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由 Dave Chinner 提交于
As reported by Nick Piggin, XFS is suffering from long pauses under highly concurrent workloads when hosted on ramdisks. The problem is that an inode buffer is stuck in the pinned state in memory and as a result either the inode buffer or one of the inodes within the buffer is stopping the tail of the log from being moved forward. The system remains in this state until a periodic log force issued by xfssyncd causes the buffer to be unpinned. The main problem is that these are stale buffers, and are hence held locked until the transaction/checkpoint that marked them state has been committed to disk. When the filesystem gets into this state, only the xfssyncd can cause the async transactions to be committed to disk and hence unpin the inode buffer. This problem was encountered when scaling the busy extent list, but only the blocking lock interface was fixed to solve the problem. Extend the same fix to the buffer trylock operations - if we fail to lock a pinned, stale buffer, then force the log immediately so that when the next attempt to lock it comes around, it will have been unpinned. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de>
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