Mercurial > hg > graal-compiler
view src/share/vm/gc_implementation/g1/concurrentZFThread.cpp @ 1591:f16f1d7893de
6941378: G1: change default value of G1UseFixedWindowMMUTracker to true
Summary: Rather than changing the default value of the G1UseFixedWindowMMUTracker, the flag and associated guarantee have been removed.
Reviewed-by: jcoomes, tonyp, ysr
author | johnc |
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date | Mon, 24 May 2010 17:11:22 -0700 |
parents | f99f695bb8ef |
children | c18cbe5936b8 |
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/* * Copyright 2001-2009 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/_concurrentZFThread.cpp.incl" // ======= 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)); }