Mercurial > hg > truffle
diff src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | bb843ebc7c55 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,250 @@ +/* + * Copyright 2005-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ +# include "incls/_precompiled.incl" +# include "incls/_vmCMSOperations.cpp.incl" + +HS_DTRACE_PROBE_DECL(hs_private, cms__initmark__begin); +HS_DTRACE_PROBE_DECL(hs_private, cms__initmark__end); + +HS_DTRACE_PROBE_DECL(hs_private, cms__remark__begin); +HS_DTRACE_PROBE_DECL(hs_private, cms__remark__end); + +////////////////////////////////////////////////////////// +// Methods in abstract class VM_CMS_Operation +////////////////////////////////////////////////////////// +void VM_CMS_Operation::acquire_pending_list_lock() { + // The caller may block while communicating + // with the SLT thread in order to acquire/release the PLL. + ConcurrentMarkSweepThread::slt()-> + manipulatePLL(SurrogateLockerThread::acquirePLL); +} + +void VM_CMS_Operation::release_and_notify_pending_list_lock() { + // The caller may block while communicating + // with the SLT thread in order to acquire/release the PLL. + ConcurrentMarkSweepThread::slt()-> + manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL); +} + +void VM_CMS_Operation::verify_before_gc() { + if (VerifyBeforeGC && + GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { + HandleMark hm; + FreelistLocker x(_collector); + MutexLockerEx y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag); + Universe::heap()->prepare_for_verify(); + Universe::verify(true); + } +} + +void VM_CMS_Operation::verify_after_gc() { + if (VerifyAfterGC && + GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) { + HandleMark hm; + FreelistLocker x(_collector); + MutexLockerEx y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag); + Universe::verify(true); + } +} + +bool VM_CMS_Operation::lost_race() const { + if (CMSCollector::abstract_state() == CMSCollector::Idling) { + // We lost a race to a foreground collection + // -- there's nothing to do + return true; + } + assert(CMSCollector::abstract_state() == legal_state(), + "Inconsistent collector state?"); + return false; +} + +bool VM_CMS_Operation::doit_prologue() { + assert(Thread::current()->is_ConcurrentGC_thread(), "just checking"); + assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock"); + assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(), + "Possible deadlock"); + + if (needs_pll()) { + acquire_pending_list_lock(); + } + // Get the Heap_lock after the pending_list_lock. + Heap_lock->lock(); + if (lost_race()) { + assert(_prologue_succeeded == false, "Initialized in c'tor"); + Heap_lock->unlock(); + if (needs_pll()) { + release_and_notify_pending_list_lock(); + } + } else { + _prologue_succeeded = true; + } + return _prologue_succeeded; +} + +void VM_CMS_Operation::doit_epilogue() { + assert(Thread::current()->is_ConcurrentGC_thread(), "just checking"); + assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock"); + assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(), + "Possible deadlock"); + + // Release the Heap_lock first. + Heap_lock->unlock(); + if (needs_pll()) { + release_and_notify_pending_list_lock(); + } +} + +////////////////////////////////////////////////////////// +// Methods in class VM_CMS_Initial_Mark +////////////////////////////////////////////////////////// +void VM_CMS_Initial_Mark::doit() { + if (lost_race()) { + // Nothing to do. + return; + } + HS_DTRACE_PROBE(hs_private, cms__initmark__begin); + + GenCollectedHeap* gch = GenCollectedHeap::heap(); + GCCauseSetter gccs(gch, GCCause::_cms_initial_mark); + + VM_CMS_Operation::verify_before_gc(); + + IsGCActiveMark x; // stop-world GC active + _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsInitial); + + VM_CMS_Operation::verify_after_gc(); + HS_DTRACE_PROBE(hs_private, cms__initmark__end); +} + +////////////////////////////////////////////////////////// +// Methods in class VM_CMS_Final_Remark_Operation +////////////////////////////////////////////////////////// +void VM_CMS_Final_Remark::doit() { + if (lost_race()) { + // Nothing to do. + return; + } + HS_DTRACE_PROBE(hs_private, cms__remark__begin); + + GenCollectedHeap* gch = GenCollectedHeap::heap(); + GCCauseSetter gccs(gch, GCCause::_cms_final_remark); + + VM_CMS_Operation::verify_before_gc(); + + IsGCActiveMark x; // stop-world GC active + _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsFinal); + + VM_CMS_Operation::verify_after_gc(); + HS_DTRACE_PROBE(hs_private, cms__remark__end); +} + +// VM operation to invoke a concurrent collection of a +// GenCollectedHeap heap. +void VM_GenCollectFullConcurrent::doit() { + assert(Thread::current()->is_VM_thread(), "Should be VM thread"); + + GenCollectedHeap* gch = GenCollectedHeap::heap(); + if (_gc_count_before == gch->total_collections()) { + // The "full" of do_full_collection call below "forces" + // a collection; the second arg, 0, below ensures that + // only the young gen is collected. XXX In the future, + // we'll probably need to have something in this interface + // to say do this only if we are sure we will not bail + // out to a full collection in this attempt, but that's + // for the future. + assert(SafepointSynchronize::is_at_safepoint(), + "We can only be executing this arm of if at a safepoint"); + GCCauseSetter gccs(gch, _gc_cause); + gch->do_full_collection(gch->must_clear_all_soft_refs(), + 0 /* collect only youngest gen */); + } // Else no need for a foreground young gc + assert((_gc_count_before < gch->total_collections()) || + (GC_locker::is_active() /* gc may have been skipped */ + && (_gc_count_before == gch->total_collections())), + "total_collections() should be monotonically increasing"); + + MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag); + if (gch->total_full_collections() == _full_gc_count_before) { + // Disable iCMS until the full collection is done. + CMSCollector::disable_icms(); + // In case CMS thread was in icms_wait(), wake it up. + CMSCollector::start_icms(); + // Nudge the CMS thread to start a concurrent collection + CMSCollector::request_full_gc(_full_gc_count_before); + } else { + FullGCCount_lock->notify_all(); // Inform the Java thread its work is done + } +} + +bool VM_GenCollectFullConcurrent::evaluate_at_safepoint() const { + Thread* thr = Thread::current(); + assert(thr != NULL, "Unexpected tid"); + if (!thr->is_Java_thread()) { + assert(thr->is_VM_thread(), "Expected to be evaluated by VM thread"); + GenCollectedHeap* gch = GenCollectedHeap::heap(); + if (_gc_count_before != gch->total_collections()) { + // No need to do a young gc, we'll just nudge the CMS thread + // in the doit() method above, to be executed soon. + assert(_gc_count_before < gch->total_collections(), + "total_collections() should be monotnically increasing"); + return false; // no need for foreground young gc + } + } + return true; // may still need foreground young gc +} + + +void VM_GenCollectFullConcurrent::doit_epilogue() { + Thread* thr = Thread::current(); + assert(thr->is_Java_thread(), "just checking"); + JavaThread* jt = (JavaThread*)thr; + // Release the Heap_lock first. + Heap_lock->unlock(); + release_and_notify_pending_list_lock(); + + // It is fine to test whether completed collections has + // exceeded our request count without locking because + // the completion count is monotonically increasing; + // this will break for very long-running apps when the + // count overflows and wraps around. XXX fix me !!! + // e.g. at the rate of 1 full gc per ms, this could + // overflow in about 1000 years. + GenCollectedHeap* gch = GenCollectedHeap::heap(); + if (gch->total_full_collections_completed() <= _full_gc_count_before) { + // Now, wait for witnessing concurrent gc cycle to complete, + // but do so in native mode, because we want to lock the + // FullGCEvent_lock, which may be needed by the VM thread + // or by the CMS thread, so we do not want to be suspended + // while holding that lock. + ThreadToNativeFromVM native(jt); + MutexLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); + // Either a concurrent or a stop-world full gc is sufficient + // witness to our request. + while (gch->total_full_collections_completed() <= _full_gc_count_before) { + FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag); + } + } + // Enable iCMS back. + CMSCollector::enable_icms(); +}