[PATCH 2/3] blk-mq: Always complete remote completions requests in softirq
STALE2155d
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2020-10-28 22:30:35
Also in:
linux-rt-users, lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2021-01-27 · Re: [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq · Daniel Wagner <hidden>
- 2021-01-26 · Re: [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq · Sebastian Andrzej Siewior <bigeasy@linutronix.de>
- 2021-01-26 · Re: [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq · Sebastian Andrzej Siewior <bigeasy@linutronix.de>
- 2021-01-26 · Re: [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq · Christoph Hellwig <hch@infradead.org>
- 2021-01-26 · Re: [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq · Christoph Hellwig <hch@infradead.org>
Controllers with multiple queues have their IRQ-handelers pinned to a CPU. The core shouldn't need to complete the request on a remote CPU. Remove this case and always raise the softirq to complete the request. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- block/blk-mq.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 421a40968c9ff..769d2d532a825 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c@@ -626,19 +626,7 @@ static void __blk_mq_complete_request_remote(void *data) { struct request *rq = data; - /* - * For most of single queue controllers, there is only one irq vector - * for handling I/O completion, and the only irq's affinity is set - * to all possible CPUs. On most of ARCHs, this affinity means the irq - * is handled on one specific CPU. - * - * So complete I/O requests in softirq context in case of single queue - * devices to avoid degrading I/O performance due to irqsoff latency. - */ - if (rq->q->nr_hw_queues == 1) - blk_mq_trigger_softirq(rq); - else - rq->q->mq_ops->complete(rq); + blk_mq_trigger_softirq(rq); } static inline bool blk_mq_complete_need_ipi(struct request *rq)
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2.28.0