diff -r e97540c35e38 -r fc200fcd4e05 hotspot/src/share/vm/gc_implementation/g1/concurrentZFThread.cpp --- a/hotspot/src/share/vm/gc_implementation/g1/concurrentZFThread.cpp Wed Jan 19 13:04:37 2011 -0800 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,194 +0,0 @@ -/* - * Copyright (c) 2001, 2010, 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 "gc_implementation/g1/concurrentZFThread.hpp" -#include "gc_implementation/g1/g1CollectedHeap.inline.hpp" -#include "gc_implementation/g1/heapRegion.hpp" -#include "memory/space.inline.hpp" -#include "runtime/mutexLocker.hpp" -#include "utilities/copy.hpp" - -// ======= Concurrent Zero-Fill Thread ======== - -// The CM thread is created when the G1 garbage collector is used - -int ConcurrentZFThread::_region_allocs = 0; -int ConcurrentZFThread::_sync_zfs = 0; -int ConcurrentZFThread::_zf_waits = 0; -int ConcurrentZFThread::_regions_filled = 0; - -ConcurrentZFThread::ConcurrentZFThread() : - ConcurrentGCThread() -{ - create_and_start(); -} - -void ConcurrentZFThread::wait_for_ZF_completed(HeapRegion* hr) { - assert(ZF_mon->owned_by_self(), "Precondition."); - note_zf_wait(); - while (hr->zero_fill_state() == HeapRegion::ZeroFilling) { - ZF_mon->wait(Mutex::_no_safepoint_check_flag); - } -} - -void ConcurrentZFThread::processHeapRegion(HeapRegion* hr) { - assert(!Universe::heap()->is_gc_active(), - "This should not happen during GC."); - assert(hr != NULL, "Precondition"); - // These are unlocked reads, but if this test is successful, then no - // other thread will attempt this zero filling. Only a GC thread can - // modify the ZF state of a region whose state is zero-filling, and this - // should only happen while the ZF thread is locking out GC. - if (hr->zero_fill_state() == HeapRegion::ZeroFilling - && hr->zero_filler() == Thread::current()) { - assert(hr->top() == hr->bottom(), "better be empty!"); - assert(!hr->isHumongous(), "Only free regions on unclean list."); - Copy::fill_to_words(hr->bottom(), hr->capacity()/HeapWordSize); - note_region_filled(); - } -} - -void ConcurrentZFThread::run() { - initialize_in_thread(); - Thread* thr_self = Thread::current(); - _vtime_start = os::elapsedVTime(); - wait_for_universe_init(); - - G1CollectedHeap* g1 = G1CollectedHeap::heap(); - _sts.join(); - while (!_should_terminate) { - _sts.leave(); - - { - MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag); - - // This local variable will hold a region being zero-filled. This - // region will neither be on the unclean or zero-filled lists, and - // will not be available for allocation; thus, we might have an - // allocation fail, causing a full GC, because of this, but this is a - // price we will pay. (In future, we might want to make the fact - // that there's a region being zero-filled apparent to the G1 heap, - // which could then wait for it in this extreme case...) - HeapRegion* to_fill; - - while (!g1->should_zf() - || (to_fill = g1->pop_unclean_region_list_locked()) == NULL) - ZF_mon->wait(Mutex::_no_safepoint_check_flag); - while (to_fill->zero_fill_state() == HeapRegion::ZeroFilling) - ZF_mon->wait(Mutex::_no_safepoint_check_flag); - - // So now to_fill is non-NULL and is not ZeroFilling. It might be - // Allocated or ZeroFilled. (The latter could happen if this thread - // starts the zero-filling of a region, but a GC intervenes and - // pushes new regions needing on the front of the filling on the - // front of the list.) - - switch (to_fill->zero_fill_state()) { - case HeapRegion::Allocated: - to_fill = NULL; - break; - - case HeapRegion::NotZeroFilled: - to_fill->set_zero_fill_in_progress(thr_self); - - ZF_mon->unlock(); - _sts.join(); - processHeapRegion(to_fill); - _sts.leave(); - ZF_mon->lock_without_safepoint_check(); - - if (to_fill->zero_fill_state() == HeapRegion::ZeroFilling - && to_fill->zero_filler() == thr_self) { - to_fill->set_zero_fill_complete(); - (void)g1->put_free_region_on_list_locked(to_fill); - } - break; - - case HeapRegion::ZeroFilled: - (void)g1->put_free_region_on_list_locked(to_fill); - break; - - case HeapRegion::ZeroFilling: - ShouldNotReachHere(); - break; - } - } - _vtime_accum = (os::elapsedVTime() - _vtime_start); - _sts.join(); - } - _sts.leave(); - - assert(_should_terminate, "just checking"); - terminate(); -} - -bool ConcurrentZFThread::offer_yield() { - if (_sts.should_yield()) { - _sts.yield("Concurrent ZF"); - return true; - } else { - return false; - } -} - -void ConcurrentZFThread::stop() { - // it is ok to take late safepoints here, if needed - MutexLockerEx mu(Terminator_lock); - _should_terminate = true; - while (!_has_terminated) { - Terminator_lock->wait(); - } -} - -void ConcurrentZFThread::print() const { - print_on(tty); -} - -void ConcurrentZFThread::print_on(outputStream* st) const { - st->print("\"G1 Concurrent Zero-Fill Thread\" "); - Thread::print_on(st); - st->cr(); -} - - -double ConcurrentZFThread::_vtime_accum; - -void ConcurrentZFThread::print_summary_info() { - gclog_or_tty->print("\nConcurrent Zero-Filling:\n"); - gclog_or_tty->print(" Filled %d regions, used %5.2fs.\n", - _regions_filled, - vtime_accum()); - gclog_or_tty->print(" Of %d region allocs, %d (%5.2f%%) required sync ZF,\n", - _region_allocs, _sync_zfs, - (_region_allocs > 0 ? - (float)_sync_zfs/(float)_region_allocs*100.0 : - 0.0)); - gclog_or_tty->print(" and %d (%5.2f%%) required a ZF wait.\n", - _zf_waits, - (_region_allocs > 0 ? - (float)_zf_waits/(float)_region_allocs*100.0 : - 0.0)); - -}