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

Thu, 21 Aug 2014 11:47:10 +0200

author
tschatzl
date
Thu, 21 Aug 2014 11:47:10 +0200
changeset 7051
1f1d373cd044
child 7052
8d5f66b42c53
permissions
-rw-r--r--

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

     1 /*
     2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #include "precompiled.hpp"
    26 #include "gc_implementation/g1/g1PageBasedVirtualSpace.hpp"
    27 #include "oops/markOop.hpp"
    28 #include "oops/oop.inline.hpp"
    29 #include "services/memTracker.hpp"
    30 #ifdef TARGET_OS_FAMILY_linux
    31 # include "os_linux.inline.hpp"
    32 #endif
    33 #ifdef TARGET_OS_FAMILY_solaris
    34 # include "os_solaris.inline.hpp"
    35 #endif
    36 #ifdef TARGET_OS_FAMILY_windows
    37 # include "os_windows.inline.hpp"
    38 #endif
    39 #ifdef TARGET_OS_FAMILY_aix
    40 # include "os_aix.inline.hpp"
    41 #endif
    42 #ifdef TARGET_OS_FAMILY_bsd
    43 # include "os_bsd.inline.hpp"
    44 #endif
    45 #include "utilities/bitMap.inline.hpp"
    47 G1PageBasedVirtualSpace::G1PageBasedVirtualSpace() : _low_boundary(NULL),
    48   _high_boundary(NULL), _committed(), _page_size(0), _special(false), _executable(false) {
    49 }
    51 bool G1PageBasedVirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t page_size) {
    52   if (!rs.is_reserved()) {
    53     return false;  // Allocation failed.
    54   }
    55   assert(_low_boundary == NULL, "VirtualSpace already initialized");
    56   assert(page_size > 0, "Granularity must be non-zero.");
    58   _low_boundary  = rs.base();
    59   _high_boundary = _low_boundary + rs.size();
    61   _special = rs.special();
    62   _executable = rs.executable();
    64   _page_size = page_size;
    66   assert(_committed.size() == 0, "virtual space initialized more than once");
    67   uintx size_in_bits = rs.size() / page_size;
    68   _committed.resize(size_in_bits, /* in_resource_area */ false);
    70   if (_special) {
    71     _committed.set_range(0, size_in_bits);
    72   }
    74   return true;
    75 }
    78 G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {
    79   release();
    80 }
    82 void G1PageBasedVirtualSpace::release() {
    83   // This does not release memory it never reserved.
    84   // Caller must release via rs.release();
    85   _low_boundary           = NULL;
    86   _high_boundary          = NULL;
    87   _special                = false;
    88   _executable             = false;
    89   _page_size              = 0;
    90   _committed.resize(0, false);
    91 }
    93 size_t G1PageBasedVirtualSpace::committed_size() const {
    94   return _committed.count_one_bits() * _page_size;
    95 }
    97 size_t G1PageBasedVirtualSpace::reserved_size() const {
    98   return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
    99 }
   101 size_t G1PageBasedVirtualSpace::uncommitted_size()  const {
   102   return reserved_size() - committed_size();
   103 }
   105 uintptr_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
   106   return (addr - _low_boundary) / _page_size;
   107 }
   109 bool G1PageBasedVirtualSpace::is_area_committed(uintptr_t start, size_t size_in_pages) const {
   110   uintptr_t end = start + size_in_pages;
   111   return _committed.get_next_zero_offset(start, end) >= end;
   112 }
   114 bool G1PageBasedVirtualSpace::is_area_uncommitted(uintptr_t start, size_t size_in_pages) const {
   115   uintptr_t end = start + size_in_pages;
   116   return _committed.get_next_one_offset(start, end) >= end;
   117 }
   119 char* G1PageBasedVirtualSpace::page_start(uintptr_t index) {
   120   return _low_boundary + index * _page_size;
   121 }
   123 size_t G1PageBasedVirtualSpace::byte_size_for_pages(size_t num) {
   124   return num * _page_size;
   125 }
   127 MemRegion G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) {
   128   // We need to make sure to commit all pages covered by the given area.
   129   guarantee(is_area_uncommitted(start, size_in_pages), "Specified area is not uncommitted");
   131   if (!_special) {
   132     os::commit_memory_or_exit(page_start(start), byte_size_for_pages(size_in_pages), _executable,
   133                               err_msg("Failed to commit pages from "SIZE_FORMAT" of length "SIZE_FORMAT, start, size_in_pages));
   134   }
   135   _committed.set_range(start, start + size_in_pages);
   137   MemRegion result((HeapWord*)page_start(start), byte_size_for_pages(size_in_pages) / HeapWordSize);
   138   return result;
   139 }
   141 MemRegion G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) {
   142   guarantee(is_area_committed(start, size_in_pages), "checking");
   144   if (!_special) {
   145     os::uncommit_memory(page_start(start), byte_size_for_pages(size_in_pages));
   146   }
   148   _committed.clear_range(start, start + size_in_pages);
   150   MemRegion result((HeapWord*)page_start(start), byte_size_for_pages(size_in_pages) / HeapWordSize);
   151   return result;
   152 }
   154 bool G1PageBasedVirtualSpace::contains(const void* p) const {
   155   return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
   156 }
   158 #ifndef PRODUCT
   159 void G1PageBasedVirtualSpace::print_on(outputStream* out) {
   160   out->print   ("Virtual space:");
   161   if (special()) out->print(" (pinned in memory)");
   162   out->cr();
   163   out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
   164   out->print_cr(" - reserved:  " SIZE_FORMAT, reserved_size());
   165   out->print_cr(" - [low_b, high_b]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]",  p2i(_low_boundary), p2i(_high_boundary));
   166 }
   168 void G1PageBasedVirtualSpace::print() {
   169   print_on(tty);
   170 }
   171 #endif

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