From: Christoph Hellwig <hch@lst.de>
To: Salman Qazi <sqazi@google.com>
Cc: Jens Axboe <axboe@kernel.dk>, Ming Lei <ming.lei@redhat.com>,
Bart Van Assche <bvanassche@acm.org>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Jesse Barnes <jsbarnes@google.com>,
Gwendal Grignou <gwendal@google.com>,
Hannes Reinecke <hare@suse.com>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v3] block: Limit number of items taken from the I/O scheduler in one go
Date: Fri, 24 Apr 2020 17:39:40 +0200 [thread overview]
Message-ID: <20200424153940.GA17253@lst.de> (raw)
In-Reply-To: <20200424150321.38617-1-sqazi@google.com>
> + /*
> + * A return of -EAGAIN is an indication that hctx->dispatch is not
> + * empty and we must run again in order to avoid starving flushes.
> + */
> + if (__blk_mq_sched_dispatch_requests(hctx) == -EAGAIN) {
> + if (__blk_mq_sched_dispatch_requests(hctx) == -EAGAIN)
> + blk_mq_run_hw_queue(hctx, true);
> + }
The comment doesn't explain why we give up after the second attempt and
do a blk_mq_run_hw_queue instead.
prev parent reply other threads:[~2020-04-24 15:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 15:03 [PATCH v3] block: Limit number of items taken from the I/O scheduler in one go Salman Qazi
2020-04-24 15:17 ` Jens Axboe
2020-04-24 15:39 ` Christoph Hellwig [this message]
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