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mhahnenberg@apple.com authored
https://bugs.webkit.org/show_bug.cgi?id=84763 Reviewed by Geoffrey Garen. The desired behavior for the GC timer is to collect at some point in the future, regardless of how little we've allocated. A secondary goal, which is almost if not as important, is for the timer to collect sooner if there is the potential to collect a greater amount of memory. Conversely, as we allocate more memory we'd like to reduce the delay to the next collection. If we're allocating quickly enough, the timer should be preempted in favor of a normal allocation-triggered collection. If allocation were to slow or stop, we'd like the timer to be able to opportunistically run a collection without us having to allocate to the hard limit set by the Heap. This type of policy can be described in terms of the amount of CPU we are willing to dedicate to reclaim a single MB of memory. For example, we might be willing to dedicate 1% of our CPU to reclaim 1 MB. We base our CPU usage off of the length of the last collection, e.g. if our last collection took 1ms, we would want to wait about 100ms before running another collection to reclaim 1 MB. These constants should be tune-able, e.g. 0.1% CPU = 1 MB vs. 1% CPU = 1 MB vs. 10% CPU = 1 MB. * API/JSBase.cpp: Use the new reportAbandonedObjectGraph. (JSGarbageCollect): * API/JSContextRef.cpp: Ditto. * heap/Heap.cpp: (JSC::Heap::Heap): (JSC::Heap::reportAbandonedObjectGraph): Similar to reportExtraMemoryCost. Clients call this function to notify the Heap that some unknown number of JSC objects might have just been abandoned and are now garbage. The Heap might schedule a new collection timer based on this notification. (JSC): (JSC::Heap::collect): Renamed m_lastFullGCSize to the less confusing m_sizeAfterLastCollect. * heap/Heap.h: (Heap): * heap/MarkedAllocator.h: (JSC::MarkedAllocator::zapFreeList): Fixed a bug in zapFreeList that failed to nullify the current allocator's FreeList once zapping was complete. * runtime/GCActivityCallback.cpp: Removed didAbandonObjectGraph because it was replaced by Heap::reportAbandonedObjectGraph. (JSC): * runtime/GCActivityCallback.h: (JSC::GCActivityCallback::willCollect): (DefaultGCActivityCallback): * runtime/GCActivityCallbackCF.cpp: Refactored the GC timer code so that we now schedule the timer based on how much we have allocated since the last collection up to a certain amount. We use the length of the previous GC to try to keep our total cost of opportunistic timer-triggered collections around 1% of the CPU per MB of garbage we expect to reclaim up to a maximum of 5 MB. (DefaultGCActivityCallbackPlatformData): (JSC): (JSC::DefaultGCActivityCallback::~DefaultGCActivityCallback): (JSC::DefaultGCActivityCallback::commonConstructor): (JSC::scheduleTimer): (JSC::cancelTimer): (JSC::DefaultGCActivityCallback::didAllocate): git-svn-id: http://svn.webkit.org/repository/webkit/trunk@115156 268f45cc-cd09-0410-ab3c-d52691b4dbfc
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