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From: Matthew Wilcox <matthew@wil.cx>
To: Lin Ming <ming.m.lin@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	Alan Stern <stern@rowland.harvard.edu>,
	"Rafael J. Wysocki" <rjw@sisk.pl>, Shaohua Li <shli@kernel.org>,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	linux-scsi@vger.kernel.org
Subject: Re: [PATCH v5 3/4] block: implement runtime pm strategy
Date: Fri, 6 Jul 2012 01:27:52 -0600	[thread overview]
Message-ID: <20120706072752.GD17681@parisc-linux.org> (raw)
In-Reply-To: <1341547472-6863-4-git-send-email-ming.m.lin@intel.com>

On Fri, Jul 06, 2012 at 12:04:31PM +0800, Lin Ming wrote:
> When a request is added:
>     If device is suspended or is suspending and the request is not a
>     PM request, resume the device.
> 
> When a request finishes:
>     Call pm_runtime_mark_last_busy().
> 
> When pick a request:
>     If device is resuming/suspending, then only PM request is allowed to go.
>     Return NULL for other cases.

This only works for drivers which are struct request based.  For those
that handle struct bio directly, nr_pending will always be 0.

I think the right place to increment nr_pending is in generic_make_request.
But I'm not sure where to decrement it.  I think we need a blk_bio_endio()
which does some housekeeping and then calls bio_endio().

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

  parent reply	other threads:[~2012-07-06  7:35 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-06  4:04 [PATCH v5 0/4] block layer runtime pm Lin Ming
2012-07-06  4:04 ` [PATCH v5 1/4] block: add a flag to identify PM request Lin Ming
2012-07-06  4:04 ` [PATCH v5 2/4] block: add runtime pm helpers Lin Ming
2012-07-06  4:04 ` [PATCH v5 3/4] block: implement runtime pm strategy Lin Ming
2012-07-06  5:00   ` James Bottomley
2012-07-06  6:07     ` Lin Ming
2012-07-06  8:05       ` James Bottomley
2012-07-06 14:59         ` Alan Stern
2013-01-14  7:18         ` Aaron Lu
2012-07-06  7:27   ` Matthew Wilcox [this message]
2012-07-06 14:21   ` Alan Stern
2012-07-06 14:51     ` Lin Ming
2012-07-06  4:04 ` [PATCH v5 4/4] [SCSI] sd: change to auto suspend mode Lin Ming

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