Mercurial > hg > graal-jvmci-8
diff src/share/vm/gc_implementation/g1/heapRegionType.hpp @ 20481:c02ec279b062
8057768: Make heap region region type in G1 HeapRegion explicit
Reviewed-by: brutisso, tschatzl
author | brutisso |
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date | Tue, 16 Sep 2014 14:27:40 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/g1/heapRegionType.hpp Tue Sep 16 14:27:40 2014 +0200 @@ -0,0 +1,134 @@ +/* + * 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_HEAPREGIONTYPE_HPP +#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONTYPE_HPP + +#include "memory/allocation.hpp" + +#define hrt_assert_is_valid(tag) \ + assert(is_valid((tag)), err_msg("invalid HR type: %u", (uint) (tag))) + +class HeapRegionType VALUE_OBJ_CLASS_SPEC { +private: + // We encode the value of the heap region type so the generation can be + // determined quickly. The tag is split into two parts: + // + // major type (young, humongous) : top N-1 bits + // minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit + // + // If there's need to increase the number of minor types in the + // future, we'll have to increase the size of the latter and hence + // decrease the size of the former. + // + // 0000 0 [ 0] Free + // + // 0001 0 Young Mask + // 0001 0 [ 2] Eden + // 0001 1 [ 3] Survivor + // + // 0010 0 Humongous Mask + // 0010 0 [ 4] Humongous Starts + // 0010 1 [ 5] Humongous Continues + // + // 01000 [ 8] Old + typedef enum { + FreeTag = 0, + + YoungMask = 2, + EdenTag = YoungMask, + SurvTag = YoungMask + 1, + + HumMask = 4, + HumStartsTag = HumMask, + HumContTag = HumMask + 1, + + OldTag = 8 + } Tag; + + volatile Tag _tag; + + static bool is_valid(Tag tag); + + Tag get() const { + hrt_assert_is_valid(_tag); + return _tag; + } + + // Sets the type to 'tag'. + void set(Tag tag) { + hrt_assert_is_valid(tag); + hrt_assert_is_valid(_tag); + _tag = tag; + } + + // Sets the type to 'tag', expecting the type to be 'before'. This + // is available for when we want to add sanity checking to the type + // transition. + void set_from(Tag tag, Tag before) { + hrt_assert_is_valid(tag); + hrt_assert_is_valid(before); + hrt_assert_is_valid(_tag); + assert(_tag == before, + err_msg("HR tag: %u, expected: %u new tag; %u", _tag, before, tag)); + _tag = tag; + } + +public: + // Queries + + bool is_free() const { return get() == FreeTag; } + + bool is_young() const { return (get() & YoungMask) != 0; } + bool is_eden() const { return get() == EdenTag; } + bool is_survivor() const { return get() == SurvTag; } + + bool is_humongous() const { return (get() & HumMask) != 0; } + bool is_starts_humongous() const { return get() == HumStartsTag; } + bool is_continues_humongous() const { return get() == HumContTag; } + + bool is_old() const { return get() == OldTag; } + + // Setters + + void set_free() { set(FreeTag); } + + void set_eden() { set_from(EdenTag, FreeTag); } + void set_eden_pre_gc() { set_from(EdenTag, SurvTag); } + void set_survivor() { set_from(SurvTag, FreeTag); } + + void set_starts_humongous() { set_from(HumStartsTag, FreeTag); } + void set_continues_humongous() { set_from(HumContTag, FreeTag); } + + void set_old() { set(OldTag); } + + // Misc + + const char* get_str() const; + const char* get_short_str() const; + + HeapRegionType() : _tag(FreeTag) { hrt_assert_is_valid(_tag); } +}; + +#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONTYPE_HPP