From: Bart Van Assche <Bart.VanAssche@wdc.com>
To: "hch@infradead.org" <hch@infradead.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"axboe@fb.com" <axboe@fb.com>,
"ming.lei@redhat.com" <ming.lei@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"tom81094@gmail.com" <tom81094@gmail.com>,
"paolo.valente@linaro.org" <paolo.valente@linaro.org>,
Bart Van Assche <Bart.VanAssche@wdc.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"oleksandr@natalenko.name" <oleksandr@natalenko.name>,
"john.garry@huawei.com" <john.garry@huawei.com>,
"osandov@fb.com" <osandov@fb.com>,
"loberman@redhat.com" <loberman@redhat.com>
Subject: Re: [PATCH V9 6/7] SCSI: allow to pass null rq to scsi_prep_state_check()
Date: Fri, 13 Oct 2017 23:16:12 +0000 [thread overview]
Message-ID: <1507936571.13345.51.camel@wdc.com> (raw)
In-Reply-To: <20171013180532.29304-7-ming.lei@redhat.com>
On Sat, 2017-10-14 at 02:05 +0800, Ming Lei wrote:
> In the following patch, we will implement scsi_get_budget()
> which need to call scsi_prep_state_check() when rq isn't
> dequeued yet.
My understanding is that this change is only needed because scsi_mq_get_budget()
calls scsi_prep_state_check() with the req argument set to NULL. Since
scsi_prep_state_check() tests for sdev states other than SDEV_RUNNING and since
the purpose of this series is to optimize performance for the case SDEV_RUNNING
I'm not sure it's a good idea to make scsi_mq_get_budget() call
scsi_prep_state_check(). And if scsi_mq_get_budget() wouldn't call
scsi_prep_state_check() then this patch is not necessary.
Bart.
next prev parent reply other threads:[~2017-10-13 23:16 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-13 18:05 [PATCH V9 0/7] blk-mq-sched: improve sequential I/O performance Ming Lei
2017-10-13 18:05 ` [PATCH V9 1/7] blk-mq-sched: dispatch from scheduler only after progress is made on ->dispatch Ming Lei
2017-10-13 18:05 ` [PATCH V9 2/7] blk-mq-sched: move actual dispatching into one helper Ming Lei
2017-10-13 18:05 ` [PATCH V9 3/7] sbitmap: introduce __sbitmap_for_each_set() Ming Lei
2017-10-13 18:05 ` [PATCH V9 4/7] blk-mq: introduce .get_budget and .put_budget in blk_mq_ops Ming Lei
2017-10-13 23:43 ` Bart Van Assche
2017-10-14 7:34 ` Ming Lei
2017-10-13 18:05 ` [PATCH V9 5/7] blk-mq-sched: improve dispatching from sw queue Ming Lei
2017-10-13 18:05 ` [PATCH V9 6/7] SCSI: allow to pass null rq to scsi_prep_state_check() Ming Lei
2017-10-13 23:16 ` Bart Van Assche [this message]
2017-10-14 8:06 ` Ming Lei
2017-10-13 18:05 ` [PATCH V9 7/7] SCSI: implement .get_budget and .put_budget for blk-mq Ming Lei
2017-10-13 19:08 ` [PATCH V9 0/7] blk-mq-sched: improve sequential I/O performance Jens Axboe
2017-10-13 19:21 ` Jens Axboe
2017-10-13 20:23 ` Jens Axboe
2017-10-14 5:23 ` Ming Lei
2017-10-14 7:10 ` Ming Lei
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