--- 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));
-
-}