Mercurial > hg > graal-compiler
view src/share/vm/gc_implementation/g1/g1MarkSweep.hpp @ 1973:631f79e71e90
6974966: G1: unnecessary direct-to-old allocations
Summary: This change revamps the slow allocation path of G1. Improvements include the following: a) Allocations directly to old regions are now totally banned. G1 now only allows allocations out of young regions (with the only exception being humongous regions). b) The thread that allocates a new region (which is now guaranteed to be young) does not dirty all its cards. Each thread that successfully allocates out of a young region is now responsible for dirtying the cards that corresponding to the "block" that just got allocated. c) allocate_new_tlab() and mem_allocate() are now implemented differently and TLAB allocations are only done by allocate_new_tlab(). d) If a thread schedules an evacuation pause in order to satisfy an allocation request, it will perform the allocation at the end of the safepoint so that the thread that initiated the GC also gets "first pick" of any space made available by the GC. e) If a thread is unable to allocate a humongous object it will schedule an evacuation pause in case it reclaims enough regions so that the humongous allocation can be satisfied aftewards. f) The G1 policy is more careful to set the young list target length to be the survivor number +1. g) Lots of code tidy up, removal, refactoring to make future changes easier.
Reviewed-by: johnc, ysr
| author | tonyp |
|---|---|
| date | Tue, 24 Aug 2010 17:24:33 -0400 |
| parents | f95d63e2154a |
| children | f2110083203d |
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/* * 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. * */ #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1MARKSWEEP_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_G1MARKSWEEP_HPP #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" #include "gc_implementation/g1/heapRegion.hpp" #include "memory/genMarkSweep.hpp" #include "memory/generation.hpp" #include "memory/universe.hpp" #include "oops/markOop.hpp" #include "oops/oop.hpp" #include "runtime/timer.hpp" #include "utilities/growableArray.hpp" class ReferenceProcessor; // G1MarkSweep takes care of global mark-compact garbage collection for a // G1CollectedHeap using a four-phase pointer forwarding algorithm. All // generations are assumed to support marking; those that can also support // compaction. // // Class unloading will only occur when a full gc is invoked. class G1MarkSweep : AllStatic { friend class VM_G1MarkSweep; friend class Scavenge; public: static void invoke_at_safepoint(ReferenceProcessor* rp, bool clear_all_softrefs); private: // Mark live objects static void mark_sweep_phase1(bool& marked_for_deopt, bool clear_all_softrefs); // Calculate new addresses static void mark_sweep_phase2(); // Update pointers static void mark_sweep_phase3(); // Move objects to new positions static void mark_sweep_phase4(); static void allocate_stacks(); }; #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1MARKSWEEP_HPP