author | tonyp |
Thu, 14 Oct 2010 10:38:14 -0400 | |
changeset 6980 | d19831e79825 |
parent 5547 | f4b087cbb361 |
child 7397 | 5b173b4ca846 |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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6941466: Oracle rebranding changes for Hotspot repositories
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4029
diff
changeset
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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6941466: Oracle rebranding changes for Hotspot repositories
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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* |
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*/ |
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#include "incls/_precompiled.incl" |
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#include "incls/_concurrentZFThread.cpp.incl" |
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// ======= Concurrent Zero-Fill Thread ======== |
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// The CM thread is created when the G1 garbage collector is used |
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int ConcurrentZFThread::_region_allocs = 0; |
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int ConcurrentZFThread::_sync_zfs = 0; |
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int ConcurrentZFThread::_zf_waits = 0; |
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int ConcurrentZFThread::_regions_filled = 0; |
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ConcurrentZFThread::ConcurrentZFThread() : |
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ConcurrentGCThread() |
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{ |
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create_and_start(); |
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} |
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void ConcurrentZFThread::wait_for_ZF_completed(HeapRegion* hr) { |
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assert(ZF_mon->owned_by_self(), "Precondition."); |
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note_zf_wait(); |
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while (hr->zero_fill_state() == HeapRegion::ZeroFilling) { |
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ZF_mon->wait(Mutex::_no_safepoint_check_flag); |
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} |
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} |
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void ConcurrentZFThread::processHeapRegion(HeapRegion* hr) { |
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assert(!Universe::heap()->is_gc_active(), |
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"This should not happen during GC."); |
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assert(hr != NULL, "Precondition"); |
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// These are unlocked reads, but if this test is successful, then no |
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// other thread will attempt this zero filling. Only a GC thread can |
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// modify the ZF state of a region whose state is zero-filling, and this |
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// should only happen while the ZF thread is locking out GC. |
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if (hr->zero_fill_state() == HeapRegion::ZeroFilling |
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&& hr->zero_filler() == Thread::current()) { |
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assert(hr->top() == hr->bottom(), "better be empty!"); |
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assert(!hr->isHumongous(), "Only free regions on unclean list."); |
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Copy::fill_to_words(hr->bottom(), hr->capacity()/HeapWordSize); |
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note_region_filled(); |
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} |
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} |
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void ConcurrentZFThread::run() { |
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initialize_in_thread(); |
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Thread* thr_self = Thread::current(); |
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_vtime_start = os::elapsedVTime(); |
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wait_for_universe_init(); |
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G1CollectedHeap* g1 = G1CollectedHeap::heap(); |
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_sts.join(); |
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while (!_should_terminate) { |
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_sts.leave(); |
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{ |
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MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag); |
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// This local variable will hold a region being zero-filled. This |
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// region will neither be on the unclean or zero-filled lists, and |
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// will not be available for allocation; thus, we might have an |
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// allocation fail, causing a full GC, because of this, but this is a |
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// price we will pay. (In future, we might want to make the fact |
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// that there's a region being zero-filled apparent to the G1 heap, |
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// which could then wait for it in this extreme case...) |
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HeapRegion* to_fill; |
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while (!g1->should_zf() |
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|| (to_fill = g1->pop_unclean_region_list_locked()) == NULL) |
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ZF_mon->wait(Mutex::_no_safepoint_check_flag); |
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while (to_fill->zero_fill_state() == HeapRegion::ZeroFilling) |
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ZF_mon->wait(Mutex::_no_safepoint_check_flag); |
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// So now to_fill is non-NULL and is not ZeroFilling. It might be |
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// Allocated or ZeroFilled. (The latter could happen if this thread |
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// starts the zero-filling of a region, but a GC intervenes and |
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// pushes new regions needing on the front of the filling on the |
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// front of the list.) |
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switch (to_fill->zero_fill_state()) { |
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case HeapRegion::Allocated: |
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to_fill = NULL; |
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break; |
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case HeapRegion::NotZeroFilled: |
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to_fill->set_zero_fill_in_progress(thr_self); |
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ZF_mon->unlock(); |
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_sts.join(); |
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processHeapRegion(to_fill); |
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_sts.leave(); |
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ZF_mon->lock_without_safepoint_check(); |
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if (to_fill->zero_fill_state() == HeapRegion::ZeroFilling |
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&& to_fill->zero_filler() == thr_self) { |
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to_fill->set_zero_fill_complete(); |
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(void)g1->put_free_region_on_list_locked(to_fill); |
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} |
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break; |
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case HeapRegion::ZeroFilled: |
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(void)g1->put_free_region_on_list_locked(to_fill); |
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break; |
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case HeapRegion::ZeroFilling: |
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ShouldNotReachHere(); |
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break; |
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} |
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} |
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_vtime_accum = (os::elapsedVTime() - _vtime_start); |
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_sts.join(); |
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} |
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_sts.leave(); |
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assert(_should_terminate, "just checking"); |
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terminate(); |
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} |
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bool ConcurrentZFThread::offer_yield() { |
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if (_sts.should_yield()) { |
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_sts.yield("Concurrent ZF"); |
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return true; |
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} else { |
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return false; |
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} |
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} |
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void ConcurrentZFThread::stop() { |
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// it is ok to take late safepoints here, if needed |
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MutexLockerEx mu(Terminator_lock); |
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_should_terminate = true; |
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while (!_has_terminated) { |
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Terminator_lock->wait(); |
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} |
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} |
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void ConcurrentZFThread::print() const { |
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print_on(tty); |
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} |
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void ConcurrentZFThread::print_on(outputStream* st) const { |
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st->print("\"G1 Concurrent Zero-Fill Thread\" "); |
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Thread::print_on(st); |
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st->cr(); |
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} |
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double ConcurrentZFThread::_vtime_accum; |
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void ConcurrentZFThread::print_summary_info() { |
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gclog_or_tty->print("\nConcurrent Zero-Filling:\n"); |
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gclog_or_tty->print(" Filled %d regions, used %5.2fs.\n", |
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_regions_filled, |
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vtime_accum()); |
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gclog_or_tty->print(" Of %d region allocs, %d (%5.2f%%) required sync ZF,\n", |
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_region_allocs, _sync_zfs, |
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(_region_allocs > 0 ? |
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(float)_sync_zfs/(float)_region_allocs*100.0 : |
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0.0)); |
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gclog_or_tty->print(" and %d (%5.2f%%) required a ZF wait.\n", |
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_zf_waits, |
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(_region_allocs > 0 ? |
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(float)_zf_waits/(float)_region_allocs*100.0 : |
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0.0)); |
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} |