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 const char * os::Linux::_glibc_version = NULL; 148 const char * os::Linux::_libpthread_version = NULL; 149 pthread_condattr_t os::Linux::_condattr[1]; 150 151 static jlong initial_time_count=0; 152 153 static int clock_tics_per_sec = 100; 154 155 // For diagnostics to print a message once. see run_periodic_checks 156 static sigset_t check_signal_done; 157 static bool check_signals = true; 158 159 // Signal number used to suspend/resume a thread 160 161 // do not use any signal number less than SIGSEGV, see 4355769 162 static int SR_signum = SIGUSR2; 163 sigset_t SR_sigset; 164 165 // Declarations 166 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 167 168 // utility functions 169 170 static int SR_initialize(); 171 172 julong os::available_memory() { 173 return Linux::available_memory(); 174 } 175 176 julong os::Linux::available_memory() { 177 // values in struct sysinfo are "unsigned long" 178 struct sysinfo si; 179 sysinfo(&si); 180 181 return (julong)si.freeram * si.mem_unit; 182 } 183 184 julong os::physical_memory() { 185 return Linux::physical_memory(); 186 } 187 188 // Return true if user is running as root. 189 190 bool os::have_special_privileges() { 191 static bool init = false; 192 static bool privileges = false; 193 if (!init) { 194 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 195 init = true; 196 } 197 return privileges; 198 } 199 200 201 #ifndef SYS_gettid 202 // i386: 224, ia64: 1105, amd64: 186, sparc 143 203 #ifdef __ia64__ 204 #define SYS_gettid 1105 205 #else 206 #ifdef __i386__ 207 #define SYS_gettid 224 208 #else 209 #ifdef __amd64__ 210 #define SYS_gettid 186 211 #else 212 #ifdef __sparc__ 213 #define SYS_gettid 143 214 #else 215 #error define gettid for the arch 216 #endif 217 #endif 218 #endif 219 #endif 220 #endif 221 222 // Cpu architecture string 223 static char cpu_arch[] = HOTSPOT_LIB_ARCH; 224 225 226 // pid_t gettid() 227 // 228 // Returns the kernel thread id of the currently running thread. Kernel 229 // thread id is used to access /proc. 230 pid_t os::Linux::gettid() { 231 int rslt = syscall(SYS_gettid); 232 assert(rslt != -1, "must be."); // old linuxthreads implementation? 233 return (pid_t)rslt; 234 } 235 236 // Most versions of linux have a bug where the number of processors are 237 // determined by looking at the /proc file system. In a chroot environment, 238 // the system call returns 1. This causes the VM to act as if it is 239 // a single processor and elide locking (see is_MP() call). 240 static bool unsafe_chroot_detected = false; 241 static const char *unstable_chroot_error = "/proc file system not found.\n" 242 "Java may be unstable running multithreaded in a chroot " 243 "environment on Linux when /proc filesystem is not mounted."; 244 245 void os::Linux::initialize_system_info() { 246 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 247 if (processor_count() == 1) { 248 pid_t pid = os::Linux::gettid(); 249 char fname[32]; 250 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 251 FILE *fp = fopen(fname, "r"); 252 if (fp == NULL) { 253 unsafe_chroot_detected = true; 254 } else { 255 fclose(fp); 256 } 257 } 258 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 259 assert(processor_count() > 0, "linux error"); 260 } 261 262 void os::init_system_properties_values() { 263 // The next steps are taken in the product version: 264 // 265 // Obtain the JAVA_HOME value from the location of libjvm.so. 266 // This library should be located at: 267 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 268 // 269 // If "/jre/lib/" appears at the right place in the path, then we 270 // assume libjvm.so is installed in a JDK and we use this path. 271 // 272 // Otherwise exit with message: "Could not create the Java virtual machine." 273 // 274 // The following extra steps are taken in the debugging version: 275 // 276 // If "/jre/lib/" does NOT appear at the right place in the path 277 // instead of exit check for $JAVA_HOME environment variable. 278 // 279 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 280 // then we append a fake suffix "hotspot/libjvm.so" to this path so 281 // it looks like libjvm.so is installed there 282 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 283 // 284 // Otherwise exit. 285 // 286 // Important note: if the location of libjvm.so changes this 287 // code needs to be changed accordingly. 288 289 // See ld(1): 290 // The linker uses the following search paths to locate required 291 // shared libraries: 292 // 1: ... 293 // ... 294 // 7: The default directories, normally /lib and /usr/lib. 295 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 296 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 297 #else 298 #define DEFAULT_LIBPATH "/lib:/usr/lib" 299 #endif 300 301 // Base path of extensions installed on the system. 302 #define SYS_EXT_DIR "/usr/java/packages" 303 #define EXTENSIONS_DIR "/lib/ext" 304 305 // Buffer that fits several sprintfs. 306 // Note that the space for the colon and the trailing null are provided 307 // by the nulls included by the sizeof operator. 308 const size_t bufsize = 309 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 310 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 311 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 312 313 // sysclasspath, java_home, dll_dir 314 { 315 char *pslash; 316 os::jvm_path(buf, bufsize); 317 318 // Found the full path to libjvm.so. 319 // Now cut the path to <java_home>/jre if we can. 320 pslash = strrchr(buf, '/'); 321 if (pslash != NULL) { 322 *pslash = '\0'; // Get rid of /libjvm.so. 323 } 324 pslash = strrchr(buf, '/'); 325 if (pslash != NULL) { 326 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 327 } 328 Arguments::set_dll_dir(buf); 329 330 if (pslash != NULL) { 331 pslash = strrchr(buf, '/'); 332 if (pslash != NULL) { 333 *pslash = '\0'; // Get rid of /<arch>. 334 pslash = strrchr(buf, '/'); 335 if (pslash != NULL) { 336 *pslash = '\0'; // Get rid of /lib. 337 } 338 } 339 } 340 Arguments::set_java_home(buf); 341 set_boot_path('/', ':'); 342 } 343 344 // Where to look for native libraries. 345 // 346 // Note: Due to a legacy implementation, most of the library path 347 // is set in the launcher. This was to accomodate linking restrictions 348 // on legacy Linux implementations (which are no longer supported). 349 // Eventually, all the library path setting will be done here. 350 // 351 // However, to prevent the proliferation of improperly built native 352 // libraries, the new path component /usr/java/packages is added here. 353 // Eventually, all the library path setting will be done here. 354 { 355 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 356 // should always exist (until the legacy problem cited above is 357 // addressed). 358 const char *v = ::getenv("LD_LIBRARY_PATH"); 359 const char *v_colon = ":"; 360 if (v == NULL) { v = ""; v_colon = ""; } 361 // That's +1 for the colon and +1 for the trailing '\0'. 362 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 363 strlen(v) + 1 + 364 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 365 mtInternal); 366 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 367 Arguments::set_library_path(ld_library_path); 368 FREE_C_HEAP_ARRAY(char, ld_library_path); 369 } 370 371 // Extensions directories. 372 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 373 Arguments::set_ext_dirs(buf); 374 375 FREE_C_HEAP_ARRAY(char, buf); 376 377 #undef DEFAULT_LIBPATH 378 #undef SYS_EXT_DIR 379 #undef EXTENSIONS_DIR 380 } 381 382 //////////////////////////////////////////////////////////////////////////////// 383 // breakpoint support 384 385 void os::breakpoint() { 386 BREAKPOINT; 387 } 388 389 extern "C" void breakpoint() { 390 // use debugger to set breakpoint here 391 } 392 393 //////////////////////////////////////////////////////////////////////////////// 394 // signal support 395 396 debug_only(static bool signal_sets_initialized = false); 397 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 398 399 bool os::Linux::is_sig_ignored(int sig) { 400 struct sigaction oact; 401 sigaction(sig, (struct sigaction*)NULL, &oact); 402 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 403 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 404 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 405 return true; 406 } else { 407 return false; 408 } 409 } 410 411 void os::Linux::signal_sets_init() { 412 // Should also have an assertion stating we are still single-threaded. 413 assert(!signal_sets_initialized, "Already initialized"); 414 // Fill in signals that are necessarily unblocked for all threads in 415 // the VM. Currently, we unblock the following signals: 416 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 417 // by -Xrs (=ReduceSignalUsage)); 418 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 419 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 420 // the dispositions or masks wrt these signals. 421 // Programs embedding the VM that want to use the above signals for their 422 // own purposes must, at this time, use the "-Xrs" option to prevent 423 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 424 // (See bug 4345157, and other related bugs). 425 // In reality, though, unblocking these signals is really a nop, since 426 // these signals are not blocked by default. 427 sigemptyset(&unblocked_sigs); 428 sigemptyset(&allowdebug_blocked_sigs); 429 sigaddset(&unblocked_sigs, SIGILL); 430 sigaddset(&unblocked_sigs, SIGSEGV); 431 sigaddset(&unblocked_sigs, SIGBUS); 432 sigaddset(&unblocked_sigs, SIGFPE); 433 #if defined(PPC64) 434 sigaddset(&unblocked_sigs, SIGTRAP); 435 #endif 436 sigaddset(&unblocked_sigs, SR_signum); 437 438 if (!ReduceSignalUsage) { 439 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 440 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 441 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 442 } 443 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 444 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 445 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 446 } 447 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 448 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 449 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 450 } 451 } 452 // Fill in signals that are blocked by all but the VM thread. 453 sigemptyset(&vm_sigs); 454 if (!ReduceSignalUsage) { 455 sigaddset(&vm_sigs, BREAK_SIGNAL); 456 } 457 debug_only(signal_sets_initialized = true); 458 459 } 460 461 // These are signals that are unblocked while a thread is running Java. 462 // (For some reason, they get blocked by default.) 463 sigset_t* os::Linux::unblocked_signals() { 464 assert(signal_sets_initialized, "Not initialized"); 465 return &unblocked_sigs; 466 } 467 468 // These are the signals that are blocked while a (non-VM) thread is 469 // running Java. Only the VM thread handles these signals. 470 sigset_t* os::Linux::vm_signals() { 471 assert(signal_sets_initialized, "Not initialized"); 472 return &vm_sigs; 473 } 474 475 // These are signals that are blocked during cond_wait to allow debugger in 476 sigset_t* os::Linux::allowdebug_blocked_signals() { 477 assert(signal_sets_initialized, "Not initialized"); 478 return &allowdebug_blocked_sigs; 479 } 480 481 void os::Linux::hotspot_sigmask(Thread* thread) { 482 483 //Save caller's signal mask before setting VM signal mask 484 sigset_t caller_sigmask; 485 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 486 487 OSThread* osthread = thread->osthread(); 488 osthread->set_caller_sigmask(caller_sigmask); 489 490 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 491 492 if (!ReduceSignalUsage) { 493 if (thread->is_VM_thread()) { 494 // Only the VM thread handles BREAK_SIGNAL ... 495 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 496 } else { 497 // ... all other threads block BREAK_SIGNAL 498 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 499 } 500 } 501 } 502 503 ////////////////////////////////////////////////////////////////////////////// 504 // detecting pthread library 505 506 void os::Linux::libpthread_init() { 507 // Save glibc and pthread version strings. 508 #if !defined(_CS_GNU_LIBC_VERSION) || \ 509 !defined(_CS_GNU_LIBPTHREAD_VERSION) 510 #error "glibc too old (< 2.3.2)" 511 #endif 512 513 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 514 assert(n > 0, "cannot retrieve glibc version"); 515 char *str = (char *)malloc(n, mtInternal); 516 confstr(_CS_GNU_LIBC_VERSION, str, n); 517 os::Linux::set_glibc_version(str); 518 519 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 520 assert(n > 0, "cannot retrieve pthread version"); 521 str = (char *)malloc(n, mtInternal); 522 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 523 os::Linux::set_libpthread_version(str); 524 } 525 526 ///////////////////////////////////////////////////////////////////////////// 527 // thread stack expansion 528 529 // os::Linux::manually_expand_stack() takes care of expanding the thread 530 // stack. Note that this is normally not needed: pthread stacks allocate 531 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 532 // committed. Therefore it is not necessary to expand the stack manually. 533 // 534 // Manually expanding the stack was historically needed on LinuxThreads 535 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 536 // it is kept to deal with very rare corner cases: 537 // 538 // For one, user may run the VM on an own implementation of threads 539 // whose stacks are - like the old LinuxThreads - implemented using 540 // mmap(MAP_GROWSDOWN). 541 // 542 // Also, this coding may be needed if the VM is running on the primordial 543 // thread. Normally we avoid running on the primordial thread; however, 544 // user may still invoke the VM on the primordial thread. 545 // 546 // The following historical comment describes the details about running 547 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 548 549 550 // Force Linux kernel to expand current thread stack. If "bottom" is close 551 // to the stack guard, caller should block all signals. 552 // 553 // MAP_GROWSDOWN: 554 // A special mmap() flag that is used to implement thread stacks. It tells 555 // kernel that the memory region should extend downwards when needed. This 556 // allows early versions of LinuxThreads to only mmap the first few pages 557 // when creating a new thread. Linux kernel will automatically expand thread 558 // stack as needed (on page faults). 559 // 560 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 561 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 562 // region, it's hard to tell if the fault is due to a legitimate stack 563 // access or because of reading/writing non-exist memory (e.g. buffer 564 // overrun). As a rule, if the fault happens below current stack pointer, 565 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 566 // application (see Linux kernel fault.c). 567 // 568 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 569 // stack overflow detection. 570 // 571 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 572 // not use MAP_GROWSDOWN. 573 // 574 // To get around the problem and allow stack banging on Linux, we need to 575 // manually expand thread stack after receiving the SIGSEGV. 576 // 577 // There are two ways to expand thread stack to address "bottom", we used 578 // both of them in JVM before 1.5: 579 // 1. adjust stack pointer first so that it is below "bottom", and then 580 // touch "bottom" 581 // 2. mmap() the page in question 582 // 583 // Now alternate signal stack is gone, it's harder to use 2. For instance, 584 // if current sp is already near the lower end of page 101, and we need to 585 // call mmap() to map page 100, it is possible that part of the mmap() frame 586 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 587 // That will destroy the mmap() frame and cause VM to crash. 588 // 589 // The following code works by adjusting sp first, then accessing the "bottom" 590 // page to force a page fault. Linux kernel will then automatically expand the 591 // stack mapping. 592 // 593 // _expand_stack_to() assumes its frame size is less than page size, which 594 // should always be true if the function is not inlined. 595 596 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 597 #define NOINLINE 598 #else 599 #define NOINLINE __attribute__ ((noinline)) 600 #endif 601 602 static void _expand_stack_to(address bottom) NOINLINE; 603 604 static void _expand_stack_to(address bottom) { 605 address sp; 606 size_t size; 607 volatile char *p; 608 609 // Adjust bottom to point to the largest address within the same page, it 610 // gives us a one-page buffer if alloca() allocates slightly more memory. 611 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 612 bottom += os::Linux::page_size() - 1; 613 614 // sp might be slightly above current stack pointer; if that's the case, we 615 // will alloca() a little more space than necessary, which is OK. Don't use 616 // os::current_stack_pointer(), as its result can be slightly below current 617 // stack pointer, causing us to not alloca enough to reach "bottom". 618 sp = (address)&sp; 619 620 if (sp > bottom) { 621 size = sp - bottom; 622 p = (volatile char *)alloca(size); 623 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 624 p[0] = '\0'; 625 } 626 } 627 628 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 629 assert(t!=NULL, "just checking"); 630 assert(t->osthread()->expanding_stack(), "expand should be set"); 631 assert(t->stack_base() != NULL, "stack_base was not initialized"); 632 633 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 634 sigset_t mask_all, old_sigset; 635 sigfillset(&mask_all); 636 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 637 _expand_stack_to(addr); 638 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 639 return true; 640 } 641 return false; 642 } 643 644 ////////////////////////////////////////////////////////////////////////////// 645 // create new thread 646 647 // Thread start routine for all newly created threads 648 static void *java_start(Thread *thread) { 649 // Try to randomize the cache line index of hot stack frames. 650 // This helps when threads of the same stack traces evict each other's 651 // cache lines. The threads can be either from the same JVM instance, or 652 // from different JVM instances. The benefit is especially true for 653 // processors with hyperthreading technology. 654 static int counter = 0; 655 int pid = os::current_process_id(); 656 alloca(((pid ^ counter++) & 7) * 128); 657 658 thread->initialize_thread_current(); 659 660 OSThread* osthread = thread->osthread(); 661 Monitor* sync = osthread->startThread_lock(); 662 663 osthread->set_thread_id(os::current_thread_id()); 664 665 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 666 os::current_thread_id(), (uintx) pthread_self()); 667 668 if (UseNUMA) { 669 int lgrp_id = os::numa_get_group_id(); 670 if (lgrp_id != -1) { 671 thread->set_lgrp_id(lgrp_id); 672 } 673 } 674 // initialize signal mask for this thread 675 os::Linux::hotspot_sigmask(thread); 676 677 // initialize floating point control register 678 os::Linux::init_thread_fpu_state(); 679 680 // handshaking with parent thread 681 { 682 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 683 684 // notify parent thread 685 osthread->set_state(INITIALIZED); 686 sync->notify_all(); 687 688 // wait until os::start_thread() 689 while (osthread->get_state() == INITIALIZED) { 690 sync->wait(Mutex::_no_safepoint_check_flag); 691 } 692 } 693 694 // call one more level start routine 695 thread->run(); 696 697 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 698 os::current_thread_id(), (uintx) pthread_self()); 699 700 return 0; 701 } 702 703 bool os::create_thread(Thread* thread, ThreadType thr_type, 704 size_t stack_size) { 705 assert(thread->osthread() == NULL, "caller responsible"); 706 707 // Allocate the OSThread object 708 OSThread* osthread = new OSThread(NULL, NULL); 709 if (osthread == NULL) { 710 return false; 711 } 712 713 // set the correct thread state 714 osthread->set_thread_type(thr_type); 715 716 // Initial state is ALLOCATED but not INITIALIZED 717 osthread->set_state(ALLOCATED); 718 719 thread->set_osthread(osthread); 720 721 // init thread attributes 722 pthread_attr_t attr; 723 pthread_attr_init(&attr); 724 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 725 726 // stack size 727 // calculate stack size if it's not specified by caller 728 if (stack_size == 0) { 729 stack_size = os::Linux::default_stack_size(thr_type); 730 731 switch (thr_type) { 732 case os::java_thread: 733 // Java threads use ThreadStackSize which default value can be 734 // changed with the flag -Xss 735 assert(JavaThread::stack_size_at_create() > 0, "this should be set"); 736 stack_size = JavaThread::stack_size_at_create(); 737 break; 738 case os::compiler_thread: 739 if (CompilerThreadStackSize > 0) { 740 stack_size = (size_t)(CompilerThreadStackSize * K); 741 break; 742 } // else fall through: 743 // use VMThreadStackSize if CompilerThreadStackSize is not defined 744 case os::vm_thread: 745 case os::pgc_thread: 746 case os::cgc_thread: 747 case os::watcher_thread: 748 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 749 break; 750 } 751 } 752 753 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 754 pthread_attr_setstacksize(&attr, stack_size); 755 756 // glibc guard page 757 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 758 759 ThreadState state; 760 761 { 762 pthread_t tid; 763 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 764 765 char buf[64]; 766 if (ret == 0) { 767 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 768 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 769 } else { 770 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 771 strerror(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 772 } 773 774 pthread_attr_destroy(&attr); 775 776 if (ret != 0) { 777 // Need to clean up stuff we've allocated so far 778 thread->set_osthread(NULL); 779 delete osthread; 780 return false; 781 } 782 783 // Store pthread info into the OSThread 784 osthread->set_pthread_id(tid); 785 786 // Wait until child thread is either initialized or aborted 787 { 788 Monitor* sync_with_child = osthread->startThread_lock(); 789 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 790 while ((state = osthread->get_state()) == ALLOCATED) { 791 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 792 } 793 } 794 } 795 796 // Aborted due to thread limit being reached 797 if (state == ZOMBIE) { 798 thread->set_osthread(NULL); 799 delete osthread; 800 return false; 801 } 802 803 // The thread is returned suspended (in state INITIALIZED), 804 // and is started higher up in the call chain 805 assert(state == INITIALIZED, "race condition"); 806 return true; 807 } 808 809 ///////////////////////////////////////////////////////////////////////////// 810 // attach existing thread 811 812 // bootstrap the main thread 813 bool os::create_main_thread(JavaThread* thread) { 814 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 815 return create_attached_thread(thread); 816 } 817 818 bool os::create_attached_thread(JavaThread* thread) { 819 #ifdef ASSERT 820 thread->verify_not_published(); 821 #endif 822 823 // Allocate the OSThread object 824 OSThread* osthread = new OSThread(NULL, NULL); 825 826 if (osthread == NULL) { 827 return false; 828 } 829 830 // Store pthread info into the OSThread 831 osthread->set_thread_id(os::Linux::gettid()); 832 osthread->set_pthread_id(::pthread_self()); 833 834 // initialize floating point control register 835 os::Linux::init_thread_fpu_state(); 836 837 // Initial thread state is RUNNABLE 838 osthread->set_state(RUNNABLE); 839 840 thread->set_osthread(osthread); 841 842 if (UseNUMA) { 843 int lgrp_id = os::numa_get_group_id(); 844 if (lgrp_id != -1) { 845 thread->set_lgrp_id(lgrp_id); 846 } 847 } 848 849 if (os::Linux::is_initial_thread()) { 850 // If current thread is initial thread, its stack is mapped on demand, 851 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 852 // the entire stack region to avoid SEGV in stack banging. 853 // It is also useful to get around the heap-stack-gap problem on SuSE 854 // kernel (see 4821821 for details). We first expand stack to the top 855 // of yellow zone, then enable stack yellow zone (order is significant, 856 // enabling yellow zone first will crash JVM on SuSE Linux), so there 857 // is no gap between the last two virtual memory regions. 858 859 JavaThread *jt = (JavaThread *)thread; 860 address addr = jt->stack_reserved_zone_base(); 861 assert(addr != NULL, "initialization problem?"); 862 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 863 864 osthread->set_expanding_stack(); 865 os::Linux::manually_expand_stack(jt, addr); 866 osthread->clear_expanding_stack(); 867 } 868 869 // initialize signal mask for this thread 870 // and save the caller's signal mask 871 os::Linux::hotspot_sigmask(thread); 872 873 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 874 os::current_thread_id(), (uintx) pthread_self()); 875 876 return true; 877 } 878 879 void os::pd_start_thread(Thread* thread) { 880 OSThread * osthread = thread->osthread(); 881 assert(osthread->get_state() != INITIALIZED, "just checking"); 882 Monitor* sync_with_child = osthread->startThread_lock(); 883 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 884 sync_with_child->notify(); 885 } 886 887 // Free Linux resources related to the OSThread 888 void os::free_thread(OSThread* osthread) { 889 assert(osthread != NULL, "osthread not set"); 890 891 if (Thread::current()->osthread() == osthread) { 892 // Restore caller's signal mask 893 sigset_t sigmask = osthread->caller_sigmask(); 894 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 895 } 896 897 delete osthread; 898 } 899 900 ////////////////////////////////////////////////////////////////////////////// 901 // initial thread 902 903 // Check if current thread is the initial thread, similar to Solaris thr_main. 904 bool os::Linux::is_initial_thread(void) { 905 char dummy; 906 // If called before init complete, thread stack bottom will be null. 907 // Can be called if fatal error occurs before initialization. 908 if (initial_thread_stack_bottom() == NULL) return false; 909 assert(initial_thread_stack_bottom() != NULL && 910 initial_thread_stack_size() != 0, 911 "os::init did not locate initial thread's stack region"); 912 if ((address)&dummy >= initial_thread_stack_bottom() && 913 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 914 return true; 915 } else { 916 return false; 917 } 918 } 919 920 // Find the virtual memory area that contains addr 921 static bool find_vma(address addr, address* vma_low, address* vma_high) { 922 FILE *fp = fopen("/proc/self/maps", "r"); 923 if (fp) { 924 address low, high; 925 while (!feof(fp)) { 926 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 927 if (low <= addr && addr < high) { 928 if (vma_low) *vma_low = low; 929 if (vma_high) *vma_high = high; 930 fclose(fp); 931 return true; 932 } 933 } 934 for (;;) { 935 int ch = fgetc(fp); 936 if (ch == EOF || ch == (int)'\n') break; 937 } 938 } 939 fclose(fp); 940 } 941 return false; 942 } 943 944 // Locate initial thread stack. This special handling of initial thread stack 945 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 946 // bogus value for initial thread. 947 void os::Linux::capture_initial_stack(size_t max_size) { 948 // stack size is the easy part, get it from RLIMIT_STACK 949 size_t stack_size; 950 struct rlimit rlim; 951 getrlimit(RLIMIT_STACK, &rlim); 952 stack_size = rlim.rlim_cur; 953 954 // 6308388: a bug in ld.so will relocate its own .data section to the 955 // lower end of primordial stack; reduce ulimit -s value a little bit 956 // so we won't install guard page on ld.so's data section. 957 stack_size -= 2 * page_size(); 958 959 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 960 // 7.1, in both cases we will get 2G in return value. 961 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 962 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 963 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 964 // in case other parts in glibc still assumes 2M max stack size. 965 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 966 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 967 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 968 stack_size = 2 * K * K IA64_ONLY(*2); 969 } 970 // Try to figure out where the stack base (top) is. This is harder. 971 // 972 // When an application is started, glibc saves the initial stack pointer in 973 // a global variable "__libc_stack_end", which is then used by system 974 // libraries. __libc_stack_end should be pretty close to stack top. The 975 // variable is available since the very early days. However, because it is 976 // a private interface, it could disappear in the future. 977 // 978 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 979 // to __libc_stack_end, it is very close to stack top, but isn't the real 980 // stack top. Note that /proc may not exist if VM is running as a chroot 981 // program, so reading /proc/<pid>/stat could fail. Also the contents of 982 // /proc/<pid>/stat could change in the future (though unlikely). 983 // 984 // We try __libc_stack_end first. If that doesn't work, look for 985 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 986 // as a hint, which should work well in most cases. 987 988 uintptr_t stack_start; 989 990 // try __libc_stack_end first 991 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 992 if (p && *p) { 993 stack_start = *p; 994 } else { 995 // see if we can get the start_stack field from /proc/self/stat 996 FILE *fp; 997 int pid; 998 char state; 999 int ppid; 1000 int pgrp; 1001 int session; 1002 int nr; 1003 int tpgrp; 1004 unsigned long flags; 1005 unsigned long minflt; 1006 unsigned long cminflt; 1007 unsigned long majflt; 1008 unsigned long cmajflt; 1009 unsigned long utime; 1010 unsigned long stime; 1011 long cutime; 1012 long cstime; 1013 long prio; 1014 long nice; 1015 long junk; 1016 long it_real; 1017 uintptr_t start; 1018 uintptr_t vsize; 1019 intptr_t rss; 1020 uintptr_t rsslim; 1021 uintptr_t scodes; 1022 uintptr_t ecode; 1023 int i; 1024 1025 // Figure what the primordial thread stack base is. Code is inspired 1026 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1027 // followed by command name surrounded by parentheses, state, etc. 1028 char stat[2048]; 1029 int statlen; 1030 1031 fp = fopen("/proc/self/stat", "r"); 1032 if (fp) { 1033 statlen = fread(stat, 1, 2047, fp); 1034 stat[statlen] = '\0'; 1035 fclose(fp); 1036 1037 // Skip pid and the command string. Note that we could be dealing with 1038 // weird command names, e.g. user could decide to rename java launcher 1039 // to "java 1.4.2 :)", then the stat file would look like 1040 // 1234 (java 1.4.2 :)) R ... ... 1041 // We don't really need to know the command string, just find the last 1042 // occurrence of ")" and then start parsing from there. See bug 4726580. 1043 char * s = strrchr(stat, ')'); 1044 1045 i = 0; 1046 if (s) { 1047 // Skip blank chars 1048 do { s++; } while (s && isspace(*s)); 1049 1050 #define _UFM UINTX_FORMAT 1051 #define _DFM INTX_FORMAT 1052 1053 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1054 // 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 1055 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, 1056 &state, // 3 %c 1057 &ppid, // 4 %d 1058 &pgrp, // 5 %d 1059 &session, // 6 %d 1060 &nr, // 7 %d 1061 &tpgrp, // 8 %d 1062 &flags, // 9 %lu 1063 &minflt, // 10 %lu 1064 &cminflt, // 11 %lu 1065 &majflt, // 12 %lu 1066 &cmajflt, // 13 %lu 1067 &utime, // 14 %lu 1068 &stime, // 15 %lu 1069 &cutime, // 16 %ld 1070 &cstime, // 17 %ld 1071 &prio, // 18 %ld 1072 &nice, // 19 %ld 1073 &junk, // 20 %ld 1074 &it_real, // 21 %ld 1075 &start, // 22 UINTX_FORMAT 1076 &vsize, // 23 UINTX_FORMAT 1077 &rss, // 24 INTX_FORMAT 1078 &rsslim, // 25 UINTX_FORMAT 1079 &scodes, // 26 UINTX_FORMAT 1080 &ecode, // 27 UINTX_FORMAT 1081 &stack_start); // 28 UINTX_FORMAT 1082 } 1083 1084 #undef _UFM 1085 #undef _DFM 1086 1087 if (i != 28 - 2) { 1088 assert(false, "Bad conversion from /proc/self/stat"); 1089 // product mode - assume we are the initial thread, good luck in the 1090 // embedded case. 1091 warning("Can't detect initial thread stack location - bad conversion"); 1092 stack_start = (uintptr_t) &rlim; 1093 } 1094 } else { 1095 // For some reason we can't open /proc/self/stat (for example, running on 1096 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1097 // most cases, so don't abort: 1098 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1099 stack_start = (uintptr_t) &rlim; 1100 } 1101 } 1102 1103 // Now we have a pointer (stack_start) very close to the stack top, the 1104 // next thing to do is to figure out the exact location of stack top. We 1105 // can find out the virtual memory area that contains stack_start by 1106 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1107 // and its upper limit is the real stack top. (again, this would fail if 1108 // running inside chroot, because /proc may not exist.) 1109 1110 uintptr_t stack_top; 1111 address low, high; 1112 if (find_vma((address)stack_start, &low, &high)) { 1113 // success, "high" is the true stack top. (ignore "low", because initial 1114 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1115 stack_top = (uintptr_t)high; 1116 } else { 1117 // failed, likely because /proc/self/maps does not exist 1118 warning("Can't detect initial thread stack location - find_vma failed"); 1119 // best effort: stack_start is normally within a few pages below the real 1120 // stack top, use it as stack top, and reduce stack size so we won't put 1121 // guard page outside stack. 1122 stack_top = stack_start; 1123 stack_size -= 16 * page_size(); 1124 } 1125 1126 // stack_top could be partially down the page so align it 1127 stack_top = align_size_up(stack_top, page_size()); 1128 1129 if (max_size && stack_size > max_size) { 1130 _initial_thread_stack_size = max_size; 1131 } else { 1132 _initial_thread_stack_size = stack_size; 1133 } 1134 1135 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1136 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1137 } 1138 1139 //////////////////////////////////////////////////////////////////////////////// 1140 // time support 1141 1142 // Time since start-up in seconds to a fine granularity. 1143 // Used by VMSelfDestructTimer and the MemProfiler. 1144 double os::elapsedTime() { 1145 1146 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1147 } 1148 1149 jlong os::elapsed_counter() { 1150 return javaTimeNanos() - initial_time_count; 1151 } 1152 1153 jlong os::elapsed_frequency() { 1154 return NANOSECS_PER_SEC; // nanosecond resolution 1155 } 1156 1157 bool os::supports_vtime() { return true; } 1158 bool os::enable_vtime() { return false; } 1159 bool os::vtime_enabled() { return false; } 1160 1161 double os::elapsedVTime() { 1162 struct rusage usage; 1163 int retval = getrusage(RUSAGE_THREAD, &usage); 1164 if (retval == 0) { 1165 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); 1166 } else { 1167 // better than nothing, but not much 1168 return elapsedTime(); 1169 } 1170 } 1171 1172 jlong os::javaTimeMillis() { 1173 timeval time; 1174 int status = gettimeofday(&time, NULL); 1175 assert(status != -1, "linux error"); 1176 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1177 } 1178 1179 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1180 timeval time; 1181 int status = gettimeofday(&time, NULL); 1182 assert(status != -1, "linux error"); 1183 seconds = jlong(time.tv_sec); 1184 nanos = jlong(time.tv_usec) * 1000; 1185 } 1186 1187 1188 #ifndef CLOCK_MONOTONIC 1189 #define CLOCK_MONOTONIC (1) 1190 #endif 1191 1192 void os::Linux::clock_init() { 1193 // we do dlopen's in this particular order due to bug in linux 1194 // dynamical loader (see 6348968) leading to crash on exit 1195 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1196 if (handle == NULL) { 1197 handle = dlopen("librt.so", RTLD_LAZY); 1198 } 1199 1200 if (handle) { 1201 int (*clock_getres_func)(clockid_t, struct timespec*) = 1202 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1203 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1204 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1205 if (clock_getres_func && clock_gettime_func) { 1206 // See if monotonic clock is supported by the kernel. Note that some 1207 // early implementations simply return kernel jiffies (updated every 1208 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1209 // for nano time (though the monotonic property is still nice to have). 1210 // It's fixed in newer kernels, however clock_getres() still returns 1211 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1212 // resolution for now. Hopefully as people move to new kernels, this 1213 // won't be a problem. 1214 struct timespec res; 1215 struct timespec tp; 1216 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1217 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1218 // yes, monotonic clock is supported 1219 _clock_gettime = clock_gettime_func; 1220 return; 1221 } else { 1222 // close librt if there is no monotonic clock 1223 dlclose(handle); 1224 } 1225 } 1226 } 1227 warning("No monotonic clock was available - timed services may " \ 1228 "be adversely affected if the time-of-day clock changes"); 1229 } 1230 1231 #ifndef SYS_clock_getres 1232 #if defined(IA32) || defined(AMD64) 1233 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1234 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1235 #else 1236 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1237 #define sys_clock_getres(x,y) -1 1238 #endif 1239 #else 1240 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1241 #endif 1242 1243 void os::Linux::fast_thread_clock_init() { 1244 if (!UseLinuxPosixThreadCPUClocks) { 1245 return; 1246 } 1247 clockid_t clockid; 1248 struct timespec tp; 1249 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1250 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1251 1252 // Switch to using fast clocks for thread cpu time if 1253 // the sys_clock_getres() returns 0 error code. 1254 // Note, that some kernels may support the current thread 1255 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1256 // returned by the pthread_getcpuclockid(). 1257 // If the fast Posix clocks are supported then the sys_clock_getres() 1258 // must return at least tp.tv_sec == 0 which means a resolution 1259 // better than 1 sec. This is extra check for reliability. 1260 1261 if (pthread_getcpuclockid_func && 1262 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1263 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1264 _supports_fast_thread_cpu_time = true; 1265 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1266 } 1267 } 1268 1269 jlong os::javaTimeNanos() { 1270 if (os::supports_monotonic_clock()) { 1271 struct timespec tp; 1272 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1273 assert(status == 0, "gettime error"); 1274 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1275 return result; 1276 } else { 1277 timeval time; 1278 int status = gettimeofday(&time, NULL); 1279 assert(status != -1, "linux error"); 1280 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1281 return 1000 * usecs; 1282 } 1283 } 1284 1285 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1286 if (os::supports_monotonic_clock()) { 1287 info_ptr->max_value = ALL_64_BITS; 1288 1289 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1290 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1291 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1292 } else { 1293 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1294 info_ptr->max_value = ALL_64_BITS; 1295 1296 // gettimeofday is a real time clock so it skips 1297 info_ptr->may_skip_backward = true; 1298 info_ptr->may_skip_forward = true; 1299 } 1300 1301 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1302 } 1303 1304 // Return the real, user, and system times in seconds from an 1305 // arbitrary fixed point in the past. 1306 bool os::getTimesSecs(double* process_real_time, 1307 double* process_user_time, 1308 double* process_system_time) { 1309 struct tms ticks; 1310 clock_t real_ticks = times(&ticks); 1311 1312 if (real_ticks == (clock_t) (-1)) { 1313 return false; 1314 } else { 1315 double ticks_per_second = (double) clock_tics_per_sec; 1316 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1317 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1318 *process_real_time = ((double) real_ticks) / ticks_per_second; 1319 1320 return true; 1321 } 1322 } 1323 1324 1325 char * os::local_time_string(char *buf, size_t buflen) { 1326 struct tm t; 1327 time_t long_time; 1328 time(&long_time); 1329 localtime_r(&long_time, &t); 1330 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1331 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1332 t.tm_hour, t.tm_min, t.tm_sec); 1333 return buf; 1334 } 1335 1336 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1337 return localtime_r(clock, res); 1338 } 1339 1340 //////////////////////////////////////////////////////////////////////////////// 1341 // runtime exit support 1342 1343 // Note: os::shutdown() might be called very early during initialization, or 1344 // called from signal handler. Before adding something to os::shutdown(), make 1345 // sure it is async-safe and can handle partially initialized VM. 1346 void os::shutdown() { 1347 1348 // allow PerfMemory to attempt cleanup of any persistent resources 1349 perfMemory_exit(); 1350 1351 // needs to remove object in file system 1352 AttachListener::abort(); 1353 1354 // flush buffered output, finish log files 1355 ostream_abort(); 1356 1357 // Check for abort hook 1358 abort_hook_t abort_hook = Arguments::abort_hook(); 1359 if (abort_hook != NULL) { 1360 abort_hook(); 1361 } 1362 1363 } 1364 1365 // Note: os::abort() might be called very early during initialization, or 1366 // called from signal handler. Before adding something to os::abort(), make 1367 // sure it is async-safe and can handle partially initialized VM. 1368 void os::abort(bool dump_core, void* siginfo, const void* context) { 1369 os::shutdown(); 1370 if (dump_core) { 1371 #ifndef PRODUCT 1372 fdStream out(defaultStream::output_fd()); 1373 out.print_raw("Current thread is "); 1374 char buf[16]; 1375 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1376 out.print_raw_cr(buf); 1377 out.print_raw_cr("Dumping core ..."); 1378 #endif 1379 ::abort(); // dump core 1380 } 1381 1382 ::exit(1); 1383 } 1384 1385 // Die immediately, no exit hook, no abort hook, no cleanup. 1386 void os::die() { 1387 ::abort(); 1388 } 1389 1390 1391 // This method is a copy of JDK's sysGetLastErrorString 1392 // from src/solaris/hpi/src/system_md.c 1393 1394 size_t os::lasterror(char *buf, size_t len) { 1395 if (errno == 0) return 0; 1396 1397 const char *s = ::strerror(errno); 1398 size_t n = ::strlen(s); 1399 if (n >= len) { 1400 n = len - 1; 1401 } 1402 ::strncpy(buf, s, n); 1403 buf[n] = '\0'; 1404 return n; 1405 } 1406 1407 // thread_id is kernel thread id (similar to Solaris LWP id) 1408 intx os::current_thread_id() { return os::Linux::gettid(); } 1409 int os::current_process_id() { 1410 return ::getpid(); 1411 } 1412 1413 // DLL functions 1414 1415 const char* os::dll_file_extension() { return ".so"; } 1416 1417 // This must be hard coded because it's the system's temporary 1418 // directory not the java application's temp directory, ala java.io.tmpdir. 1419 const char* os::get_temp_directory() { return "/tmp"; } 1420 1421 static bool file_exists(const char* filename) { 1422 struct stat statbuf; 1423 if (filename == NULL || strlen(filename) == 0) { 1424 return false; 1425 } 1426 return os::stat(filename, &statbuf) == 0; 1427 } 1428 1429 bool os::dll_build_name(char* buffer, size_t buflen, 1430 const char* pname, const char* fname) { 1431 bool retval = false; 1432 // Copied from libhpi 1433 const size_t pnamelen = pname ? strlen(pname) : 0; 1434 1435 // Return error on buffer overflow. 1436 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1437 return retval; 1438 } 1439 1440 if (pnamelen == 0) { 1441 snprintf(buffer, buflen, "lib%s.so", fname); 1442 retval = true; 1443 } else if (strchr(pname, *os::path_separator()) != NULL) { 1444 int n; 1445 char** pelements = split_path(pname, &n); 1446 if (pelements == NULL) { 1447 return false; 1448 } 1449 for (int i = 0; i < n; i++) { 1450 // Really shouldn't be NULL, but check can't hurt 1451 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1452 continue; // skip the empty path values 1453 } 1454 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1455 if (file_exists(buffer)) { 1456 retval = true; 1457 break; 1458 } 1459 } 1460 // release the storage 1461 for (int i = 0; i < n; i++) { 1462 if (pelements[i] != NULL) { 1463 FREE_C_HEAP_ARRAY(char, pelements[i]); 1464 } 1465 } 1466 if (pelements != NULL) { 1467 FREE_C_HEAP_ARRAY(char*, pelements); 1468 } 1469 } else { 1470 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1471 retval = true; 1472 } 1473 return retval; 1474 } 1475 1476 // check if addr is inside libjvm.so 1477 bool os::address_is_in_vm(address addr) { 1478 static address libjvm_base_addr; 1479 Dl_info dlinfo; 1480 1481 if (libjvm_base_addr == NULL) { 1482 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1483 libjvm_base_addr = (address)dlinfo.dli_fbase; 1484 } 1485 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1486 } 1487 1488 if (dladdr((void *)addr, &dlinfo) != 0) { 1489 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1490 } 1491 1492 return false; 1493 } 1494 1495 bool os::dll_address_to_function_name(address addr, char *buf, 1496 int buflen, int *offset, 1497 bool demangle) { 1498 // buf is not optional, but offset is optional 1499 assert(buf != NULL, "sanity check"); 1500 1501 Dl_info dlinfo; 1502 1503 if (dladdr((void*)addr, &dlinfo) != 0) { 1504 // see if we have a matching symbol 1505 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1506 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1507 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1508 } 1509 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1510 return true; 1511 } 1512 // no matching symbol so try for just file info 1513 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1514 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1515 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1516 return true; 1517 } 1518 } 1519 } 1520 1521 buf[0] = '\0'; 1522 if (offset != NULL) *offset = -1; 1523 return false; 1524 } 1525 1526 struct _address_to_library_name { 1527 address addr; // input : memory address 1528 size_t buflen; // size of fname 1529 char* fname; // output: library name 1530 address base; // library base addr 1531 }; 1532 1533 static int address_to_library_name_callback(struct dl_phdr_info *info, 1534 size_t size, void *data) { 1535 int i; 1536 bool found = false; 1537 address libbase = NULL; 1538 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1539 1540 // iterate through all loadable segments 1541 for (i = 0; i < info->dlpi_phnum; i++) { 1542 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1543 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1544 // base address of a library is the lowest address of its loaded 1545 // segments. 1546 if (libbase == NULL || libbase > segbase) { 1547 libbase = segbase; 1548 } 1549 // see if 'addr' is within current segment 1550 if (segbase <= d->addr && 1551 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1552 found = true; 1553 } 1554 } 1555 } 1556 1557 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1558 // so dll_address_to_library_name() can fall through to use dladdr() which 1559 // can figure out executable name from argv[0]. 1560 if (found && info->dlpi_name && info->dlpi_name[0]) { 1561 d->base = libbase; 1562 if (d->fname) { 1563 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1564 } 1565 return 1; 1566 } 1567 return 0; 1568 } 1569 1570 bool os::dll_address_to_library_name(address addr, char* buf, 1571 int buflen, int* offset) { 1572 // buf is not optional, but offset is optional 1573 assert(buf != NULL, "sanity check"); 1574 1575 Dl_info dlinfo; 1576 struct _address_to_library_name data; 1577 1578 // There is a bug in old glibc dladdr() implementation that it could resolve 1579 // to wrong library name if the .so file has a base address != NULL. Here 1580 // we iterate through the program headers of all loaded libraries to find 1581 // out which library 'addr' really belongs to. This workaround can be 1582 // removed once the minimum requirement for glibc is moved to 2.3.x. 1583 data.addr = addr; 1584 data.fname = buf; 1585 data.buflen = buflen; 1586 data.base = NULL; 1587 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1588 1589 if (rslt) { 1590 // buf already contains library name 1591 if (offset) *offset = addr - data.base; 1592 return true; 1593 } 1594 if (dladdr((void*)addr, &dlinfo) != 0) { 1595 if (dlinfo.dli_fname != NULL) { 1596 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1597 } 1598 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1599 *offset = addr - (address)dlinfo.dli_fbase; 1600 } 1601 return true; 1602 } 1603 1604 buf[0] = '\0'; 1605 if (offset) *offset = -1; 1606 return false; 1607 } 1608 1609 // Loads .dll/.so and 1610 // in case of error it checks if .dll/.so was built for the 1611 // same architecture as Hotspot is running on 1612 1613 1614 // Remember the stack's state. The Linux dynamic linker will change 1615 // the stack to 'executable' at most once, so we must safepoint only once. 1616 bool os::Linux::_stack_is_executable = false; 1617 1618 // VM operation that loads a library. This is necessary if stack protection 1619 // of the Java stacks can be lost during loading the library. If we 1620 // do not stop the Java threads, they can stack overflow before the stacks 1621 // are protected again. 1622 class VM_LinuxDllLoad: public VM_Operation { 1623 private: 1624 const char *_filename; 1625 char *_ebuf; 1626 int _ebuflen; 1627 void *_lib; 1628 public: 1629 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1630 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1631 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1632 void doit() { 1633 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1634 os::Linux::_stack_is_executable = true; 1635 } 1636 void* loaded_library() { return _lib; } 1637 }; 1638 1639 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1640 void * result = NULL; 1641 bool load_attempted = false; 1642 1643 // Check whether the library to load might change execution rights 1644 // of the stack. If they are changed, the protection of the stack 1645 // guard pages will be lost. We need a safepoint to fix this. 1646 // 1647 // See Linux man page execstack(8) for more info. 1648 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1649 ElfFile ef(filename); 1650 if (!ef.specifies_noexecstack()) { 1651 if (!is_init_completed()) { 1652 os::Linux::_stack_is_executable = true; 1653 // This is OK - No Java threads have been created yet, and hence no 1654 // stack guard pages to fix. 1655 // 1656 // This should happen only when you are building JDK7 using a very 1657 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1658 // 1659 // Dynamic loader will make all stacks executable after 1660 // this function returns, and will not do that again. 1661 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1662 } else { 1663 warning("You have loaded library %s which might have disabled stack guard. " 1664 "The VM will try to fix the stack guard now.\n" 1665 "It's highly recommended that you fix the library with " 1666 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1667 filename); 1668 1669 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1670 JavaThread *jt = JavaThread::current(); 1671 if (jt->thread_state() != _thread_in_native) { 1672 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1673 // that requires ExecStack. Cannot enter safe point. Let's give up. 1674 warning("Unable to fix stack guard. Giving up."); 1675 } else { 1676 if (!LoadExecStackDllInVMThread) { 1677 // This is for the case where the DLL has an static 1678 // constructor function that executes JNI code. We cannot 1679 // load such DLLs in the VMThread. 1680 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1681 } 1682 1683 ThreadInVMfromNative tiv(jt); 1684 debug_only(VMNativeEntryWrapper vew;) 1685 1686 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1687 VMThread::execute(&op); 1688 if (LoadExecStackDllInVMThread) { 1689 result = op.loaded_library(); 1690 } 1691 load_attempted = true; 1692 } 1693 } 1694 } 1695 } 1696 1697 if (!load_attempted) { 1698 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1699 } 1700 1701 if (result != NULL) { 1702 // Successful loading 1703 return result; 1704 } 1705 1706 Elf32_Ehdr elf_head; 1707 int diag_msg_max_length=ebuflen-strlen(ebuf); 1708 char* diag_msg_buf=ebuf+strlen(ebuf); 1709 1710 if (diag_msg_max_length==0) { 1711 // No more space in ebuf for additional diagnostics message 1712 return NULL; 1713 } 1714 1715 1716 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1717 1718 if (file_descriptor < 0) { 1719 // Can't open library, report dlerror() message 1720 return NULL; 1721 } 1722 1723 bool failed_to_read_elf_head= 1724 (sizeof(elf_head)!= 1725 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1726 1727 ::close(file_descriptor); 1728 if (failed_to_read_elf_head) { 1729 // file i/o error - report dlerror() msg 1730 return NULL; 1731 } 1732 1733 typedef struct { 1734 Elf32_Half code; // Actual value as defined in elf.h 1735 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1736 char elf_class; // 32 or 64 bit 1737 char endianess; // MSB or LSB 1738 char* name; // String representation 1739 } arch_t; 1740 1741 #ifndef EM_486 1742 #define EM_486 6 /* Intel 80486 */ 1743 #endif 1744 #ifndef EM_AARCH64 1745 #define EM_AARCH64 183 /* ARM AARCH64 */ 1746 #endif 1747 1748 static const arch_t arch_array[]={ 1749 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1750 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1751 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1752 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1753 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1754 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1755 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1756 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1757 #if defined(VM_LITTLE_ENDIAN) 1758 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1759 #else 1760 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"}, 1761 #endif 1762 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1763 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1764 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1765 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1766 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1767 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1768 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1769 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1770 }; 1771 1772 #if (defined IA32) 1773 static Elf32_Half running_arch_code=EM_386; 1774 #elif (defined AMD64) 1775 static Elf32_Half running_arch_code=EM_X86_64; 1776 #elif (defined IA64) 1777 static Elf32_Half running_arch_code=EM_IA_64; 1778 #elif (defined __sparc) && (defined _LP64) 1779 static Elf32_Half running_arch_code=EM_SPARCV9; 1780 #elif (defined __sparc) && (!defined _LP64) 1781 static Elf32_Half running_arch_code=EM_SPARC; 1782 #elif (defined __powerpc64__) 1783 static Elf32_Half running_arch_code=EM_PPC64; 1784 #elif (defined __powerpc__) 1785 static Elf32_Half running_arch_code=EM_PPC; 1786 #elif (defined ARM) 1787 static Elf32_Half running_arch_code=EM_ARM; 1788 #elif (defined S390) 1789 static Elf32_Half running_arch_code=EM_S390; 1790 #elif (defined ALPHA) 1791 static Elf32_Half running_arch_code=EM_ALPHA; 1792 #elif (defined MIPSEL) 1793 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1794 #elif (defined PARISC) 1795 static Elf32_Half running_arch_code=EM_PARISC; 1796 #elif (defined MIPS) 1797 static Elf32_Half running_arch_code=EM_MIPS; 1798 #elif (defined M68K) 1799 static Elf32_Half running_arch_code=EM_68K; 1800 #elif (defined AARCH64) 1801 static Elf32_Half running_arch_code=EM_AARCH64; 1802 #else 1803 #error Method os::dll_load requires that one of following is defined:\ 1804 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64 1805 #endif 1806 1807 // Identify compatability class for VM's architecture and library's architecture 1808 // Obtain string descriptions for architectures 1809 1810 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1811 int running_arch_index=-1; 1812 1813 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1814 if (running_arch_code == arch_array[i].code) { 1815 running_arch_index = i; 1816 } 1817 if (lib_arch.code == arch_array[i].code) { 1818 lib_arch.compat_class = arch_array[i].compat_class; 1819 lib_arch.name = arch_array[i].name; 1820 } 1821 } 1822 1823 assert(running_arch_index != -1, 1824 "Didn't find running architecture code (running_arch_code) in arch_array"); 1825 if (running_arch_index == -1) { 1826 // Even though running architecture detection failed 1827 // we may still continue with reporting dlerror() message 1828 return NULL; 1829 } 1830 1831 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1832 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1833 return NULL; 1834 } 1835 1836 #ifndef S390 1837 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1838 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1839 return NULL; 1840 } 1841 #endif // !S390 1842 1843 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1844 if (lib_arch.name!=NULL) { 1845 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1846 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1847 lib_arch.name, arch_array[running_arch_index].name); 1848 } else { 1849 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1850 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1851 lib_arch.code, 1852 arch_array[running_arch_index].name); 1853 } 1854 } 1855 1856 return NULL; 1857 } 1858 1859 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1860 int ebuflen) { 1861 void * result = ::dlopen(filename, RTLD_LAZY); 1862 if (result == NULL) { 1863 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1864 ebuf[ebuflen-1] = '\0'; 1865 } 1866 return result; 1867 } 1868 1869 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1870 int ebuflen) { 1871 void * result = NULL; 1872 if (LoadExecStackDllInVMThread) { 1873 result = dlopen_helper(filename, ebuf, ebuflen); 1874 } 1875 1876 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1877 // library that requires an executable stack, or which does not have this 1878 // stack attribute set, dlopen changes the stack attribute to executable. The 1879 // read protection of the guard pages gets lost. 1880 // 1881 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1882 // may have been queued at the same time. 1883 1884 if (!_stack_is_executable) { 1885 JavaThread *jt = Threads::first(); 1886 1887 while (jt) { 1888 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1889 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1890 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1891 warning("Attempt to reguard stack yellow zone failed."); 1892 } 1893 } 1894 jt = jt->next(); 1895 } 1896 } 1897 1898 return result; 1899 } 1900 1901 void* os::dll_lookup(void* handle, const char* name) { 1902 void* res = dlsym(handle, name); 1903 return res; 1904 } 1905 1906 void* os::get_default_process_handle() { 1907 return (void*)::dlopen(NULL, RTLD_LAZY); 1908 } 1909 1910 static bool _print_ascii_file(const char* filename, outputStream* st) { 1911 int fd = ::open(filename, O_RDONLY); 1912 if (fd == -1) { 1913 return false; 1914 } 1915 1916 char buf[32]; 1917 int bytes; 1918 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1919 st->print_raw(buf, bytes); 1920 } 1921 1922 ::close(fd); 1923 1924 return true; 1925 } 1926 1927 void os::print_dll_info(outputStream *st) { 1928 st->print_cr("Dynamic libraries:"); 1929 1930 char fname[32]; 1931 pid_t pid = os::Linux::gettid(); 1932 1933 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1934 1935 if (!_print_ascii_file(fname, st)) { 1936 st->print("Can not get library information for pid = %d\n", pid); 1937 } 1938 } 1939 1940 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1941 FILE *procmapsFile = NULL; 1942 1943 // Open the procfs maps file for the current process 1944 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1945 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1946 char line[PATH_MAX + 100]; 1947 1948 // Read line by line from 'file' 1949 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1950 u8 base, top, offset, inode; 1951 char permissions[5]; 1952 char device[6]; 1953 char name[PATH_MAX + 1]; 1954 1955 // Parse fields from line 1956 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1957 &base, &top, permissions, &offset, device, &inode, name); 1958 1959 // Filter by device id '00:00' so that we only get file system mapped files. 1960 if (strcmp(device, "00:00") != 0) { 1961 1962 // Call callback with the fields of interest 1963 if(callback(name, (address)base, (address)top, param)) { 1964 // Oops abort, callback aborted 1965 fclose(procmapsFile); 1966 return 1; 1967 } 1968 } 1969 } 1970 fclose(procmapsFile); 1971 } 1972 return 0; 1973 } 1974 1975 void os::print_os_info_brief(outputStream* st) { 1976 os::Linux::print_distro_info(st); 1977 1978 os::Posix::print_uname_info(st); 1979 1980 os::Linux::print_libversion_info(st); 1981 1982 } 1983 1984 void os::print_os_info(outputStream* st) { 1985 st->print("OS:"); 1986 1987 os::Linux::print_distro_info(st); 1988 1989 os::Posix::print_uname_info(st); 1990 1991 // Print warning if unsafe chroot environment detected 1992 if (unsafe_chroot_detected) { 1993 st->print("WARNING!! "); 1994 st->print_cr("%s", unstable_chroot_error); 1995 } 1996 1997 os::Linux::print_libversion_info(st); 1998 1999 os::Posix::print_rlimit_info(st); 2000 2001 os::Posix::print_load_average(st); 2002 2003 os::Linux::print_full_memory_info(st); 2004 } 2005 2006 // Try to identify popular distros. 2007 // Most Linux distributions have a /etc/XXX-release file, which contains 2008 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2009 // file that also contains the OS version string. Some have more than one 2010 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2011 // /etc/redhat-release.), so the order is important. 2012 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2013 // their own specific XXX-release file as well as a redhat-release file. 2014 // Because of this the XXX-release file needs to be searched for before the 2015 // redhat-release file. 2016 // Since Red Hat has a lsb-release file that is not very descriptive the 2017 // search for redhat-release needs to be before lsb-release. 2018 // Since the lsb-release file is the new standard it needs to be searched 2019 // before the older style release files. 2020 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2021 // next to last resort. The os-release file is a new standard that contains 2022 // distribution information and the system-release file seems to be an old 2023 // standard that has been replaced by the lsb-release and os-release files. 2024 // Searching for the debian_version file is the last resort. It contains 2025 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2026 // "Debian " is printed before the contents of the debian_version file. 2027 2028 const char* distro_files[] = { 2029 "/etc/oracle-release", 2030 "/etc/mandriva-release", 2031 "/etc/mandrake-release", 2032 "/etc/sun-release", 2033 "/etc/redhat-release", 2034 "/etc/lsb-release", 2035 "/etc/SuSE-release", 2036 "/etc/turbolinux-release", 2037 "/etc/gentoo-release", 2038 "/etc/ltib-release", 2039 "/etc/angstrom-version", 2040 "/etc/system-release", 2041 "/etc/os-release", 2042 NULL }; 2043 2044 void os::Linux::print_distro_info(outputStream* st) { 2045 for (int i = 0;; i++) { 2046 const char* file = distro_files[i]; 2047 if (file == NULL) { 2048 break; // done 2049 } 2050 // If file prints, we found it. 2051 if (_print_ascii_file(file, st)) { 2052 return; 2053 } 2054 } 2055 2056 if (file_exists("/etc/debian_version")) { 2057 st->print("Debian "); 2058 _print_ascii_file("/etc/debian_version", st); 2059 } else { 2060 st->print("Linux"); 2061 } 2062 st->cr(); 2063 } 2064 2065 static void parse_os_info(char* distro, size_t length, const char* file) { 2066 FILE* fp = fopen(file, "r"); 2067 if (fp != NULL) { 2068 char buf[256]; 2069 // get last line of the file. 2070 while (fgets(buf, sizeof(buf), fp)) { } 2071 // Edit out extra stuff in expected ubuntu format 2072 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL) { 2073 char* ptr = strstr(buf, "\""); // the name is in quotes 2074 if (ptr != NULL) { 2075 ptr++; // go beyond first quote 2076 char* nl = strchr(ptr, '\"'); 2077 if (nl != NULL) *nl = '\0'; 2078 strncpy(distro, ptr, length); 2079 } else { 2080 ptr = strstr(buf, "="); 2081 ptr++; // go beyond equals then 2082 char* nl = strchr(ptr, '\n'); 2083 if (nl != NULL) *nl = '\0'; 2084 strncpy(distro, ptr, length); 2085 } 2086 } else { 2087 // if not in expected Ubuntu format, print out whole line minus \n 2088 char* nl = strchr(buf, '\n'); 2089 if (nl != NULL) *nl = '\0'; 2090 strncpy(distro, buf, length); 2091 } 2092 // close distro file 2093 fclose(fp); 2094 } 2095 } 2096 2097 void os::get_summary_os_info(char* buf, size_t buflen) { 2098 for (int i = 0;; i++) { 2099 const char* file = distro_files[i]; 2100 if (file == NULL) { 2101 break; // ran out of distro_files 2102 } 2103 if (file_exists(file)) { 2104 parse_os_info(buf, buflen, file); 2105 return; 2106 } 2107 } 2108 // special case for debian 2109 if (file_exists("/etc/debian_version")) { 2110 strncpy(buf, "Debian ", buflen); 2111 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2112 } else { 2113 strncpy(buf, "Linux", buflen); 2114 } 2115 } 2116 2117 void os::Linux::print_libversion_info(outputStream* st) { 2118 // libc, pthread 2119 st->print("libc:"); 2120 st->print("%s ", os::Linux::glibc_version()); 2121 st->print("%s ", os::Linux::libpthread_version()); 2122 st->cr(); 2123 } 2124 2125 void os::Linux::print_full_memory_info(outputStream* st) { 2126 st->print("\n/proc/meminfo:\n"); 2127 _print_ascii_file("/proc/meminfo", st); 2128 st->cr(); 2129 } 2130 2131 void os::print_memory_info(outputStream* st) { 2132 2133 st->print("Memory:"); 2134 st->print(" %dk page", os::vm_page_size()>>10); 2135 2136 // values in struct sysinfo are "unsigned long" 2137 struct sysinfo si; 2138 sysinfo(&si); 2139 2140 st->print(", physical " UINT64_FORMAT "k", 2141 os::physical_memory() >> 10); 2142 st->print("(" UINT64_FORMAT "k free)", 2143 os::available_memory() >> 10); 2144 st->print(", swap " UINT64_FORMAT "k", 2145 ((jlong)si.totalswap * si.mem_unit) >> 10); 2146 st->print("(" UINT64_FORMAT "k free)", 2147 ((jlong)si.freeswap * si.mem_unit) >> 10); 2148 st->cr(); 2149 } 2150 2151 // Print the first "model name" line and the first "flags" line 2152 // that we find and nothing more. We assume "model name" comes 2153 // before "flags" so if we find a second "model name", then the 2154 // "flags" field is considered missing. 2155 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2156 #if defined(IA32) || defined(AMD64) 2157 // Other platforms have less repetitive cpuinfo files 2158 FILE *fp = fopen("/proc/cpuinfo", "r"); 2159 if (fp) { 2160 while (!feof(fp)) { 2161 if (fgets(buf, buflen, fp)) { 2162 // Assume model name comes before flags 2163 bool model_name_printed = false; 2164 if (strstr(buf, "model name") != NULL) { 2165 if (!model_name_printed) { 2166 st->print_raw("\nCPU Model and flags from /proc/cpuinfo:\n"); 2167 st->print_raw(buf); 2168 model_name_printed = true; 2169 } else { 2170 // model name printed but not flags? Odd, just return 2171 fclose(fp); 2172 return true; 2173 } 2174 } 2175 // print the flags line too 2176 if (strstr(buf, "flags") != NULL) { 2177 st->print_raw(buf); 2178 fclose(fp); 2179 return true; 2180 } 2181 } 2182 } 2183 fclose(fp); 2184 } 2185 #endif // x86 platforms 2186 return false; 2187 } 2188 2189 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2190 // Only print the model name if the platform provides this as a summary 2191 if (!print_model_name_and_flags(st, buf, buflen)) { 2192 st->print("\n/proc/cpuinfo:\n"); 2193 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2194 st->print_cr(" <Not Available>"); 2195 } 2196 } 2197 } 2198 2199 #if defined(AMD64) || defined(IA32) || defined(X32) 2200 const char* search_string = "model name"; 2201 #elif defined(SPARC) 2202 const char* search_string = "cpu"; 2203 #elif defined(PPC64) 2204 const char* search_string = "cpu"; 2205 #else 2206 const char* search_string = "Processor"; 2207 #endif 2208 2209 // Parses the cpuinfo file for string representing the model name. 2210 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2211 FILE* fp = fopen("/proc/cpuinfo", "r"); 2212 if (fp != NULL) { 2213 while (!feof(fp)) { 2214 char buf[256]; 2215 if (fgets(buf, sizeof(buf), fp)) { 2216 char* start = strstr(buf, search_string); 2217 if (start != NULL) { 2218 char *ptr = start + strlen(search_string); 2219 char *end = buf + strlen(buf); 2220 while (ptr != end) { 2221 // skip whitespace and colon for the rest of the name. 2222 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2223 break; 2224 } 2225 ptr++; 2226 } 2227 if (ptr != end) { 2228 // reasonable string, get rid of newline and keep the rest 2229 char* nl = strchr(buf, '\n'); 2230 if (nl != NULL) *nl = '\0'; 2231 strncpy(cpuinfo, ptr, length); 2232 fclose(fp); 2233 return; 2234 } 2235 } 2236 } 2237 } 2238 fclose(fp); 2239 } 2240 // cpuinfo not found or parsing failed, just print generic string. The entire 2241 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2242 #if defined(AMD64) 2243 strncpy(cpuinfo, "x86_64", length); 2244 #elif defined(IA32) 2245 strncpy(cpuinfo, "x86_32", length); 2246 #elif defined(IA64) 2247 strncpy(cpuinfo, "IA64", length); 2248 #elif defined(SPARC) 2249 strncpy(cpuinfo, "sparcv9", length); 2250 #elif defined(AARCH64) 2251 strncpy(cpuinfo, "AArch64", length); 2252 #elif defined(ARM) 2253 strncpy(cpuinfo, "ARM", length); 2254 #elif defined(PPC) 2255 strncpy(cpuinfo, "PPC64", length); 2256 #elif defined(ZERO_LIBARCH) 2257 strncpy(cpuinfo, ZERO_LIBARCH, length); 2258 #else 2259 strncpy(cpuinfo, "unknown", length); 2260 #endif 2261 } 2262 2263 static void print_signal_handler(outputStream* st, int sig, 2264 char* buf, size_t buflen); 2265 2266 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2267 st->print_cr("Signal Handlers:"); 2268 print_signal_handler(st, SIGSEGV, buf, buflen); 2269 print_signal_handler(st, SIGBUS , buf, buflen); 2270 print_signal_handler(st, SIGFPE , buf, buflen); 2271 print_signal_handler(st, SIGPIPE, buf, buflen); 2272 print_signal_handler(st, SIGXFSZ, buf, buflen); 2273 print_signal_handler(st, SIGILL , buf, buflen); 2274 print_signal_handler(st, SR_signum, buf, buflen); 2275 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2276 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2277 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2278 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2279 #if defined(PPC64) 2280 print_signal_handler(st, SIGTRAP, buf, buflen); 2281 #endif 2282 } 2283 2284 static char saved_jvm_path[MAXPATHLEN] = {0}; 2285 2286 // Find the full path to the current module, libjvm.so 2287 void os::jvm_path(char *buf, jint buflen) { 2288 // Error checking. 2289 if (buflen < MAXPATHLEN) { 2290 assert(false, "must use a large-enough buffer"); 2291 buf[0] = '\0'; 2292 return; 2293 } 2294 // Lazy resolve the path to current module. 2295 if (saved_jvm_path[0] != 0) { 2296 strcpy(buf, saved_jvm_path); 2297 return; 2298 } 2299 2300 char dli_fname[MAXPATHLEN]; 2301 bool ret = dll_address_to_library_name( 2302 CAST_FROM_FN_PTR(address, os::jvm_path), 2303 dli_fname, sizeof(dli_fname), NULL); 2304 assert(ret, "cannot locate libjvm"); 2305 char *rp = NULL; 2306 if (ret && dli_fname[0] != '\0') { 2307 rp = realpath(dli_fname, buf); 2308 } 2309 if (rp == NULL) { 2310 return; 2311 } 2312 2313 if (Arguments::sun_java_launcher_is_altjvm()) { 2314 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2315 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2316 // If "/jre/lib/" appears at the right place in the string, then 2317 // assume we are installed in a JDK and we're done. Otherwise, check 2318 // for a JAVA_HOME environment variable and fix up the path so it 2319 // looks like libjvm.so is installed there (append a fake suffix 2320 // hotspot/libjvm.so). 2321 const char *p = buf + strlen(buf) - 1; 2322 for (int count = 0; p > buf && count < 5; ++count) { 2323 for (--p; p > buf && *p != '/'; --p) 2324 /* empty */ ; 2325 } 2326 2327 if (strncmp(p, "/jre/lib/", 9) != 0) { 2328 // Look for JAVA_HOME in the environment. 2329 char* java_home_var = ::getenv("JAVA_HOME"); 2330 if (java_home_var != NULL && java_home_var[0] != 0) { 2331 char* jrelib_p; 2332 int len; 2333 2334 // Check the current module name "libjvm.so". 2335 p = strrchr(buf, '/'); 2336 if (p == NULL) { 2337 return; 2338 } 2339 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2340 2341 rp = realpath(java_home_var, buf); 2342 if (rp == NULL) { 2343 return; 2344 } 2345 2346 // determine if this is a legacy image or modules image 2347 // modules image doesn't have "jre" subdirectory 2348 len = strlen(buf); 2349 assert(len < buflen, "Ran out of buffer room"); 2350 jrelib_p = buf + len; 2351 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2352 if (0 != access(buf, F_OK)) { 2353 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2354 } 2355 2356 if (0 == access(buf, F_OK)) { 2357 // Use current module name "libjvm.so" 2358 len = strlen(buf); 2359 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2360 } else { 2361 // Go back to path of .so 2362 rp = realpath(dli_fname, buf); 2363 if (rp == NULL) { 2364 return; 2365 } 2366 } 2367 } 2368 } 2369 } 2370 2371 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2372 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2373 } 2374 2375 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2376 // no prefix required, not even "_" 2377 } 2378 2379 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2380 // no suffix required 2381 } 2382 2383 //////////////////////////////////////////////////////////////////////////////// 2384 // sun.misc.Signal support 2385 2386 static volatile jint sigint_count = 0; 2387 2388 static void UserHandler(int sig, void *siginfo, void *context) { 2389 // 4511530 - sem_post is serialized and handled by the manager thread. When 2390 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2391 // don't want to flood the manager thread with sem_post requests. 2392 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2393 return; 2394 } 2395 2396 // Ctrl-C is pressed during error reporting, likely because the error 2397 // handler fails to abort. Let VM die immediately. 2398 if (sig == SIGINT && is_error_reported()) { 2399 os::die(); 2400 } 2401 2402 os::signal_notify(sig); 2403 } 2404 2405 void* os::user_handler() { 2406 return CAST_FROM_FN_PTR(void*, UserHandler); 2407 } 2408 2409 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2410 struct timespec ts; 2411 // Semaphore's are always associated with CLOCK_REALTIME 2412 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2413 // see unpackTime for discussion on overflow checking 2414 if (sec >= MAX_SECS) { 2415 ts.tv_sec += MAX_SECS; 2416 ts.tv_nsec = 0; 2417 } else { 2418 ts.tv_sec += sec; 2419 ts.tv_nsec += nsec; 2420 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2421 ts.tv_nsec -= NANOSECS_PER_SEC; 2422 ++ts.tv_sec; // note: this must be <= max_secs 2423 } 2424 } 2425 2426 return ts; 2427 } 2428 2429 extern "C" { 2430 typedef void (*sa_handler_t)(int); 2431 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2432 } 2433 2434 void* os::signal(int signal_number, void* handler) { 2435 struct sigaction sigAct, oldSigAct; 2436 2437 sigfillset(&(sigAct.sa_mask)); 2438 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2439 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2440 2441 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2442 // -1 means registration failed 2443 return (void *)-1; 2444 } 2445 2446 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2447 } 2448 2449 void os::signal_raise(int signal_number) { 2450 ::raise(signal_number); 2451 } 2452 2453 // The following code is moved from os.cpp for making this 2454 // code platform specific, which it is by its very nature. 2455 2456 // Will be modified when max signal is changed to be dynamic 2457 int os::sigexitnum_pd() { 2458 return NSIG; 2459 } 2460 2461 // a counter for each possible signal value 2462 static volatile jint pending_signals[NSIG+1] = { 0 }; 2463 2464 // Linux(POSIX) specific hand shaking semaphore. 2465 static sem_t sig_sem; 2466 static PosixSemaphore sr_semaphore; 2467 2468 void os::signal_init_pd() { 2469 // Initialize signal structures 2470 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2471 2472 // Initialize signal semaphore 2473 ::sem_init(&sig_sem, 0, 0); 2474 } 2475 2476 void os::signal_notify(int sig) { 2477 Atomic::inc(&pending_signals[sig]); 2478 ::sem_post(&sig_sem); 2479 } 2480 2481 static int check_pending_signals(bool wait) { 2482 Atomic::store(0, &sigint_count); 2483 for (;;) { 2484 for (int i = 0; i < NSIG + 1; i++) { 2485 jint n = pending_signals[i]; 2486 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2487 return i; 2488 } 2489 } 2490 if (!wait) { 2491 return -1; 2492 } 2493 JavaThread *thread = JavaThread::current(); 2494 ThreadBlockInVM tbivm(thread); 2495 2496 bool threadIsSuspended; 2497 do { 2498 thread->set_suspend_equivalent(); 2499 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2500 ::sem_wait(&sig_sem); 2501 2502 // were we externally suspended while we were waiting? 2503 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2504 if (threadIsSuspended) { 2505 // The semaphore has been incremented, but while we were waiting 2506 // another thread suspended us. We don't want to continue running 2507 // while suspended because that would surprise the thread that 2508 // suspended us. 2509 ::sem_post(&sig_sem); 2510 2511 thread->java_suspend_self(); 2512 } 2513 } while (threadIsSuspended); 2514 } 2515 } 2516 2517 int os::signal_lookup() { 2518 return check_pending_signals(false); 2519 } 2520 2521 int os::signal_wait() { 2522 return check_pending_signals(true); 2523 } 2524 2525 //////////////////////////////////////////////////////////////////////////////// 2526 // Virtual Memory 2527 2528 int os::vm_page_size() { 2529 // Seems redundant as all get out 2530 assert(os::Linux::page_size() != -1, "must call os::init"); 2531 return os::Linux::page_size(); 2532 } 2533 2534 // Solaris allocates memory by pages. 2535 int os::vm_allocation_granularity() { 2536 assert(os::Linux::page_size() != -1, "must call os::init"); 2537 return os::Linux::page_size(); 2538 } 2539 2540 // Rationale behind this function: 2541 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2542 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2543 // samples for JITted code. Here we create private executable mapping over the code cache 2544 // and then we can use standard (well, almost, as mapping can change) way to provide 2545 // info for the reporting script by storing timestamp and location of symbol 2546 void linux_wrap_code(char* base, size_t size) { 2547 static volatile jint cnt = 0; 2548 2549 if (!UseOprofile) { 2550 return; 2551 } 2552 2553 char buf[PATH_MAX+1]; 2554 int num = Atomic::add(1, &cnt); 2555 2556 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2557 os::get_temp_directory(), os::current_process_id(), num); 2558 unlink(buf); 2559 2560 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2561 2562 if (fd != -1) { 2563 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2564 if (rv != (off_t)-1) { 2565 if (::write(fd, "", 1) == 1) { 2566 mmap(base, size, 2567 PROT_READ|PROT_WRITE|PROT_EXEC, 2568 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2569 } 2570 } 2571 ::close(fd); 2572 unlink(buf); 2573 } 2574 } 2575 2576 static bool recoverable_mmap_error(int err) { 2577 // See if the error is one we can let the caller handle. This 2578 // list of errno values comes from JBS-6843484. I can't find a 2579 // Linux man page that documents this specific set of errno 2580 // values so while this list currently matches Solaris, it may 2581 // change as we gain experience with this failure mode. 2582 switch (err) { 2583 case EBADF: 2584 case EINVAL: 2585 case ENOTSUP: 2586 // let the caller deal with these errors 2587 return true; 2588 2589 default: 2590 // Any remaining errors on this OS can cause our reserved mapping 2591 // to be lost. That can cause confusion where different data 2592 // structures think they have the same memory mapped. The worst 2593 // scenario is if both the VM and a library think they have the 2594 // same memory mapped. 2595 return false; 2596 } 2597 } 2598 2599 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2600 int err) { 2601 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2602 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2603 strerror(err), err); 2604 } 2605 2606 static void warn_fail_commit_memory(char* addr, size_t size, 2607 size_t alignment_hint, bool exec, 2608 int err) { 2609 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2610 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2611 alignment_hint, exec, strerror(err), err); 2612 } 2613 2614 // NOTE: Linux kernel does not really reserve the pages for us. 2615 // All it does is to check if there are enough free pages 2616 // left at the time of mmap(). This could be a potential 2617 // problem. 2618 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2619 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2620 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2621 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2622 if (res != (uintptr_t) MAP_FAILED) { 2623 if (UseNUMAInterleaving) { 2624 numa_make_global(addr, size); 2625 } 2626 return 0; 2627 } 2628 2629 int err = errno; // save errno from mmap() call above 2630 2631 if (!recoverable_mmap_error(err)) { 2632 warn_fail_commit_memory(addr, size, exec, err); 2633 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2634 } 2635 2636 return err; 2637 } 2638 2639 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2640 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2641 } 2642 2643 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2644 const char* mesg) { 2645 assert(mesg != NULL, "mesg must be specified"); 2646 int err = os::Linux::commit_memory_impl(addr, size, exec); 2647 if (err != 0) { 2648 // the caller wants all commit errors to exit with the specified mesg: 2649 warn_fail_commit_memory(addr, size, exec, err); 2650 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2651 } 2652 } 2653 2654 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2655 #ifndef MAP_HUGETLB 2656 #define MAP_HUGETLB 0x40000 2657 #endif 2658 2659 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2660 #ifndef MADV_HUGEPAGE 2661 #define MADV_HUGEPAGE 14 2662 #endif 2663 2664 int os::Linux::commit_memory_impl(char* addr, size_t size, 2665 size_t alignment_hint, bool exec) { 2666 int err = os::Linux::commit_memory_impl(addr, size, exec); 2667 if (err == 0) { 2668 realign_memory(addr, size, alignment_hint); 2669 } 2670 return err; 2671 } 2672 2673 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2674 bool exec) { 2675 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2676 } 2677 2678 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2679 size_t alignment_hint, bool exec, 2680 const char* mesg) { 2681 assert(mesg != NULL, "mesg must be specified"); 2682 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2683 if (err != 0) { 2684 // the caller wants all commit errors to exit with the specified mesg: 2685 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2686 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2687 } 2688 } 2689 2690 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2691 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2692 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2693 // be supported or the memory may already be backed by huge pages. 2694 ::madvise(addr, bytes, MADV_HUGEPAGE); 2695 } 2696 } 2697 2698 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2699 // This method works by doing an mmap over an existing mmaping and effectively discarding 2700 // the existing pages. However it won't work for SHM-based large pages that cannot be 2701 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2702 // small pages on top of the SHM segment. This method always works for small pages, so we 2703 // allow that in any case. 2704 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2705 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2706 } 2707 } 2708 2709 void os::numa_make_global(char *addr, size_t bytes) { 2710 Linux::numa_interleave_memory(addr, bytes); 2711 } 2712 2713 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2714 // bind policy to MPOL_PREFERRED for the current thread. 2715 #define USE_MPOL_PREFERRED 0 2716 2717 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2718 // To make NUMA and large pages more robust when both enabled, we need to ease 2719 // the requirements on where the memory should be allocated. MPOL_BIND is the 2720 // default policy and it will force memory to be allocated on the specified 2721 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2722 // the specified node, but will not force it. Using this policy will prevent 2723 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2724 // free large pages. 2725 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2726 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2727 } 2728 2729 bool os::numa_topology_changed() { return false; } 2730 2731 size_t os::numa_get_groups_num() { 2732 int max_node = Linux::numa_max_node(); 2733 return max_node > 0 ? max_node + 1 : 1; 2734 } 2735 2736 int os::numa_get_group_id() { 2737 int cpu_id = Linux::sched_getcpu(); 2738 if (cpu_id != -1) { 2739 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2740 if (lgrp_id != -1) { 2741 return lgrp_id; 2742 } 2743 } 2744 return 0; 2745 } 2746 2747 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2748 for (size_t i = 0; i < size; i++) { 2749 ids[i] = i; 2750 } 2751 return size; 2752 } 2753 2754 bool os::get_page_info(char *start, page_info* info) { 2755 return false; 2756 } 2757 2758 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2759 page_info* page_found) { 2760 return end; 2761 } 2762 2763 2764 int os::Linux::sched_getcpu_syscall(void) { 2765 unsigned int cpu = 0; 2766 int retval = -1; 2767 2768 #if defined(IA32) 2769 #ifndef SYS_getcpu 2770 #define SYS_getcpu 318 2771 #endif 2772 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2773 #elif defined(AMD64) 2774 // Unfortunately we have to bring all these macros here from vsyscall.h 2775 // to be able to compile on old linuxes. 2776 #define __NR_vgetcpu 2 2777 #define VSYSCALL_START (-10UL << 20) 2778 #define VSYSCALL_SIZE 1024 2779 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2780 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2781 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2782 retval = vgetcpu(&cpu, NULL, NULL); 2783 #endif 2784 2785 return (retval == -1) ? retval : cpu; 2786 } 2787 2788 // Something to do with the numa-aware allocator needs these symbols 2789 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2790 extern "C" JNIEXPORT void numa_error(char *where) { } 2791 2792 2793 // If we are running with libnuma version > 2, then we should 2794 // be trying to use symbols with versions 1.1 2795 // If we are running with earlier version, which did not have symbol versions, 2796 // we should use the base version. 2797 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2798 void *f = dlvsym(handle, name, "libnuma_1.1"); 2799 if (f == NULL) { 2800 f = dlsym(handle, name); 2801 } 2802 return f; 2803 } 2804 2805 bool os::Linux::libnuma_init() { 2806 // sched_getcpu() should be in libc. 2807 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2808 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2809 2810 // If it's not, try a direct syscall. 2811 if (sched_getcpu() == -1) { 2812 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2813 (void*)&sched_getcpu_syscall)); 2814 } 2815 2816 if (sched_getcpu() != -1) { // Does it work? 2817 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2818 if (handle != NULL) { 2819 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2820 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2821 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2822 libnuma_dlsym(handle, "numa_max_node"))); 2823 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2824 libnuma_dlsym(handle, "numa_available"))); 2825 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2826 libnuma_dlsym(handle, "numa_tonode_memory"))); 2827 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2828 libnuma_dlsym(handle, "numa_interleave_memory"))); 2829 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2830 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2831 2832 2833 if (numa_available() != -1) { 2834 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2835 // Create a cpu -> node mapping 2836 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2837 rebuild_cpu_to_node_map(); 2838 return true; 2839 } 2840 } 2841 } 2842 return false; 2843 } 2844 2845 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2846 // The table is later used in get_node_by_cpu(). 2847 void os::Linux::rebuild_cpu_to_node_map() { 2848 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2849 // in libnuma (possible values are starting from 16, 2850 // and continuing up with every other power of 2, but less 2851 // than the maximum number of CPUs supported by kernel), and 2852 // is a subject to change (in libnuma version 2 the requirements 2853 // are more reasonable) we'll just hardcode the number they use 2854 // in the library. 2855 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2856 2857 size_t cpu_num = os::active_processor_count(); 2858 size_t cpu_map_size = NCPUS / BitsPerCLong; 2859 size_t cpu_map_valid_size = 2860 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2861 2862 cpu_to_node()->clear(); 2863 cpu_to_node()->at_grow(cpu_num - 1); 2864 size_t node_num = numa_get_groups_num(); 2865 2866 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2867 for (size_t i = 0; i < node_num; i++) { 2868 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2869 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2870 if (cpu_map[j] != 0) { 2871 for (size_t k = 0; k < BitsPerCLong; k++) { 2872 if (cpu_map[j] & (1UL << k)) { 2873 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2874 } 2875 } 2876 } 2877 } 2878 } 2879 } 2880 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2881 } 2882 2883 int os::Linux::get_node_by_cpu(int cpu_id) { 2884 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2885 return cpu_to_node()->at(cpu_id); 2886 } 2887 return -1; 2888 } 2889 2890 GrowableArray<int>* os::Linux::_cpu_to_node; 2891 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2892 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2893 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2894 os::Linux::numa_available_func_t os::Linux::_numa_available; 2895 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2896 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2897 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2898 unsigned long* os::Linux::_numa_all_nodes; 2899 2900 bool os::pd_uncommit_memory(char* addr, size_t size) { 2901 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2902 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2903 return res != (uintptr_t) MAP_FAILED; 2904 } 2905 2906 static address get_stack_commited_bottom(address bottom, size_t size) { 2907 address nbot = bottom; 2908 address ntop = bottom + size; 2909 2910 size_t page_sz = os::vm_page_size(); 2911 unsigned pages = size / page_sz; 2912 2913 unsigned char vec[1]; 2914 unsigned imin = 1, imax = pages + 1, imid; 2915 int mincore_return_value = 0; 2916 2917 assert(imin <= imax, "Unexpected page size"); 2918 2919 while (imin < imax) { 2920 imid = (imax + imin) / 2; 2921 nbot = ntop - (imid * page_sz); 2922 2923 // Use a trick with mincore to check whether the page is mapped or not. 2924 // mincore sets vec to 1 if page resides in memory and to 0 if page 2925 // is swapped output but if page we are asking for is unmapped 2926 // it returns -1,ENOMEM 2927 mincore_return_value = mincore(nbot, page_sz, vec); 2928 2929 if (mincore_return_value == -1) { 2930 // Page is not mapped go up 2931 // to find first mapped page 2932 if (errno != EAGAIN) { 2933 assert(errno == ENOMEM, "Unexpected mincore errno"); 2934 imax = imid; 2935 } 2936 } else { 2937 // Page is mapped go down 2938 // to find first not mapped page 2939 imin = imid + 1; 2940 } 2941 } 2942 2943 nbot = nbot + page_sz; 2944 2945 // Adjust stack bottom one page up if last checked page is not mapped 2946 if (mincore_return_value == -1) { 2947 nbot = nbot + page_sz; 2948 } 2949 2950 return nbot; 2951 } 2952 2953 2954 // Linux uses a growable mapping for the stack, and if the mapping for 2955 // the stack guard pages is not removed when we detach a thread the 2956 // stack cannot grow beyond the pages where the stack guard was 2957 // mapped. If at some point later in the process the stack expands to 2958 // that point, the Linux kernel cannot expand the stack any further 2959 // because the guard pages are in the way, and a segfault occurs. 2960 // 2961 // However, it's essential not to split the stack region by unmapping 2962 // a region (leaving a hole) that's already part of the stack mapping, 2963 // so if the stack mapping has already grown beyond the guard pages at 2964 // the time we create them, we have to truncate the stack mapping. 2965 // So, we need to know the extent of the stack mapping when 2966 // create_stack_guard_pages() is called. 2967 2968 // We only need this for stacks that are growable: at the time of 2969 // writing thread stacks don't use growable mappings (i.e. those 2970 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2971 // only applies to the main thread. 2972 2973 // If the (growable) stack mapping already extends beyond the point 2974 // where we're going to put our guard pages, truncate the mapping at 2975 // that point by munmap()ping it. This ensures that when we later 2976 // munmap() the guard pages we don't leave a hole in the stack 2977 // mapping. This only affects the main/initial thread 2978 2979 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 2980 if (os::Linux::is_initial_thread()) { 2981 // As we manually grow stack up to bottom inside create_attached_thread(), 2982 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 2983 // we don't need to do anything special. 2984 // Check it first, before calling heavy function. 2985 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 2986 unsigned char vec[1]; 2987 2988 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 2989 // Fallback to slow path on all errors, including EAGAIN 2990 stack_extent = (uintptr_t) get_stack_commited_bottom( 2991 os::Linux::initial_thread_stack_bottom(), 2992 (size_t)addr - stack_extent); 2993 } 2994 2995 if (stack_extent < (uintptr_t)addr) { 2996 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 2997 } 2998 } 2999 3000 return os::commit_memory(addr, size, !ExecMem); 3001 } 3002 3003 // If this is a growable mapping, remove the guard pages entirely by 3004 // munmap()ping them. If not, just call uncommit_memory(). This only 3005 // affects the main/initial thread, but guard against future OS changes 3006 // It's safe to always unmap guard pages for initial thread because we 3007 // always place it right after end of the mapped region 3008 3009 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3010 uintptr_t stack_extent, stack_base; 3011 3012 if (os::Linux::is_initial_thread()) { 3013 return ::munmap(addr, size) == 0; 3014 } 3015 3016 return os::uncommit_memory(addr, size); 3017 } 3018 3019 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3020 // at 'requested_addr'. If there are existing memory mappings at the same 3021 // location, however, they will be overwritten. If 'fixed' is false, 3022 // 'requested_addr' is only treated as a hint, the return value may or 3023 // may not start from the requested address. Unlike Linux mmap(), this 3024 // function returns NULL to indicate failure. 3025 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3026 char * addr; 3027 int flags; 3028 3029 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3030 if (fixed) { 3031 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3032 flags |= MAP_FIXED; 3033 } 3034 3035 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3036 // touch an uncommitted page. Otherwise, the read/write might 3037 // succeed if we have enough swap space to back the physical page. 3038 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3039 flags, -1, 0); 3040 3041 return addr == MAP_FAILED ? NULL : addr; 3042 } 3043 3044 static int anon_munmap(char * addr, size_t size) { 3045 return ::munmap(addr, size) == 0; 3046 } 3047 3048 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3049 size_t alignment_hint) { 3050 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3051 } 3052 3053 bool os::pd_release_memory(char* addr, size_t size) { 3054 return anon_munmap(addr, size); 3055 } 3056 3057 static bool linux_mprotect(char* addr, size_t size, int prot) { 3058 // Linux wants the mprotect address argument to be page aligned. 3059 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3060 3061 // According to SUSv3, mprotect() should only be used with mappings 3062 // established by mmap(), and mmap() always maps whole pages. Unaligned 3063 // 'addr' likely indicates problem in the VM (e.g. trying to change 3064 // protection of malloc'ed or statically allocated memory). Check the 3065 // caller if you hit this assert. 3066 assert(addr == bottom, "sanity check"); 3067 3068 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3069 return ::mprotect(bottom, size, prot) == 0; 3070 } 3071 3072 // Set protections specified 3073 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3074 bool is_committed) { 3075 unsigned int p = 0; 3076 switch (prot) { 3077 case MEM_PROT_NONE: p = PROT_NONE; break; 3078 case MEM_PROT_READ: p = PROT_READ; break; 3079 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3080 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3081 default: 3082 ShouldNotReachHere(); 3083 } 3084 // is_committed is unused. 3085 return linux_mprotect(addr, bytes, p); 3086 } 3087 3088 bool os::guard_memory(char* addr, size_t size) { 3089 return linux_mprotect(addr, size, PROT_NONE); 3090 } 3091 3092 bool os::unguard_memory(char* addr, size_t size) { 3093 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3094 } 3095 3096 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3097 size_t page_size) { 3098 bool result = false; 3099 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3100 MAP_ANONYMOUS|MAP_PRIVATE, 3101 -1, 0); 3102 if (p != MAP_FAILED) { 3103 void *aligned_p = align_ptr_up(p, page_size); 3104 3105 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3106 3107 munmap(p, page_size * 2); 3108 } 3109 3110 if (warn && !result) { 3111 warning("TransparentHugePages is not supported by the operating system."); 3112 } 3113 3114 return result; 3115 } 3116 3117 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3118 bool result = false; 3119 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3120 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3121 -1, 0); 3122 3123 if (p != MAP_FAILED) { 3124 // We don't know if this really is a huge page or not. 3125 FILE *fp = fopen("/proc/self/maps", "r"); 3126 if (fp) { 3127 while (!feof(fp)) { 3128 char chars[257]; 3129 long x = 0; 3130 if (fgets(chars, sizeof(chars), fp)) { 3131 if (sscanf(chars, "%lx-%*x", &x) == 1 3132 && x == (long)p) { 3133 if (strstr (chars, "hugepage")) { 3134 result = true; 3135 break; 3136 } 3137 } 3138 } 3139 } 3140 fclose(fp); 3141 } 3142 munmap(p, page_size); 3143 } 3144 3145 if (warn && !result) { 3146 warning("HugeTLBFS is not supported by the operating system."); 3147 } 3148 3149 return result; 3150 } 3151 3152 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3153 // 3154 // From the coredump_filter documentation: 3155 // 3156 // - (bit 0) anonymous private memory 3157 // - (bit 1) anonymous shared memory 3158 // - (bit 2) file-backed private memory 3159 // - (bit 3) file-backed shared memory 3160 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3161 // effective only if the bit 2 is cleared) 3162 // - (bit 5) hugetlb private memory 3163 // - (bit 6) hugetlb shared memory 3164 // 3165 static void set_coredump_filter(void) { 3166 FILE *f; 3167 long cdm; 3168 3169 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3170 return; 3171 } 3172 3173 if (fscanf(f, "%lx", &cdm) != 1) { 3174 fclose(f); 3175 return; 3176 } 3177 3178 rewind(f); 3179 3180 if ((cdm & LARGEPAGES_BIT) == 0) { 3181 cdm |= LARGEPAGES_BIT; 3182 fprintf(f, "%#lx", cdm); 3183 } 3184 3185 fclose(f); 3186 } 3187 3188 // Large page support 3189 3190 static size_t _large_page_size = 0; 3191 3192 size_t os::Linux::find_large_page_size() { 3193 size_t large_page_size = 0; 3194 3195 // large_page_size on Linux is used to round up heap size. x86 uses either 3196 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3197 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3198 // page as large as 256M. 3199 // 3200 // Here we try to figure out page size by parsing /proc/meminfo and looking 3201 // for a line with the following format: 3202 // Hugepagesize: 2048 kB 3203 // 3204 // If we can't determine the value (e.g. /proc is not mounted, or the text 3205 // format has been changed), we'll use the largest page size supported by 3206 // the processor. 3207 3208 #ifndef ZERO 3209 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3210 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M); 3211 #endif // ZERO 3212 3213 FILE *fp = fopen("/proc/meminfo", "r"); 3214 if (fp) { 3215 while (!feof(fp)) { 3216 int x = 0; 3217 char buf[16]; 3218 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3219 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3220 large_page_size = x * K; 3221 break; 3222 } 3223 } else { 3224 // skip to next line 3225 for (;;) { 3226 int ch = fgetc(fp); 3227 if (ch == EOF || ch == (int)'\n') break; 3228 } 3229 } 3230 } 3231 fclose(fp); 3232 } 3233 3234 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3235 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3236 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3237 proper_unit_for_byte_size(large_page_size)); 3238 } 3239 3240 return large_page_size; 3241 } 3242 3243 size_t os::Linux::setup_large_page_size() { 3244 _large_page_size = Linux::find_large_page_size(); 3245 const size_t default_page_size = (size_t)Linux::page_size(); 3246 if (_large_page_size > default_page_size) { 3247 _page_sizes[0] = _large_page_size; 3248 _page_sizes[1] = default_page_size; 3249 _page_sizes[2] = 0; 3250 } 3251 3252 return _large_page_size; 3253 } 3254 3255 bool os::Linux::setup_large_page_type(size_t page_size) { 3256 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3257 FLAG_IS_DEFAULT(UseSHM) && 3258 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3259 3260 // The type of large pages has not been specified by the user. 3261 3262 // Try UseHugeTLBFS and then UseSHM. 3263 UseHugeTLBFS = UseSHM = true; 3264 3265 // Don't try UseTransparentHugePages since there are known 3266 // performance issues with it turned on. This might change in the future. 3267 UseTransparentHugePages = false; 3268 } 3269 3270 if (UseTransparentHugePages) { 3271 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3272 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3273 UseHugeTLBFS = false; 3274 UseSHM = false; 3275 return true; 3276 } 3277 UseTransparentHugePages = false; 3278 } 3279 3280 if (UseHugeTLBFS) { 3281 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3282 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3283 UseSHM = false; 3284 return true; 3285 } 3286 UseHugeTLBFS = false; 3287 } 3288 3289 return UseSHM; 3290 } 3291 3292 void os::large_page_init() { 3293 if (!UseLargePages && 3294 !UseTransparentHugePages && 3295 !UseHugeTLBFS && 3296 !UseSHM) { 3297 // Not using large pages. 3298 return; 3299 } 3300 3301 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3302 // The user explicitly turned off large pages. 3303 // Ignore the rest of the large pages flags. 3304 UseTransparentHugePages = false; 3305 UseHugeTLBFS = false; 3306 UseSHM = false; 3307 return; 3308 } 3309 3310 size_t large_page_size = Linux::setup_large_page_size(); 3311 UseLargePages = Linux::setup_large_page_type(large_page_size); 3312 3313 set_coredump_filter(); 3314 } 3315 3316 #ifndef SHM_HUGETLB 3317 #define SHM_HUGETLB 04000 3318 #endif 3319 3320 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3321 char* req_addr, bool exec) { 3322 // "exec" is passed in but not used. Creating the shared image for 3323 // the code cache doesn't have an SHM_X executable permission to check. 3324 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3325 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3326 3327 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) { 3328 return NULL; // Fallback to small pages. 3329 } 3330 3331 key_t key = IPC_PRIVATE; 3332 char *addr; 3333 3334 bool warn_on_failure = UseLargePages && 3335 (!FLAG_IS_DEFAULT(UseLargePages) || 3336 !FLAG_IS_DEFAULT(UseSHM) || 3337 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3338 char msg[128]; 3339 3340 // Create a large shared memory region to attach to based on size. 3341 // Currently, size is the total size of the heap 3342 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3343 if (shmid == -1) { 3344 // Possible reasons for shmget failure: 3345 // 1. shmmax is too small for Java heap. 3346 // > check shmmax value: cat /proc/sys/kernel/shmmax 3347 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3348 // 2. not enough large page memory. 3349 // > check available large pages: cat /proc/meminfo 3350 // > increase amount of large pages: 3351 // echo new_value > /proc/sys/vm/nr_hugepages 3352 // Note 1: different Linux may use different name for this property, 3353 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3354 // Note 2: it's possible there's enough physical memory available but 3355 // they are so fragmented after a long run that they can't 3356 // coalesce into large pages. Try to reserve large pages when 3357 // the system is still "fresh". 3358 if (warn_on_failure) { 3359 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3360 warning("%s", msg); 3361 } 3362 return NULL; 3363 } 3364 3365 // attach to the region 3366 addr = (char*)shmat(shmid, req_addr, 0); 3367 int err = errno; 3368 3369 // Remove shmid. If shmat() is successful, the actual shared memory segment 3370 // will be deleted when it's detached by shmdt() or when the process 3371 // terminates. If shmat() is not successful this will remove the shared 3372 // segment immediately. 3373 shmctl(shmid, IPC_RMID, NULL); 3374 3375 if ((intptr_t)addr == -1) { 3376 if (warn_on_failure) { 3377 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3378 warning("%s", msg); 3379 } 3380 return NULL; 3381 } 3382 3383 return addr; 3384 } 3385 3386 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3387 int error) { 3388 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3389 3390 bool warn_on_failure = UseLargePages && 3391 (!FLAG_IS_DEFAULT(UseLargePages) || 3392 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3393 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3394 3395 if (warn_on_failure) { 3396 char msg[128]; 3397 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3398 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3399 warning("%s", msg); 3400 } 3401 } 3402 3403 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3404 char* req_addr, 3405 bool exec) { 3406 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3407 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3408 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3409 3410 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3411 char* addr = (char*)::mmap(req_addr, bytes, prot, 3412 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3413 -1, 0); 3414 3415 if (addr == MAP_FAILED) { 3416 warn_on_large_pages_failure(req_addr, bytes, errno); 3417 return NULL; 3418 } 3419 3420 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3421 3422 return addr; 3423 } 3424 3425 // Helper for os::Linux::reserve_memory_special_huge_tlbfs_mixed(). 3426 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3427 // (req_addr != NULL) or with a given alignment. 3428 // - bytes shall be a multiple of alignment. 3429 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3430 // - alignment sets the alignment at which memory shall be allocated. 3431 // It must be a multiple of allocation granularity. 3432 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3433 // req_addr or NULL. 3434 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3435 3436 size_t extra_size = bytes; 3437 if (req_addr == NULL && alignment > 0) { 3438 extra_size += alignment; 3439 } 3440 3441 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3442 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3443 -1, 0); 3444 if (start == MAP_FAILED) { 3445 start = NULL; 3446 } else { 3447 if (req_addr != NULL) { 3448 if (start != req_addr) { 3449 ::munmap(start, extra_size); 3450 start = NULL; 3451 } 3452 } else { 3453 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3454 char* const end_aligned = start_aligned + bytes; 3455 char* const end = start + extra_size; 3456 if (start_aligned > start) { 3457 ::munmap(start, start_aligned - start); 3458 } 3459 if (end_aligned < end) { 3460 ::munmap(end_aligned, end - end_aligned); 3461 } 3462 start = start_aligned; 3463 } 3464 } 3465 return start; 3466 3467 } 3468 3469 // Reserve memory using mmap(MAP_HUGETLB). 3470 // - bytes shall be a multiple of alignment. 3471 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3472 // - alignment sets the alignment at which memory shall be allocated. 3473 // It must be a multiple of allocation granularity. 3474 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3475 // req_addr or NULL. 3476 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3477 size_t alignment, 3478 char* req_addr, 3479 bool exec) { 3480 size_t large_page_size = os::large_page_size(); 3481 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3482 3483 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3484 assert(is_size_aligned(bytes, alignment), "Must be"); 3485 3486 // First reserve - but not commit - the address range in small pages. 3487 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3488 3489 if (start == NULL) { 3490 return NULL; 3491 } 3492 3493 assert(is_ptr_aligned(start, alignment), "Must be"); 3494 3495 char* end = start + bytes; 3496 3497 // Find the regions of the allocated chunk that can be promoted to large pages. 3498 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3499 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3500 3501 size_t lp_bytes = lp_end - lp_start; 3502 3503 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3504 3505 if (lp_bytes == 0) { 3506 // The mapped region doesn't even span the start and the end of a large page. 3507 // Fall back to allocate a non-special area. 3508 ::munmap(start, end - start); 3509 return NULL; 3510 } 3511 3512 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3513 3514 void* result; 3515 3516 // Commit small-paged leading area. 3517 if (start != lp_start) { 3518 result = ::mmap(start, lp_start - start, prot, 3519 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3520 -1, 0); 3521 if (result == MAP_FAILED) { 3522 ::munmap(lp_start, end - lp_start); 3523 return NULL; 3524 } 3525 } 3526 3527 // Commit large-paged area. 3528 result = ::mmap(lp_start, lp_bytes, prot, 3529 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3530 -1, 0); 3531 if (result == MAP_FAILED) { 3532 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3533 // If the mmap above fails, the large pages region will be unmapped and we 3534 // have regions before and after with small pages. Release these regions. 3535 // 3536 // | mapped | unmapped | mapped | 3537 // ^ ^ ^ ^ 3538 // start lp_start lp_end end 3539 // 3540 ::munmap(start, lp_start - start); 3541 ::munmap(lp_end, end - lp_end); 3542 return NULL; 3543 } 3544 3545 // Commit small-paged trailing area. 3546 if (lp_end != end) { 3547 result = ::mmap(lp_end, end - lp_end, prot, 3548 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3549 -1, 0); 3550 if (result == MAP_FAILED) { 3551 ::munmap(start, lp_end - start); 3552 return NULL; 3553 } 3554 } 3555 3556 return start; 3557 } 3558 3559 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3560 size_t alignment, 3561 char* req_addr, 3562 bool exec) { 3563 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3564 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3565 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3566 assert(is_power_of_2(os::large_page_size()), "Must be"); 3567 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3568 3569 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3570 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3571 } else { 3572 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3573 } 3574 } 3575 3576 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3577 char* req_addr, bool exec) { 3578 assert(UseLargePages, "only for large pages"); 3579 3580 char* addr; 3581 if (UseSHM) { 3582 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3583 } else { 3584 assert(UseHugeTLBFS, "must be"); 3585 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3586 } 3587 3588 if (addr != NULL) { 3589 if (UseNUMAInterleaving) { 3590 numa_make_global(addr, bytes); 3591 } 3592 3593 // The memory is committed 3594 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3595 } 3596 3597 return addr; 3598 } 3599 3600 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3601 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3602 return shmdt(base) == 0; 3603 } 3604 3605 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3606 return pd_release_memory(base, bytes); 3607 } 3608 3609 bool os::release_memory_special(char* base, size_t bytes) { 3610 bool res; 3611 if (MemTracker::tracking_level() > NMT_minimal) { 3612 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3613 res = os::Linux::release_memory_special_impl(base, bytes); 3614 if (res) { 3615 tkr.record((address)base, bytes); 3616 } 3617 3618 } else { 3619 res = os::Linux::release_memory_special_impl(base, bytes); 3620 } 3621 return res; 3622 } 3623 3624 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3625 assert(UseLargePages, "only for large pages"); 3626 bool res; 3627 3628 if (UseSHM) { 3629 res = os::Linux::release_memory_special_shm(base, bytes); 3630 } else { 3631 assert(UseHugeTLBFS, "must be"); 3632 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3633 } 3634 return res; 3635 } 3636 3637 size_t os::large_page_size() { 3638 return _large_page_size; 3639 } 3640 3641 // With SysV SHM the entire memory region must be allocated as shared 3642 // memory. 3643 // HugeTLBFS allows application to commit large page memory on demand. 3644 // However, when committing memory with HugeTLBFS fails, the region 3645 // that was supposed to be committed will lose the old reservation 3646 // and allow other threads to steal that memory region. Because of this 3647 // behavior we can't commit HugeTLBFS memory. 3648 bool os::can_commit_large_page_memory() { 3649 return UseTransparentHugePages; 3650 } 3651 3652 bool os::can_execute_large_page_memory() { 3653 return UseTransparentHugePages || UseHugeTLBFS; 3654 } 3655 3656 // Reserve memory at an arbitrary address, only if that area is 3657 // available (and not reserved for something else). 3658 3659 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3660 const int max_tries = 10; 3661 char* base[max_tries]; 3662 size_t size[max_tries]; 3663 const size_t gap = 0x000000; 3664 3665 // Assert only that the size is a multiple of the page size, since 3666 // that's all that mmap requires, and since that's all we really know 3667 // about at this low abstraction level. If we need higher alignment, 3668 // we can either pass an alignment to this method or verify alignment 3669 // in one of the methods further up the call chain. See bug 5044738. 3670 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3671 3672 // Repeatedly allocate blocks until the block is allocated at the 3673 // right spot. 3674 3675 // Linux mmap allows caller to pass an address as hint; give it a try first, 3676 // if kernel honors the hint then we can return immediately. 3677 char * addr = anon_mmap(requested_addr, bytes, false); 3678 if (addr == requested_addr) { 3679 return requested_addr; 3680 } 3681 3682 if (addr != NULL) { 3683 // mmap() is successful but it fails to reserve at the requested address 3684 anon_munmap(addr, bytes); 3685 } 3686 3687 int i; 3688 for (i = 0; i < max_tries; ++i) { 3689 base[i] = reserve_memory(bytes); 3690 3691 if (base[i] != NULL) { 3692 // Is this the block we wanted? 3693 if (base[i] == requested_addr) { 3694 size[i] = bytes; 3695 break; 3696 } 3697 3698 // Does this overlap the block we wanted? Give back the overlapped 3699 // parts and try again. 3700 3701 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3702 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3703 unmap_memory(base[i], top_overlap); 3704 base[i] += top_overlap; 3705 size[i] = bytes - top_overlap; 3706 } else { 3707 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3708 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3709 unmap_memory(requested_addr, bottom_overlap); 3710 size[i] = bytes - bottom_overlap; 3711 } else { 3712 size[i] = bytes; 3713 } 3714 } 3715 } 3716 } 3717 3718 // Give back the unused reserved pieces. 3719 3720 for (int j = 0; j < i; ++j) { 3721 if (base[j] != NULL) { 3722 unmap_memory(base[j], size[j]); 3723 } 3724 } 3725 3726 if (i < max_tries) { 3727 return requested_addr; 3728 } else { 3729 return NULL; 3730 } 3731 } 3732 3733 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3734 return ::read(fd, buf, nBytes); 3735 } 3736 3737 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3738 return ::pread(fd, buf, nBytes, offset); 3739 } 3740 3741 // Short sleep, direct OS call. 3742 // 3743 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3744 // sched_yield(2) will actually give up the CPU: 3745 // 3746 // * Alone on this pariticular CPU, keeps running. 3747 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3748 // (pre 2.6.39). 3749 // 3750 // So calling this with 0 is an alternative. 3751 // 3752 void os::naked_short_sleep(jlong ms) { 3753 struct timespec req; 3754 3755 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3756 req.tv_sec = 0; 3757 if (ms > 0) { 3758 req.tv_nsec = (ms % 1000) * 1000000; 3759 } else { 3760 req.tv_nsec = 1; 3761 } 3762 3763 nanosleep(&req, NULL); 3764 3765 return; 3766 } 3767 3768 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3769 void os::infinite_sleep() { 3770 while (true) { // sleep forever ... 3771 ::sleep(100); // ... 100 seconds at a time 3772 } 3773 } 3774 3775 // Used to convert frequent JVM_Yield() to nops 3776 bool os::dont_yield() { 3777 return DontYieldALot; 3778 } 3779 3780 void os::naked_yield() { 3781 sched_yield(); 3782 } 3783 3784 //////////////////////////////////////////////////////////////////////////////// 3785 // thread priority support 3786 3787 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3788 // only supports dynamic priority, static priority must be zero. For real-time 3789 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3790 // However, for large multi-threaded applications, SCHED_RR is not only slower 3791 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3792 // of 5 runs - Sep 2005). 3793 // 3794 // The following code actually changes the niceness of kernel-thread/LWP. It 3795 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3796 // not the entire user process, and user level threads are 1:1 mapped to kernel 3797 // threads. It has always been the case, but could change in the future. For 3798 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3799 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3800 3801 int os::java_to_os_priority[CriticalPriority + 1] = { 3802 19, // 0 Entry should never be used 3803 3804 4, // 1 MinPriority 3805 3, // 2 3806 2, // 3 3807 3808 1, // 4 3809 0, // 5 NormPriority 3810 -1, // 6 3811 3812 -2, // 7 3813 -3, // 8 3814 -4, // 9 NearMaxPriority 3815 3816 -5, // 10 MaxPriority 3817 3818 -5 // 11 CriticalPriority 3819 }; 3820 3821 static int prio_init() { 3822 if (ThreadPriorityPolicy == 1) { 3823 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3824 // if effective uid is not root. Perhaps, a more elegant way of doing 3825 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3826 if (geteuid() != 0) { 3827 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3828 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3829 } 3830 ThreadPriorityPolicy = 0; 3831 } 3832 } 3833 if (UseCriticalJavaThreadPriority) { 3834 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3835 } 3836 return 0; 3837 } 3838 3839 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3840 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3841 3842 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3843 return (ret == 0) ? OS_OK : OS_ERR; 3844 } 3845 3846 OSReturn os::get_native_priority(const Thread* const thread, 3847 int *priority_ptr) { 3848 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3849 *priority_ptr = java_to_os_priority[NormPriority]; 3850 return OS_OK; 3851 } 3852 3853 errno = 0; 3854 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3855 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3856 } 3857 3858 // Hint to the underlying OS that a task switch would not be good. 3859 // Void return because it's a hint and can fail. 3860 void os::hint_no_preempt() {} 3861 3862 //////////////////////////////////////////////////////////////////////////////// 3863 // suspend/resume support 3864 3865 // the low-level signal-based suspend/resume support is a remnant from the 3866 // old VM-suspension that used to be for java-suspension, safepoints etc, 3867 // within hotspot. Now there is a single use-case for this: 3868 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3869 // that runs in the watcher thread. 3870 // The remaining code is greatly simplified from the more general suspension 3871 // code that used to be used. 3872 // 3873 // The protocol is quite simple: 3874 // - suspend: 3875 // - sends a signal to the target thread 3876 // - polls the suspend state of the osthread using a yield loop 3877 // - target thread signal handler (SR_handler) sets suspend state 3878 // and blocks in sigsuspend until continued 3879 // - resume: 3880 // - sets target osthread state to continue 3881 // - sends signal to end the sigsuspend loop in the SR_handler 3882 // 3883 // Note that the SR_lock plays no role in this suspend/resume protocol. 3884 3885 static void resume_clear_context(OSThread *osthread) { 3886 osthread->set_ucontext(NULL); 3887 osthread->set_siginfo(NULL); 3888 } 3889 3890 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3891 ucontext_t* context) { 3892 osthread->set_ucontext(context); 3893 osthread->set_siginfo(siginfo); 3894 } 3895 3896 // Handler function invoked when a thread's execution is suspended or 3897 // resumed. We have to be careful that only async-safe functions are 3898 // called here (Note: most pthread functions are not async safe and 3899 // should be avoided.) 3900 // 3901 // Note: sigwait() is a more natural fit than sigsuspend() from an 3902 // interface point of view, but sigwait() prevents the signal hander 3903 // from being run. libpthread would get very confused by not having 3904 // its signal handlers run and prevents sigwait()'s use with the 3905 // mutex granting granting signal. 3906 // 3907 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3908 // 3909 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3910 // Save and restore errno to avoid confusing native code with EINTR 3911 // after sigsuspend. 3912 int old_errno = errno; 3913 3914 Thread* thread = Thread::current(); 3915 OSThread* osthread = thread->osthread(); 3916 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3917 3918 os::SuspendResume::State current = osthread->sr.state(); 3919 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 3920 suspend_save_context(osthread, siginfo, context); 3921 3922 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 3923 os::SuspendResume::State state = osthread->sr.suspended(); 3924 if (state == os::SuspendResume::SR_SUSPENDED) { 3925 sigset_t suspend_set; // signals for sigsuspend() 3926 3927 // get current set of blocked signals and unblock resume signal 3928 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3929 sigdelset(&suspend_set, SR_signum); 3930 3931 sr_semaphore.signal(); 3932 // wait here until we are resumed 3933 while (1) { 3934 sigsuspend(&suspend_set); 3935 3936 os::SuspendResume::State result = osthread->sr.running(); 3937 if (result == os::SuspendResume::SR_RUNNING) { 3938 sr_semaphore.signal(); 3939 break; 3940 } 3941 } 3942 3943 } else if (state == os::SuspendResume::SR_RUNNING) { 3944 // request was cancelled, continue 3945 } else { 3946 ShouldNotReachHere(); 3947 } 3948 3949 resume_clear_context(osthread); 3950 } else if (current == os::SuspendResume::SR_RUNNING) { 3951 // request was cancelled, continue 3952 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 3953 // ignore 3954 } else { 3955 // ignore 3956 } 3957 3958 errno = old_errno; 3959 } 3960 3961 static int SR_initialize() { 3962 struct sigaction act; 3963 char *s; 3964 3965 // Get signal number to use for suspend/resume 3966 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3967 int sig = ::strtol(s, 0, 10); 3968 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 3969 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 3970 SR_signum = sig; 3971 } else { 3972 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 3973 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 3974 } 3975 } 3976 3977 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3978 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3979 3980 sigemptyset(&SR_sigset); 3981 sigaddset(&SR_sigset, SR_signum); 3982 3983 // Set up signal handler for suspend/resume 3984 act.sa_flags = SA_RESTART|SA_SIGINFO; 3985 act.sa_handler = (void (*)(int)) SR_handler; 3986 3987 // SR_signum is blocked by default. 3988 // 4528190 - We also need to block pthread restart signal (32 on all 3989 // supported Linux platforms). Note that LinuxThreads need to block 3990 // this signal for all threads to work properly. So we don't have 3991 // to use hard-coded signal number when setting up the mask. 3992 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3993 3994 if (sigaction(SR_signum, &act, 0) == -1) { 3995 return -1; 3996 } 3997 3998 // Save signal flag 3999 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4000 return 0; 4001 } 4002 4003 static int sr_notify(OSThread* osthread) { 4004 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4005 assert_status(status == 0, status, "pthread_kill"); 4006 return status; 4007 } 4008 4009 // "Randomly" selected value for how long we want to spin 4010 // before bailing out on suspending a thread, also how often 4011 // we send a signal to a thread we want to resume 4012 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4013 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4014 4015 // returns true on success and false on error - really an error is fatal 4016 // but this seems the normal response to library errors 4017 static bool do_suspend(OSThread* osthread) { 4018 assert(osthread->sr.is_running(), "thread should be running"); 4019 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4020 4021 // mark as suspended and send signal 4022 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4023 // failed to switch, state wasn't running? 4024 ShouldNotReachHere(); 4025 return false; 4026 } 4027 4028 if (sr_notify(osthread) != 0) { 4029 ShouldNotReachHere(); 4030 } 4031 4032 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4033 while (true) { 4034 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4035 break; 4036 } else { 4037 // timeout 4038 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4039 if (cancelled == os::SuspendResume::SR_RUNNING) { 4040 return false; 4041 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4042 // make sure that we consume the signal on the semaphore as well 4043 sr_semaphore.wait(); 4044 break; 4045 } else { 4046 ShouldNotReachHere(); 4047 return false; 4048 } 4049 } 4050 } 4051 4052 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4053 return true; 4054 } 4055 4056 static void do_resume(OSThread* osthread) { 4057 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4058 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4059 4060 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4061 // failed to switch to WAKEUP_REQUEST 4062 ShouldNotReachHere(); 4063 return; 4064 } 4065 4066 while (true) { 4067 if (sr_notify(osthread) == 0) { 4068 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4069 if (osthread->sr.is_running()) { 4070 return; 4071 } 4072 } 4073 } else { 4074 ShouldNotReachHere(); 4075 } 4076 } 4077 4078 guarantee(osthread->sr.is_running(), "Must be running!"); 4079 } 4080 4081 /////////////////////////////////////////////////////////////////////////////////// 4082 // signal handling (except suspend/resume) 4083 4084 // This routine may be used by user applications as a "hook" to catch signals. 4085 // The user-defined signal handler must pass unrecognized signals to this 4086 // routine, and if it returns true (non-zero), then the signal handler must 4087 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4088 // routine will never retun false (zero), but instead will execute a VM panic 4089 // routine kill the process. 4090 // 4091 // If this routine returns false, it is OK to call it again. This allows 4092 // the user-defined signal handler to perform checks either before or after 4093 // the VM performs its own checks. Naturally, the user code would be making 4094 // a serious error if it tried to handle an exception (such as a null check 4095 // or breakpoint) that the VM was generating for its own correct operation. 4096 // 4097 // This routine may recognize any of the following kinds of signals: 4098 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4099 // It should be consulted by handlers for any of those signals. 4100 // 4101 // The caller of this routine must pass in the three arguments supplied 4102 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4103 // field of the structure passed to sigaction(). This routine assumes that 4104 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4105 // 4106 // Note that the VM will print warnings if it detects conflicting signal 4107 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4108 // 4109 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4110 siginfo_t* siginfo, 4111 void* ucontext, 4112 int abort_if_unrecognized); 4113 4114 void signalHandler(int sig, siginfo_t* info, void* uc) { 4115 assert(info != NULL && uc != NULL, "it must be old kernel"); 4116 int orig_errno = errno; // Preserve errno value over signal handler. 4117 JVM_handle_linux_signal(sig, info, uc, true); 4118 errno = orig_errno; 4119 } 4120 4121 4122 // This boolean allows users to forward their own non-matching signals 4123 // to JVM_handle_linux_signal, harmlessly. 4124 bool os::Linux::signal_handlers_are_installed = false; 4125 4126 // For signal-chaining 4127 struct sigaction sigact[NSIG]; 4128 uint64_t sigs = 0; 4129 #if (64 < NSIG-1) 4130 #error "Not all signals can be encoded in sigs. Adapt its type!" 4131 #endif 4132 bool os::Linux::libjsig_is_loaded = false; 4133 typedef struct sigaction *(*get_signal_t)(int); 4134 get_signal_t os::Linux::get_signal_action = NULL; 4135 4136 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4137 struct sigaction *actp = NULL; 4138 4139 if (libjsig_is_loaded) { 4140 // Retrieve the old signal handler from libjsig 4141 actp = (*get_signal_action)(sig); 4142 } 4143 if (actp == NULL) { 4144 // Retrieve the preinstalled signal handler from jvm 4145 actp = get_preinstalled_handler(sig); 4146 } 4147 4148 return actp; 4149 } 4150 4151 static bool call_chained_handler(struct sigaction *actp, int sig, 4152 siginfo_t *siginfo, void *context) { 4153 // Call the old signal handler 4154 if (actp->sa_handler == SIG_DFL) { 4155 // It's more reasonable to let jvm treat it as an unexpected exception 4156 // instead of taking the default action. 4157 return false; 4158 } else if (actp->sa_handler != SIG_IGN) { 4159 if ((actp->sa_flags & SA_NODEFER) == 0) { 4160 // automaticlly block the signal 4161 sigaddset(&(actp->sa_mask), sig); 4162 } 4163 4164 sa_handler_t hand = NULL; 4165 sa_sigaction_t sa = NULL; 4166 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4167 // retrieve the chained handler 4168 if (siginfo_flag_set) { 4169 sa = actp->sa_sigaction; 4170 } else { 4171 hand = actp->sa_handler; 4172 } 4173 4174 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4175 actp->sa_handler = SIG_DFL; 4176 } 4177 4178 // try to honor the signal mask 4179 sigset_t oset; 4180 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4181 4182 // call into the chained handler 4183 if (siginfo_flag_set) { 4184 (*sa)(sig, siginfo, context); 4185 } else { 4186 (*hand)(sig); 4187 } 4188 4189 // restore the signal mask 4190 pthread_sigmask(SIG_SETMASK, &oset, 0); 4191 } 4192 // Tell jvm's signal handler the signal is taken care of. 4193 return true; 4194 } 4195 4196 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4197 bool chained = false; 4198 // signal-chaining 4199 if (UseSignalChaining) { 4200 struct sigaction *actp = get_chained_signal_action(sig); 4201 if (actp != NULL) { 4202 chained = call_chained_handler(actp, sig, siginfo, context); 4203 } 4204 } 4205 return chained; 4206 } 4207 4208 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4209 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4210 return &sigact[sig]; 4211 } 4212 return NULL; 4213 } 4214 4215 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4216 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4217 sigact[sig] = oldAct; 4218 sigs |= (uint64_t)1 << (sig-1); 4219 } 4220 4221 // for diagnostic 4222 int sigflags[NSIG]; 4223 4224 int os::Linux::get_our_sigflags(int sig) { 4225 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4226 return sigflags[sig]; 4227 } 4228 4229 void os::Linux::set_our_sigflags(int sig, int flags) { 4230 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4231 if (sig > 0 && sig < NSIG) { 4232 sigflags[sig] = flags; 4233 } 4234 } 4235 4236 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4237 // Check for overwrite. 4238 struct sigaction oldAct; 4239 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4240 4241 void* oldhand = oldAct.sa_sigaction 4242 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4243 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4244 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4245 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4246 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4247 if (AllowUserSignalHandlers || !set_installed) { 4248 // Do not overwrite; user takes responsibility to forward to us. 4249 return; 4250 } else if (UseSignalChaining) { 4251 // save the old handler in jvm 4252 save_preinstalled_handler(sig, oldAct); 4253 // libjsig also interposes the sigaction() call below and saves the 4254 // old sigaction on it own. 4255 } else { 4256 fatal("Encountered unexpected pre-existing sigaction handler " 4257 "%#lx for signal %d.", (long)oldhand, sig); 4258 } 4259 } 4260 4261 struct sigaction sigAct; 4262 sigfillset(&(sigAct.sa_mask)); 4263 sigAct.sa_handler = SIG_DFL; 4264 if (!set_installed) { 4265 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4266 } else { 4267 sigAct.sa_sigaction = signalHandler; 4268 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4269 } 4270 // Save flags, which are set by ours 4271 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4272 sigflags[sig] = sigAct.sa_flags; 4273 4274 int ret = sigaction(sig, &sigAct, &oldAct); 4275 assert(ret == 0, "check"); 4276 4277 void* oldhand2 = oldAct.sa_sigaction 4278 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4279 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4280 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4281 } 4282 4283 // install signal handlers for signals that HotSpot needs to 4284 // handle in order to support Java-level exception handling. 4285 4286 void os::Linux::install_signal_handlers() { 4287 if (!signal_handlers_are_installed) { 4288 signal_handlers_are_installed = true; 4289 4290 // signal-chaining 4291 typedef void (*signal_setting_t)(); 4292 signal_setting_t begin_signal_setting = NULL; 4293 signal_setting_t end_signal_setting = NULL; 4294 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4295 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4296 if (begin_signal_setting != NULL) { 4297 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4298 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4299 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4300 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4301 libjsig_is_loaded = true; 4302 assert(UseSignalChaining, "should enable signal-chaining"); 4303 } 4304 if (libjsig_is_loaded) { 4305 // Tell libjsig jvm is setting signal handlers 4306 (*begin_signal_setting)(); 4307 } 4308 4309 set_signal_handler(SIGSEGV, true); 4310 set_signal_handler(SIGPIPE, true); 4311 set_signal_handler(SIGBUS, true); 4312 set_signal_handler(SIGILL, true); 4313 set_signal_handler(SIGFPE, true); 4314 #if defined(PPC64) 4315 set_signal_handler(SIGTRAP, true); 4316 #endif 4317 set_signal_handler(SIGXFSZ, true); 4318 4319 if (libjsig_is_loaded) { 4320 // Tell libjsig jvm finishes setting signal handlers 4321 (*end_signal_setting)(); 4322 } 4323 4324 // We don't activate signal checker if libjsig is in place, we trust ourselves 4325 // and if UserSignalHandler is installed all bets are off. 4326 // Log that signal checking is off only if -verbose:jni is specified. 4327 if (CheckJNICalls) { 4328 if (libjsig_is_loaded) { 4329 if (PrintJNIResolving) { 4330 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4331 } 4332 check_signals = false; 4333 } 4334 if (AllowUserSignalHandlers) { 4335 if (PrintJNIResolving) { 4336 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4337 } 4338 check_signals = false; 4339 } 4340 } 4341 } 4342 } 4343 4344 // This is the fastest way to get thread cpu time on Linux. 4345 // Returns cpu time (user+sys) for any thread, not only for current. 4346 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4347 // It might work on 2.6.10+ with a special kernel/glibc patch. 4348 // For reference, please, see IEEE Std 1003.1-2004: 4349 // http://www.unix.org/single_unix_specification 4350 4351 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4352 struct timespec tp; 4353 int rc = os::Linux::clock_gettime(clockid, &tp); 4354 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4355 4356 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4357 } 4358 4359 ///// 4360 // glibc on Linux platform uses non-documented flag 4361 // to indicate, that some special sort of signal 4362 // trampoline is used. 4363 // We will never set this flag, and we should 4364 // ignore this flag in our diagnostic 4365 #ifdef SIGNIFICANT_SIGNAL_MASK 4366 #undef SIGNIFICANT_SIGNAL_MASK 4367 #endif 4368 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4369 4370 static const char* get_signal_handler_name(address handler, 4371 char* buf, int buflen) { 4372 int offset = 0; 4373 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4374 if (found) { 4375 // skip directory names 4376 const char *p1, *p2; 4377 p1 = buf; 4378 size_t len = strlen(os::file_separator()); 4379 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4380 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4381 } else { 4382 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4383 } 4384 return buf; 4385 } 4386 4387 static void print_signal_handler(outputStream* st, int sig, 4388 char* buf, size_t buflen) { 4389 struct sigaction sa; 4390 4391 sigaction(sig, NULL, &sa); 4392 4393 // See comment for SIGNIFICANT_SIGNAL_MASK define 4394 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4395 4396 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4397 4398 address handler = (sa.sa_flags & SA_SIGINFO) 4399 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4400 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4401 4402 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4403 st->print("SIG_DFL"); 4404 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4405 st->print("SIG_IGN"); 4406 } else { 4407 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4408 } 4409 4410 st->print(", sa_mask[0]="); 4411 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4412 4413 address rh = VMError::get_resetted_sighandler(sig); 4414 // May be, handler was resetted by VMError? 4415 if (rh != NULL) { 4416 handler = rh; 4417 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4418 } 4419 4420 st->print(", sa_flags="); 4421 os::Posix::print_sa_flags(st, sa.sa_flags); 4422 4423 // Check: is it our handler? 4424 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4425 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4426 // It is our signal handler 4427 // check for flags, reset system-used one! 4428 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4429 st->print( 4430 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4431 os::Linux::get_our_sigflags(sig)); 4432 } 4433 } 4434 st->cr(); 4435 } 4436 4437 4438 #define DO_SIGNAL_CHECK(sig) \ 4439 do { \ 4440 if (!sigismember(&check_signal_done, sig)) { \ 4441 os::Linux::check_signal_handler(sig); \ 4442 } \ 4443 } while (0) 4444 4445 // This method is a periodic task to check for misbehaving JNI applications 4446 // under CheckJNI, we can add any periodic checks here 4447 4448 void os::run_periodic_checks() { 4449 if (check_signals == false) return; 4450 4451 // SEGV and BUS if overridden could potentially prevent 4452 // generation of hs*.log in the event of a crash, debugging 4453 // such a case can be very challenging, so we absolutely 4454 // check the following for a good measure: 4455 DO_SIGNAL_CHECK(SIGSEGV); 4456 DO_SIGNAL_CHECK(SIGILL); 4457 DO_SIGNAL_CHECK(SIGFPE); 4458 DO_SIGNAL_CHECK(SIGBUS); 4459 DO_SIGNAL_CHECK(SIGPIPE); 4460 DO_SIGNAL_CHECK(SIGXFSZ); 4461 #if defined(PPC64) 4462 DO_SIGNAL_CHECK(SIGTRAP); 4463 #endif 4464 4465 // ReduceSignalUsage allows the user to override these handlers 4466 // see comments at the very top and jvm_solaris.h 4467 if (!ReduceSignalUsage) { 4468 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4469 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4470 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4471 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4472 } 4473 4474 DO_SIGNAL_CHECK(SR_signum); 4475 } 4476 4477 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4478 4479 static os_sigaction_t os_sigaction = NULL; 4480 4481 void os::Linux::check_signal_handler(int sig) { 4482 char buf[O_BUFLEN]; 4483 address jvmHandler = NULL; 4484 4485 4486 struct sigaction act; 4487 if (os_sigaction == NULL) { 4488 // only trust the default sigaction, in case it has been interposed 4489 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4490 if (os_sigaction == NULL) return; 4491 } 4492 4493 os_sigaction(sig, (struct sigaction*)NULL, &act); 4494 4495 4496 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4497 4498 address thisHandler = (act.sa_flags & SA_SIGINFO) 4499 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4500 : CAST_FROM_FN_PTR(address, act.sa_handler); 4501 4502 4503 switch (sig) { 4504 case SIGSEGV: 4505 case SIGBUS: 4506 case SIGFPE: 4507 case SIGPIPE: 4508 case SIGILL: 4509 case SIGXFSZ: 4510 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4511 break; 4512 4513 case SHUTDOWN1_SIGNAL: 4514 case SHUTDOWN2_SIGNAL: 4515 case SHUTDOWN3_SIGNAL: 4516 case BREAK_SIGNAL: 4517 jvmHandler = (address)user_handler(); 4518 break; 4519 4520 default: 4521 if (sig == SR_signum) { 4522 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4523 } else { 4524 return; 4525 } 4526 break; 4527 } 4528 4529 if (thisHandler != jvmHandler) { 4530 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4531 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4532 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4533 // No need to check this sig any longer 4534 sigaddset(&check_signal_done, sig); 4535 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4536 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4537 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4538 exception_name(sig, buf, O_BUFLEN)); 4539 } 4540 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4541 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4542 tty->print("expected:"); 4543 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4544 tty->cr(); 4545 tty->print(" found:"); 4546 os::Posix::print_sa_flags(tty, act.sa_flags); 4547 tty->cr(); 4548 // No need to check this sig any longer 4549 sigaddset(&check_signal_done, sig); 4550 } 4551 4552 // Dump all the signal 4553 if (sigismember(&check_signal_done, sig)) { 4554 print_signal_handlers(tty, buf, O_BUFLEN); 4555 } 4556 } 4557 4558 extern void report_error(char* file_name, int line_no, char* title, 4559 char* format, ...); 4560 4561 // this is called _before_ the most of global arguments have been parsed 4562 void os::init(void) { 4563 char dummy; // used to get a guess on initial stack address 4564 // first_hrtime = gethrtime(); 4565 4566 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4567 4568 init_random(1234567); 4569 4570 ThreadCritical::initialize(); 4571 4572 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4573 if (Linux::page_size() == -1) { 4574 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4575 strerror(errno)); 4576 } 4577 init_page_sizes((size_t) Linux::page_size()); 4578 4579 Linux::initialize_system_info(); 4580 4581 // main_thread points to the aboriginal thread 4582 Linux::_main_thread = pthread_self(); 4583 4584 Linux::clock_init(); 4585 initial_time_count = javaTimeNanos(); 4586 4587 // pthread_condattr initialization for monotonic clock 4588 int status; 4589 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4590 if ((status = pthread_condattr_init(_condattr)) != 0) { 4591 fatal("pthread_condattr_init: %s", strerror(status)); 4592 } 4593 // Only set the clock if CLOCK_MONOTONIC is available 4594 if (os::supports_monotonic_clock()) { 4595 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4596 if (status == EINVAL) { 4597 warning("Unable to use monotonic clock with relative timed-waits" \ 4598 " - changes to the time-of-day clock may have adverse affects"); 4599 } else { 4600 fatal("pthread_condattr_setclock: %s", strerror(status)); 4601 } 4602 } 4603 } 4604 // else it defaults to CLOCK_REALTIME 4605 4606 // retrieve entry point for pthread_setname_np 4607 Linux::_pthread_setname_np = 4608 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4609 4610 } 4611 4612 // To install functions for atexit system call 4613 extern "C" { 4614 static void perfMemory_exit_helper() { 4615 perfMemory_exit(); 4616 } 4617 } 4618 4619 // this is called _after_ the global arguments have been parsed 4620 jint os::init_2(void) { 4621 Linux::fast_thread_clock_init(); 4622 4623 // Allocate a single page and mark it as readable for safepoint polling 4624 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4625 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4626 4627 os::set_polling_page(polling_page); 4628 4629 #ifndef PRODUCT 4630 if (Verbose && PrintMiscellaneous) { 4631 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", 4632 (intptr_t)polling_page); 4633 } 4634 #endif 4635 4636 if (!UseMembar) { 4637 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4638 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4639 os::set_memory_serialize_page(mem_serialize_page); 4640 4641 #ifndef PRODUCT 4642 if (Verbose && PrintMiscellaneous) { 4643 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", 4644 (intptr_t)mem_serialize_page); 4645 } 4646 #endif 4647 } 4648 4649 // initialize suspend/resume support - must do this before signal_sets_init() 4650 if (SR_initialize() != 0) { 4651 perror("SR_initialize failed"); 4652 return JNI_ERR; 4653 } 4654 4655 Linux::signal_sets_init(); 4656 Linux::install_signal_handlers(); 4657 4658 // Check minimum allowable stack size for thread creation and to initialize 4659 // the java system classes, including StackOverflowError - depends on page 4660 // size. Add a page for compiler2 recursion in main thread. 4661 // Add in 2*BytesPerWord times page size to account for VM stack during 4662 // class initialization depending on 32 or 64 bit VM. 4663 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4664 JavaThread::stack_guard_zone_size() + 4665 JavaThread::stack_shadow_zone_size() + 4666 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4667 4668 size_t threadStackSizeInBytes = ThreadStackSize * K; 4669 if (threadStackSizeInBytes != 0 && 4670 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4671 tty->print_cr("\nThe stack size specified is too small, " 4672 "Specify at least " SIZE_FORMAT "k", 4673 os::Linux::min_stack_allowed/ K); 4674 return JNI_ERR; 4675 } 4676 4677 // Make the stack size a multiple of the page size so that 4678 // the yellow/red zones can be guarded. 4679 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4680 vm_page_size())); 4681 4682 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4683 4684 #if defined(IA32) 4685 workaround_expand_exec_shield_cs_limit(); 4686 #endif 4687 4688 Linux::libpthread_init(); 4689 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4690 tty->print_cr("[HotSpot is running with %s, %s]\n", 4691 Linux::glibc_version(), Linux::libpthread_version()); 4692 } 4693 4694 if (UseNUMA) { 4695 if (!Linux::libnuma_init()) { 4696 UseNUMA = false; 4697 } else { 4698 if ((Linux::numa_max_node() < 1)) { 4699 // There's only one node(they start from 0), disable NUMA. 4700 UseNUMA = false; 4701 } 4702 } 4703 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4704 // we can make the adaptive lgrp chunk resizing work. If the user specified 4705 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4706 // disable adaptive resizing. 4707 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4708 if (FLAG_IS_DEFAULT(UseNUMA)) { 4709 UseNUMA = false; 4710 } else { 4711 if (FLAG_IS_DEFAULT(UseLargePages) && 4712 FLAG_IS_DEFAULT(UseSHM) && 4713 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4714 UseLargePages = false; 4715 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4716 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4717 UseAdaptiveSizePolicy = false; 4718 UseAdaptiveNUMAChunkSizing = false; 4719 } 4720 } 4721 } 4722 if (!UseNUMA && ForceNUMA) { 4723 UseNUMA = true; 4724 } 4725 } 4726 4727 if (MaxFDLimit) { 4728 // set the number of file descriptors to max. print out error 4729 // if getrlimit/setrlimit fails but continue regardless. 4730 struct rlimit nbr_files; 4731 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4732 if (status != 0) { 4733 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4734 perror("os::init_2 getrlimit failed"); 4735 } 4736 } else { 4737 nbr_files.rlim_cur = nbr_files.rlim_max; 4738 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4739 if (status != 0) { 4740 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4741 perror("os::init_2 setrlimit failed"); 4742 } 4743 } 4744 } 4745 } 4746 4747 // Initialize lock used to serialize thread creation (see os::create_thread) 4748 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4749 4750 // at-exit methods are called in the reverse order of their registration. 4751 // atexit functions are called on return from main or as a result of a 4752 // call to exit(3C). There can be only 32 of these functions registered 4753 // and atexit() does not set errno. 4754 4755 if (PerfAllowAtExitRegistration) { 4756 // only register atexit functions if PerfAllowAtExitRegistration is set. 4757 // atexit functions can be delayed until process exit time, which 4758 // can be problematic for embedded VM situations. Embedded VMs should 4759 // call DestroyJavaVM() to assure that VM resources are released. 4760 4761 // note: perfMemory_exit_helper atexit function may be removed in 4762 // the future if the appropriate cleanup code can be added to the 4763 // VM_Exit VMOperation's doit method. 4764 if (atexit(perfMemory_exit_helper) != 0) { 4765 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4766 } 4767 } 4768 4769 // initialize thread priority policy 4770 prio_init(); 4771 4772 return JNI_OK; 4773 } 4774 4775 // Mark the polling page as unreadable 4776 void os::make_polling_page_unreadable(void) { 4777 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4778 fatal("Could not disable polling page"); 4779 } 4780 } 4781 4782 // Mark the polling page as readable 4783 void os::make_polling_page_readable(void) { 4784 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4785 fatal("Could not enable polling page"); 4786 } 4787 } 4788 4789 // older glibc versions don't have this macro (which expands to 4790 // an optimized bit-counting function) so we have to roll our own 4791 #ifndef CPU_COUNT 4792 4793 static int _cpu_count(const cpu_set_t* cpus) { 4794 int count = 0; 4795 // only look up to the number of configured processors 4796 for (int i = 0; i < os::processor_count(); i++) { 4797 if (CPU_ISSET(i, cpus)) { 4798 count++; 4799 } 4800 } 4801 return count; 4802 } 4803 4804 #define CPU_COUNT(cpus) _cpu_count(cpus) 4805 4806 #endif // CPU_COUNT 4807 4808 // Get the current number of available processors for this process. 4809 // This value can change at any time during a process's lifetime. 4810 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 4811 // If it appears there may be more than 1024 processors then we do a 4812 // dynamic check - see 6515172 for details. 4813 // If anything goes wrong we fallback to returning the number of online 4814 // processors - which can be greater than the number available to the process. 4815 int os::active_processor_count() { 4816 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 4817 cpu_set_t* cpus_p = &cpus; 4818 int cpus_size = sizeof(cpu_set_t); 4819 4820 int configured_cpus = processor_count(); // upper bound on available cpus 4821 int cpu_count = 0; 4822 4823 // old build platforms may not support dynamic cpu sets 4824 #ifdef CPU_ALLOC 4825 4826 // To enable easy testing of the dynamic path on different platforms we 4827 // introduce a diagnostic flag: UseCpuAllocPath 4828 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 4829 // kernel may use a mask bigger than cpu_set_t 4830 log_trace(os)("active_processor_count: using dynamic path %s" 4831 "- configured processors: %d", 4832 UseCpuAllocPath ? "(forced) " : "", 4833 configured_cpus); 4834 cpus_p = CPU_ALLOC(configured_cpus); 4835 if (cpus_p != NULL) { 4836 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 4837 // zero it just to be safe 4838 CPU_ZERO_S(cpus_size, cpus_p); 4839 } 4840 else { 4841 // failed to allocate so fallback to online cpus 4842 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4843 log_trace(os)("active_processor_count: " 4844 "CPU_ALLOC failed (%s) - using " 4845 "online processor count: %d", 4846 strerror(errno), online_cpus); 4847 return online_cpus; 4848 } 4849 } 4850 else { 4851 log_trace(os)("active_processor_count: using static path - configured processors: %d", 4852 configured_cpus); 4853 } 4854 #else // CPU_ALLOC 4855 // these stubs won't be executed 4856 #define CPU_COUNT_S(size, cpus) -1 4857 #define CPU_FREE(cpus) 4858 4859 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 4860 configured_cpus); 4861 #endif // CPU_ALLOC 4862 4863 // pid 0 means the current thread - which we have to assume represents the process 4864 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 4865 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4866 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 4867 } 4868 else { 4869 cpu_count = CPU_COUNT(cpus_p); 4870 } 4871 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 4872 } 4873 else { 4874 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 4875 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 4876 "which may exceed available processors", strerror(errno), cpu_count); 4877 } 4878 4879 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4880 CPU_FREE(cpus_p); 4881 } 4882 4883 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check"); 4884 return cpu_count; 4885 } 4886 4887 void os::set_native_thread_name(const char *name) { 4888 if (Linux::_pthread_setname_np) { 4889 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 4890 snprintf(buf, sizeof(buf), "%s", name); 4891 buf[sizeof(buf) - 1] = '\0'; 4892 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 4893 // ERANGE should not happen; all other errors should just be ignored. 4894 assert(rc != ERANGE, "pthread_setname_np failed"); 4895 } 4896 } 4897 4898 bool os::distribute_processes(uint length, uint* distribution) { 4899 // Not yet implemented. 4900 return false; 4901 } 4902 4903 bool os::bind_to_processor(uint processor_id) { 4904 // Not yet implemented. 4905 return false; 4906 } 4907 4908 /// 4909 4910 void os::SuspendedThreadTask::internal_do_task() { 4911 if (do_suspend(_thread->osthread())) { 4912 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4913 do_task(context); 4914 do_resume(_thread->osthread()); 4915 } 4916 } 4917 4918 class PcFetcher : public os::SuspendedThreadTask { 4919 public: 4920 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4921 ExtendedPC result(); 4922 protected: 4923 void do_task(const os::SuspendedThreadTaskContext& context); 4924 private: 4925 ExtendedPC _epc; 4926 }; 4927 4928 ExtendedPC PcFetcher::result() { 4929 guarantee(is_done(), "task is not done yet."); 4930 return _epc; 4931 } 4932 4933 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4934 Thread* thread = context.thread(); 4935 OSThread* osthread = thread->osthread(); 4936 if (osthread->ucontext() != NULL) { 4937 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext()); 4938 } else { 4939 // NULL context is unexpected, double-check this is the VMThread 4940 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4941 } 4942 } 4943 4944 // Suspends the target using the signal mechanism and then grabs the PC before 4945 // resuming the target. Used by the flat-profiler only 4946 ExtendedPC os::get_thread_pc(Thread* thread) { 4947 // Make sure that it is called by the watcher for the VMThread 4948 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4949 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4950 4951 PcFetcher fetcher(thread); 4952 fetcher.run(); 4953 return fetcher.result(); 4954 } 4955 4956 //////////////////////////////////////////////////////////////////////////////// 4957 // debug support 4958 4959 bool os::find(address addr, outputStream* st) { 4960 Dl_info dlinfo; 4961 memset(&dlinfo, 0, sizeof(dlinfo)); 4962 if (dladdr(addr, &dlinfo) != 0) { 4963 st->print(PTR_FORMAT ": ", p2i(addr)); 4964 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 4965 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 4966 p2i(addr) - p2i(dlinfo.dli_saddr)); 4967 } else if (dlinfo.dli_fbase != NULL) { 4968 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 4969 } else { 4970 st->print("<absolute address>"); 4971 } 4972 if (dlinfo.dli_fname != NULL) { 4973 st->print(" in %s", dlinfo.dli_fname); 4974 } 4975 if (dlinfo.dli_fbase != NULL) { 4976 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 4977 } 4978 st->cr(); 4979 4980 if (Verbose) { 4981 // decode some bytes around the PC 4982 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 4983 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 4984 address lowest = (address) dlinfo.dli_sname; 4985 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4986 if (begin < lowest) begin = lowest; 4987 Dl_info dlinfo2; 4988 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 4989 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 4990 end = (address) dlinfo2.dli_saddr; 4991 } 4992 Disassembler::decode(begin, end, st); 4993 } 4994 return true; 4995 } 4996 return false; 4997 } 4998 4999 //////////////////////////////////////////////////////////////////////////////// 5000 // misc 5001 5002 // This does not do anything on Linux. This is basically a hook for being 5003 // able to use structured exception handling (thread-local exception filters) 5004 // on, e.g., Win32. 5005 void 5006 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5007 JavaCallArguments* args, Thread* thread) { 5008 f(value, method, args, thread); 5009 } 5010 5011 void os::print_statistics() { 5012 } 5013 5014 bool os::message_box(const char* title, const char* message) { 5015 int i; 5016 fdStream err(defaultStream::error_fd()); 5017 for (i = 0; i < 78; i++) err.print_raw("="); 5018 err.cr(); 5019 err.print_raw_cr(title); 5020 for (i = 0; i < 78; i++) err.print_raw("-"); 5021 err.cr(); 5022 err.print_raw_cr(message); 5023 for (i = 0; i < 78; i++) err.print_raw("="); 5024 err.cr(); 5025 5026 char buf[16]; 5027 // Prevent process from exiting upon "read error" without consuming all CPU 5028 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5029 5030 return buf[0] == 'y' || buf[0] == 'Y'; 5031 } 5032 5033 int os::stat(const char *path, struct stat *sbuf) { 5034 char pathbuf[MAX_PATH]; 5035 if (strlen(path) > MAX_PATH - 1) { 5036 errno = ENAMETOOLONG; 5037 return -1; 5038 } 5039 os::native_path(strcpy(pathbuf, path)); 5040 return ::stat(pathbuf, sbuf); 5041 } 5042 5043 bool os::check_heap(bool force) { 5044 return true; 5045 } 5046 5047 // Is a (classpath) directory empty? 5048 bool os::dir_is_empty(const char* path) { 5049 DIR *dir = NULL; 5050 struct dirent *ptr; 5051 5052 dir = opendir(path); 5053 if (dir == NULL) return true; 5054 5055 // Scan the directory 5056 bool result = true; 5057 char buf[sizeof(struct dirent) + MAX_PATH]; 5058 while (result && (ptr = ::readdir(dir)) != NULL) { 5059 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5060 result = false; 5061 } 5062 } 5063 closedir(dir); 5064 return result; 5065 } 5066 5067 // This code originates from JDK's sysOpen and open64_w 5068 // from src/solaris/hpi/src/system_md.c 5069 5070 int os::open(const char *path, int oflag, int mode) { 5071 if (strlen(path) > MAX_PATH - 1) { 5072 errno = ENAMETOOLONG; 5073 return -1; 5074 } 5075 5076 // All file descriptors that are opened in the Java process and not 5077 // specifically destined for a subprocess should have the close-on-exec 5078 // flag set. If we don't set it, then careless 3rd party native code 5079 // might fork and exec without closing all appropriate file descriptors 5080 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5081 // turn might: 5082 // 5083 // - cause end-of-file to fail to be detected on some file 5084 // descriptors, resulting in mysterious hangs, or 5085 // 5086 // - might cause an fopen in the subprocess to fail on a system 5087 // suffering from bug 1085341. 5088 // 5089 // (Yes, the default setting of the close-on-exec flag is a Unix 5090 // design flaw) 5091 // 5092 // See: 5093 // 1085341: 32-bit stdio routines should support file descriptors >255 5094 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5095 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5096 // 5097 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5098 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5099 // because it saves a system call and removes a small window where the flag 5100 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5101 // and we fall back to using FD_CLOEXEC (see below). 5102 #ifdef O_CLOEXEC 5103 oflag |= O_CLOEXEC; 5104 #endif 5105 5106 int fd = ::open64(path, oflag, mode); 5107 if (fd == -1) return -1; 5108 5109 //If the open succeeded, the file might still be a directory 5110 { 5111 struct stat64 buf64; 5112 int ret = ::fstat64(fd, &buf64); 5113 int st_mode = buf64.st_mode; 5114 5115 if (ret != -1) { 5116 if ((st_mode & S_IFMT) == S_IFDIR) { 5117 errno = EISDIR; 5118 ::close(fd); 5119 return -1; 5120 } 5121 } else { 5122 ::close(fd); 5123 return -1; 5124 } 5125 } 5126 5127 #ifdef FD_CLOEXEC 5128 // Validate that the use of the O_CLOEXEC flag on open above worked. 5129 // With recent kernels, we will perform this check exactly once. 5130 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5131 if (!O_CLOEXEC_is_known_to_work) { 5132 int flags = ::fcntl(fd, F_GETFD); 5133 if (flags != -1) { 5134 if ((flags & FD_CLOEXEC) != 0) 5135 O_CLOEXEC_is_known_to_work = 1; 5136 else 5137 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5138 } 5139 } 5140 #endif 5141 5142 return fd; 5143 } 5144 5145 5146 // create binary file, rewriting existing file if required 5147 int os::create_binary_file(const char* path, bool rewrite_existing) { 5148 int oflags = O_WRONLY | O_CREAT; 5149 if (!rewrite_existing) { 5150 oflags |= O_EXCL; 5151 } 5152 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5153 } 5154 5155 // return current position of file pointer 5156 jlong os::current_file_offset(int fd) { 5157 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5158 } 5159 5160 // move file pointer to the specified offset 5161 jlong os::seek_to_file_offset(int fd, jlong offset) { 5162 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5163 } 5164 5165 // This code originates from JDK's sysAvailable 5166 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5167 5168 int os::available(int fd, jlong *bytes) { 5169 jlong cur, end; 5170 int mode; 5171 struct stat64 buf64; 5172 5173 if (::fstat64(fd, &buf64) >= 0) { 5174 mode = buf64.st_mode; 5175 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5176 int n; 5177 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5178 *bytes = n; 5179 return 1; 5180 } 5181 } 5182 } 5183 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5184 return 0; 5185 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5186 return 0; 5187 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5188 return 0; 5189 } 5190 *bytes = end - cur; 5191 return 1; 5192 } 5193 5194 // Map a block of memory. 5195 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5196 char *addr, size_t bytes, bool read_only, 5197 bool allow_exec) { 5198 int prot; 5199 int flags = MAP_PRIVATE; 5200 5201 if (read_only) { 5202 prot = PROT_READ; 5203 } else { 5204 prot = PROT_READ | PROT_WRITE; 5205 } 5206 5207 if (allow_exec) { 5208 prot |= PROT_EXEC; 5209 } 5210 5211 if (addr != NULL) { 5212 flags |= MAP_FIXED; 5213 } 5214 5215 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5216 fd, file_offset); 5217 if (mapped_address == MAP_FAILED) { 5218 return NULL; 5219 } 5220 return mapped_address; 5221 } 5222 5223 5224 // Remap a block of memory. 5225 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5226 char *addr, size_t bytes, bool read_only, 5227 bool allow_exec) { 5228 // same as map_memory() on this OS 5229 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5230 allow_exec); 5231 } 5232 5233 5234 // Unmap a block of memory. 5235 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5236 return munmap(addr, bytes) == 0; 5237 } 5238 5239 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5240 5241 static clockid_t thread_cpu_clockid(Thread* thread) { 5242 pthread_t tid = thread->osthread()->pthread_id(); 5243 clockid_t clockid; 5244 5245 // Get thread clockid 5246 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5247 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5248 return clockid; 5249 } 5250 5251 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5252 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5253 // of a thread. 5254 // 5255 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5256 // the fast estimate available on the platform. 5257 5258 jlong os::current_thread_cpu_time() { 5259 if (os::Linux::supports_fast_thread_cpu_time()) { 5260 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5261 } else { 5262 // return user + sys since the cost is the same 5263 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5264 } 5265 } 5266 5267 jlong os::thread_cpu_time(Thread* thread) { 5268 // consistent with what current_thread_cpu_time() returns 5269 if (os::Linux::supports_fast_thread_cpu_time()) { 5270 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5271 } else { 5272 return slow_thread_cpu_time(thread, true /* user + sys */); 5273 } 5274 } 5275 5276 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5277 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5278 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5279 } else { 5280 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5281 } 5282 } 5283 5284 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5285 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5286 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5287 } else { 5288 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5289 } 5290 } 5291 5292 // -1 on error. 5293 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5294 pid_t tid = thread->osthread()->thread_id(); 5295 char *s; 5296 char stat[2048]; 5297 int statlen; 5298 char proc_name[64]; 5299 int count; 5300 long sys_time, user_time; 5301 char cdummy; 5302 int idummy; 5303 long ldummy; 5304 FILE *fp; 5305 5306 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5307 fp = fopen(proc_name, "r"); 5308 if (fp == NULL) return -1; 5309 statlen = fread(stat, 1, 2047, fp); 5310 stat[statlen] = '\0'; 5311 fclose(fp); 5312 5313 // Skip pid and the command string. Note that we could be dealing with 5314 // weird command names, e.g. user could decide to rename java launcher 5315 // to "java 1.4.2 :)", then the stat file would look like 5316 // 1234 (java 1.4.2 :)) R ... ... 5317 // We don't really need to know the command string, just find the last 5318 // occurrence of ")" and then start parsing from there. See bug 4726580. 5319 s = strrchr(stat, ')'); 5320 if (s == NULL) return -1; 5321 5322 // Skip blank chars 5323 do { s++; } while (s && isspace(*s)); 5324 5325 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5326 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5327 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5328 &user_time, &sys_time); 5329 if (count != 13) return -1; 5330 if (user_sys_cpu_time) { 5331 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5332 } else { 5333 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5334 } 5335 } 5336 5337 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5338 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5339 info_ptr->may_skip_backward = false; // elapsed time not wall time 5340 info_ptr->may_skip_forward = false; // elapsed time not wall time 5341 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5342 } 5343 5344 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5345 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5346 info_ptr->may_skip_backward = false; // elapsed time not wall time 5347 info_ptr->may_skip_forward = false; // elapsed time not wall time 5348 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5349 } 5350 5351 bool os::is_thread_cpu_time_supported() { 5352 return true; 5353 } 5354 5355 // System loadavg support. Returns -1 if load average cannot be obtained. 5356 // Linux doesn't yet have a (official) notion of processor sets, 5357 // so just return the system wide load average. 5358 int os::loadavg(double loadavg[], int nelem) { 5359 return ::getloadavg(loadavg, nelem); 5360 } 5361 5362 void os::pause() { 5363 char filename[MAX_PATH]; 5364 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5365 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5366 } else { 5367 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5368 } 5369 5370 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5371 if (fd != -1) { 5372 struct stat buf; 5373 ::close(fd); 5374 while (::stat(filename, &buf) == 0) { 5375 (void)::poll(NULL, 0, 100); 5376 } 5377 } else { 5378 jio_fprintf(stderr, 5379 "Could not open pause file '%s', continuing immediately.\n", filename); 5380 } 5381 } 5382 5383 5384 // Refer to the comments in os_solaris.cpp park-unpark. The next two 5385 // comment paragraphs are worth repeating here: 5386 // 5387 // Assumption: 5388 // Only one parker can exist on an event, which is why we allocate 5389 // them per-thread. Multiple unparkers can coexist. 5390 // 5391 // _Event serves as a restricted-range semaphore. 5392 // -1 : thread is blocked, i.e. there is a waiter 5393 // 0 : neutral: thread is running or ready, 5394 // could have been signaled after a wait started 5395 // 1 : signaled - thread is running or ready 5396 // 5397 5398 // utility to compute the abstime argument to timedwait: 5399 // millis is the relative timeout time 5400 // abstime will be the absolute timeout time 5401 // TODO: replace compute_abstime() with unpackTime() 5402 5403 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5404 if (millis < 0) millis = 0; 5405 5406 jlong seconds = millis / 1000; 5407 millis %= 1000; 5408 if (seconds > 50000000) { // see man cond_timedwait(3T) 5409 seconds = 50000000; 5410 } 5411 5412 if (os::supports_monotonic_clock()) { 5413 struct timespec now; 5414 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5415 assert_status(status == 0, status, "clock_gettime"); 5416 abstime->tv_sec = now.tv_sec + seconds; 5417 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5418 if (nanos >= NANOSECS_PER_SEC) { 5419 abstime->tv_sec += 1; 5420 nanos -= NANOSECS_PER_SEC; 5421 } 5422 abstime->tv_nsec = nanos; 5423 } else { 5424 struct timeval now; 5425 int status = gettimeofday(&now, NULL); 5426 assert(status == 0, "gettimeofday"); 5427 abstime->tv_sec = now.tv_sec + seconds; 5428 long usec = now.tv_usec + millis * 1000; 5429 if (usec >= 1000000) { 5430 abstime->tv_sec += 1; 5431 usec -= 1000000; 5432 } 5433 abstime->tv_nsec = usec * 1000; 5434 } 5435 return abstime; 5436 } 5437 5438 void os::PlatformEvent::park() { // AKA "down()" 5439 // Transitions for _Event: 5440 // -1 => -1 : illegal 5441 // 1 => 0 : pass - return immediately 5442 // 0 => -1 : block; then set _Event to 0 before returning 5443 5444 // Invariant: Only the thread associated with the Event/PlatformEvent 5445 // may call park(). 5446 // TODO: assert that _Assoc != NULL or _Assoc == Self 5447 assert(_nParked == 0, "invariant"); 5448 5449 int v; 5450 for (;;) { 5451 v = _Event; 5452 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5453 } 5454 guarantee(v >= 0, "invariant"); 5455 if (v == 0) { 5456 // Do this the hard way by blocking ... 5457 int status = pthread_mutex_lock(_mutex); 5458 assert_status(status == 0, status, "mutex_lock"); 5459 guarantee(_nParked == 0, "invariant"); 5460 ++_nParked; 5461 while (_Event < 0) { 5462 status = pthread_cond_wait(_cond, _mutex); 5463 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5464 // Treat this the same as if the wait was interrupted 5465 if (status == ETIME) { status = EINTR; } 5466 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5467 } 5468 --_nParked; 5469 5470 _Event = 0; 5471 status = pthread_mutex_unlock(_mutex); 5472 assert_status(status == 0, status, "mutex_unlock"); 5473 // Paranoia to ensure our locked and lock-free paths interact 5474 // correctly with each other. 5475 OrderAccess::fence(); 5476 } 5477 guarantee(_Event >= 0, "invariant"); 5478 } 5479 5480 int os::PlatformEvent::park(jlong millis) { 5481 // Transitions for _Event: 5482 // -1 => -1 : illegal 5483 // 1 => 0 : pass - return immediately 5484 // 0 => -1 : block; then set _Event to 0 before returning 5485 5486 guarantee(_nParked == 0, "invariant"); 5487 5488 int v; 5489 for (;;) { 5490 v = _Event; 5491 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5492 } 5493 guarantee(v >= 0, "invariant"); 5494 if (v != 0) return OS_OK; 5495 5496 // We do this the hard way, by blocking the thread. 5497 // Consider enforcing a minimum timeout value. 5498 struct timespec abst; 5499 compute_abstime(&abst, millis); 5500 5501 int ret = OS_TIMEOUT; 5502 int status = pthread_mutex_lock(_mutex); 5503 assert_status(status == 0, status, "mutex_lock"); 5504 guarantee(_nParked == 0, "invariant"); 5505 ++_nParked; 5506 5507 // Object.wait(timo) will return because of 5508 // (a) notification 5509 // (b) timeout 5510 // (c) thread.interrupt 5511 // 5512 // Thread.interrupt and object.notify{All} both call Event::set. 5513 // That is, we treat thread.interrupt as a special case of notification. 5514 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5515 // We assume all ETIME returns are valid. 5516 // 5517 // TODO: properly differentiate simultaneous notify+interrupt. 5518 // In that case, we should propagate the notify to another waiter. 5519 5520 while (_Event < 0) { 5521 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5522 assert_status(status == 0 || status == EINTR || 5523 status == ETIME || status == ETIMEDOUT, 5524 status, "cond_timedwait"); 5525 if (!FilterSpuriousWakeups) break; // previous semantics 5526 if (status == ETIME || status == ETIMEDOUT) break; 5527 // We consume and ignore EINTR and spurious wakeups. 5528 } 5529 --_nParked; 5530 if (_Event >= 0) { 5531 ret = OS_OK; 5532 } 5533 _Event = 0; 5534 status = pthread_mutex_unlock(_mutex); 5535 assert_status(status == 0, status, "mutex_unlock"); 5536 assert(_nParked == 0, "invariant"); 5537 // Paranoia to ensure our locked and lock-free paths interact 5538 // correctly with each other. 5539 OrderAccess::fence(); 5540 return ret; 5541 } 5542 5543 void os::PlatformEvent::unpark() { 5544 // Transitions for _Event: 5545 // 0 => 1 : just return 5546 // 1 => 1 : just return 5547 // -1 => either 0 or 1; must signal target thread 5548 // That is, we can safely transition _Event from -1 to either 5549 // 0 or 1. 5550 // See also: "Semaphores in Plan 9" by Mullender & Cox 5551 // 5552 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5553 // that it will take two back-to-back park() calls for the owning 5554 // thread to block. This has the benefit of forcing a spurious return 5555 // from the first park() call after an unpark() call which will help 5556 // shake out uses of park() and unpark() without condition variables. 5557 5558 if (Atomic::xchg(1, &_Event) >= 0) return; 5559 5560 // Wait for the thread associated with the event to vacate 5561 int status = pthread_mutex_lock(_mutex); 5562 assert_status(status == 0, status, "mutex_lock"); 5563 int AnyWaiters = _nParked; 5564 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5565 status = pthread_mutex_unlock(_mutex); 5566 assert_status(status == 0, status, "mutex_unlock"); 5567 if (AnyWaiters != 0) { 5568 // Note that we signal() *after* dropping the lock for "immortal" Events. 5569 // This is safe and avoids a common class of futile wakeups. In rare 5570 // circumstances this can cause a thread to return prematurely from 5571 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5572 // will simply re-test the condition and re-park itself. 5573 // This provides particular benefit if the underlying platform does not 5574 // provide wait morphing. 5575 status = pthread_cond_signal(_cond); 5576 assert_status(status == 0, status, "cond_signal"); 5577 } 5578 } 5579 5580 5581 // JSR166 5582 // ------------------------------------------------------- 5583 5584 // The solaris and linux implementations of park/unpark are fairly 5585 // conservative for now, but can be improved. They currently use a 5586 // mutex/condvar pair, plus a a count. 5587 // Park decrements count if > 0, else does a condvar wait. Unpark 5588 // sets count to 1 and signals condvar. Only one thread ever waits 5589 // on the condvar. Contention seen when trying to park implies that someone 5590 // is unparking you, so don't wait. And spurious returns are fine, so there 5591 // is no need to track notifications. 5592 5593 // This code is common to linux and solaris and will be moved to a 5594 // common place in dolphin. 5595 // 5596 // The passed in time value is either a relative time in nanoseconds 5597 // or an absolute time in milliseconds. Either way it has to be unpacked 5598 // into suitable seconds and nanoseconds components and stored in the 5599 // given timespec structure. 5600 // Given time is a 64-bit value and the time_t used in the timespec is only 5601 // a signed-32-bit value (except on 64-bit Linux) we have to watch for 5602 // overflow if times way in the future are given. Further on Solaris versions 5603 // prior to 10 there is a restriction (see cond_timedwait) that the specified 5604 // number of seconds, in abstime, is less than current_time + 100,000,000. 5605 // As it will be 28 years before "now + 100000000" will overflow we can 5606 // ignore overflow and just impose a hard-limit on seconds using the value 5607 // of "now + 100,000,000". This places a limit on the timeout of about 3.17 5608 // years from "now". 5609 5610 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5611 assert(time > 0, "convertTime"); 5612 time_t max_secs = 0; 5613 5614 if (!os::supports_monotonic_clock() || isAbsolute) { 5615 struct timeval now; 5616 int status = gettimeofday(&now, NULL); 5617 assert(status == 0, "gettimeofday"); 5618 5619 max_secs = now.tv_sec + MAX_SECS; 5620 5621 if (isAbsolute) { 5622 jlong secs = time / 1000; 5623 if (secs > max_secs) { 5624 absTime->tv_sec = max_secs; 5625 } else { 5626 absTime->tv_sec = secs; 5627 } 5628 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5629 } else { 5630 jlong secs = time / NANOSECS_PER_SEC; 5631 if (secs >= MAX_SECS) { 5632 absTime->tv_sec = max_secs; 5633 absTime->tv_nsec = 0; 5634 } else { 5635 absTime->tv_sec = now.tv_sec + secs; 5636 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5637 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5638 absTime->tv_nsec -= NANOSECS_PER_SEC; 5639 ++absTime->tv_sec; // note: this must be <= max_secs 5640 } 5641 } 5642 } 5643 } else { 5644 // must be relative using monotonic clock 5645 struct timespec now; 5646 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5647 assert_status(status == 0, status, "clock_gettime"); 5648 max_secs = now.tv_sec + MAX_SECS; 5649 jlong secs = time / NANOSECS_PER_SEC; 5650 if (secs >= MAX_SECS) { 5651 absTime->tv_sec = max_secs; 5652 absTime->tv_nsec = 0; 5653 } else { 5654 absTime->tv_sec = now.tv_sec + secs; 5655 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5656 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5657 absTime->tv_nsec -= NANOSECS_PER_SEC; 5658 ++absTime->tv_sec; // note: this must be <= max_secs 5659 } 5660 } 5661 } 5662 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5663 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5664 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5665 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5666 } 5667 5668 void Parker::park(bool isAbsolute, jlong time) { 5669 // Ideally we'd do something useful while spinning, such 5670 // as calling unpackTime(). 5671 5672 // Optional fast-path check: 5673 // Return immediately if a permit is available. 5674 // We depend on Atomic::xchg() having full barrier semantics 5675 // since we are doing a lock-free update to _counter. 5676 if (Atomic::xchg(0, &_counter) > 0) return; 5677 5678 Thread* thread = Thread::current(); 5679 assert(thread->is_Java_thread(), "Must be JavaThread"); 5680 JavaThread *jt = (JavaThread *)thread; 5681 5682 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5683 // Check interrupt before trying to wait 5684 if (Thread::is_interrupted(thread, false)) { 5685 return; 5686 } 5687 5688 // Next, demultiplex/decode time arguments 5689 timespec absTime; 5690 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5691 return; 5692 } 5693 if (time > 0) { 5694 unpackTime(&absTime, isAbsolute, time); 5695 } 5696 5697 5698 // Enter safepoint region 5699 // Beware of deadlocks such as 6317397. 5700 // The per-thread Parker:: mutex is a classic leaf-lock. 5701 // In particular a thread must never block on the Threads_lock while 5702 // holding the Parker:: mutex. If safepoints are pending both the 5703 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5704 ThreadBlockInVM tbivm(jt); 5705 5706 // Don't wait if cannot get lock since interference arises from 5707 // unblocking. Also. check interrupt before trying wait 5708 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5709 return; 5710 } 5711 5712 int status; 5713 if (_counter > 0) { // no wait needed 5714 _counter = 0; 5715 status = pthread_mutex_unlock(_mutex); 5716 assert_status(status == 0, status, "invariant"); 5717 // Paranoia to ensure our locked and lock-free paths interact 5718 // correctly with each other and Java-level accesses. 5719 OrderAccess::fence(); 5720 return; 5721 } 5722 5723 #ifdef ASSERT 5724 // Don't catch signals while blocked; let the running threads have the signals. 5725 // (This allows a debugger to break into the running thread.) 5726 sigset_t oldsigs; 5727 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5728 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5729 #endif 5730 5731 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5732 jt->set_suspend_equivalent(); 5733 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5734 5735 assert(_cur_index == -1, "invariant"); 5736 if (time == 0) { 5737 _cur_index = REL_INDEX; // arbitrary choice when not timed 5738 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5739 } else { 5740 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5741 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5742 } 5743 _cur_index = -1; 5744 assert_status(status == 0 || status == EINTR || 5745 status == ETIME || status == ETIMEDOUT, 5746 status, "cond_timedwait"); 5747 5748 #ifdef ASSERT 5749 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5750 #endif 5751 5752 _counter = 0; 5753 status = pthread_mutex_unlock(_mutex); 5754 assert_status(status == 0, status, "invariant"); 5755 // Paranoia to ensure our locked and lock-free paths interact 5756 // correctly with each other and Java-level accesses. 5757 OrderAccess::fence(); 5758 5759 // If externally suspended while waiting, re-suspend 5760 if (jt->handle_special_suspend_equivalent_condition()) { 5761 jt->java_suspend_self(); 5762 } 5763 } 5764 5765 void Parker::unpark() { 5766 int status = pthread_mutex_lock(_mutex); 5767 assert_status(status == 0, status, "invariant"); 5768 const int s = _counter; 5769 _counter = 1; 5770 // must capture correct index before unlocking 5771 int index = _cur_index; 5772 status = pthread_mutex_unlock(_mutex); 5773 assert_status(status == 0, status, "invariant"); 5774 if (s < 1 && index != -1) { 5775 // thread is definitely parked 5776 status = pthread_cond_signal(&_cond[index]); 5777 assert_status(status == 0, status, "invariant"); 5778 } 5779 } 5780 5781 5782 extern char** environ; 5783 5784 // Run the specified command in a separate process. Return its exit value, 5785 // or -1 on failure (e.g. can't fork a new process). 5786 // Unlike system(), this function can be called from signal handler. It 5787 // doesn't block SIGINT et al. 5788 int os::fork_and_exec(char* cmd) { 5789 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5790 5791 pid_t pid = fork(); 5792 5793 if (pid < 0) { 5794 // fork failed 5795 return -1; 5796 5797 } else if (pid == 0) { 5798 // child process 5799 5800 execve("/bin/sh", (char* const*)argv, environ); 5801 5802 // execve failed 5803 _exit(-1); 5804 5805 } else { 5806 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5807 // care about the actual exit code, for now. 5808 5809 int status; 5810 5811 // Wait for the child process to exit. This returns immediately if 5812 // the child has already exited. */ 5813 while (waitpid(pid, &status, 0) < 0) { 5814 switch (errno) { 5815 case ECHILD: return 0; 5816 case EINTR: break; 5817 default: return -1; 5818 } 5819 } 5820 5821 if (WIFEXITED(status)) { 5822 // The child exited normally; get its exit code. 5823 return WEXITSTATUS(status); 5824 } else if (WIFSIGNALED(status)) { 5825 // The child exited because of a signal 5826 // The best value to return is 0x80 + signal number, 5827 // because that is what all Unix shells do, and because 5828 // it allows callers to distinguish between process exit and 5829 // process death by signal. 5830 return 0x80 + WTERMSIG(status); 5831 } else { 5832 // Unknown exit code; pass it through 5833 return status; 5834 } 5835 } 5836 } 5837 5838 // is_headless_jre() 5839 // 5840 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5841 // in order to report if we are running in a headless jre 5842 // 5843 // Since JDK8 xawt/libmawt.so was moved into the same directory 5844 // as libawt.so, and renamed libawt_xawt.so 5845 // 5846 bool os::is_headless_jre() { 5847 struct stat statbuf; 5848 char buf[MAXPATHLEN]; 5849 char libmawtpath[MAXPATHLEN]; 5850 const char *xawtstr = "/xawt/libmawt.so"; 5851 const char *new_xawtstr = "/libawt_xawt.so"; 5852 char *p; 5853 5854 // Get path to libjvm.so 5855 os::jvm_path(buf, sizeof(buf)); 5856 5857 // Get rid of libjvm.so 5858 p = strrchr(buf, '/'); 5859 if (p == NULL) { 5860 return false; 5861 } else { 5862 *p = '\0'; 5863 } 5864 5865 // Get rid of client or server 5866 p = strrchr(buf, '/'); 5867 if (p == NULL) { 5868 return false; 5869 } else { 5870 *p = '\0'; 5871 } 5872 5873 // check xawt/libmawt.so 5874 strcpy(libmawtpath, buf); 5875 strcat(libmawtpath, xawtstr); 5876 if (::stat(libmawtpath, &statbuf) == 0) return false; 5877 5878 // check libawt_xawt.so 5879 strcpy(libmawtpath, buf); 5880 strcat(libmawtpath, new_xawtstr); 5881 if (::stat(libmawtpath, &statbuf) == 0) return false; 5882 5883 return true; 5884 } 5885 5886 // Get the default path to the core file 5887 // Returns the length of the string 5888 int os::get_core_path(char* buffer, size_t bufferSize) { 5889 /* 5890 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5891 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5892 */ 5893 const int core_pattern_len = 129; 5894 char core_pattern[core_pattern_len] = {0}; 5895 5896 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5897 if (core_pattern_file == -1) { 5898 return -1; 5899 } 5900 5901 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5902 ::close(core_pattern_file); 5903 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5904 return -1; 5905 } 5906 if (core_pattern[ret-1] == '\n') { 5907 core_pattern[ret-1] = '\0'; 5908 } else { 5909 core_pattern[ret] = '\0'; 5910 } 5911 5912 char *pid_pos = strstr(core_pattern, "%p"); 5913 int written; 5914 5915 if (core_pattern[0] == '/') { 5916 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5917 } else { 5918 char cwd[PATH_MAX]; 5919 5920 const char* p = get_current_directory(cwd, PATH_MAX); 5921 if (p == NULL) { 5922 return -1; 5923 } 5924 5925 if (core_pattern[0] == '|') { 5926 written = jio_snprintf(buffer, bufferSize, 5927 "\"%s\" (or dumping to %s/core.%d)", 5928 &core_pattern[1], p, current_process_id()); 5929 } else { 5930 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5931 } 5932 } 5933 5934 if (written < 0) { 5935 return -1; 5936 } 5937 5938 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5939 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5940 5941 if (core_uses_pid_file != -1) { 5942 char core_uses_pid = 0; 5943 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5944 ::close(core_uses_pid_file); 5945 5946 if (core_uses_pid == '1') { 5947 jio_snprintf(buffer + written, bufferSize - written, 5948 ".%d", current_process_id()); 5949 } 5950 } 5951 } 5952 5953 return strlen(buffer); 5954 } 5955 5956 bool os::start_debugging(char *buf, int buflen) { 5957 int len = (int)strlen(buf); 5958 char *p = &buf[len]; 5959 5960 jio_snprintf(p, buflen-len, 5961 "\n\n" 5962 "Do you want to debug the problem?\n\n" 5963 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 5964 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 5965 "Otherwise, press RETURN to abort...", 5966 os::current_process_id(), os::current_process_id(), 5967 os::current_thread_id(), os::current_thread_id()); 5968 5969 bool yes = os::message_box("Unexpected Error", buf); 5970 5971 if (yes) { 5972 // yes, user asked VM to launch debugger 5973 jio_snprintf(buf, sizeof(buf), "gdb /proc/%d/exe %d", 5974 os::current_process_id(), os::current_process_id()); 5975 5976 os::fork_and_exec(buf); 5977 yes = false; 5978 } 5979 return yes; 5980 } 5981 5982 5983 5984 /////////////// Unit tests /////////////// 5985 5986 #ifndef PRODUCT 5987 5988 #define test_log(...) \ 5989 do { \ 5990 if (VerboseInternalVMTests) { \ 5991 tty->print_cr(__VA_ARGS__); \ 5992 tty->flush(); \ 5993 } \ 5994 } while (false) 5995 5996 class TestReserveMemorySpecial : AllStatic { 5997 public: 5998 static void small_page_write(void* addr, size_t size) { 5999 size_t page_size = os::vm_page_size(); 6000 6001 char* end = (char*)addr + size; 6002 for (char* p = (char*)addr; p < end; p += page_size) { 6003 *p = 1; 6004 } 6005 } 6006 6007 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6008 if (!UseHugeTLBFS) { 6009 return; 6010 } 6011 6012 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6013 6014 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6015 6016 if (addr != NULL) { 6017 small_page_write(addr, size); 6018 6019 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6020 } 6021 } 6022 6023 static void test_reserve_memory_special_huge_tlbfs_only() { 6024 if (!UseHugeTLBFS) { 6025 return; 6026 } 6027 6028 size_t lp = os::large_page_size(); 6029 6030 for (size_t size = lp; size <= lp * 10; size += lp) { 6031 test_reserve_memory_special_huge_tlbfs_only(size); 6032 } 6033 } 6034 6035 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6036 size_t lp = os::large_page_size(); 6037 size_t ag = os::vm_allocation_granularity(); 6038 6039 // sizes to test 6040 const size_t sizes[] = { 6041 lp, lp + ag, lp + lp / 2, lp * 2, 6042 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6043 lp * 10, lp * 10 + lp / 2 6044 }; 6045 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6046 6047 // For each size/alignment combination, we test three scenarios: 6048 // 1) with req_addr == NULL 6049 // 2) with a non-null req_addr at which we expect to successfully allocate 6050 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6051 // expect the allocation to either fail or to ignore req_addr 6052 6053 // Pre-allocate two areas; they shall be as large as the largest allocation 6054 // and aligned to the largest alignment we will be testing. 6055 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6056 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6057 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6058 -1, 0); 6059 assert(mapping1 != MAP_FAILED, "should work"); 6060 6061 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6062 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6063 -1, 0); 6064 assert(mapping2 != MAP_FAILED, "should work"); 6065 6066 // Unmap the first mapping, but leave the second mapping intact: the first 6067 // mapping will serve as a value for a "good" req_addr (case 2). The second 6068 // mapping, still intact, as "bad" req_addr (case 3). 6069 ::munmap(mapping1, mapping_size); 6070 6071 // Case 1 6072 test_log("%s, req_addr NULL:", __FUNCTION__); 6073 test_log("size align result"); 6074 6075 for (int i = 0; i < num_sizes; i++) { 6076 const size_t size = sizes[i]; 6077 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6078 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6079 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6080 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6081 if (p != NULL) { 6082 assert(is_ptr_aligned(p, alignment), "must be"); 6083 small_page_write(p, size); 6084 os::Linux::release_memory_special_huge_tlbfs(p, size); 6085 } 6086 } 6087 } 6088 6089 // Case 2 6090 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6091 test_log("size align req_addr result"); 6092 6093 for (int i = 0; i < num_sizes; i++) { 6094 const size_t size = sizes[i]; 6095 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6096 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6097 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6098 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6099 size, alignment, p2i(req_addr), p2i(p), 6100 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6101 if (p != NULL) { 6102 assert(p == req_addr, "must be"); 6103 small_page_write(p, size); 6104 os::Linux::release_memory_special_huge_tlbfs(p, size); 6105 } 6106 } 6107 } 6108 6109 // Case 3 6110 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6111 test_log("size align req_addr result"); 6112 6113 for (int i = 0; i < num_sizes; i++) { 6114 const size_t size = sizes[i]; 6115 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6116 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6117 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6118 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6119 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6120 // as the area around req_addr contains already existing mappings, the API should always 6121 // return NULL (as per contract, it cannot return another address) 6122 assert(p == NULL, "must be"); 6123 } 6124 } 6125 6126 ::munmap(mapping2, mapping_size); 6127 6128 } 6129 6130 static void test_reserve_memory_special_huge_tlbfs() { 6131 if (!UseHugeTLBFS) { 6132 return; 6133 } 6134 6135 test_reserve_memory_special_huge_tlbfs_only(); 6136 test_reserve_memory_special_huge_tlbfs_mixed(); 6137 } 6138 6139 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6140 if (!UseSHM) { 6141 return; 6142 } 6143 6144 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6145 6146 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6147 6148 if (addr != NULL) { 6149 assert(is_ptr_aligned(addr, alignment), "Check"); 6150 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6151 6152 small_page_write(addr, size); 6153 6154 os::Linux::release_memory_special_shm(addr, size); 6155 } 6156 } 6157 6158 static void test_reserve_memory_special_shm() { 6159 size_t lp = os::large_page_size(); 6160 size_t ag = os::vm_allocation_granularity(); 6161 6162 for (size_t size = ag; size < lp * 3; size += ag) { 6163 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6164 test_reserve_memory_special_shm(size, alignment); 6165 } 6166 } 6167 } 6168 6169 static void test() { 6170 test_reserve_memory_special_huge_tlbfs(); 6171 test_reserve_memory_special_shm(); 6172 } 6173 }; 6174 6175 void TestReserveMemorySpecial_test() { 6176 TestReserveMemorySpecial::test(); 6177 } 6178 6179 #endif