Mercurial > hg > graal-jvmci-8
view src/share/vm/gc_implementation/g1/concurrentZFThread.hpp @ 1886:72a161e62cc4
6991377: G1: race between concurrent refinement and humongous object allocation
Summary: There is a race between the concurrent refinement threads and the humongous object allocation that can cause the concurrent refinement threads to corrupt the part of the BOT that it is being initialized by the humongous object allocation operation. The solution is to do the humongous object allocation in careful steps to ensure that the concurrent refinement threads always have a consistent view over the BOT, region contents, and top. The fix includes some very minor tidying up in sparsePRT.
Reviewed-by: jcoomes, johnc, ysr
author | tonyp |
---|---|
date | Sat, 16 Oct 2010 17:12:19 -0400 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
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/* * Copyright (c) 2001, 2009, 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. * */ // The Concurrent ZF Thread. Performs concurrent zero-filling. class ConcurrentZFThread: public ConcurrentGCThread { friend class VMStructs; friend class ZeroFillRegionClosure; private: // Zero fill the heap region. void processHeapRegion(HeapRegion* r); // Stats // Allocation (protected by heap lock). static int _region_allocs; // Number of regions allocated static int _sync_zfs; // Synchronous zero-fills + static int _zf_waits; // Wait for conc zero-fill completion. // Number of regions CFZ thread fills. static int _regions_filled; double _vtime_start; // Initial virtual time. // These are static because the "print_summary_info" method is, and // it currently assumes there is only one ZF thread. We'll change when // we need to. static double _vtime_accum; // Initial virtual time. static double vtime_accum() { return _vtime_accum; } // Offer yield for GC. Returns true if yield occurred. bool offer_yield(); public: // Constructor ConcurrentZFThread(); // Main loop. virtual void run(); // Printing void print_on(outputStream* st) const; void print() const; // Waits until "r" has been zero-filled. Requires caller to hold the // ZF_mon. static void wait_for_ZF_completed(HeapRegion* r); // Get or clear the current unclean region. Should be done // while holding the ZF_needed_mon lock. // shutdown void stop(); // Stats static void note_region_alloc() {_region_allocs++; } static void note_sync_zfs() { _sync_zfs++; } static void note_zf_wait() { _zf_waits++; } static void note_region_filled() { _regions_filled++; } static void print_summary_info(); };