Messages in this thread | | | Date | Fri, 5 Aug 2011 13:12:29 +0800 | Subject | Re: [PATCH] block: Make rq_affinity = 1 work as expected. | From | Shaohua Li <> |
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2011/8/5 Tao Ma <tm@tao.ma>: > From: Tao Ma <boyu.mt@taobao.com> > > Commit 5757a6d76c introduced a new rq_affinity = 2 so as to make > the request completed in the __make_request cpu. But it makes the > old rq_affinity = 1 not work any more. The root cause is that > if the 'cpu' and 'req->cpu' is in the same group and cpu != req->cpu, > ccpu will be the same as group_cpu, so the completion will be > excuted in the 'cpu' not 'group_cpu'. > > This patch fix problem by simpling removing group_cpu and the codes > are more explicit now. If ccpu == cpu, we complete in cpu, otherwise > we raise_blk_irq to ccpu. good catch. This changed old behavior and can cause more lock contention. and if user doesn't care about lock contention, he can use rq_affinity = 2
Reviewed-by: Shaohua Li <shaohua.li@intel.com>
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