OLD | NEW |
1 /* | 1 /* |
2 * Copyright (C) 2013 Google Inc. All rights reserved. | 2 * Copyright (C) 2013 Google Inc. All rights reserved. |
3 * | 3 * |
4 * Redistribution and use in source and binary forms, with or without | 4 * Redistribution and use in source and binary forms, with or without |
5 * modification, are permitted provided that the following conditions are | 5 * modification, are permitted provided that the following conditions are |
6 * met: | 6 * met: |
7 * | 7 * |
8 * * Redistributions of source code must retain the above copyright | 8 * * Redistributions of source code must retain the above copyright |
9 * notice, this list of conditions and the following disclaimer. | 9 * notice, this list of conditions and the following disclaimer. |
10 * * Redistributions in binary form must reproduce the above | 10 * * Redistributions in binary form must reproduce the above |
(...skipping 799 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
810 m_gcState = gcState; | 810 m_gcState = gcState; |
811 } | 811 } |
812 | 812 |
813 #undef VERIFY_STATE_TRANSITION | 813 #undef VERIFY_STATE_TRANSITION |
814 | 814 |
815 ThreadState::GCState ThreadState::gcState() const | 815 ThreadState::GCState ThreadState::gcState() const |
816 { | 816 { |
817 return m_gcState; | 817 return m_gcState; |
818 } | 818 } |
819 | 819 |
820 void ThreadState::didV8MajorGC(bool forceGC) | 820 void ThreadState::didV8MajorGC() |
821 { | 821 { |
822 checkThread(); | 822 checkThread(); |
823 if (isMainThread()) { | 823 if (isMainThread()) { |
824 // Lower the estimated live object size because the V8 major GC is | 824 // Lower the estimated live object size because the V8 major GC is |
825 // expected to have collected a lot of DOM wrappers and dropped | 825 // expected to have collected a lot of DOM wrappers and dropped |
826 // references to their DOM objects. | 826 // references to their DOM objects. |
827 Heap::setEstimatedLiveObjectSize(Heap::estimatedLiveObjectSize() / 2); | 827 Heap::setEstimatedLiveObjectSize(Heap::estimatedLiveObjectSize() / 2); |
828 | 828 |
829 if (forceGC) { | |
830 // This single GC is not enough for two reasons: | |
831 // (1) The GC is not precise because the GC scans on-stack pointer
s conservatively. | |
832 // (2) One GC is not enough to break a chain of persistent handles
. It's possible that | |
833 // some heap allocated objects own objects that contain persis
tent handles | |
834 // pointing to other heap allocated objects. To break the chai
n, we need multiple GCs. | |
835 // | |
836 // Regarding (1), we force a precise GC at the end of the current ev
ent loop. So if you want | |
837 // to collect all garbage, you need to wait until the next event loo
p. | |
838 // Regarding (2), it would be OK in practice to trigger only one GC
per gcEpilogue, because | |
839 // GCController.collectAll() forces 7 V8's GC. | |
840 Heap::collectGarbage(ThreadState::HeapPointersOnStack, ThreadState::
GCWithSweep, Heap::ForcedGC); | |
841 | |
842 // Forces a precise GC at the end of the current event loop. | |
843 ThreadState::current()->setGCState(ThreadState::FullGCScheduled); | |
844 return; | |
845 } | |
846 | |
847 // If under memory pressure, complete sweeping before initiating | 829 // If under memory pressure, complete sweeping before initiating |
848 // the urgent conservative GC. | 830 // the urgent conservative GC. |
849 if (shouldForceMemoryPressureGC()) | 831 if (shouldForceMemoryPressureGC()) |
850 completeSweep(); | 832 completeSweep(); |
851 | 833 |
852 // Schedule an Oilpan GC to avoid the following scenario: | 834 // Schedule an Oilpan GC to avoid the following scenario: |
853 // (1) A DOM object X holds a v8::Persistent to a V8 object. | 835 // (1) A DOM object X holds a v8::Persistent to a V8 object. |
854 // Assume that X is small but the V8 object is huge. | 836 // Assume that X is small but the V8 object is huge. |
855 // The v8::Persistent is released when X is destructed. | 837 // The v8::Persistent is released when X is destructed. |
856 // (2) X's DOM wrapper is created. | 838 // (2) X's DOM wrapper is created. |
(...skipping 624 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
1481 json->beginArray(it->key.ascii().data()); | 1463 json->beginArray(it->key.ascii().data()); |
1482 for (size_t age = 0; age <= maxHeapObjectAge; ++age) | 1464 for (size_t age = 0; age <= maxHeapObjectAge; ++age) |
1483 json->pushInteger(it->value.ages[age]); | 1465 json->pushInteger(it->value.ages[age]); |
1484 json->endArray(); | 1466 json->endArray(); |
1485 } | 1467 } |
1486 TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("blink_gc"), s
tatsName, this, json.release()); | 1468 TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("blink_gc"), s
tatsName, this, json.release()); |
1487 } | 1469 } |
1488 #endif | 1470 #endif |
1489 | 1471 |
1490 } // namespace blink | 1472 } // namespace blink |
OLD | NEW |