Deallocate objects on a serial queue specific for deallocation (faceb…

…ookarchive#1737) [Performance] Prevent GCD thread explosion due to object deallocation workloads (serial deallocation queue).
george-gw · Jun 17, 2016 · aa5d730 · aa5d730
1 parent efab1a4
commit aa5d730
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Showing 5 changed files with 22 additions and 4 deletions.
diff --git a/AsyncDisplayKit/ASMultiplexImageNode.mm b/AsyncDisplayKit/ASMultiplexImageNode.mm
@@ -531,7 +531,7 @@ - (void)_clearImage
   BOOL shouldReleaseImageOnBackgroundThread = imageSize.width > kMinReleaseImageOnBackgroundSize.width ||
   imageSize.height > kMinReleaseImageOnBackgroundSize.height;
   if (shouldReleaseImageOnBackgroundThread) {
-    ASPerformBlockOnBackgroundThread(^{
+    ASPerformBlockOnDeallocationQueue(^{
       image = nil;
     });
   }

diff --git a/AsyncDisplayKit/ASNetworkImageNode.mm b/AsyncDisplayKit/ASNetworkImageNode.mm
@@ -378,7 +378,7 @@ - (void)_clearImage
   BOOL shouldReleaseImageOnBackgroundThread = imageSize.width > kMinReleaseImageOnBackgroundSize.width ||
                                               imageSize.height > kMinReleaseImageOnBackgroundSize.height;
   if (shouldReleaseImageOnBackgroundThread) {
-    ASPerformBlockOnBackgroundThread(^{
+    ASPerformBlockOnDeallocationQueue(^{
       image = nil;
     });
   }

diff --git a/AsyncDisplayKit/ASTextNode.mm b/AsyncDisplayKit/ASTextNode.mm
@@ -260,7 +260,7 @@ - (void)_invalidateRenderer
     // actually dealloc.
     __block ASTextKitRenderer *renderer = _renderer;
 
-    ASPerformBlockOnBackgroundThread(^{
+    ASPerformBlockOnDeallocationQueue(^{
       renderer = nil;
     });
     _renderer = nil;

diff --git a/AsyncDisplayKit/Private/ASInternalHelpers.h b/AsyncDisplayKit/Private/ASInternalHelpers.h
@@ -17,8 +17,15 @@ ASDISPLAYNODE_EXTERN_C_BEGIN
 
 BOOL ASSubclassOverridesSelector(Class superclass, Class subclass, SEL selector);
 BOOL ASSubclassOverridesClassSelector(Class superclass, Class subclass, SEL selector);
+
+/// Dispatches the given block to the main queue if not already running on the main thread
 void ASPerformBlockOnMainThread(void (^block)());
-void ASPerformBlockOnBackgroundThread(void (^block)()); // DISPATCH_QUEUE_PRIORITY_DEFAULT 
+
+/// Dispatches the given block to a background queue with priority of DISPATCH_QUEUE_PRIORITY_DEFAULT if not already run on a background queue
+void ASPerformBlockOnBackgroundThread(void (^block)()); // DISPATCH_QUEUE_PRIORITY_DEFAULT
+
+/// Dispatches a block on to a serial queue that's main purpose is for deallocation of objects on a background thread
+void ASPerformBlockOnDeallocationQueue(void (^block)());
 
 CGFloat ASScreenScale();
 

diff --git a/AsyncDisplayKit/Private/ASInternalHelpers.mm b/AsyncDisplayKit/Private/ASInternalHelpers.mm
@@ -52,6 +52,17 @@ void ASPerformBlockOnBackgroundThread(void (^block)())
   }
 }
 
+void ASPerformBlockOnDeallocationQueue(void (^block)())
+{
+  static dispatch_queue_t queue;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    queue = dispatch_queue_create("org.AsyncDisplayKit.deallocationQueue", DISPATCH_QUEUE_SERIAL);
+  });
+
+  dispatch_async(queue, block);
+}
+
 CGFloat ASScreenScale()
 {
   static CGFloat __scale = 0.0;