NSOperationQueueバックグラウンドで画像を処理するために多数のインスタンスを使用する Cocoa アプリケーションがあります。各キューは、基本的に以下を使用してNSImageオブジェクトをCGImageRefインスタンスに変換する呼び出し操作を処理します。
CGImageRef ref = [image CGImageForProposedRect:NULL context:nil hints:nil];
一部のユーザーは、アプリが突然応答しなくなったと不満を漏らしています。ActivityMonitor.app を使用してプロセス サンプルを収集するよう依頼しました。レポートはすべて非常に似ています。
への呼び出しの直後にdrainキュー/スレッドがスタックしている間に、メインスレッドが自動解放プールを通過しているようです。__spin_lockImageProviderReleaseInfoCallback
ドキュメントによると、すべてのパラメータCGImageForProposedRect:はオプションです。バックグラウンド スレッドから呼び出すことができる場合、彼らは何も言いません。多分それが問題ですか？ほとんどすべての場合に機能するため、私はそれを疑っています（アプリを何百回も問題なく起動しました...）
キューがスタックする理由はありますか?
完全なプロセスのサンプル:
OS Version: Mac OS X 10.6.8 (10K549)
Report Version: 6
Call graph:
1971 Thread_905 DispatchQueue_1: com.apple.main-thread (serial)
1971 0x2e6d
1971 NSApplicationMain
1971 -[NSApplication run]
1971 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:]
1971 _DPSNextEvent
1971 AEProcessAppleEvent
1971 aeProcessAppleEvent
1971 dispatchEventAndSendReply(AEDesc const*, AEDesc*)
1971 aeDispatchAppleEvent(AEDesc const*, AEDesc*, unsigned long, unsigned char*)
1971 _NSAppleEventManagerGenericHandler
1971 -[NSAutoreleasePool drain]
1971 NSPopAutoreleasePool
1971 _CFAutoreleasePoolPop
1971 CFRelease
1971 -[NSImage dealloc]
1971 -[NSImage _deallocAuxiliaryStorage]
1971 -[NSCGImageSnapshotRep dealloc]
1971 _CFRelease
1971 image_finalize
1971 _CFRelease
1971 image_provider_finalize
1971 ImageProviderReleaseInfoCallback
1971 __spin_lock
1971 Thread_943 DispatchQueue_2: com.apple.libdispatch-manager (serial)
1971 start_wqthread
1971 _pthread_wqthread
1971 _dispatch_worker_thread2
1971 _dispatch_queue_invoke
1971 _dispatch_mgr_invoke
1971 kevent
1971 Thread_944 DispatchQueue_6: com.apple.root.default-priority (concurrent)
1971 start_wqthread
1971 _pthread_wqthread
1971 _dispatch_worker_thread2
1971 _dispatch_call_block_and_release
1971 ____NSOQSchedule_block_invoke_2
1971 -[__NSOperationInternal start]
1971 -[NSInvocationOperation main]
1971 -[NSInvocation invoke]
1971 __invoking___
1971 0x17a64
1971 0x244cf
1971 0x22a97
1971 -[NSImage CGImageForProposedRect:context:hints:]
1971 -[NSImage _usingBestRepresentationForRect:context:hints:body:]
1971 __-[NSImage CGImageForProposedRect:context:hints:]_block_invoke_1
1971 -[NSImage _snapshotRepForRep:rect:context:processedHints:]
1971 -[NSImage _createSnapshotRepForRep:rect:context:processedHints:]
1971 -[NSImageRep CGImageForProposedRect:context:hints:flipped:]
1971 -[NSIconRefImageRep CGImageForProposedRect:context:hints:]
1971 _ISCreateCGImageForType
1971 _ISGetCGImageRefForISImageRef
1971 _ISImageRefIterator(void*, unsigned char, short (*)(void*, void*), void*)
1971 _ISGoThruImageStorages
1971 _ISGoThruImageStorages
1971 MergeBestStorageIntoContext(void*, void*)
1971 _CFRelease
1971 image_finalize
1971 _CFRelease
1971 image_provider_finalize
1971 ImageProviderReleaseInfoCallback
1971 __spin_lock
1971 Thread_980 DispatchQueue_6: com.apple.root.default-priority (concurrent)
1971 start_wqthread
1971 _pthread_wqthread
1971 _dispatch_worker_thread2
1971 _dispatch_call_block_and_release
1971 ____NSOQSchedule_block_invoke_2
1971 -[__NSOperationInternal start]
1971 NSPopAutoreleasePool
1971 _CFAutoreleasePoolPop
1971 CFRelease
1971 -[NSImage dealloc]
1971 -[NSImage _deallocAuxiliaryStorage]
1971 -[NSCGImageSnapshotRep dealloc]
1971 _CFRelease
1971 image_finalize
1971 _CFRelease
1971 image_provider_finalize
1971 ImageProviderReleaseInfoCallback
1971 glueReleaseInfo
1971 JP2ReleaseInfoCallback
1971 _cg_JP2TearDownDecompressor
1971 _CFRelease
1971 __CFBasicHashDrain
1971 __CFDictionaryCallback
1971 _CFRelease
1971 _CGImageReadSessionFinalize
1971 _CFRelease
1971 _CGImageReadFinalize
1971 _CFRelease
1971 __CFDataDeallocate
1971 _ISReleaseStorageRef
1971 _CFRelease
1971 __CFArrayReleaseValues
1971 _CFRelease
1971 image_finalize
1971 _CFRelease
1971 image_provider_finalize
1971 ImageProviderReleaseInfoCallback
1971 __spin_lock
1971 Thread_1013 DispatchQueue_6: com.apple.root.default-priority (concurrent)
1971 start_wqthread
1971 _pthread_wqthread
1971 _dispatch_worker_thread2
1971 _dispatch_call_block_and_release
1971 ____NSOQSchedule_block_invoke_2
1971 -[__NSOperationInternal start]
1971 -[NSInvocationOperation main]
1971 -[NSInvocation invoke]
1971 __invoking___
1971 0x17a64
1971 0x244cf
1971 0x22a97
1971 -[NSImage CGImageForProposedRect:context:hints:]
1971 -[NSImage _usingBestRepresentationForRect:context:hints:body:]
1971 __-[NSImage CGImageForProposedRect:context:hints:]_block_invoke_1
1971 -[NSImage _snapshotRepForRep:rect:context:processedHints:]
1971 -[NSImage _createSnapshotRepForRep:rect:context:processedHints:]
1971 -[NSImageRep CGImageForProposedRect:context:hints:flipped:]
1971 -[NSIconRefImageRep CGImageForProposedRect:context:hints:]
1971 _ISCreateCGImageForType
1971 _ISGetCGImageRefForISImageRef
1971 _ISImageRefIterator(void*, unsigned char, short (*)(void*, void*), void*)
1971 _ISGoThruImageStorages
1971 MergeBestStorageIntoContext(void*, void*)
1971 _CFRelease
1971 image_finalize
1971 _CFRelease
1971 image_provider_finalize
1971 ImageProviderReleaseInfoCallback
1971 __spin_lock
1971 Thread_1019 DispatchQueue_6: com.apple.root.default-priority (concurrent)
1971 start_wqthread
1971 _pthread_wqthread
1971 _dispatch_worker_thread2
1971 _dispatch_call_block_and_release
1971 ____NSOQSchedule_block_invoke_2
1971 -[__NSOperationInternal start]
1971 NSPopAutoreleasePool
1971 _CFAutoreleasePoolPop
1971 CFRelease
1971 -[NSImage dealloc]
1971 -[NSImage _deallocAuxiliaryStorage]
1971 -[NSCGImageSnapshotRep dealloc]
1971 _CFRelease
1971 image_finalize
1971 _CFRelease
1971 image_provider_finalize
1971 ImageProviderReleaseInfoCallback
1971 __spin_lock
1971 Thread_1031
1971 thread_start
1971 _pthread_start
1971 startIOThread(void*)
1971 CVDisplayLink::runIOThread()
1971 pthread_cond_wait$UNIX2003
1971 _pthread_cond_wait
1971 __semwait_signal
Total number in stack (recursive counted multiple, when >=5):
17 _CFRelease
6 ImageProviderReleaseInfoCallback
6 image_finalize
6 image_provider_finalize
5 __spin_lock
5 _dispatch_worker_thread2
5 _pthread_wqthread
5 start_wqthread
Sort by top of stack, same collapsed (when >= 5):
__spin_lock 9855
__semwait_signal 1971
kevent 1971