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

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rev 5146 : [mq]: first-patch
   1 /*
   2  * Copyright (c) 2001, 2012, 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  *


 131       oop(bottom)->oop_iterate(cl2, mr);
 132     }
 133   }
 134 }
 135 
 136 // Minimum region size; we won't go lower than that.
 137 // We might want to decrease this in the future, to deal with small
 138 // heaps a bit more efficiently.
 139 #define MIN_REGION_SIZE  (      1024 * 1024 )
 140 
 141 // Maximum region size; we don't go higher than that. There's a good
 142 // reason for having an upper bound. We don't want regions to get too
 143 // large, otherwise cleanup's effectiveness would decrease as there
 144 // will be fewer opportunities to find totally empty regions after
 145 // marking.
 146 #define MAX_REGION_SIZE  ( 32 * 1024 * 1024 )
 147 
 148 // The automatic region size calculation will try to have around this
 149 // many regions in the heap (based on the min heap size).
 150 #define TARGET_REGION_NUMBER          2048




 151 
 152 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
 153   // region_size in bytes
 154   uintx region_size = G1HeapRegionSize;
 155   if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
 156     // We base the automatic calculation on the min heap size. This
 157     // can be problematic if the spread between min and max is quite
 158     // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
 159     // the max size, the region size might be way too large for the
 160     // min size. Either way, some users might have to set the region
 161     // size manually for some -Xms / -Xmx combos.
 162 
 163     region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
 164                        (uintx) MIN_REGION_SIZE);
 165   }
 166 
 167   int region_size_log = log2_long((jlong) region_size);
 168   // Recalculate the region size to make sure it's a power of
 169   // 2. This means that region_size is the largest power of 2 that's
 170   // <= what we've calculated so far.


   1 /*
   2  * Copyright (c) 2001, 2013, 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  *


 131       oop(bottom)->oop_iterate(cl2, mr);
 132     }
 133   }
 134 }
 135 
 136 // Minimum region size; we won't go lower than that.
 137 // We might want to decrease this in the future, to deal with small
 138 // heaps a bit more efficiently.
 139 #define MIN_REGION_SIZE  (      1024 * 1024 )
 140 
 141 // Maximum region size; we don't go higher than that. There's a good
 142 // reason for having an upper bound. We don't want regions to get too
 143 // large, otherwise cleanup's effectiveness would decrease as there
 144 // will be fewer opportunities to find totally empty regions after
 145 // marking.
 146 #define MAX_REGION_SIZE  ( 32 * 1024 * 1024 )
 147 
 148 // The automatic region size calculation will try to have around this
 149 // many regions in the heap (based on the min heap size).
 150 #define TARGET_REGION_NUMBER          2048
 151 
 152 size_t HeapRegion::max_region_size() {
 153   return (size_t)MAX_REGION_SIZE;
 154 }
 155 
 156 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
 157   // region_size in bytes
 158   uintx region_size = G1HeapRegionSize;
 159   if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
 160     // We base the automatic calculation on the min heap size. This
 161     // can be problematic if the spread between min and max is quite
 162     // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
 163     // the max size, the region size might be way too large for the
 164     // min size. Either way, some users might have to set the region
 165     // size manually for some -Xms / -Xmx combos.
 166 
 167     region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
 168                        (uintx) MIN_REGION_SIZE);
 169   }
 170 
 171   int region_size_log = log2_long((jlong) region_size);
 172   // Recalculate the region size to make sure it's a power of
 173   // 2. This means that region_size is the largest power of 2 that's
 174   // <= what we've calculated so far.