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src/hotspot/share/gc/g1/g1CollectionSetChooser.hpp

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rev 53416 : imported patch 8217330-split-collectionsetchooser
rev 53418 : imported patch 8217328-rename-collectionsetchooser


   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  *
  23  */
  24 
  25 #ifndef SHARE_GC_G1_COLLECTIONSETCHOOSER_HPP
  26 #define SHARE_GC_G1_COLLECTIONSETCHOOSER_HPP
  27 
  28 #include "gc/g1/heapRegion.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "runtime/globals.hpp"
  31 
  32 class G1CollectionSetCandidates;
  33 class WorkGang;
  34 
  35 // Helper class to calculate collection set candidates, and containing some related
  36 // methods.
  37 class CollectionSetChooser : public AllStatic {
  38   static uint calculate_work_chunk_size(uint num_workers, uint num_regions);
  39 public:
  40   CollectionSetChooser();
  41 
  42   static size_t mixed_gc_live_threshold_bytes() {
  43     return HeapRegion::GrainBytes * (size_t) G1MixedGCLiveThresholdPercent / 100;
  44   }
  45 
  46   static bool region_occupancy_low_enough_for_evac(size_t live_bytes) {
  47     return live_bytes < mixed_gc_live_threshold_bytes();
  48   }
  49 
  50   // Determine whether to add the given region to the collection set candidates or
  51   // not. Currently, we skip pinned regions and regions whose live
  52   // bytes are over the threshold. Humongous regions may be reclaimed during cleanup.
  53   // Regions also need a complete remembered set to be a candidate.
  54   static bool should_add(HeapRegion* hr);
  55 
  56   // Build and return set of collection set candidates sorted by decreasing gc
  57   // efficiency.
  58   static G1CollectionSetCandidates* build(WorkGang* workers, uint max_num_regions);
  59 };
  60 
  61 #endif // SHARE_GC_G1_COLLECTIONSETCHOOSER_HPP


   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  *
  23  */
  24 
  25 #ifndef SHARE_GC_G1_G1COLLECTIONSETCHOOSER_HPP
  26 #define SHARE_GC_G1_G1COLLECTIONSETCHOOSER_HPP
  27 
  28 #include "gc/g1/heapRegion.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "runtime/globals.hpp"
  31 
  32 class G1CollectionSetCandidates;
  33 class WorkGang;
  34 
  35 // Helper class to calculate collection set candidates, and containing some related
  36 // methods.
  37 class G1CollectionSetChooser : public AllStatic {
  38   static uint calculate_work_chunk_size(uint num_workers, uint num_regions);
  39 public:
  40   G1CollectionSetChooser();
  41 
  42   static size_t mixed_gc_live_threshold_bytes() {
  43     return HeapRegion::GrainBytes * (size_t) G1MixedGCLiveThresholdPercent / 100;
  44   }
  45 
  46   static bool region_occupancy_low_enough_for_evac(size_t live_bytes) {
  47     return live_bytes < mixed_gc_live_threshold_bytes();
  48   }
  49 
  50   // Determine whether to add the given region to the collection set candidates or
  51   // not. Currently, we skip pinned regions and regions whose live
  52   // bytes are over the threshold. Humongous regions may be reclaimed during cleanup.
  53   // Regions also need a complete remembered set to be a candidate.
  54   static bool should_add(HeapRegion* hr);
  55 
  56   // Build and return set of collection set candidates sorted by decreasing gc
  57   // efficiency.
  58   static G1CollectionSetCandidates* build(WorkGang* workers, uint max_num_regions);
  59 };
  60 
  61 #endif // SHARE_GC_G1_G1COLLECTIONSETCHOOSER_HPP
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