Mercurial > hg > truffle
diff src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp @ 20337:1f1d373cd044
8038423: G1: Decommit memory within heap
Summary: Allow G1 to decommit memory of arbitrary regions within the heap and their associated auxiliary data structures card table, BOT, hot card cache, and mark bitmaps.
Reviewed-by: mgerdin, brutisso, jwilhelm
author | tschatzl |
---|---|
date | Thu, 21 Aug 2014 11:47:10 +0200 |
parents | |
children | ae52ee069062 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp Thu Aug 21 11:47:10 2014 +0200 @@ -0,0 +1,111 @@ +/* + * 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_G1PAGEBASEDVIRTUALSPACE_HPP +#define SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP + +#include "memory/allocation.hpp" +#include "memory/memRegion.hpp" +#include "runtime/virtualspace.hpp" +#include "utilities/bitMap.hpp" + +// Virtual space management helper for a virtual space with an OS page allocation +// granularity. +// (De-)Allocation requests are always OS page aligned by passing a page index +// and multiples of pages. +// The implementation gives an error when trying to commit or uncommit pages that +// have already been committed or uncommitted. +class G1PageBasedVirtualSpace VALUE_OBJ_CLASS_SPEC { + friend class VMStructs; + private: + // Reserved area addresses. + char* _low_boundary; + char* _high_boundary; + + // The commit/uncommit granularity in bytes. + size_t _page_size; + + // Bitmap used for verification of commit/uncommit operations. + BitMap _committed; + + // Indicates that the entire space has been committed and pinned in memory, + // os::commit_memory() or os::uncommit_memory() have no function. + bool _special; + + // Indicates whether the committed space should be executable. + bool _executable; + + // Returns the index of the page which contains the given address. + uintptr_t addr_to_page_index(char* addr) const; + // Returns the address of the given page index. + char* page_start(uintptr_t index); + // Returns the byte size of the given number of pages. + size_t byte_size_for_pages(size_t num); + + // Returns true if the entire area is backed by committed memory. + bool is_area_committed(uintptr_t start, size_t size_in_pages) const; + // Returns true if the entire area is not backed by committed memory. + bool is_area_uncommitted(uintptr_t start, size_t size_in_pages) const; + + public: + + // Commit the given area of pages starting at start being size_in_pages large. + MemRegion commit(uintptr_t start, size_t size_in_pages); + + // Uncommit the given area of pages starting at start being size_in_pages large. + MemRegion uncommit(uintptr_t start, size_t size_in_pages); + + bool special() const { return _special; } + + // Initialization + G1PageBasedVirtualSpace(); + bool initialize_with_granularity(ReservedSpace rs, size_t page_size); + + // Destruction + ~G1PageBasedVirtualSpace(); + + // Amount of reserved memory. + size_t reserved_size() const; + // Memory used in this virtual space. + size_t committed_size() const; + // Memory left to use/expand in this virtual space. + size_t uncommitted_size() const; + + bool contains(const void* p) const; + + MemRegion reserved() { + MemRegion x((HeapWord*)_low_boundary, reserved_size() / HeapWordSize); + return x; + } + + void release(); + + void check_for_contiguity() PRODUCT_RETURN; + + // Debugging + void print_on(outputStream* out) PRODUCT_RETURN; + void print(); +}; + +#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1PAGEBASEDVIRTUALSPACE_HPP