Use MutableIntObjectMap for SurfaceMountingManager view registry (#56646)#56646
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javache wants to merge 1 commit intofacebook:mainfrom
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Use MutableIntObjectMap for SurfaceMountingManager view registry (#56646)#56646javache wants to merge 1 commit intofacebook:mainfrom
javache wants to merge 1 commit intofacebook:mainfrom
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…ebook#56646) Summary: Replace `ConcurrentHashMap<Int, ViewState>` with `MutableIntObjectMap<ViewState>` + `ReentrantReadWriteLock` in `SurfaceMountingManager`, behind the `useOptimizedViewRegistryOnAndroid` feature flag. `ConcurrentHashMap<Int, ViewState>` boxes every `Int` key to `java.lang.Integer` (16 bytes) and allocates a `Node` object per entry (~32 bytes). `MutableIntObjectMap` from `androidx.collection` uses a Swiss Table layout with primitive `IntArray` keys — ~9 bytes/entry vs ~56-64 bytes, a ~6x reduction in map overhead. For a complex surface with 2000+ views, this saves ~90KB per surface in map overhead alone, plus reduced GC pressure from eliminating `Integer` boxing. The `ReentrantReadWriteLock` replaces CHM's built-in concurrency. This matches the access pattern: reads from any thread (`getEventEmitter`, `enqueuePendingEvent`), writes almost exclusively from the UI thread. Readers never block each other. `stopSurface` snapshots entries under the write lock and processes `onViewStateDeleted` outside the lock to minimize reader blocking. Changelog: [Internal] Reviewed By: sammy-SC Differential Revision: D102797904
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This pull request has been merged in 06b23b8. |
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This pull request was successfully merged by @javache in 06b23b8 When will my fix make it into a release? | How to file a pick request? |
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Summary:
Replace
ConcurrentHashMap<Int, ViewState>withMutableIntObjectMap<ViewState>+ReentrantReadWriteLockinSurfaceMountingManager, behind theuseOptimizedViewRegistryOnAndroidfeature flag.ConcurrentHashMap<Int, ViewState>boxes everyIntkey tojava.lang.Integer(16 bytes) and allocates aNodeobject per entry (~32 bytes).MutableIntObjectMapfromandroidx.collectionuses a Swiss Table layout with primitiveIntArraykeys — ~9 bytes/entry vs ~56-64 bytes, a ~6x reduction in map overhead. For a complex surface with 2000+ views, this saves ~90KB per surface in map overhead alone, plus reduced GC pressure from eliminatingIntegerboxing.The
ReentrantReadWriteLockreplaces CHM's built-in concurrency. This matches the access pattern: reads from any thread (getEventEmitter,enqueuePendingEvent), writes almost exclusively from the UI thread. Readers never block each other.stopSurfacesnapshots entries under the write lock and processesonViewStateDeletedoutside the lock to minimize reader blocking.Changelog: [Internal]
Reviewed By: sammy-SC
Differential Revision: D102797904