jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp@e7d0505c8a30 (annotated)

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

Fri, 10 Oct 2014 15:51:58 +0200

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 7052: 8d5f66b42c53
child 7509: ae52ee069062
permissions: -rw-r--r--

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

 /*
  * 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.
  *
  */
 #include "precompiled.hpp"
 #include "gc_implementation/g1/g1PageBasedVirtualSpace.hpp"
 #include "oops/markOop.hpp"
 #include "oops/oop.inline.hpp"
 #include "services/memTracker.hpp"
 #ifdef TARGET_OS_FAMILY_linux
 # include "os_linux.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_solaris
 # include "os_solaris.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_windows
 # include "os_windows.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_aix
 # include "os_aix.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_bsd
 # include "os_bsd.inline.hpp"
 #endif
 #include "utilities/bitMap.inline.hpp"
 G1PageBasedVirtualSpace::G1PageBasedVirtualSpace() : _low_boundary(NULL),
   _high_boundary(NULL), _committed(), _page_size(0), _special(false), _executable(false) {
 }
 bool G1PageBasedVirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t page_size) {
   if (!rs.is_reserved()) {
     return false;  // Allocation failed.
   }
   assert(_low_boundary == NULL, "VirtualSpace already initialized");
   assert(page_size > 0, "Granularity must be non-zero.");
   _low_boundary  = rs.base();
   _high_boundary = _low_boundary + rs.size();
   _special = rs.special();
   _executable = rs.executable();
   _page_size = page_size;
   assert(_committed.size() == 0, "virtual space initialized more than once");
   uintx size_in_bits = rs.size() / page_size;
   _committed.resize(size_in_bits, /* in_resource_area */ false);
   return true;
 }
 G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {
   release();
 }
 void G1PageBasedVirtualSpace::release() {
   // This does not release memory it never reserved.
   // Caller must release via rs.release();
   _low_boundary           = NULL;
   _high_boundary          = NULL;
   _special                = false;
   _executable             = false;
   _page_size              = 0;
   _committed.resize(0, false);
 }
 size_t G1PageBasedVirtualSpace::committed_size() const {
   return _committed.count_one_bits() * _page_size;
 }
 size_t G1PageBasedVirtualSpace::reserved_size() const {
   return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
 }
 size_t G1PageBasedVirtualSpace::uncommitted_size()  const {
   return reserved_size() - committed_size();
 }
 uintptr_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
   return (addr - _low_boundary) / _page_size;
 }
 bool G1PageBasedVirtualSpace::is_area_committed(uintptr_t start, size_t size_in_pages) const {
   uintptr_t end = start + size_in_pages;
   return _committed.get_next_zero_offset(start, end) >= end;
 }
 bool G1PageBasedVirtualSpace::is_area_uncommitted(uintptr_t start, size_t size_in_pages) const {
   uintptr_t end = start + size_in_pages;
   return _committed.get_next_one_offset(start, end) >= end;
 }
 char* G1PageBasedVirtualSpace::page_start(uintptr_t index) {
   return _low_boundary + index * _page_size;
 }
 size_t G1PageBasedVirtualSpace::byte_size_for_pages(size_t num) {
   return num * _page_size;
 }
 MemRegion G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) {
   // We need to make sure to commit all pages covered by the given area.
   guarantee(is_area_uncommitted(start, size_in_pages), "Specified area is not uncommitted");
   if (!_special) {
     os::commit_memory_or_exit(page_start(start), byte_size_for_pages(size_in_pages), _executable,
                               err_msg("Failed to commit pages from "SIZE_FORMAT" of length "SIZE_FORMAT, start, size_in_pages));
   }
   _committed.set_range(start, start + size_in_pages);
   MemRegion result((HeapWord*)page_start(start), byte_size_for_pages(size_in_pages) / HeapWordSize);
   return result;
 }
 MemRegion G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) {
   guarantee(is_area_committed(start, size_in_pages), "checking");
   if (!_special) {
     os::uncommit_memory(page_start(start), byte_size_for_pages(size_in_pages));
   }
   _committed.clear_range(start, start + size_in_pages);
   MemRegion result((HeapWord*)page_start(start), byte_size_for_pages(size_in_pages) / HeapWordSize);
   return result;
 }
 bool G1PageBasedVirtualSpace::contains(const void* p) const {
   return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
 }
 #ifndef PRODUCT
 void G1PageBasedVirtualSpace::print_on(outputStream* out) {
   out->print   ("Virtual space:");
   if (special()) out->print(" (pinned in memory)");
   out->cr();
   out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
   out->print_cr(" - reserved:  " SIZE_FORMAT, reserved_size());
   out->print_cr(" - [low_b, high_b]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]",  p2i(_low_boundary), p2i(_high_boundary));
 }
 void G1PageBasedVirtualSpace::print() {
   print_on(tty);
 }
 #endif

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp@e7d0505c8a30 (annotated)

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