From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-block@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
David Runge <dave@sleepmap.de>,
linux-rt-users@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Daniel Wagner <dwagner@suse.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq
Date: Wed, 28 Oct 2020 15:12:50 +0100 [thread overview]
Message-ID: <20201028141251.3608598-2-bigeasy@linutronix.de> (raw)
In-Reply-To: <20201028141251.3608598-1-bigeasy@linutronix.de>
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)
--
2.28.0
next prev parent reply other threads:[~2020-10-29 0:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 17:50 5.9.1-rt18: issues with Firewire card on AMD hardware David Runge
2020-10-23 11:04 ` [PATCH RFC] blk-mq: Don't IPI requests on PREEMPT_RT Sebastian Andrzej Siewior
2020-10-23 11:21 ` Christoph Hellwig
2020-10-23 13:52 ` Sebastian Andrzej Siewior
2020-10-27 9:26 ` Christoph Hellwig
2020-10-27 10:11 ` Sebastian Andrzej Siewior
2020-10-27 16:07 ` Christoph Hellwig
2020-10-27 17:05 ` Thomas Gleixner
2020-10-27 17:23 ` Christoph Hellwig
2020-10-27 17:59 ` Sebastian Andrzej Siewior
2020-10-27 20:58 ` Sebastian Andrzej Siewior
2020-10-28 6:56 ` Christoph Hellwig
2020-10-28 14:12 ` [PATCH 1/3] blk-mq: Don't complete on a remote CPU in force threaded mode Sebastian Andrzej Siewior
2020-10-28 14:12 ` Sebastian Andrzej Siewior [this message]
2020-10-28 14:12 ` [PATCH 3/3] blk-mq: Use llist_head for blk_cpu_done Sebastian Andrzej Siewior
2020-10-28 14:44 ` Christoph Hellwig
2020-10-28 14:47 ` Sebastian Andrzej Siewior
2020-10-29 13:12 ` Sebastian Andrzej Siewior
2020-10-29 14:05 ` Christoph Hellwig
2020-10-29 14:56 ` Sebastian Andrzej Siewior
2020-10-29 14:57 ` Christoph Hellwig
2020-10-29 20:03 ` Sagi Grimberg
2020-10-29 21:01 ` Sebastian Andrzej Siewior
2020-10-29 21:07 ` Sagi Grimberg
2020-10-31 10:41 ` Sebastian Andrzej Siewior
2020-10-31 15:00 ` Jens Axboe
2020-10-31 15:01 ` Jens Axboe
2020-10-31 18:09 ` Christoph Hellwig
2020-11-02 9:55 ` Sebastian Andrzej Siewior
2020-11-02 18:12 ` Christoph Hellwig
2020-11-04 19:15 ` Sagi Grimberg
2020-11-06 15:23 ` Sebastian Andrzej Siewior
2020-10-28 10:04 ` [PATCH RFC] blk-mq: Don't IPI requests on PREEMPT_RT Peter Zijlstra
2020-10-26 0:37 ` 5.9.1-rt18: issues with Firewire card on AMD hardware David Runge
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