Re: [patch 1/2]block: change force plug flush call order

From: Jens Axboe
Date: Wed Aug 24 2011 - 09:59:16 EST


On 2011-08-24 10:55, Shaohua Li wrote:
> Do blk_flush_plug_list() first and then add new request at the tail. New
> request can't be merged to existing requests, but later new requests might
> be merged with this new one. If blk_flush_plug_list() is done later, the
> merge doesn't happen.
> Believe it or not, this fixes a 10% regression running sysbench workload.

Heh, funky. But conceptually it makes sense to flush first, since we
already know that this request isn't mergeable already. Applied.

--
Jens Axboe

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