // these stubs won't be executed 4901 #define CPU_COUNT_S(size, cpus) -1 4902 #define CPU_FREE(cpus) 4903 4904 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 4905 configured_cpus); 4906 #endif // CPU_ALLOC 4907 4908 // pid 0 means the current thread - which we have to assume represents the process 4909 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 4910 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4911 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 4912 } 4913 else { 4914 cpu_count = CPU_COUNT(cpus_p); 4915 } 4916 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 4917 } 4918 else { 4919 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 4920 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 4921 "which may exceed available processors", strerror(errno), cpu_count); 4922 } 4923 4924 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4925 CPU_FREE(cpus_p); 4926 } 4927 4928 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check"); 4929 return cpu_count; 4930 } 4931 4932 void os::set_native_thread_name(const char *name) { 4933 if (Linux::_pthread_setname_np) { 4934 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 4935 snprintf(buf, sizeof(buf), "%s", name); 4936 buf[sizeof(buf) - 1] = '\0'; 4937 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 4938 // ERANGE should not happen; all other errors should just be ignored. 4939 assert(rc != ERANGE, "pthread_setname_np failed"); 4940 } 4941 } 4942 4943 bool os::distribute_processes(uint length, uint* distribution) { 4944 // Not yet implemented. 4945 return false; 4946 } 4947 4948 bool os::bind_to_processor(uint processor_id) { 4949 // Not yet implemented. 4950 return false; 4951 } 4952 4953 /// 4954 4955 void os::SuspendedThreadTask::internal_do_task() { 4956 if (do_suspend(_thread->osthread())) { 4957 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4958 do_task(context); 4959 do_resume(_thread->osthread()); 4960 } 4961 } 4962 4963 class PcFetcher : public os::SuspendedThreadTask { 4964 public: 4965 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4966 ExtendedPC result(); 4967 protected: 4968 void do_task(const os::SuspendedThreadTaskContext& context); 4969 private: 4970 ExtendedPC _epc; 4971 }; 4972 4973 ExtendedPC PcFetcher::result() { 4974 guarantee(is_done(), "task is not done yet."); 4975 return _epc; 4976 } 4977 4978 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4979 Thread* thread = context.thread(); 4980 OSThread* osthread = thread->osthread(); 4981 if (osthread->ucontext() != NULL) { 4982 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext()); 4983 } else { 4984 // NULL context is unexpected, double-check this is the VMThread 4985 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4986 } 4987 } 4988 4989 // Suspends the target using the signal mechanism and then grabs the PC before 4990 // resuming the target. Used by the flat-profiler only 4991 ExtendedPC os::get_thread_pc(Thread* thread) { 4992 // Make sure that it is called by the watcher for the VMThread 4993 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4994 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4995 4996 PcFetcher fetcher(thread); 4997 fetcher.run(); 4998 return fetcher.result(); 4999 } 5000 5001 //////////////////////////////////////////////////////////////////////////////// 5002 // debug support 5003 5004 bool os::find(address addr, outputStream* st) { 5005 Dl_info dlinfo; 5006 memset(&dlinfo, 0, sizeof(dlinfo)); 5007 if (dladdr(addr, &dlinfo) != 0) { 5008 st->print(PTR_FORMAT ": ", p2i(addr)); 5009 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5010 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5011 p2i(addr) - p2i(dlinfo.dli_saddr)); 5012 } else if (dlinfo.dli_fbase != NULL) { 5013 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5014 } else { 5015 st->print("<absolute address>"); 5016 } 5017 if (dlinfo.dli_fname != NULL) { 5018 st->print(" in %s", dlinfo.dli_fname); 5019 } 5020 if (dlinfo.dli_fbase != NULL) { 5021 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5022 } 5023 st->cr(); 5024 5025 if (Verbose) { 5026 // decode some bytes around the PC 5027 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5028 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5029 address lowest = (address) dlinfo.dli_sname; 5030 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5031 if (begin < lowest) begin = lowest; 5032 Dl_info dlinfo2; 5033 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5034 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5035 end = (address) dlinfo2.dli_saddr; 5036 } 5037 Disassembler::decode(begin, end, st); 5038 } 5039 return true; 5040 } 5041 return false; 5042 } 5043 5044 //////////////////////////////////////////////////////////////////////////////// 5045 // misc 5046 5047 // This does not do anything on Linux. This is basically a hook for being 5048 // able to use structured exception handling (thread-local exception filters) 5049 // on, e.g., Win32. 5050 void 5051 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5052 JavaCallArguments* args, Thread* thread) { 5053 f(value, method, args, thread); 5054 } 5055 5056 void os::print_statistics() { 5057 } 5058 5059 bool os::message_box(const char* title, const char* message) { 5060 int i; 5061 fdStream err(defaultStream::error_fd()); 5062 for (i = 0; i < 78; i++) err.print_raw("="); 5063 err.cr(); 5064 err.print_raw_cr(title); 5065 for (i = 0; i < 78; i++) err.print_raw("-"); 5066 err.cr(); 5067 err.print_raw_cr(message); 5068 for (i = 0; i < 78; i++) err.print_raw("="); 5069 err.cr(); 5070 5071 char buf[16]; 5072 // Prevent process from exiting upon "read error" without consuming all CPU 5073 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5074 5075 return buf[0] == 'y' || buf[0] == 'Y'; 5076 } 5077 5078 int os::stat(const char *path, struct stat *sbuf) { 5079 char pathbuf[MAX_PATH]; 5080 if (strlen(path) > MAX_PATH - 1) { 5081 errno = ENAMETOOLONG; 5082 return -1; 5083 } 5084 os::native_path(strcpy(pathbuf, path)); 5085 return ::stat(pathbuf, sbuf); 5086 } 5087 5088 bool os::check_heap(bool force) { 5089 return true; 5090 } 5091 5092 // Is a (classpath) directory empty? 5093 bool os::dir_is_empty(const char* path) { 5094 DIR *dir = NULL; 5095 struct dirent *ptr; 5096 5097 dir = opendir(path); 5098 if (dir == NULL) return true; 5099 5100 // Scan the directory 5101 bool result = true; 5102 char buf[sizeof(struct dirent) + MAX_PATH]; 5103 while (result && (ptr = ::readdir(dir)) != NULL) { 5104 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5105 result = false; 5106 } 5107 } 5108 closedir(dir); 5109 return result; 5110 } 5111 5112 // This code originates from JDK's sysOpen and open64_w 5113 // from src/solaris/hpi/src/system_md.c 5114 5115 int os::open(const char *path, int oflag, int mode) { 5116 if (strlen(path) > MAX_PATH - 1) { 5117 errno = ENAMETOOLONG; 5118 return -1; 5119 } 5120 5121 // All file descriptors that are opened in the Java process and not 5122 // specifically destined for a subprocess should have the close-on-exec 5123 // flag set. If we don't set it, then careless 3rd party native code 5124 // might fork and exec without closing all appropriate file descriptors 5125 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5126 // turn might: 5127 // 5128 // - cause end-of-file to fail to be detected on some file 5129 // descriptors, resulting in mysterious hangs, or 5130 // 5131 // - might cause an fopen in the subprocess to fail on a system 5132 // suffering from bug 1085341. 5133 // 5134 // (Yes, the default setting of the close-on-exec flag is a Unix 5135 // design flaw) 5136 // 5137 // See: 5138 // 1085341: 32-bit stdio routines should support file descriptors >255 5139 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5140 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5141 // 5142 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5143 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5144 // because it saves a system call and removes a small window where the flag 5145 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5146 // and we fall back to using FD_CLOEXEC (see below). 5147 #ifdef O_CLOEXEC 5148 oflag |= O_CLOEXEC; 5149 #endif 5150 5151 int fd = ::open64(path, oflag, mode); 5152 if (fd == -1) return -1; 5153 5154 //If the open succeeded, the file might still be a directory 5155 { 5156 struct stat64 buf64; 5157 int ret = ::fstat64(fd, &buf64); 5158 int st_mode = buf64.st_mode; 5159 5160 if (ret != -1) { 5161 if ((st_mode & S_IFMT) == S_IFDIR) { 5162 errno = EISDIR; 5163 ::close(fd); 5164 return -1; 5165 } 5166 } else { 5167 ::close(fd); 5168 return -1; 5169 } 5170 } 5171 5172 #ifdef FD_CLOEXEC 5173 // Validate that the use of the O_CLOEXEC flag on open above worked. 5174 // With recent kernels, we will perform this check exactly once. 5175 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5176 if (!O_CLOEXEC_is_known_to_work) { 5177 int flags = ::fcntl(fd, F_GETFD); 5178 if (flags != -1) { 5179 if ((flags & FD_CLOEXEC) != 0) 5180 O_CLOEXEC_is_known_to_work = 1; 5181 else 5182 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5183 } 5184 } 5185 #endif 5186 5187 return fd; 5188 } 5189 5190 5191 // create binary file, rewriting existing file if required 5192 int os::create_binary_file(const char* path, bool rewrite_existing) { 5193 int oflags = O_WRONLY | O_CREAT; 5194 if (!rewrite_existing) { 5195 oflags |= O_EXCL; 5196 } 5197 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5198 } 5199 5200 // return current position of file pointer 5201 jlong os::current_file_offset(int fd) { 5202 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5203 } 5204 5205 // move file pointer to the specified offset 5206 jlong os::seek_to_file_offset(int fd, jlong offset) { 5207 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5208 } 5209 5210 // This code originates from JDK's sysAvailable 5211 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5212 5213 int os::available(int fd, jlong *bytes) { 5214 jlong cur, end; 5215 int mode; 5216 struct stat64 buf64; 5217 5218 if (::fstat64(fd, &buf64) >= 0) { 5219 mode = buf64.st_mode; 5220 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5221 int n; 5222 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5223 *bytes = n; 5224 return 1; 5225 } 5226 } 5227 } 5228 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5229 return 0; 5230 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5231 return 0; 5232 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5233 return 0; 5234 } 5235 *bytes = end - cur; 5236 return 1; 5237 } 5238 5239 // Map a block of memory. 5240 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5241 char *addr, size_t bytes, bool read_only, 5242 bool allow_exec) { 5243 int prot; 5244 int flags = MAP_PRIVATE; 5245 5246 if (read_only) { 5247 prot = PROT_READ; 5248 } else { 5249 prot = PROT_READ | PROT_WRITE; 5250 } 5251 5252 if (allow_exec) { 5253 prot |= PROT_EXEC; 5254 } 5255 5256 if (addr != NULL) { 5257 flags |= MAP_FIXED; 5258 } 5259 5260 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5261 fd, file_offset); 5262 if (mapped_address == MAP_FAILED) { 5263 return NULL; 5264 } 5265 return mapped_address; 5266 } 5267 5268 5269 // Remap a block of memory. 5270 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5271 char *addr, size_t bytes, bool read_only, 5272 bool allow_exec) { 5273 // same as map_memory() on this OS 5274 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5275 allow_exec); 5276 } 5277 5278 5279 // Unmap a block of memory. 5280 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5281 return munmap(addr, bytes) == 0; 5282 } 5283 5284 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5285 5286 static clockid_t thread_cpu_clockid(Thread* thread) { 5287 pthread_t tid = thread->osthread()->pthread_id(); 5288 clockid_t clockid; 5289 5290 // Get thread clockid 5291 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5292 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5293 return clockid; 5294 } 5295 5296 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5297 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5298 // of a thread. 5299 // 5300 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5301 // the fast estimate available on the platform. 5302 5303 jlong os::current_thread_cpu_time() { 5304 if (os::Linux::supports_fast_thread_cpu_time()) { 5305 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5306 } else { 5307 // return user + sys since the cost is the same 5308 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5309 } 5310 } 5311 5312 jlong os::thread_cpu_time(Thread* thread) { 5313 // consistent with what current_thread_cpu_time() returns 5314 if (os::Linux::supports_fast_thread_cpu_time()) { 5315 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5316 } else { 5317 return slow_thread_cpu_time(thread, true /* user + sys */); 5318 } 5319 } 5320 5321 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5322 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5323 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5324 } else { 5325 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5326 } 5327 } 5328 5329 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5330 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5331 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5332 } else { 5333 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5334 } 5335 } 5336 5337 // -1 on error. 5338 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5339 pid_t tid = thread->osthread()->thread_id(); 5340 char *s; 5341 char stat[2048]; 5342 int statlen; 5343 char proc_name[64]; 5344 int count; 5345 long sys_time, user_time; 5346 char cdummy; 5347 int idummy; 5348 long ldummy; 5349 FILE *fp; 5350 5351 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5352 fp = fopen(proc_name, "r"); 5353 if (fp == NULL) return -1; 5354 statlen = fread(stat, 1, 2047, fp); 5355 stat[statlen] = '\0'; 5356 fclose(fp); 5357 5358 // Skip pid and the command string. Note that we could be dealing with 5359 // weird command names, e.g. user could decide to rename java launcher 5360 // to "java 1.4.2 :)", then the stat file would look like 5361 // 1234 (java 1.4.2 :)) R ... ... 5362 // We don't really need to know the command string, just find the last 5363 // occurrence of ")" and then start parsing from there. See bug 4726580. 5364 s = strrchr(stat, ')'); 5365 if (s == NULL) return -1; 5366 5367 // Skip blank chars 5368 do { s++; } while (s && isspace(*s)); 5369 5370 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5371 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5372 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5373 &user_time, &sys_time); 5374 if (count != 13) return -1; 5375 if (user_sys_cpu_time) { 5376 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5377 } else { 5378 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5379 } 5380 } 5381 5382 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5383 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5384 info_ptr->may_skip_backward = false; // elapsed time not wall time 5385 info_ptr->may_skip_forward = false; // elapsed time not wall time 5386 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5387 } 5388 5389 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5390 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5391 info_ptr->may_skip_backward = false; // elapsed time not wall time 5392 info_ptr->may_skip_forward = false; // elapsed time not wall time 5393 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5394 } 5395 5396 bool os::is_thread_cpu_time_supported() { 5397 return true; 5398 } 5399 5400 // System loadavg support. Returns -1 if load average cannot be obtained. 5401 // Linux doesn't yet have a (official) notion of processor sets, 5402 // so just return the system wide load average. 5403 int os::loadavg(double loadavg[], int nelem) { 5404 return ::getloadavg(loadavg, nelem); 5405 } 5406 5407 void os::pause() { 5408 char filename[MAX_PATH]; 5409 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5410 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5411 } else { 5412 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5413 } 5414 5415 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5416 if (fd != -1) { 5417 struct stat buf; 5418 ::close(fd); 5419 while (::stat(filename, &buf) == 0) { 5420 (void)::poll(NULL, 0, 100); 5421 } 5422 } else { 5423 jio_fprintf(stderr, 5424 "Could not open pause file '%s', continuing immediately.\n", filename); 5425 } 5426 } 5427 5428 5429 // Refer to the comments in os_solaris.cpp park-unpark. The next two 5430 // comment paragraphs are worth repeating here: 5431 // 5432 // Assumption: 5433 // Only one parker can exist on an event, which is why we allocate 5434 // them per-thread. Multiple unparkers can coexist. 5435 // 5436 // _Event serves as a restricted-range semaphore. 5437 // -1 : thread is blocked, i.e. there is a waiter 5438 // 0 : neutral: thread is running or ready, 5439 // could have been signaled after a wait started 5440 // 1 : signaled - thread is running or ready 5441 // 5442 5443 // utility to compute the abstime argument to timedwait: 5444 // millis is the relative timeout time 5445 // abstime will be the absolute timeout time 5446 // TODO: replace compute_abstime() with unpackTime() 5447 5448 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5449 if (millis < 0) millis = 0; 5450 5451 jlong seconds = millis / 1000; 5452 millis %= 1000; 5453 if (seconds > 50000000) { // see man cond_timedwait(3T) 5454 seconds = 50000000; 5455 } 5456 5457 if (os::supports_monotonic_clock()) { 5458 struct timespec now; 5459 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5460 assert_status(status == 0, status, "clock_gettime"); 5461 abstime->tv_sec = now.tv_sec + seconds; 5462 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5463 if (nanos >= NANOSECS_PER_SEC) { 5464 abstime->tv_sec += 1; 5465 nanos -= NANOSECS_PER_SEC; 5466 } 5467 abstime->tv_nsec = nanos; 5468 } else { 5469 struct timeval now; 5470 int status = gettimeofday(&now, NULL); 5471 assert(status == 0, "gettimeofday"); 5472 abstime->tv_sec = now.tv_sec + seconds; 5473 long usec = now.tv_usec + millis * 1000; 5474 if (usec >= 1000000) { 5475 abstime->tv_sec += 1; 5476 usec -= 1000000; 5477 } 5478 abstime->tv_nsec = usec * 1000; 5479 } 5480 return abstime; 5481 } 5482 5483 void os::PlatformEvent::park() { // AKA "down()" 5484 // Transitions for _Event: 5485 // -1 => -1 : illegal 5486 // 1 => 0 : pass - return immediately 5487 // 0 => -1 : block; then set _Event to 0 before returning 5488 5489 // Invariant: Only the thread associated with the Event/PlatformEvent 5490 // may call park(). 5491 // TODO: assert that _Assoc != NULL or _Assoc == Self 5492 assert(_nParked == 0, "invariant"); 5493 5494 int v; 5495 for (;;) { 5496 v = _Event; 5497 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5498 } 5499 guarantee(v >= 0, "invariant"); 5500 if (v == 0) { 5501 // Do this the hard way by blocking ... 5502 int status = pthread_mutex_lock(_mutex); 5503 assert_status(status == 0, status, "mutex_lock"); 5504 guarantee(_nParked == 0, "invariant"); 5505 ++_nParked; 5506 while (_Event < 0) { 5507 status = pthread_cond_wait(_cond, _mutex); 5508 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5509 // Treat this the same as if the wait was interrupted 5510 if (status == ETIME) { status = EINTR; } 5511 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5512 } 5513 --_nParked; 5514 5515 _Event = 0; 5516 status = pthread_mutex_unlock(_mutex); 5517 assert_status(status == 0, status, "mutex_unlock"); 5518 // Paranoia to ensure our locked and lock-free paths interact 5519 // correctly with each other. 5520 OrderAccess::fence(); 5521 } 5522 guarantee(_Event >= 0, "invariant"); 5523 } 5524 5525 int os::PlatformEvent::park(jlong millis) { 5526 // Transitions for _Event: 5527 // -1 => -1 : illegal 5528 // 1 => 0 : pass - return immediately 5529 // 0 => -1 : block; then set _Event to 0 before returning 5530 5531 guarantee(_nParked == 0, "invariant"); 5532 5533 int v; 5534 for (;;) { 5535 v = _Event; 5536 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5537 } 5538 guarantee(v >= 0, "invariant"); 5539 if (v != 0) return OS_OK; 5540 5541 // We do this the hard way, by blocking the thread. 5542 // Consider enforcing a minimum timeout value. 5543 struct timespec abst; 5544 compute_abstime(&abst, millis); 5545 5546 int ret = OS_TIMEOUT; 5547 int status = pthread_mutex_lock(_mutex); 5548 assert_status(status == 0, status, "mutex_lock"); 5549 guarantee(_nParked == 0, "invariant"); 5550 ++_nParked; 5551 5552 // Object.wait(timo) will return because of 5553 // (a) notification 5554 // (b) timeout 5555 // (c) thread.interrupt 5556 // 5557 // Thread.interrupt and object.notify{All} both call Event::set. 5558 // That is, we treat thread.interrupt as a special case of notification. 5559 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5560 // We assume all ETIME returns are valid. 5561 // 5562 // TODO: properly differentiate simultaneous notify+interrupt. 5563 // In that case, we should propagate the notify to another waiter. 5564 5565 while (_Event < 0) { 5566 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5567 assert_status(status == 0 || status == EINTR || 5568 status == ETIME || status == ETIMEDOUT, 5569 status, "cond_timedwait"); 5570 if (!FilterSpuriousWakeups) break; // previous semantics 5571 if (status == ETIME || status == ETIMEDOUT) break; 5572 // We consume and ignore EINTR and spurious wakeups. 5573 } 5574 --_nParked; 5575 if (_Event >= 0) { 5576 ret = OS_OK; 5577 } 5578 _Event = 0; 5579 status = pthread_mutex_unlock(_mutex); 5580 assert_status(status == 0, status, "mutex_unlock"); 5581 assert(_nParked == 0, "invariant"); 5582 // Paranoia to ensure our locked and lock-free paths interact 5583 // correctly with each other. 5584 OrderAccess::fence(); 5585 return ret; 5586 } 5587 5588 void os::PlatformEvent::unpark() { 5589 // Transitions for _Event: 5590 // 0 => 1 : just return 5591 // 1 => 1 : just return 5592 // -1 => either 0 or 1; must signal target thread 5593 // That is, we can safely transition _Event from -1 to either 5594 // 0 or 1. 5595 // See also: "Semaphores in Plan 9" by Mullender & Cox 5596 // 5597 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5598 // that it will take two back-to-back park() calls for the owning 5599 // thread to block. This has the benefit of forcing a spurious return 5600 // from the first park() call after an unpark() call which will help 5601 // shake out uses of park() and unpark() without condition variables. 5602 5603 if (Atomic::xchg(1, &_Event) >= 0) return; 5604 5605 // Wait for the thread associated with the event to vacate 5606 int status = pthread_mutex_lock(_mutex); 5607 assert_status(status == 0, status, "mutex_lock"); 5608 int AnyWaiters = _nParked; 5609 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5610 status = pthread_mutex_unlock(_mutex); 5611 assert_status(status == 0, status, "mutex_unlock"); 5612 if (AnyWaiters != 0) { 5613 // Note that we signal() *after* dropping the lock for "immortal" Events. 5614 // This is safe and avoids a common class of futile wakeups. In rare 5615 // circumstances this can cause a thread to return prematurely from 5616 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5617 // will simply re-test the condition and re-park itself. 5618 // This provides particular benefit if the underlying platform does not 5619 // provide wait morphing. 5620 status = pthread_cond_signal(_cond); 5621 assert_status(status == 0, status, "cond_signal"); 5622 } 5623 } 5624 5625 5626 // JSR166 5627 // ------------------------------------------------------- 5628 5629 // The solaris and linux implementations of park/unpark are fairly 5630 // conservative for now, but can be improved. They currently use a 5631 // mutex/condvar pair, plus a a count. 5632 // Park decrements count if > 0, else does a condvar wait. Unpark 5633 // sets count to 1 and signals condvar. Only one thread ever waits 5634 // on the condvar. Contention seen when trying to park implies that someone 5635 // is unparking you, so don't wait. And spurious returns are fine, so there 5636 // is no need to track notifications. 5637 5638 // This code is common to linux and solaris and will be moved to a 5639 // common place in dolphin. 5640 // 5641 // The passed in time value is either a relative time in nanoseconds 5642 // or an absolute time in milliseconds. Either way it has to be unpacked 5643 // into suitable seconds and nanoseconds components and stored in the 5644 // given timespec structure. 5645 // Given time is a 64-bit value and the time_t used in the timespec is only 5646 // a signed-32-bit value (except on 64-bit Linux) we have to watch for 5647 // overflow if times way in the future are given. Further on Solaris versions 5648 // prior to 10 there is a restriction (see cond_timedwait) that the specified 5649 // number of seconds, in abstime, is less than current_time + 100,000,000. 5650 // As it will be 28 years before "now + 100000000" will overflow we can 5651 // ignore overflow and just impose a hard-limit on seconds using the value 5652 // of "now + 100,000,000". This places a limit on the timeout of about 3.17 5653 // years from "now". 5654 5655 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5656 assert(time > 0, "convertTime"); 5657 time_t max_secs = 0; 5658 5659 if (!os::supports_monotonic_clock() || isAbsolute) { 5660 struct timeval now; 5661 int status = gettimeofday(&now, NULL); 5662 assert(status == 0, "gettimeofday"); 5663 5664 max_secs = now.tv_sec + MAX_SECS; 5665 5666 if (isAbsolute) { 5667 jlong secs = time / 1000; 5668 if (secs > max_secs) { 5669 absTime->tv_sec = max_secs; 5670 } else { 5671 absTime->tv_sec = secs; 5672 } 5673 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5674 } else { 5675 jlong secs = time / NANOSECS_PER_SEC; 5676 if (secs >= MAX_SECS) { 5677 absTime->tv_sec = max_secs; 5678 absTime->tv_nsec = 0; 5679 } else { 5680 absTime->tv_sec = now.tv_sec + secs; 5681 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5682 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5683 absTime->tv_nsec -= NANOSECS_PER_SEC; 5684 ++absTime->tv_sec; // note: this must be <= max_secs 5685 } 5686 } 5687 } 5688 } else { 5689 // must be relative using monotonic clock 5690 struct timespec now; 5691 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5692 assert_status(status == 0, status, "clock_gettime"); 5693 max_secs = now.tv_sec + MAX_SECS; 5694 jlong secs = time / NANOSECS_PER_SEC; 5695 if (secs >= MAX_SECS) { 5696 absTime->tv_sec = max_secs; 5697 absTime->tv_nsec = 0; 5698 } else { 5699 absTime->tv_sec = now.tv_sec + secs; 5700 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5701 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5702 absTime->tv_nsec -= NANOSECS_PER_SEC; 5703 ++absTime->tv_sec; // note: this must be <= max_secs 5704 } 5705 } 5706 } 5707 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5708 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5709 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5710 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5711 } 5712 5713 void Parker::park(bool isAbsolute, jlong time) { 5714 // Ideally we'd do something useful while spinning, such 5715 // as calling unpackTime(). 5716 5717 // Optional fast-path check: 5718 // Return immediately if a permit is available. 5719 // We depend on Atomic::xchg() having full barrier semantics 5720 // since we are doing a lock-free update to _counter. 5721 if (Atomic::xchg(0, &_counter) > 0) return; 5722 5723 Thread* thread = Thread::current(); 5724 assert(thread->is_Java_thread(), "Must be JavaThread"); 5725 JavaThread *jt = (JavaThread *)thread; 5726 5727 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5728 // Check interrupt before trying to wait 5729 if (Thread::is_interrupted(thread, false)) { 5730 return; 5731 } 5732 5733 // Next, demultiplex/decode time arguments 5734 timespec absTime; 5735 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5736 return; 5737 } 5738 if (time > 0) { 5739 unpackTime(&absTime, isAbsolute, time); 5740 } 5741 5742 5743 // Enter safepoint region 5744 // Beware of deadlocks such as 6317397. 5745 // The per-thread Parker:: mutex is a classic leaf-lock. 5746 // In particular a thread must never block on the Threads_lock while 5747 // holding the Parker:: mutex. If safepoints are pending both the 5748 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5749 ThreadBlockInVM tbivm(jt); 5750 5751 // Don't wait if cannot get lock since interference arises from 5752 // unblocking. Also. check interrupt before trying wait 5753 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5754 return; 5755 } 5756 5757 int status; 5758 if (_counter > 0) { // no wait needed 5759 _counter = 0; 5760 status = pthread_mutex_unlock(_mutex); 5761 assert_status(status == 0, status, "invariant"); 5762 // Paranoia to ensure our locked and lock-free paths interact 5763 // correctly with each other and Java-level accesses. 5764 OrderAccess::fence(); 5765 return; 5766 } 5767 5768 #ifdef ASSERT 5769 // Don't catch signals while blocked; let the running threads have the signals. 5770 // (This allows a debugger to break into the running thread.) 5771 sigset_t oldsigs; 5772 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5773 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5774 #endif 5775 5776 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5777 jt->set_suspend_equivalent(); 5778 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5779 5780 assert(_cur_index == -1, "invariant"); 5781 if (time == 0) { 5782 _cur_index = REL_INDEX; // arbitrary choice when not timed 5783 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5784 } else { 5785 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5786 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5787 } 5788 _cur_index = -1; 5789 assert_status(status == 0 || status == EINTR || 5790 status == ETIME || status == ETIMEDOUT, 5791 status, "cond_timedwait"); 5792 5793 #ifdef ASSERT 5794 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5795 #endif 5796 5797 _counter = 0; 5798 status = pthread_mutex_unlock(_mutex); 5799 assert_status(status == 0, status, "invariant"); 5800 // Paranoia to ensure our locked and lock-free paths interact 5801 // correctly with each other and Java-level accesses. 5802 OrderAccess::fence(); 5803 5804 // If externally suspended while waiting, re-suspend 5805 if (jt->handle_special_suspend_equivalent_condition()) { 5806 jt->java_suspend_self(); 5807 } 5808 } 5809 5810 void Parker::unpark() { 5811 int status = pthread_mutex_lock(_mutex); 5812 assert_status(status == 0, status, "invariant"); 5813 const int s = _counter; 5814 _counter = 1; 5815 // must capture correct index before unlocking 5816 int index = _cur_index; 5817 status = pthread_mutex_unlock(_mutex); 5818 assert_status(status == 0, status, "invariant"); 5819 if (s < 1 && index != -1) { 5820 // thread is definitely parked 5821 status = pthread_cond_signal(&_cond[index]); 5822 assert_status(status == 0, status, "invariant"); 5823 } 5824 } 5825 5826 5827 extern char** environ; 5828 5829 // Run the specified command in a separate process. Return its exit value, 5830 // or -1 on failure (e.g. can't fork a new process). 5831 // Unlike system(), this function can be called from signal handler. It 5832 // doesn't block SIGINT et al. 5833 int os::fork_and_exec(char* cmd) { 5834 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5835 5836 pid_t pid = fork(); 5837 5838 if (pid < 0) { 5839 // fork failed 5840 return -1; 5841 5842 } else if (pid == 0) { 5843 // child process 5844 5845 execve("/bin/sh", (char* const*)argv, environ); 5846 5847 // execve failed 5848 _exit(-1); 5849 5850 } else { 5851 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5852 // care about the actual exit code, for now. 5853 5854 int status; 5855 5856 // Wait for the child process to exit. This returns immediately if 5857 // the child has already exited. */ 5858 while (waitpid(pid, &status, 0) < 0) { 5859 switch (errno) { 5860 case ECHILD: return 0; 5861 case EINTR: break; 5862 default: return -1; 5863 } 5864 } 5865 5866 if (WIFEXITED(status)) { 5867 // The child exited normally; get its exit code. 5868 return WEXITSTATUS(status); 5869 } else if (WIFSIGNALED(status)) { 5870 // The child exited because of a signal 5871 // The best value to return is 0x80 + signal number, 5872 // because that is what all Unix shells do, and because 5873 // it allows callers to distinguish between process exit and 5874 // process death by signal. 5875 return 0x80 + WTERMSIG(status); 5876 } else { 5877 // Unknown exit code; pass it through 5878 return status; 5879 } 5880 } 5881 } 5882 5883 // is_headless_jre() 5884 // 5885 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5886 // in order to report if we are running in a headless jre 5887 // 5888 // Since JDK8 xawt/libmawt.so was moved into the same directory 5889 // as libawt.so, and renamed libawt_xawt.so 5890 // 5891 bool os::is_headless_jre() { 5892 struct stat statbuf; 5893 char buf[MAXPATHLEN]; 5894 char libmawtpath[MAXPATHLEN]; 5895 const char *xawtstr = "/xawt/libmawt.so"; 5896 const char *new_xawtstr = "/libawt_xawt.so"; 5897 char *p; 5898 5899 // Get path to libjvm.so 5900 os::jvm_path(buf, sizeof(buf)); 5901 5902 // Get rid of libjvm.so 5903 p = strrchr(buf, '/'); 5904 if (p == NULL) { 5905 return false; 5906 } else { 5907 *p = '\0'; 5908 } 5909 5910 // Get rid of client or server 5911 p = strrchr(buf, '/'); 5912 if (p == NULL) { 5913 return false; 5914 } else { 5915 *p = '\0'; 5916 } 5917 5918 // check xawt/libmawt.so 5919 strcpy(libmawtpath, buf); 5920 strcat(libmawtpath, xawtstr); 5921 if (::stat(libmawtpath, &statbuf) == 0) return false; 5922 5923 // check libawt_xawt.so 5924 strcpy(libmawtpath, buf); 5925 strcat(libmawtpath, new_xawtstr); 5926 if (::stat(libmawtpath, &statbuf) == 0) return false; 5927 5928 return true; 5929 } 5930 5931 // Get the default path to the core file 5932 // Returns the length of the string 5933 int os::get_core_path(char* buffer, size_t bufferSize) { 5934 /* 5935 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5936 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5937 */ 5938 const int core_pattern_len = 129; 5939 char core_pattern[core_pattern_len] = {0}; 5940 5941 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5942 if (core_pattern_file == -1) { 5943 return -1; 5944 } 5945 5946 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5947 ::close(core_pattern_file); 5948 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5949 return -1; 5950 } 5951 if (core_pattern[ret-1] == '\n') { 5952 core_pattern[ret-1] = '\0'; 5953 } else { 5954 core_pattern[ret] = '\0'; 5955 } 5956 5957 char *pid_pos = strstr(core_pattern, "%p"); 5958 int written; 5959 5960 if (core_pattern[0] == '/') { 5961 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5962 } else { 5963 char cwd[PATH_MAX]; 5964 5965 const char* p = get_current_directory(cwd, PATH_MAX); 5966 if (p == NULL) { 5967 return -1; 5968 } 5969 5970 if (core_pattern[0] == '|') { 5971 written = jio_snprintf(buffer, bufferSize, 5972 "\"%s\" (or dumping to %s/core.%d)", 5973 &core_pattern[1], p, current_process_id()); 5974 } else { 5975 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5976 } 5977 } 5978 5979 if (written < 0) { 5980 return -1; 5981 } 5982 5983 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5984 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5985 5986 if (core_uses_pid_file != -1) { 5987 char core_uses_pid = 0; 5988 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5989 ::close(core_uses_pid_file); 5990 5991 if (core_uses_pid == '1') { 5992 jio_snprintf(buffer + written, bufferSize - written, 5993 ".%d", current_process_id()); 5994 } 5995 } 5996 } 5997 5998 return strlen(buffer); 5999 } 6000 6001 bool os::start_debugging(char *buf, int buflen) { 6002 int len = (int)strlen(buf); 6003 char *p = &buf[len]; 6004 6005 jio_snprintf(p, buflen-len, 6006 "\n\n" 6007 "Do you want to debug the problem?\n\n" 6008 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6009 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6010 "Otherwise, press RETURN to abort...", 6011 os::current_process_id(), os::current_process_id(), 6012 os::current_thread_id(), os::current_thread_id()); 6013 6014 bool yes = os::message_box("Unexpected Error", buf); 6015 6016 if (yes) { 6017 // yes, user asked VM to launch debugger 6018 jio_snprintf(buf, sizeof(buf), "gdb /proc/%d/exe %d", 6019 os::current_process_id(), os::current_process_id()); 6020 6021 os::fork_and_exec(buf); 6022 yes = false; 6023 } 6024 return yes; 6025 } 6026 6027 6028 6029 /////////////// Unit tests /////////////// 6030 6031 #ifndef PRODUCT 6032 6033 #define test_log(...) \ 6034 do { \ 6035 if (VerboseInternalVMTests) { \ 6036 tty->print_cr(__VA_ARGS__); \ 6037 tty->flush(); \ 6038 } \ 6039 } while (false) 6040 6041 class TestReserveMemorySpecial : AllStatic { 6042 public: 6043 static void small_page_write(void* addr, size_t size) { 6044 size_t page_size = os::vm_page_size(); 6045 6046 char* end = (char*)addr + size; 6047 for (char* p = (char*)addr; p < end; p += page_size) { 6048 *p = 1; 6049 } 6050 } 6051 6052 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6053 if (!UseHugeTLBFS) { 6054 return; 6055 } 6056 6057 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6058 6059 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6060 6061 if (addr != NULL) { 6062 small_page_write(addr, size); 6063 6064 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6065 } 6066 } 6067 6068 static void test_reserve_memory_special_huge_tlbfs_only() { 6069 if (!UseHugeTLBFS) { 6070 return; 6071 } 6072 6073 size_t lp = os::large_page_size(); 6074 6075 for (size_t size = lp; size <= lp * 10; size += lp) { 6076 test_reserve_memory_special_huge_tlbfs_only(size); 6077 } 6078 } 6079 6080 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6081 size_t lp = os::large_page_size(); 6082 size_t ag = os::vm_allocation_granularity(); 6083 6084 // sizes to test 6085 const size_t sizes[] = { 6086 lp, lp + ag, lp + lp / 2, lp * 2, 6087 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6088 lp * 10, lp * 10 + lp / 2 6089 }; 6090 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6091 6092 // For each size/alignment combination, we test three scenarios: 6093 // 1) with req_addr == NULL 6094 // 2) with a non-null req_addr at which we expect to successfully allocate 6095 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6096 // expect the allocation to either fail or to ignore req_addr 6097 6098 // Pre-allocate two areas; they shall be as large as the largest allocation 6099 // and aligned to the largest alignment we will be testing. 6100 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6101 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6102 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6103 -1, 0); 6104 assert(mapping1 != MAP_FAILED, "should work"); 6105 6106 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6107 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6108 -1, 0); 6109 assert(mapping2 != MAP_FAILED, "should work"); 6110 6111 // Unmap the first mapping, but leave the second mapping intact: the first 6112 // mapping will serve as a value for a "good" req_addr (case 2). The second 6113 // mapping, still intact, as "bad" req_addr (case 3). 6114 ::munmap(mapping1, mapping_size); 6115 6116 // Case 1 6117 test_log("%s, req_addr NULL:", __FUNCTION__); 6118 test_log("size align result"); 6119 6120 for (int i = 0; i < num_sizes; i++) { 6121 const size_t size = sizes[i]; 6122 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6123 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6124 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6125 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6126 if (p != NULL) { 6127 assert(is_ptr_aligned(p, alignment), "must be"); 6128 small_page_write(p, size); 6129 os::Linux::release_memory_special_huge_tlbfs(p, size); 6130 } 6131 } 6132 } 6133 6134 // Case 2 6135 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6136 test_log("size align req_addr result"); 6137 6138 for (int i = 0; i < num_sizes; i++) { 6139 const size_t size = sizes[i]; 6140 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6141 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6142 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6143 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6144 size, alignment, p2i(req_addr), p2i(p), 6145 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6146 if (p != NULL) { 6147 assert(p == req_addr, "must be"); 6148 small_page_write(p, size); 6149 os::Linux::release_memory_special_huge_tlbfs(p, size); 6150 } 6151 } 6152 } 6153 6154 // Case 3 6155 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6156 test_log("size align req_addr result"); 6157 6158 for (int i = 0; i < num_sizes; i++) { 6159 const size_t size = sizes[i]; 6160 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6161 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6162 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6163 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6164 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6165 // as the area around req_addr contains already existing mappings, the API should always 6166 // return NULL (as per contract, it cannot return another address) 6167 assert(p == NULL, "must be"); 6168 } 6169 } 6170 6171 ::munmap(mapping2, mapping_size); 6172 6173 } 6174 6175 static void test_reserve_memory_special_huge_tlbfs() { 6176 if (!UseHugeTLBFS) { 6177 return; 6178 } 6179 6180 test_reserve_memory_special_huge_tlbfs_only(); 6181 test_reserve_memory_special_huge_tlbfs_mixed(); 6182 } 6183 6184 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6185 if (!UseSHM) { 6186 return; 6187 } 6188 6189 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6190 6191 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6192 6193 if (addr != NULL) { 6194 assert(is_ptr_aligned(addr, alignment), "Check"); 6195 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6196 6197 small_page_write(addr, size); 6198 6199 os::Linux::release_memory_special_shm(addr, size); 6200 } 6201 } 6202 6203 static void test_reserve_memory_special_shm() { 6204 size_t lp = os::large_page_size(); 6205 size_t ag = os::vm_allocation_granularity(); 6206 6207 for (size_t size = ag; size < lp * 3; size += ag) { 6208 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6209 test_reserve_memory_special_shm(size, alignment); 6210 } 6211 } 6212 } 6213 6214 static void test() { 6215 test_reserve_memory_special_huge_tlbfs(); 6216 test_reserve_memory_special_shm(); 6217 } 6218 }; 6219 6220 void TestReserveMemorySpecial_test() { 6221 TestReserveMemorySpecial::test(); 6222 } 6223 6224 #endif