1 /*
   2  * Copyright (c) 2014, 2015, 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  */
  24 
  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"
  46 
  47 G1PageBasedVirtualSpace::G1PageBasedVirtualSpace(ReservedSpace rs, size_t used_size, size_t page_size) :
  48   _low_boundary(NULL), _high_boundary(NULL), _committed(), _page_size(0), _special(false),
  49   _dirty(), _executable(false) {
  50   initialize_with_page_size(rs, used_size, page_size);
  51 }
  52 
  53 void G1PageBasedVirtualSpace::initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size) {
  54   guarantee(rs.is_reserved(), "Given reserved space must have been reserved already.");
  55 
  56   vmassert(_low_boundary == NULL, "VirtualSpace already initialized");
  57   vmassert(page_size > 0, "Page size must be non-zero.");
  58 
  59   guarantee(is_ptr_aligned(rs.base(), page_size),
  60             err_msg("Reserved space base " PTR_FORMAT " is not aligned to requested page size " SIZE_FORMAT, p2i(rs.base()), page_size));
  61   guarantee(is_size_aligned(used_size, os::vm_page_size()),
  62             err_msg("Given used reserved space size needs to be OS page size aligned (%d bytes) but is " SIZE_FORMAT, os::vm_page_size(), used_size));
  63   guarantee(used_size <= rs.size(),
  64             err_msg("Used size of reserved space " SIZE_FORMAT " bytes is smaller than reservation at " SIZE_FORMAT " bytes", used_size, rs.size()));
  65   guarantee(is_size_aligned(rs.size(), page_size),
  66             err_msg("Expected that the virtual space is size aligned, but " SIZE_FORMAT " is not aligned to page size " SIZE_FORMAT, rs.size(), page_size));
  67 
  68   _low_boundary  = rs.base();
  69   _high_boundary = _low_boundary + used_size;
  70 
  71   _special = rs.special();
  72   _executable = rs.executable();
  73 
  74   _page_size = page_size;
  75 
  76   vmassert(_committed.size() == 0, "virtual space initialized more than once");
  77   BitMap::idx_t size_in_pages = rs.size() / page_size;
  78   _committed.resize(size_in_pages, /* in_resource_area */ false);
  79   if (_special) {
  80     _dirty.resize(size_in_pages, /* in_resource_area */ false);
  81   }
  82 
  83   _tail_size = used_size % _page_size;
  84 }
  85 
  86 G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {
  87   release();
  88 }
  89 
  90 void G1PageBasedVirtualSpace::release() {
  91   // This does not release memory it never reserved.
  92   // Caller must release via rs.release();
  93   _low_boundary           = NULL;
  94   _high_boundary          = NULL;
  95   _special                = false;
  96   _executable             = false;
  97   _page_size              = 0;
  98   _tail_size              = 0;
  99   _committed.resize(0, false);
 100   _dirty.resize(0, false);
 101 }
 102 
 103 size_t G1PageBasedVirtualSpace::committed_size() const {
 104   size_t result = _committed.count_one_bits() * _page_size;
 105   // The last page might not be in full.
 106   if (is_last_page_partial() && _committed.at(_committed.size() - 1)) {
 107     result -= _page_size - _tail_size;
 108   }
 109   return result;
 110 }
 111 
 112 size_t G1PageBasedVirtualSpace::reserved_size() const {
 113   return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
 114 }
 115 
 116 size_t G1PageBasedVirtualSpace::uncommitted_size()  const {
 117   return reserved_size() - committed_size();
 118 }
 119 
 120 uintptr_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
 121   return (addr - _low_boundary) / _page_size;
 122 }
 123 
 124 bool G1PageBasedVirtualSpace::is_area_committed(uintptr_t start, size_t size_in_pages) const {
 125   uintptr_t end = start + size_in_pages;
 126   return _committed.get_next_zero_offset(start, end) >= end;
 127 }
 128 
 129 bool G1PageBasedVirtualSpace::is_area_uncommitted(uintptr_t start, size_t size_in_pages) const {
 130   uintptr_t end = start + size_in_pages;
 131   return _committed.get_next_one_offset(start, end) >= end;
 132 }
 133 
 134 char* G1PageBasedVirtualSpace::page_start(uintptr_t index) {
 135   return _low_boundary + index * _page_size;
 136 }
 137 
 138 size_t G1PageBasedVirtualSpace::byte_size_for_pages(size_t num) {
 139   return num * _page_size;
 140 }
 141 
 142 bool G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) {
 143   // We need to make sure to commit all pages covered by the given area.
 144   guarantee(is_area_uncommitted(start, size_in_pages), "Specified area is not uncommitted");
 145 
 146   bool zero_filled = true;
 147   uintptr_t end = start + size_in_pages;
 148 
 149   if (_special) {
 150     // Check for dirty pages and update zero_filled if any found.
 151     if (_dirty.get_next_one_offset(start,end) < end) {
 152       zero_filled = false;
 153       _dirty.clear_range(start, end);
 154     }
 155   } else {
 156     os::commit_memory_or_exit(page_start(start), byte_size_for_pages(size_in_pages), _executable,
 157                               err_msg("Failed to commit pages from "SIZE_FORMAT" of length "SIZE_FORMAT, start, size_in_pages));
 158   }
 159   _committed.set_range(start, end);
 160 
 161   if (AlwaysPreTouch) {
 162     os::pretouch_memory(page_start(start), page_start(start) + byte_size_for_pages(size_in_pages));
 163   }
 164   return zero_filled;
 165 }
 166 
 167 void G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) {
 168   guarantee(is_area_committed(start, size_in_pages), "checking");
 169 
 170   if (_special) {
 171     // Mark that memory is dirty. If committed again the memory might
 172     // need to be cleared explicitly.
 173     _dirty.set_range(start, start + size_in_pages);
 174   } else {
 175     os::uncommit_memory(page_start(start), byte_size_for_pages(size_in_pages));
 176   }
 177 
 178   _committed.clear_range(start, start + size_in_pages);
 179 }
 180 
 181 bool G1PageBasedVirtualSpace::contains(const void* p) const {
 182   return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
 183 }
 184 
 185 #ifndef PRODUCT
 186 void G1PageBasedVirtualSpace::print_on(outputStream* out) {
 187   out->print   ("Virtual space:");
 188   if (_special) out->print(" (pinned in memory)");
 189   out->cr();
 190   out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
 191   out->print_cr(" - reserved:  " SIZE_FORMAT, reserved_size());
 192   out->print_cr(" - preferred page size: " SIZE_FORMAT, _page_size);
 193   out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]",  p2i(_low_boundary), p2i(_high_boundary));
 194 }
 195 
 196 void G1PageBasedVirtualSpace::print() {
 197   print_on(tty);
 198 }
 199 #endif