Commit 35ae66e0 authored Aug 05, 2011 by Tao Ma Committed by Jens Axboe Aug 05, 2011

block: Make rq_affinity = 1 work as expected



Commit 5757a6d7 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.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Reviewed-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

parent f41c53a5

block/blk-softirq.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -103,7 +103,7 @@ static struct notifier_block __cpuinitdata blk_cpu_notifier = {

		void __blk_complete_request(struct request *req)
		{
		int ccpu, cpu, group_cpu = NR_CPUS;
		int ccpu, cpu;
		struct request_queue *q = req->q;
		unsigned long flags;

		@@ -117,14 +117,12 @@ void __blk_complete_request(struct request *req)
		*/
		if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && req->cpu != -1) {
		ccpu = req->cpu;
		if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) {
		if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
		ccpu = blk_cpu_to_group(ccpu);
		group_cpu = blk_cpu_to_group(cpu);
		}
		} else
		ccpu = cpu;

		if (ccpu == cpu \|\| ccpu == group_cpu) {
		if (ccpu == cpu) {
		struct list_head *list;
		do_local:
		list = &__get_cpu_var(blk_cpu_done);

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