Messages in this thread | | | Date | Tue, 30 Nov 2010 17:43:01 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH v6 0/4] ext4: Coordinate data-only flush requests sent by fsync |
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On Tue, Nov 30, 2010 at 11:39:06AM +1100, Neil Brown wrote: > Would it not be sufficient to simply gather flushes while a flush is pending. > i.e > - if no flush is pending, set the 'flush pending' flag, submit a flush, > then clear the flag. > - if a flush is pending, then wait for it to complete, and then submit a > single flush on behalf of all pending flushes. > > That way when flush is fast, you do a flush every time, and when it is slow > you gather multiple flushes together.
We can even optimize the second flush away if no other I/O has completed since the first flush has started. That will always be the case for SATA devices as the cache flush command is not queued.
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