From: Ming Lei <ming.lei@redhat.com>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"hch@infradead.org" <hch@infradead.org>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"axboe@fb.com" <axboe@fb.com>, "hare@suse.com" <hare@suse.com>,
"holger@applied-asynchrony.com" <holger@applied-asynchrony.com>,
"jejb@linux.vnet.ibm.com" <jejb@linux.vnet.ibm.com>
Subject: Re: [PATCH] SCSI: run queue if SCSI device queue isn't ready and queue is idle
Date: Wed, 6 Dec 2017 00:45:12 +0800 [thread overview]
Message-ID: <20171205164511.GC23788@ming.t460p> (raw)
In-Reply-To: <1512492105.2660.22.camel@wdc.com>
On Tue, Dec 05, 2017 at 04:41:46PM +0000, Bart Van Assche wrote:
> On Wed, 2017-12-06 at 00:28 +0800, Ming Lei wrote:
> > This is still a workaround for RESTART, see my comment before:
> >
> > https://marc.info/?l=linux-block&m=151217500929341&w=2
>
> A quote from that e-mail: "The theory about using BLK_MQ_S_SCHED_RESTART in
> current way is that we mark it after requests are added to hctx->dispatch".
> Reading that makes me wonder whether you understand the purpose of the
> BLK_MQ_S_SCHED_RESTART flag? That flag is not set after requests are added
> to the dispatch list but after requests have been *removed*. The purpose of
> that flag is to detect whether another thread has run the queue after
> requests were removed from the dispatch list and before these were readded.
> If so, the queue needs to be rerun.
If you want to discuss that, please reply on that thread of '[PATCH 4/7] blk-mq:
Avoid that request processing sta', I will reply on you there too.
--
Ming
next prev parent reply other threads:[~2017-12-05 16:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-05 7:52 [PATCH] SCSI: run queue if SCSI device queue isn't ready and queue is idle Ming Lei
2017-12-05 14:29 ` Johannes Thumshirn
2017-12-05 16:16 ` Bart Van Assche
2017-12-05 16:08 ` Bart Van Assche
2017-12-05 16:28 ` Ming Lei
2017-12-05 16:41 ` Bart Van Assche
2017-12-05 16:45 ` Ming Lei [this message]
2017-12-06 1:52 ` Ming Lei
2017-12-06 16:07 ` Bart Van Assche
2017-12-07 1:31 ` Ming Lei
2017-12-07 21:11 ` Bart Van Assche
2017-12-08 0:36 ` Ming Lei
2017-12-07 21:06 ` Bart Van Assche
2017-12-08 0:50 ` Ming Lei
2017-12-06 23:10 ` Holger Hoffstätte
2017-12-07 1:40 ` Ming Lei
2017-12-08 0:54 ` Martin K. Petersen
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