From: Christoph Hellwig <hch@infradead.org>
To: Hannes Reinecke <hare@suse.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq
Date: Mon, 25 Jan 2021 08:25:42 +0000 [thread overview]
Message-ID: <20210125082542.GC942655@infradead.org> (raw)
In-Reply-To: <30ce5ce2-8b9a-8873-4b37-c8720300942b@suse.de>
On Mon, Jan 25, 2021 at 08:10:16AM +0100, Hannes Reinecke wrote:
> I don't get this.
> This code is about _avoiding_ having to raise a softirq if the driver
> exports more than one hardware queue.
> So where exactly does the remote CPU case come in here?
__blk_mq_complete_request_remote is only called for the case where we
do not completelky locally. The case that "degrades" here is where
the device supports multiple queues, but less than the number of CPUs,
and we bounce the completion to another CPU.
next prev parent reply other threads:[~2021-01-26 4:58 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-23 20:10 [PATCH v3 0/3] blk-mq: Don't complete in IRQ, use llist_head Sebastian Andrzej Siewior
2021-01-23 20:10 ` [PATCH 1/3] smp: Process pending softirqs in flush_smp_call_function_from_idle() Sebastian Andrzej Siewior
2021-02-01 19:35 ` Sebastian Andrzej Siewior
2021-02-09 10:02 ` Peter Zijlstra
2021-02-09 11:35 ` Sebastian Andrzej Siewior
2021-02-10 13:53 ` [tip: sched/core] " tip-bot2 for Sebastian Andrzej Siewior
2021-02-17 13:17 ` tip-bot2 for Sebastian Andrzej Siewior
2021-01-23 20:10 ` [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq Sebastian Andrzej Siewior
2021-01-25 7:10 ` Hannes Reinecke
2021-01-25 8:25 ` Christoph Hellwig [this message]
2021-01-25 8:30 ` Sebastian Andrzej Siewior
2021-01-25 8:32 ` Christoph Hellwig
2021-01-25 9:29 ` Sebastian Andrzej Siewior
2021-01-25 8:22 ` Christoph Hellwig
2021-01-25 8:49 ` Christoph Hellwig
2021-01-27 11:22 ` Daniel Wagner
2021-01-23 20:10 ` [PATCH 3/3] blk-mq: Use llist_head for blk_cpu_done Sebastian Andrzej Siewior
2021-01-25 8:30 ` Christoph Hellwig
2021-01-25 8:32 ` Sebastian Andrzej Siewior
2021-01-25 8:39 ` Christoph Hellwig
2021-01-25 9:54 ` [PATCH 3/3 v2] " Sebastian Andrzej Siewior
2021-01-25 10:14 ` Christoph Hellwig
2021-01-27 11:23 ` Daniel Wagner
2021-01-25 4:27 ` [PATCH v3 0/3] blk-mq: Don't complete in IRQ, use llist_head Jens Axboe
2021-02-10 14:43 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2020-10-28 6:56 [PATCH RFC] blk-mq: Don't IPI requests on PREEMPT_RT 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 ` [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq Sebastian Andrzej Siewior
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