jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/spaceDecorator.cpp@0bfd3fb24150 (annotated)

src/share/vm/gc_implementation/shared/spaceDecorator.cpp@0bfd3fb24150 (annotated)

src/share/vm/gc_implementation/shared/spaceDecorator.cpp

Tue, 13 Apr 2010 13:52:10 -0700

author: jmasa
date: Tue, 13 Apr 2010 13:52:10 -0700
changeset 1822: 0bfd3fb24150
parent 772: 9ee9cf798b59
child 1907: c18cbe5936b8
permissions: -rw-r--r--

6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
Summary: Ensure a full GC that clears SoftReferences before throwing an out-of-memory
Reviewed-by: ysr, jcoomes

 /*
  * Copyright 2002-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 # include "incls/_precompiled.incl"
 # include "incls/_spaceDecorator.cpp.incl"
 // Catch-all file for utility classes
 #ifndef PRODUCT
 // Returns true is the location q matches the mangling
 // pattern.
 bool SpaceMangler::is_mangled(HeapWord* q) {
   // This test loses precision but is good enough
   return badHeapWord == (max_juint & (uintptr_t) q->value());
 }
 void SpaceMangler::set_top_for_allocations(HeapWord* v)  {
   if (v < end()) {
     assert(!CheckZapUnusedHeapArea || is_mangled(v),
       "The high water mark is not mangled");
   }
   _top_for_allocations = v;
 }
 // Mangle only the unused space that has not previously
 // been mangled and that has not been allocated since being
 // mangled.
 void SpaceMangler::mangle_unused_area() {
   assert(ZapUnusedHeapArea, "Mangling should not be in use");
   // Mangle between top and the high water mark.  Safeguard
   // against the space changing since top_for_allocations was
   // set.
   HeapWord* mangled_end = MIN2(top_for_allocations(), end());
   if (top() < mangled_end) {
     MemRegion mangle_mr(top(), mangled_end);
     SpaceMangler::mangle_region(mangle_mr);
     // Light weight check of mangling.
     check_mangled_unused_area(end());
   }
   // Complete check of unused area which is functional when
   // DEBUG_MANGLING is defined.
   check_mangled_unused_area_complete();
 }
 // A complete mangle is expected in the
 // exceptional case where top_for_allocations is not
 // properly tracking the high water mark for mangling.
 // This can be the case when to-space is being used for
 // scratch space during a mark-sweep-compact.  See
 // contribute_scratch() and PSMarkSweep::allocate_stacks().
 void SpaceMangler::mangle_unused_area_complete() {
   assert(ZapUnusedHeapArea, "Mangling should not be in use");
   MemRegion mangle_mr(top(), end());
   SpaceMangler::mangle_region(mangle_mr);
 }
 // Simply mangle the MemRegion mr.
 void SpaceMangler::mangle_region(MemRegion mr) {
   assert(ZapUnusedHeapArea, "Mangling should not be in use");
 #ifdef ASSERT
   if(TraceZapUnusedHeapArea) {
     gclog_or_tty->print("Mangling [0x%x to 0x%x)", mr.start(), mr.end());
   }
   Copy::fill_to_words(mr.start(), mr.word_size(), badHeapWord);
   if(TraceZapUnusedHeapArea) {
     gclog_or_tty->print_cr(" done");
   }
 #endif
 }
 // Check that top, top_for_allocations and the last
 // word of the space are mangled.  In a tight memory
 // situation even this light weight mangling could
 // cause paging by touching the end of the space.
 void  SpaceMangler::check_mangled_unused_area(HeapWord* limit) {
   if (CheckZapUnusedHeapArea) {
     // This method can be called while the spaces are
     // being reshaped so skip the test if the end of the
     // space is beyond the specified limit;
     if (end() > limit) return;
     assert(top() == end() ||
            (is_mangled(top())), "Top not mangled");
     assert((top_for_allocations() < top()) ||
            (top_for_allocations() >= end()) ||
            (is_mangled(top_for_allocations())),
            "Older unused not mangled");
     assert(top() == end() ||
            (is_mangled(end() - 1)), "End not properly mangled");
     // Only does checking when DEBUG_MANGLING is defined.
     check_mangled_unused_area_complete();
   }
 }
 #undef DEBUG_MANGLING
 // This should only be used while debugging the mangling
 // because of the high cost of checking the completeness.
 void  SpaceMangler::check_mangled_unused_area_complete() {
   if (CheckZapUnusedHeapArea) {
     assert(ZapUnusedHeapArea, "Not mangling unused area");
 #ifdef DEBUG_MANGLING
     HeapWord* q = top();
     HeapWord* limit = end();
     bool passed = true;
     while (q < limit) {
       if (!is_mangled(q)) {
         passed = false;
         break;
       }
       q++;
     }
     assert(passed, "Mangling is not complete");
 #endif
   }
 }
 #undef DEBUG_MANGLING
 #endif // not PRODUCT

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/shared/spaceDecorator.cpp@0bfd3fb24150 (annotated)

src/share/vm/gc_implementation/shared/spaceDecorator.cpp