From: Bart Van Assche <Bart.VanAssche@wdc.com>
To: "ming.lei@redhat.com" <ming.lei@redhat.com>
Cc: "hch@lst.de" <hch@lst.de>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"jthumshirn@suse.de" <jthumshirn@suse.de>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"jianchao.w.wang@oracle.com" <jianchao.w.wang@oracle.com>
Subject: Re: [PATCH v5 1/9] block: Change the preempt-only flag into a counter
Date: Wed, 8 Aug 2018 15:27:31 +0000 [thread overview]
Message-ID: <d5a518ad7777a27d26f718262ca7427d8ea4597b.camel@wdc.com> (raw)
In-Reply-To: <20180808082136.GA13518@ming.t460p>
On Wed, 2018-08-08 at 16:21 +0800, Ming Lei wrote:
> On Tue, Aug 07, 2018 at 03:51:25PM -0700, Bart Van Assche wrote:
> > The RQF_PREEMPT flag is used for three purposes:
> > - In the SCSI core, for making sure that power management reque=
sts
> > are executed if a device is in the "quiesced" state.
> > - For domain validation by SCSI drivers that use the parallel p=
ort.
> > - In the IDE driver, for IDE preempt requests.
>=20
> I think the above description may not be accurate, BLK_MQ_REQ=
_PREEMPT is
> always set inside scsi_execute(), that means any scsi_execute=
() callers
> can use the flag of RQF_PREEMPT, of course, not limited to the ab=
ove
> three cases.
Hello Ming,
What I described is for which cases we really need the RQF_PREEMPT flag=
rather
than in which cases the RQF_PREEMPT flag is set today. I think we shoul=
d split
the RQF_PREEMPT flag into three flags, one flag per case mentioned abov=
e.
Bart.
next prev parent reply other threads:[~2018-08-08 15:27 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 22:51 [PATCH v5 0/9] blk-mq: Implement runtime power management Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 1/9] block: Change the preempt-only flag into a counter Bart Van Assche
2018-08-08 8:21 ` Ming Lei
2018-08-08 15:27 ` Bart Van Assche [this message]
2018-08-07 22:51 ` [PATCH v5 2/9] block: Move power management code into a new source file Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 3/9] block, scsi: Introduce blk_pm_runtime_exit() Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 4/9] percpu-refcount: Introduce percpu_ref_is_in_use() Bart Van Assche
2018-08-08 15:23 ` Tejun Heo
2018-08-09 14:32 ` Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 5/9] block: Change the runtime power management approach (1/2) Bart Van Assche
2018-08-08 6:11 ` jianchao.wang
2018-08-08 6:43 ` jianchao.wang
2018-08-08 17:28 ` Bart Van Assche
2018-08-09 2:52 ` Ming Lei
2018-08-09 17:12 ` Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 6/9] block: Change the runtime power management approach (2/2) Bart Van Assche
2018-08-08 8:50 ` Ming Lei
2018-08-08 17:32 ` Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 7/9] block: Remove blk_pm_requeue_request() Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 8/9] blk-mq: Insert a blk_pm_put_request() call Bart Van Assche
2018-08-07 22:51 ` [PATCH v5 9/9] blk-mq: Enable support for runtime power management Bart Van Assche
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