jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp

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

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 7053: 7b2fc3129653
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) 2001, 2013, 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/g1BiasedArray.hpp"
 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp"
 #include "memory/allocation.inline.hpp"
 #include "runtime/virtualspace.hpp"
 #include "services/memTracker.hpp"
 #include "utilities/bitMap.inline.hpp"
 G1RegionToSpaceMapper::G1RegionToSpaceMapper(ReservedSpace rs,
                                              size_t commit_granularity,
                                              size_t region_granularity,
                                              MemoryType type) :
   _storage(),
   _commit_granularity(commit_granularity),
   _region_granularity(region_granularity),
   _listener(NULL),
   _commit_map() {
   guarantee(is_power_of_2(commit_granularity), "must be");
   guarantee(is_power_of_2(region_granularity), "must be");
   _storage.initialize_with_granularity(rs, commit_granularity);
   MemTracker::record_virtual_memory_type((address)rs.base(), type);
 }
 // G1RegionToSpaceMapper implementation where the region granularity is larger than
 // or the same as the commit granularity.
 // Basically, the space corresponding to one region region spans several OS pages.
 class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper {
  private:
   size_t _pages_per_region;
  public:
   G1RegionsLargerThanCommitSizeMapper(ReservedSpace rs,
                                       size_t os_commit_granularity,
                                       size_t alloc_granularity,
                                       size_t commit_factor,
                                       MemoryType type) :
      G1RegionToSpaceMapper(rs, os_commit_granularity, alloc_granularity, type),
     _pages_per_region(alloc_granularity / (os_commit_granularity * commit_factor)) {
     guarantee(alloc_granularity >= os_commit_granularity, "allocation granularity smaller than commit granularity");
     _commit_map.resize(rs.size() * commit_factor / alloc_granularity, /* in_resource_area */ false);
   }
   virtual void commit_regions(uintptr_t start_idx, size_t num_regions) {
     _storage.commit(start_idx * _pages_per_region, num_regions * _pages_per_region);
     _commit_map.set_range(start_idx, start_idx + num_regions);
     fire_on_commit(start_idx, num_regions, true);
   }
   virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions) {
     _storage.uncommit(start_idx * _pages_per_region, num_regions * _pages_per_region);
     _commit_map.clear_range(start_idx, start_idx + num_regions);
   }
 };
 // G1RegionToSpaceMapper implementation where the region granularity is smaller
 // than the commit granularity.
 // Basically, the contents of one OS page span several regions.
 class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
  private:
   class CommitRefcountArray : public G1BiasedMappedArray<uint> {
    protected:
      virtual uint default_value() const { return 0; }
   };
   size_t _regions_per_page;
   CommitRefcountArray _refcounts;
   uintptr_t region_idx_to_page_idx(uint region) const {
     return region / _regions_per_page;
   }
  public:
   G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs,
                                        size_t os_commit_granularity,
                                        size_t alloc_granularity,
                                        size_t commit_factor,
                                        MemoryType type) :
      G1RegionToSpaceMapper(rs, os_commit_granularity, alloc_granularity, type),
     _regions_per_page((os_commit_granularity * commit_factor) / alloc_granularity), _refcounts() {
     guarantee((os_commit_granularity * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");
     _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + rs.size()), os_commit_granularity);
     _commit_map.resize(rs.size() * commit_factor / alloc_granularity, /* in_resource_area */ false);
   }
   virtual void commit_regions(uintptr_t start_idx, size_t num_regions) {
     for (uintptr_t i = start_idx; i < start_idx + num_regions; i++) {
       assert(!_commit_map.at(i), err_msg("Trying to commit storage at region "INTPTR_FORMAT" that is already committed", i));
       uintptr_t idx = region_idx_to_page_idx(i);
       uint old_refcount = _refcounts.get_by_index(idx);
       bool zero_filled = false;
       if (old_refcount == 0) {
         _storage.commit(idx, 1);
         zero_filled = true;
       }
       _refcounts.set_by_index(idx, old_refcount + 1);
       _commit_map.set_bit(i);
       fire_on_commit(i, 1, zero_filled);
     }
   }
   virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions) {
     for (uintptr_t i = start_idx; i < start_idx + num_regions; i++) {
       assert(_commit_map.at(i), err_msg("Trying to uncommit storage at region "INTPTR_FORMAT" that is not committed", i));
       uintptr_t idx = region_idx_to_page_idx(i);
       uint old_refcount = _refcounts.get_by_index(idx);
       assert(old_refcount > 0, "must be");
       if (old_refcount == 1) {
         _storage.uncommit(idx, 1);
       }
       _refcounts.set_by_index(idx, old_refcount - 1);
       _commit_map.clear_bit(i);
     }
   }
 };
 void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
   if (_listener != NULL) {
     _listener->on_commit(start_idx, num_regions, zero_filled);
   }
 }
 G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs,
                                                             size_t os_commit_granularity,
                                                             size_t region_granularity,
                                                             size_t commit_factor,
                                                             MemoryType type) {
   if (region_granularity >= (os_commit_granularity * commit_factor)) {
     return new G1RegionsLargerThanCommitSizeMapper(rs, os_commit_granularity, region_granularity, commit_factor, type);
   } else {
     return new G1RegionsSmallerThanCommitSizeMapper(rs, os_commit_granularity, region_granularity, commit_factor, type);
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp