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view src/share/vm/gc_implementation/g1/g1InCSetState.hpp @ 23287:bd88fd590f4e
Restore G1 changes from e13c65f874e5 after merge
author | Gilles Duboscq <gilles.m.duboscq@oracle.com> |
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date | Fri, 08 Jan 2016 15:46:55 +0100 |
parents | c132be0fb74d |
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/* * Copyright (c) 2014, 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_G1INCSETSTATE_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_G1INCSETSTATE_HPP #include "gc_implementation/g1/g1BiasedArray.hpp" #include "memory/allocation.hpp" // Per-region state during garbage collection. struct InCSetState { public: // We use different types to represent the state value. Particularly SPARC puts // values in structs from "left to right", i.e. MSB to LSB. This results in many // unnecessary shift operations when loading and storing values of this type. // This degrades performance significantly (>10%) on that platform. // Other tested ABIs do not seem to have this problem, and actually tend to // favor smaller types, so we use the smallest usable type there. #ifdef SPARC #define CSETSTATE_FORMAT INTPTR_FORMAT typedef intptr_t in_cset_state_t; #else #define CSETSTATE_FORMAT "%d" typedef int8_t in_cset_state_t; #endif private: in_cset_state_t _value; public: enum { // Selection of the values were driven to micro-optimize the encoding and // frequency of the checks. // The most common check is whether the region is in the collection set or not. // This encoding allows us to use an != 0 check which in some architectures // (x86*) can be encoded slightly more efficently than a normal comparison // against zero. // The same situation occurs when checking whether the region is humongous // or not, which is encoded by values < 0. // The other values are simply encoded in increasing generation order, which // makes getting the next generation fast by a simple increment. Humongous = -1, // The region is humongous - note that actually any value < 0 would be possible here. NotInCSet = 0, // The region is not in the collection set. Young = 1, // The region is in the collection set and a young region. Old = 2, // The region is in the collection set and an old region. Num }; InCSetState(in_cset_state_t value = NotInCSet) : _value(value) { assert(is_valid(), err_msg("Invalid state %d", _value)); } in_cset_state_t value() const { return _value; } void set_old() { _value = Old; } bool is_in_cset_or_humongous() const { return _value != NotInCSet; } bool is_in_cset() const { return _value > NotInCSet; } bool is_humongous() const { return _value < NotInCSet; } bool is_young() const { return _value == Young; } bool is_old() const { return _value == Old; } #ifdef ASSERT bool is_default() const { return !is_in_cset_or_humongous(); } bool is_valid() const { return (_value >= Humongous) && (_value < Num); } bool is_valid_gen() const { return (_value >= Young && _value <= Old); } #endif }; // Instances of this class are used for quick tests on whether a reference points // into the collection set and into which generation or is a humongous object // // Each of the array's elements indicates whether the corresponding region is in // the collection set and if so in which generation, or a humongous region. // // We use this to speed up reference processing during young collection and // quickly reclaim humongous objects. For the latter, by making a humongous region // succeed this test, we sort-of add it to the collection set. During the reference // iteration closures, when we see a humongous region, we then simply mark it as // referenced, i.e. live. class G1InCSetStateFastTestBiasedMappedArray : public G1BiasedMappedArray<InCSetState> { protected: InCSetState default_value() const { return InCSetState::NotInCSet; } public: void set_humongous(uintptr_t index) { assert(get_by_index(index).is_default(), err_msg("State at index " INTPTR_FORMAT" should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value())); set_by_index(index, InCSetState::Humongous); } void clear_humongous(uintptr_t index) { set_by_index(index, InCSetState::NotInCSet); } void set_in_young(uintptr_t index) { assert(get_by_index(index).is_default(), err_msg("State at index " INTPTR_FORMAT" should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value())); set_by_index(index, InCSetState::Young); } void set_in_old(uintptr_t index) { assert(get_by_index(index).is_default(), err_msg("State at index " INTPTR_FORMAT" should be default but is " CSETSTATE_FORMAT, index, get_by_index(index).value())); set_by_index(index, InCSetState::Old); } bool is_in_cset_or_humongous(HeapWord* addr) const { return at(addr).is_in_cset_or_humongous(); } bool is_in_cset(HeapWord* addr) const { return at(addr).is_in_cset(); } InCSetState at(HeapWord* addr) const { return get_by_address(addr); } void clear() { G1BiasedMappedArray<InCSetState>::clear(); } }; #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1INCSETSTATE_HPP