jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp@36c7518fd486 (annotated)

src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp@36c7518fd486 (annotated)

src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp

Mon, 02 Feb 2015 10:38:39 +0100

author: tschatzl
date: Mon, 02 Feb 2015 10:38:39 +0100
changeset 7654: 36c7518fd486
parent 7509: ae52ee069062
child 7781: 33e421924c67
permissions: -rw-r--r--

8069760: When iterating over a card, G1 often iterates over much more references than are contained in the card
Summary: Properly bound the iteration work for objArray-oops.
Reviewed-by: mgerdin, kbarrett

 /*
  * 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;
   // 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;
   // 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.
   // Returns true if the given area is zero filled upon completion.
   bool commit(uintptr_t start, size_t size_in_pages);
   // Uncommit the given area of pages starting at start being size_in_pages large.
   void uncommit(uintptr_t start, size_t size_in_pages);
   // 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

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src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp@36c7518fd486 (annotated)

src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.hpp