From: Martin Kepplinger <martin.kepplinger@puri.sm>
To: Alan Stern <stern@rowland.harvard.edu>,
Bart Van Assche <bvanassche@acm.org>
Cc: jejb@linux.ibm.com, Can Guo <cang@codeaurora.org>,
martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel@puri.sm
Subject: Re: [PATCH] scsi: sd: add runtime pm to open / release
Date: Tue, 28 Jul 2020 09:02:44 +0200 [thread overview]
Message-ID: <d0ed766b-88b0-5ad5-9c10-a4c3b2f994e3@puri.sm> (raw)
In-Reply-To: <20200706164135.GE704149@rowland.harvard.edu>
On 06.07.20 18:41, Alan Stern wrote:
> On Tue, Jun 30, 2020 at 20:49:58PM -0400, Alan Stern wrote:
>> On Tue, Jun 30, 2020 at 04:31:58PM -0700, Bart Van Assche wrote:
>>> On 2020-06-30 12:38, Alan Stern wrote:
>>>> Assume that BLK_MQ_REQ_PREEMPT is set in flags. Then where exactly
>>>> does blk_queue_enter(q, flags) call blk_pm_request_resume(q)?
>>>
>>> Please take a look at how the *current* implementation of runtime power
>>> management works. Your question is relevant for the old implementation
>>> of runtime power management but not for the current implementation.
>>
>> What do you mean by "current"? I have been looking at the implementation
>> in 5.8-rc3 from Linus's tree. Should I look somewhere else?
>
> Any reply to this, or further concerns about the proposed patch?
>
> I'd like to fix up this API, and it appears that you are the only
> person to have worked on it significantly in the last two years.
>
> Alan Stern
>
Hi Alan,
Any API cleanup is of course welcome. I just wanted to remind you that
the underlying problem: broken block device runtime pm. Your initial
proposed fix "almost" did it and mounting works but during file access,
it still just looks like a runtime_resume is missing somewhere.
As we need to have that working at some point, I might look into it, but
someone who has experience in the block layer can surely do it more
efficiently.
to test, turn off polling:
echo 0 > /sys/module/block/parameters/events_dfl_poll_msecs
and enable runtime pm in your (scsi) device: power/autosuspend_delay_ms
and of course power/control (set to auto).
thanks,
martin
next prev parent reply other threads:[~2020-07-28 7:03 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 11:10 [PATCH] scsi: sd: add runtime pm to open / release Martin Kepplinger
2020-06-24 13:33 ` Bart Van Assche
2020-06-25 8:16 ` Martin Kepplinger
2020-06-25 14:52 ` Alan Stern
2020-06-26 3:53 ` Bart Van Assche
2020-06-26 15:07 ` Bart Van Assche
2020-06-26 15:44 ` Alan Stern
2020-06-28 2:37 ` Bart Van Assche
2020-06-28 13:10 ` Alan Stern
2020-06-29 9:42 ` Martin Kepplinger
2020-06-29 16:15 ` Alan Stern
2020-06-29 16:56 ` Bart Van Assche
2020-06-29 17:40 ` Alan Stern
2020-06-30 3:33 ` Martin Kepplinger
2020-06-30 13:38 ` Alan Stern
2020-06-30 15:59 ` Bart Van Assche
2020-06-30 18:02 ` Alan Stern
2020-06-30 19:23 ` Bart Van Assche
2020-06-30 19:38 ` Alan Stern
2020-06-30 23:31 ` Bart Van Assche
2020-07-01 0:49 ` Alan Stern
2020-07-06 16:41 ` Alan Stern
2020-07-28 7:02 ` Martin Kepplinger [this message]
2020-07-28 20:02 ` Alan Stern
2020-07-29 14:12 ` Martin Kepplinger
2020-07-29 14:32 ` Alan Stern
2020-07-29 14:44 ` Martin K. Petersen
2020-07-29 14:56 ` Alan Stern
2020-07-29 14:46 ` James Bottomley
2020-07-29 14:53 ` James Bottomley
2020-07-29 15:40 ` Martin Kepplinger
2020-07-29 15:44 ` James Bottomley
2020-07-29 16:43 ` Martin Kepplinger
2020-07-29 18:25 ` Alan Stern
2020-07-29 18:29 ` James Bottomley
2020-07-30 8:52 ` Martin Kepplinger
2020-07-30 8:54 ` Martin Kepplinger
2020-07-30 15:10 ` Alan Stern
2020-08-04 9:39 ` Martin Kepplinger
2020-08-07 9:51 ` Martin Kepplinger
2020-08-07 14:30 ` Alan Stern
2020-08-08 6:59 ` Martin Kepplinger
2020-08-08 15:05 ` Alan Stern
2020-08-09 9:20 ` Martin Kepplinger
2020-08-09 15:26 ` Alan Stern
2020-08-10 12:03 ` Martin Kepplinger
2020-08-10 14:13 ` Alan Stern
2020-08-11 7:55 ` Martin Kepplinger
2020-08-11 13:48 ` Alan Stern
2020-08-23 14:57 ` [PATCH] block: Fix bug in runtime-resume handling Alan Stern
2020-08-24 17:48 ` Bart Van Assche
2020-08-24 20:13 ` Alan Stern
2020-08-26 7:48 ` Martin Kepplinger
2020-08-27 17:42 ` Martin Kepplinger
2020-08-27 20:29 ` Alan Stern
2020-08-29 7:24 ` Martin Kepplinger
2020-08-29 15:26 ` Alan Stern
2020-08-29 16:33 ` Martin Kepplinger
2020-08-29 18:56 ` Alan Stern
2020-08-30 0:38 ` Bart Van Assche
2020-08-30 1:06 ` Alan Stern
2020-07-29 15:40 ` [PATCH] scsi: sd: add runtime pm to open / release Alan Stern
2020-07-29 15:49 ` James Bottomley
2020-07-29 16:17 ` Alan Stern
2020-07-29 15:52 ` Martin Kepplinger
2020-07-29 18:10 ` Douglas Gilbert
2020-07-30 8:05 ` Martin Kepplinger
2020-07-30 15:14 ` Alan Stern
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