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/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             "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             "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             "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             "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.initialize(size_in_pages);
  79   if (_special) {
  80     _dirty.initialize(size_in_pages);
  81   }
  82 
  83   _tail_size = used_size % _page_size;
  84 }
  85 
  86 G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {
  87   // This does not release memory it never reserved.
  88   // Caller must release via rs.release();
  89   _low_boundary           = NULL;
  90   _high_boundary          = NULL;
  91   _special                = false;
  92   _executable             = false;
  93   _page_size              = 0;
  94   _tail_size              = 0;
  95 }
  96 
  97 size_t G1PageBasedVirtualSpace::committed_size() const {
  98   size_t result = _committed.count_one_bits() * _page_size;
  99   // The last page might not be in full.
 100   if (is_last_page_partial() && _committed.at(_committed.size() - 1)) {
 101     result -= _page_size - _tail_size;
 102   }
 103   return result;
 104 }
 105 
 106 size_t G1PageBasedVirtualSpace::reserved_size() const {
 107   return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
 108 }
 109 
 110 size_t G1PageBasedVirtualSpace::uncommitted_size()  const {
 111   return reserved_size() - committed_size();
 112 }
 113 
 114 size_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
 115   return (addr - _low_boundary) / _page_size;
 116 }
 117 
 118 bool G1PageBasedVirtualSpace::is_area_committed(size_t start_page, size_t size_in_pages) const {
 119   size_t end_page = start_page + size_in_pages;
 120   return _committed.get_next_zero_offset(start_page, end_page) >= end_page;
 121 }
 122 
 123 bool G1PageBasedVirtualSpace::is_area_uncommitted(size_t start_page, size_t size_in_pages) const {
 124   size_t end_page = start_page + size_in_pages;
 125   return _committed.get_next_one_offset(start_page, end_page) >= end_page;
 126 }
 127 
 128 char* G1PageBasedVirtualSpace::page_start(size_t index) const {
 129   return _low_boundary + index * _page_size;
 130 }
 131 
 132 bool G1PageBasedVirtualSpace::is_after_last_page(size_t index) const {
 133   guarantee(index <= _committed.size(),
 134             "Given boundary page " SIZE_FORMAT " is beyond managed page count " SIZE_FORMAT, index, _committed.size());
 135   return index == _committed.size();
 136 }
 137 
 138 void G1PageBasedVirtualSpace::commit_preferred_pages(size_t start, size_t num_pages) {
 139   vmassert(num_pages > 0, "No full pages to commit");
 140   vmassert(start + num_pages <= _committed.size(),
 141            "Tried to commit area from page " SIZE_FORMAT " to page " SIZE_FORMAT " "
 142            "that is outside of managed space of " SIZE_FORMAT " pages",
 143            start, start + num_pages, _committed.size());
 144 
 145   char* start_addr = page_start(start);
 146   size_t size = num_pages * _page_size;
 147 
 148   os::commit_memory_or_exit(start_addr, size, _page_size, _executable,
 149                             err_msg("Failed to commit area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
 150                             p2i(start_addr), p2i(start_addr + size), size));
 151 }
 152 
 153 void G1PageBasedVirtualSpace::commit_tail() {
 154   vmassert(_tail_size > 0, "The size of the tail area must be > 0 when reaching here");
 155 
 156   char* const aligned_end_address = (char*)align_ptr_down(_high_boundary, _page_size);
 157   os::commit_memory_or_exit(aligned_end_address, _tail_size, os::vm_page_size(), _executable,
 158                             err_msg("Failed to commit tail area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
 159                             p2i(aligned_end_address), p2i(_high_boundary), _tail_size));
 160 }
 161 
 162 void G1PageBasedVirtualSpace::commit_internal(size_t start_page, size_t end_page) {
 163   guarantee(start_page < end_page,
 164             "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
 165   guarantee(end_page <= _committed.size(),
 166             "Given end page " SIZE_FORMAT " is beyond end of managed page amount of " SIZE_FORMAT, end_page, _committed.size());
 167 
 168   size_t pages = end_page - start_page;
 169   bool need_to_commit_tail = is_after_last_page(end_page) && is_last_page_partial();
 170 
 171   // If we have to commit some (partial) tail area, decrease the amount of pages to avoid
 172   // committing that in the full-page commit code.
 173   if (need_to_commit_tail) {
 174     pages--;
 175   }
 176 
 177   if (pages > 0) {
 178     commit_preferred_pages(start_page, pages);
 179   }
 180 
 181   if (need_to_commit_tail) {
 182     commit_tail();
 183   }
 184 }
 185 
 186 char* G1PageBasedVirtualSpace::bounded_end_addr(size_t end_page) const {
 187   return MIN2(_high_boundary, page_start(end_page));
 188 }
 189 
 190 void G1PageBasedVirtualSpace::pretouch_internal(size_t start_page, size_t end_page) {
 191   guarantee(start_page < end_page,
 192             "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
 193 
 194   os::pretouch_memory(page_start(start_page), bounded_end_addr(end_page));
 195 }
 196 
 197 bool G1PageBasedVirtualSpace::commit(size_t start_page, size_t size_in_pages) {
 198   // We need to make sure to commit all pages covered by the given area.
 199   guarantee(is_area_uncommitted(start_page, size_in_pages), "Specified area is not uncommitted");
 200 
 201   bool zero_filled = true;
 202   size_t end_page = start_page + size_in_pages;
 203 
 204   if (_special) {
 205     // Check for dirty pages and update zero_filled if any found.
 206     if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {
 207       zero_filled = false;
 208       _dirty.clear_range(start_page, end_page);
 209     }
 210   } else {
 211     commit_internal(start_page, end_page);
 212   }
 213   _committed.set_range(start_page, end_page);
 214 
 215   if (AlwaysPreTouch) {
 216     pretouch_internal(start_page, end_page);
 217   }
 218   return zero_filled;
 219 }
 220 
 221 void G1PageBasedVirtualSpace::uncommit_internal(size_t start_page, size_t end_page) {
 222   guarantee(start_page < end_page,
 223             "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
 224 
 225   char* start_addr = page_start(start_page);
 226   os::uncommit_memory(start_addr, pointer_delta(bounded_end_addr(end_page), start_addr, sizeof(char)));
 227 }
 228 
 229 void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages) {
 230   guarantee(is_area_committed(start_page, size_in_pages), "checking");
 231 
 232   size_t end_page = start_page + size_in_pages;
 233   if (_special) {
 234     // Mark that memory is dirty. If committed again the memory might
 235     // need to be cleared explicitly.
 236     _dirty.set_range(start_page, end_page);
 237   } else {
 238     uncommit_internal(start_page, end_page);
 239   }
 240 
 241   _committed.clear_range(start_page, end_page);
 242 }
 243 
 244 bool G1PageBasedVirtualSpace::contains(const void* p) const {
 245   return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
 246 }
 247 
 248 #ifndef PRODUCT
 249 void G1PageBasedVirtualSpace::print_on(outputStream* out) {
 250   out->print   ("Virtual space:");
 251   if (_special) out->print(" (pinned in memory)");
 252   out->cr();
 253   out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
 254   out->print_cr(" - reserved:  " SIZE_FORMAT, reserved_size());
 255   out->print_cr(" - preferred page size: " SIZE_FORMAT, _page_size);
 256   out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]",  p2i(_low_boundary), p2i(_high_boundary));
 257 }
 258 
 259 void G1PageBasedVirtualSpace::print() {
 260   print_on(tty);
 261 }
 262 #endif