Mercurial > hg > graal-compiler
view src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.cpp @ 14692:8504393de66b
8037043: put Method flag bits in predictable positions
Reviewed-by: kvn, coleenp
author | twisti |
---|---|
date | Tue, 11 Mar 2014 14:54:47 -0700 |
parents | de6a9e811145 |
children | 4ca6dc0799b6 78bbf4d43a14 |
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/* * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "classfile/systemDictionary.hpp" #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.inline.hpp" #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" #include "memory/genCollectedHeap.hpp" #include "oops/instanceRefKlass.hpp" #include "oops/oop.inline.hpp" #include "runtime/init.hpp" #include "runtime/interfaceSupport.hpp" #include "runtime/java.hpp" #include "runtime/javaCalls.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/os.hpp" #include "runtime/vmThread.hpp" // ======= Concurrent Mark Sweep Thread ======== // The CMS thread is created when Concurrent Mark Sweep is used in the // older of two generations in a generational memory system. ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::_cmst = NULL; CMSCollector* ConcurrentMarkSweepThread::_collector = NULL; bool ConcurrentMarkSweepThread::_should_terminate = false; int ConcurrentMarkSweepThread::_CMS_flag = CMS_nil; volatile jint ConcurrentMarkSweepThread::_pending_yields = 0; volatile jint ConcurrentMarkSweepThread::_pending_decrements = 0; volatile jint ConcurrentMarkSweepThread::_icms_disabled = 0; volatile bool ConcurrentMarkSweepThread::_should_run = false; // When icms is enabled, the icms thread is stopped until explicitly // started. volatile bool ConcurrentMarkSweepThread::_should_stop = true; SurrogateLockerThread* ConcurrentMarkSweepThread::_slt = NULL; SurrogateLockerThread::SLT_msg_type ConcurrentMarkSweepThread::_sltBuffer = SurrogateLockerThread::empty; Monitor* ConcurrentMarkSweepThread::_sltMonitor = NULL; ConcurrentMarkSweepThread::ConcurrentMarkSweepThread(CMSCollector* collector) : ConcurrentGCThread() { assert(UseConcMarkSweepGC, "UseConcMarkSweepGC should be set"); assert(_cmst == NULL, "CMS thread already created"); _cmst = this; assert(_collector == NULL, "Collector already set"); _collector = collector; set_name("Concurrent Mark-Sweep GC Thread"); if (os::create_thread(this, os::cgc_thread)) { // An old comment here said: "Priority should be just less // than that of VMThread". Since the VMThread runs at // NearMaxPriority, the old comment was inaccurate, but // changing the default priority to NearMaxPriority-1 // could change current behavior, so the default of // NearMaxPriority stays in place. // // Note that there's a possibility of the VMThread // starving if UseCriticalCMSThreadPriority is on. // That won't happen on Solaris for various reasons, // but may well happen on non-Solaris platforms. int native_prio; if (UseCriticalCMSThreadPriority) { native_prio = os::java_to_os_priority[CriticalPriority]; } else { native_prio = os::java_to_os_priority[NearMaxPriority]; } os::set_native_priority(this, native_prio); if (!DisableStartThread) { os::start_thread(this); } } _sltMonitor = SLT_lock; assert(!CMSIncrementalMode || icms_is_enabled(), "Error"); } void ConcurrentMarkSweepThread::run() { assert(this == cmst(), "just checking"); this->record_stack_base_and_size(); this->initialize_thread_local_storage(); this->set_active_handles(JNIHandleBlock::allocate_block()); // From this time Thread::current() should be working. assert(this == Thread::current(), "just checking"); if (BindCMSThreadToCPU && !os::bind_to_processor(CPUForCMSThread)) { warning("Couldn't bind CMS thread to processor %u", CPUForCMSThread); } // Wait until Universe::is_fully_initialized() { CMSLoopCountWarn loopX("CMS::run", "waiting for " "Universe::is_fully_initialized()", 2); MutexLockerEx x(CGC_lock, true); set_CMS_flag(CMS_cms_wants_token); // Wait until Universe is initialized and all initialization is completed. while (!is_init_completed() && !Universe::is_fully_initialized() && !_should_terminate) { CGC_lock->wait(true, 200); loopX.tick(); } // Wait until the surrogate locker thread that will do // pending list locking on our behalf has been created. // We cannot start the SLT thread ourselves since we need // to be a JavaThread to do so. CMSLoopCountWarn loopY("CMS::run", "waiting for SLT installation", 2); while (_slt == NULL && !_should_terminate) { CGC_lock->wait(true, 200); loopY.tick(); } clear_CMS_flag(CMS_cms_wants_token); } while (!_should_terminate) { sleepBeforeNextCycle(); if (_should_terminate) break; GCCause::Cause cause = _collector->_full_gc_requested ? _collector->_full_gc_cause : GCCause::_cms_concurrent_mark; _collector->collect_in_background(false, cause); } assert(_should_terminate, "just checking"); // Check that the state of any protocol for synchronization // between background (CMS) and foreground collector is "clean" // (i.e. will not potentially block the foreground collector, // requiring action by us). verify_ok_to_terminate(); // Signal that it is terminated { MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); assert(_cmst == this, "Weird!"); _cmst = NULL; Terminator_lock->notify(); } // Thread destructor usually does this.. ThreadLocalStorage::set_thread(NULL); } #ifndef PRODUCT void ConcurrentMarkSweepThread::verify_ok_to_terminate() const { assert(!(CGC_lock->owned_by_self() || cms_thread_has_cms_token() || cms_thread_wants_cms_token()), "Must renounce all worldly possessions and desires for nirvana"); _collector->verify_ok_to_terminate(); } #endif // create and start a new ConcurrentMarkSweep Thread for given CMS generation ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::start(CMSCollector* collector) { if (!_should_terminate) { assert(cmst() == NULL, "start() called twice?"); ConcurrentMarkSweepThread* th = new ConcurrentMarkSweepThread(collector); assert(cmst() == th, "Where did the just-created CMS thread go?"); return th; } return NULL; } void ConcurrentMarkSweepThread::stop() { if (CMSIncrementalMode) { // Disable incremental mode and wake up the thread so it notices the change. disable_icms(); start_icms(); } // it is ok to take late safepoints here, if needed { MutexLockerEx x(Terminator_lock); _should_terminate = true; } { // Now post a notify on CGC_lock so as to nudge // CMS thread(s) that might be slumbering in // sleepBeforeNextCycle. MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); CGC_lock->notify_all(); } { // Now wait until (all) CMS thread(s) have exited MutexLockerEx x(Terminator_lock); while(cmst() != NULL) { Terminator_lock->wait(); } } } void ConcurrentMarkSweepThread::threads_do(ThreadClosure* tc) { assert(tc != NULL, "Null ThreadClosure"); if (_cmst != NULL) { tc->do_thread(_cmst); } assert(Universe::is_fully_initialized(), "Called too early, make sure heap is fully initialized"); if (_collector != NULL) { AbstractWorkGang* gang = _collector->conc_workers(); if (gang != NULL) { gang->threads_do(tc); } } } void ConcurrentMarkSweepThread::print_on(outputStream* st) const { st->print("\"%s\" ", name()); Thread::print_on(st); st->cr(); } void ConcurrentMarkSweepThread::print_all_on(outputStream* st) { if (_cmst != NULL) { _cmst->print_on(st); st->cr(); } if (_collector != NULL) { AbstractWorkGang* gang = _collector->conc_workers(); if (gang != NULL) { gang->print_worker_threads_on(st); } } } void ConcurrentMarkSweepThread::synchronize(bool is_cms_thread) { assert(UseConcMarkSweepGC, "just checking"); MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); if (!is_cms_thread) { assert(Thread::current()->is_VM_thread(), "Not a VM thread"); CMSSynchronousYieldRequest yr; while (CMS_flag_is_set(CMS_cms_has_token)) { // indicate that we want to get the token set_CMS_flag(CMS_vm_wants_token); CGC_lock->wait(true); } // claim the token and proceed clear_CMS_flag(CMS_vm_wants_token); set_CMS_flag(CMS_vm_has_token); } else { assert(Thread::current()->is_ConcurrentGC_thread(), "Not a CMS thread"); // The following barrier assumes there's only one CMS thread. // This will need to be modified is there are more CMS threads than one. while (CMS_flag_is_set(CMS_vm_has_token | CMS_vm_wants_token)) { set_CMS_flag(CMS_cms_wants_token); CGC_lock->wait(true); } // claim the token clear_CMS_flag(CMS_cms_wants_token); set_CMS_flag(CMS_cms_has_token); } } void ConcurrentMarkSweepThread::desynchronize(bool is_cms_thread) { assert(UseConcMarkSweepGC, "just checking"); MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); if (!is_cms_thread) { assert(Thread::current()->is_VM_thread(), "Not a VM thread"); assert(CMS_flag_is_set(CMS_vm_has_token), "just checking"); clear_CMS_flag(CMS_vm_has_token); if (CMS_flag_is_set(CMS_cms_wants_token)) { // wake-up a waiting CMS thread CGC_lock->notify(); } assert(!CMS_flag_is_set(CMS_vm_has_token | CMS_vm_wants_token), "Should have been cleared"); } else { assert(Thread::current()->is_ConcurrentGC_thread(), "Not a CMS thread"); assert(CMS_flag_is_set(CMS_cms_has_token), "just checking"); clear_CMS_flag(CMS_cms_has_token); if (CMS_flag_is_set(CMS_vm_wants_token)) { // wake-up a waiting VM thread CGC_lock->notify(); } assert(!CMS_flag_is_set(CMS_cms_has_token | CMS_cms_wants_token), "Should have been cleared"); } } // Wait until any cms_lock event void ConcurrentMarkSweepThread::wait_on_cms_lock(long t_millis) { MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); if (_should_terminate || _collector->_full_gc_requested) { return; } set_CMS_flag(CMS_cms_wants_token); // to provoke notifies CGC_lock->wait(Mutex::_no_safepoint_check_flag, t_millis); clear_CMS_flag(CMS_cms_wants_token); assert(!CMS_flag_is_set(CMS_cms_has_token | CMS_cms_wants_token), "Should not be set"); } // Wait until the next synchronous GC, a concurrent full gc request, // or a timeout, whichever is earlier. void ConcurrentMarkSweepThread::wait_on_cms_lock_for_scavenge(long t_millis) { // Wait time in millis or 0 value representing infinite wait for a scavenge assert(t_millis >= 0, "Wait time for scavenge should be 0 or positive"); GenCollectedHeap* gch = GenCollectedHeap::heap(); double start_time_secs = os::elapsedTime(); double end_time_secs = start_time_secs + (t_millis / ((double) MILLIUNITS)); // Total collections count before waiting loop unsigned int before_count; { MutexLockerEx hl(Heap_lock, Mutex::_no_safepoint_check_flag); before_count = gch->total_collections(); } unsigned int loop_count = 0; while(!_should_terminate) { double now_time = os::elapsedTime(); long wait_time_millis; if(t_millis != 0) { // New wait limit wait_time_millis = (long) ((end_time_secs - now_time) * MILLIUNITS); if(wait_time_millis <= 0) { // Wait time is over break; } } else { // No wait limit, wait if necessary forever wait_time_millis = 0; } // Wait until the next event or the remaining timeout { MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); if (_should_terminate || _collector->_full_gc_requested) { return; } set_CMS_flag(CMS_cms_wants_token); // to provoke notifies assert(t_millis == 0 || wait_time_millis > 0, "Sanity"); CGC_lock->wait(Mutex::_no_safepoint_check_flag, wait_time_millis); clear_CMS_flag(CMS_cms_wants_token); assert(!CMS_flag_is_set(CMS_cms_has_token | CMS_cms_wants_token), "Should not be set"); } // Extra wait time check before entering the heap lock to get the collection count if(t_millis != 0 && os::elapsedTime() >= end_time_secs) { // Wait time is over break; } // Total collections count after the event unsigned int after_count; { MutexLockerEx hl(Heap_lock, Mutex::_no_safepoint_check_flag); after_count = gch->total_collections(); } if(before_count != after_count) { // There was a collection - success break; } // Too many loops warning if(++loop_count == 0) { warning("wait_on_cms_lock_for_scavenge() has looped %u times", loop_count - 1); } } } void ConcurrentMarkSweepThread::sleepBeforeNextCycle() { while (!_should_terminate) { if (CMSIncrementalMode) { icms_wait(); if(CMSWaitDuration >= 0) { // Wait until the next synchronous GC, a concurrent full gc // request or a timeout, whichever is earlier. wait_on_cms_lock_for_scavenge(CMSWaitDuration); } return; } else { if(CMSWaitDuration >= 0) { // Wait until the next synchronous GC, a concurrent full gc // request or a timeout, whichever is earlier. wait_on_cms_lock_for_scavenge(CMSWaitDuration); } else { // Wait until any cms_lock event or check interval not to call shouldConcurrentCollect permanently wait_on_cms_lock(CMSCheckInterval); } } // Check if we should start a CMS collection cycle if (_collector->shouldConcurrentCollect()) { return; } // .. collection criterion not yet met, let's go back // and wait some more } } // Incremental CMS void ConcurrentMarkSweepThread::start_icms() { assert(UseConcMarkSweepGC && CMSIncrementalMode, "just checking"); MutexLockerEx x(iCMS_lock, Mutex::_no_safepoint_check_flag); trace_state("start_icms"); _should_run = true; iCMS_lock->notify_all(); } void ConcurrentMarkSweepThread::stop_icms() { assert(UseConcMarkSweepGC && CMSIncrementalMode, "just checking"); MutexLockerEx x(iCMS_lock, Mutex::_no_safepoint_check_flag); if (!_should_stop) { trace_state("stop_icms"); _should_stop = true; _should_run = false; asynchronous_yield_request(); iCMS_lock->notify_all(); } } void ConcurrentMarkSweepThread::icms_wait() { assert(UseConcMarkSweepGC && CMSIncrementalMode, "just checking"); if (_should_stop && icms_is_enabled()) { MutexLockerEx x(iCMS_lock, Mutex::_no_safepoint_check_flag); trace_state("pause_icms"); _collector->stats().stop_cms_timer(); while(!_should_run && icms_is_enabled()) { iCMS_lock->wait(Mutex::_no_safepoint_check_flag); } _collector->stats().start_cms_timer(); _should_stop = false; trace_state("pause_icms end"); } } // Note: this method, although exported by the ConcurrentMarkSweepThread, // which is a non-JavaThread, can only be called by a JavaThread. // Currently this is done at vm creation time (post-vm-init) by the // main/Primordial (Java)Thread. // XXX Consider changing this in the future to allow the CMS thread // itself to create this thread? void ConcurrentMarkSweepThread::makeSurrogateLockerThread(TRAPS) { assert(UseConcMarkSweepGC, "SLT thread needed only for CMS GC"); assert(_slt == NULL, "SLT already created"); _slt = SurrogateLockerThread::make(THREAD); }