jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegionSet.inline.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/heapRegionSet.inline.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/heapRegionSet.inline.hpp

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

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 7091: a8ea2f110d87
child 7535: 7ae4e26cb1e0
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) 2011, 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.
  *
  */
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_INLINE_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_INLINE_HPP
 #include "gc_implementation/g1/heapRegionSet.hpp"
 inline void HeapRegionSetBase::add(HeapRegion* hr) {
   check_mt_safety();
   assert(hr->containing_set() == NULL, hrs_ext_msg(this, "should not already have a containing set %u"));
   assert(hr->next() == NULL, hrs_ext_msg(this, "should not already be linked"));
   assert(hr->prev() == NULL, hrs_ext_msg(this, "should not already be linked"));
   _count.increment(1u, hr->capacity());
   hr->set_containing_set(this);
   verify_region(hr);
 }
 inline void HeapRegionSetBase::remove(HeapRegion* hr) {
   check_mt_safety();
   verify_region(hr);
   assert(hr->next() == NULL, hrs_ext_msg(this, "should already be unlinked"));
   assert(hr->prev() == NULL, hrs_ext_msg(this, "should already be unlinked"));
   hr->set_containing_set(NULL);
   assert(_count.length() > 0, hrs_ext_msg(this, "pre-condition"));
   _count.decrement(1u, hr->capacity());
 }
 inline void FreeRegionList::add_ordered(HeapRegion* hr) {
   assert((length() == 0 && _head == NULL && _tail == NULL && _last == NULL) ||
          (length() >  0 && _head != NULL && _tail != NULL),
          hrs_ext_msg(this, "invariant"));
   // add() will verify the region and check mt safety.
   add(hr);
   // Now link the region
   if (_head != NULL) {
     HeapRegion* curr;
     if (_last != NULL && _last->hrm_index() < hr->hrm_index()) {
       curr = _last;
     } else {
       curr = _head;
     }
     // Find first entry with a Region Index larger than entry to insert.
     while (curr != NULL && curr->hrm_index() < hr->hrm_index()) {
       curr = curr->next();
     }
     hr->set_next(curr);
     if (curr == NULL) {
       // Adding at the end
       hr->set_prev(_tail);
       _tail->set_next(hr);
       _tail = hr;
     } else if (curr->prev() == NULL) {
       // Adding at the beginning
       hr->set_prev(NULL);
       _head = hr;
       curr->set_prev(hr);
     } else {
       hr->set_prev(curr->prev());
       hr->prev()->set_next(hr);
       curr->set_prev(hr);
     }
   } else {
     // The list was empty
     _tail = hr;
     _head = hr;
   }
   _last = hr;
 }
 inline HeapRegion* FreeRegionList::remove_from_head_impl() {
   HeapRegion* result = _head;
   _head = result->next();
   if (_head == NULL) {
     _tail = NULL;
   } else {
     _head->set_prev(NULL);
   }
   result->set_next(NULL);
   return result;
 }
 inline HeapRegion* FreeRegionList::remove_from_tail_impl() {
   HeapRegion* result = _tail;
   _tail = result->prev();
   if (_tail == NULL) {
     _head = NULL;
   } else {
     _tail->set_next(NULL);
   }
   result->set_prev(NULL);
   return result;
 }
 inline HeapRegion* FreeRegionList::remove_region(bool from_head) {
   check_mt_safety();
   verify_optional();
   if (is_empty()) {
     return NULL;
   }
   assert(length() > 0 && _head != NULL && _tail != NULL,
          hrs_ext_msg(this, "invariant"));
   HeapRegion* hr;
   if (from_head) {
     hr = remove_from_head_impl();
   } else {
     hr = remove_from_tail_impl();
   }
   if (_last == hr) {
     _last = NULL;
   }
   // remove() will verify the region and check mt safety.
   remove(hr);
   return hr;
 }
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_INLINE_HPP

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src/share/vm/gc_implementation/g1/heapRegionSet.inline.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/heapRegionSet.inline.hpp