From: Ming Lei <ming.lei@redhat.com>
To: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Jianchao Wang <jianchao.w.wang@oracle.com>,
Johannes Thumshirn <jthumshirn@suse.de>,
Alan Stern <stern@rowland.harvard.edu>
Subject: Re: [PATCH v5 1/9] block: Change the preempt-only flag into a counter
Date: Wed, 8 Aug 2018 16:21:37 +0800 [thread overview]
Message-ID: <20180808082136.GA13518@ming.t460p> (raw)
In-Reply-To: <20180807225133.27221-2-bart.vanassche@wdc.com>
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 requests
> are executed if a device is in the "quiesced" state.
> - For domain validation by SCSI drivers that use the parallel port.
> - In the IDE driver, for IDE preempt requests.
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 above
three cases.
Thanks,
Ming
next prev parent reply other threads:[~2018-08-08 8:21 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 [this message]
2018-08-08 15:27 ` Bart Van Assche
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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