| /* |
| * 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. |
| // For systems that only commits of memory in a given size (always greater than |
| // page size) the base address is required to be aligned to that page size. |
| // The actual size requested need not be aligned to that page size, but the size |
| // of the reservation passed may be rounded up to this page size. Any fragment |
| // (less than the page size) of the actual size at the tail of the request will |
| // be committed using OS small 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 size of the tail in bytes of the handled space that needs to be committed |
| // using small pages. |
| size_t _tail_size; |
| |
| // The preferred page size used for commit/uncommit in bytes. |
| size_t _page_size; |
| |
| // Bitmap used for verification of commit/uncommit operations. |
| BitMap _committed; |
| |
| // Bitmap used to keep track of which pages are dirty or not for _special |
| // spaces. This is needed because for those spaces the underlying memory |
| // will only be zero filled the first time it is committed. Calls to commit |
| // will use this bitmap and return whether or not the memory is zero filled. |
| BitMap _dirty; |
| |
| // 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; |
| |
| // Helper function for committing memory. Commit the given memory range by using |
| // _page_size pages as much as possible and the remainder with small sized pages. |
| void commit_internal(size_t start_page, size_t end_page); |
| // Commit num_pages pages of _page_size size starting from start. All argument |
| // checking has been performed. |
| void commit_preferred_pages(size_t start_page, size_t end_page); |
| // Commit space at the high end of the space that needs to be committed with small |
| // sized pages. |
| void commit_tail(); |
| |
| // Uncommit the given memory range. |
| void uncommit_internal(size_t start_page, size_t end_page); |
| |
| // Pretouch the given memory range. |
| void pretouch_internal(size_t start_page, size_t end_page); |
| |
| // 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(size_t index) const; |
| |
| // Is the given page index the last page? |
| bool is_last_page(size_t index) const { return index == (_committed.size() - 1); } |
| // Is the given page index the first after last page? |
| bool is_after_last_page(size_t index) const; |
| // Is the last page only partially covered by this space? |
| bool is_last_page_partial() const { return !is_ptr_aligned(_high_boundary, _page_size); } |
| // Returns the end address of the given page bounded by the reserved space. |
| char* bounded_end_addr(size_t end_page) const; |
| |
| // Returns true if the entire area is backed by committed memory. |
| bool is_area_committed(size_t start_page, size_t size_in_pages) const; |
| // Returns true if the entire area is not backed by committed memory. |
| bool is_area_uncommitted(size_t start_page, size_t size_in_pages) const; |
| |
| void initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size); |
| public: |
| |
| // Commit the given area of pages starting at start being size_in_pages large. |
| // Returns true if the given area is zero filled upon completion. |
| bool commit(size_t start_page, size_t size_in_pages); |
| |
| // Uncommit the given area of pages starting at start being size_in_pages large. |
| void uncommit(size_t start_page, size_t size_in_pages); |
| |
| // Initialize the given reserved space with the given base address and the size |
| // actually used. |
| // Prefer to commit in page_size chunks. |
| G1PageBasedVirtualSpace(ReservedSpace rs, size_t used_size, 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 |