[FLINK-24035][network] Notify the buffer listeners when the local buffer pool receives available notification from the global pool#17030
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wsry wants to merge 4 commits intoapache:masterfrom
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[FLINK-24035][network] Notify the buffer listeners when the local buffer pool receives available notification from the global pool#17030wsry wants to merge 4 commits intoapache:masterfrom
wsry wants to merge 4 commits intoapache:masterfrom
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added 3 commits
August 27, 2021 19:42
… help debugging when the case is stuck This closes apache#17009.
…otified when recycling buffers Previously, the buffer listener will be removed from the listener queue when notified and then it will be added to the listener queue again if it needs more buffers. However, if some buffers are recycled meanwhile, the buffer listener will not be notified of the available buffers. For example: 1. Thread 1 calls LocalBufferPool#recycle(). 2. Thread 1 reaches LocalBufferPool#fireBufferAvailableNotification() and listener.notifyBufferAvailable() is invoked, but Thread 1 sleeps before acquiring the lock to registeredListeners.add(listener). 3. Thread 2 is being woken up as a result of notifyBufferAvailable() call. It takes the buffer, but it needs more buffers. 4. Other threads, return all buffers, including this one that has been recycled. None are taken. Are all in the LocalBufferPool. 5. Thread 1 wakes up, and continues fireBufferAvailableNotification() invocation. 6. Thread 1 re-adds listener that's waiting for more buffer registeredListeners.add(listener). 7. Thread 1 exits loop LocalBufferPool#recycle(MemorySegment, int) inside, as the original memory segment has been used. At the end we have a state where all buffers are in the LocalBufferPool, so no new recycle() calls will happen, but there is still one listener waiting for a buffer (despite buffers being available). This change fixes the issue by letting the buffer listener request multiple buffers one after another without having to enqueue BufferListener to the registeredListener queue. This closes apache#17009.
…fy the code This closes apache#17009.
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This fix is still under testing. |
…fer pool receives available notification from the global pool Previously, The buffer listeners are not notified when the the local buffer pool receives available notification from the global pool. This may cause potential deadlock issue: 1. A LocalBufferPool is created but there is no available buffers in the global NetworkBufferPool. 2. The LocalBufferPool registers an available buffer listener to the global NetworkBufferPool. 3. The BufferManager requests buffers from the LocalBufferPool but no buffer is available. As a result, it registers an available buffer listener to the LocalBufferPool. 4. A buffer is recycled to the global NetworkBufferPool and the LocalBufferPool is notified about the available buffer. 5. The LocalBufferPool requests the available buffer from the global NetworkBufferPool but the registered available buffer listener of BufferManager is not notified and it can never get a chance to be notified so deadlock occurs. This patch fixes this issue by notifying the buffer listeners when the local buffer pool receives available notification from the global pool.
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@flinkbot run azure |
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@flinkbot run azure |
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Abandoned. |
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@Public(Evolving): (yes / no)Documentation