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From: Tejun Heo <tj@kernel.org>
To: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Christoph Lameter <cl@linux.com>, NeilBrown <neilb@suse.com>
Subject: Re: [PATCH 1/5] percpu-refcount: Introduce percpu_ref_switch_to_atomic_nowait()
Date: Mon, 11 Sep 2017 06:13:31 -0700	[thread overview]
Message-ID: <20170911131331.GE1774378@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20170908235226.26622-2-bart.vanassche@wdc.com>

On Fri, Sep 08, 2017 at 04:52:22PM -0700, Bart Van Assche wrote:
> The blk-mq core keeps track of the number of request queue users
> through q->q_usage_count. Make it possible to switch this counter
> to atomic mode from the context of the block layer power management
> code by introducing percpu_ref_switch_to_atomic_nowait().

Do you ever have to switch back?  If so, how do you know whether the
previous transition finished?

Thanks.

-- 
tejun

  parent reply	other threads:[~2017-09-11 13:13 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-08 23:52 [PATCH 0/5] Make SCSI device suspend work reliably Bart Van Assche
2017-09-08 23:52 ` [PATCH 1/5] percpu-refcount: Introduce percpu_ref_switch_to_atomic_nowait() Bart Van Assche
2017-09-11  8:42   ` Johannes Thumshirn
2017-09-11 16:10     ` Bart Van Assche
2017-09-11 13:13   ` Tejun Heo [this message]
2017-09-11 16:09     ` Bart Van Assche
2017-09-11 16:37       ` tj
2017-09-11 16:55         ` Bart Van Assche
2017-09-11 17:20           ` Tejun Heo
2017-09-11 17:29             ` Bart Van Assche
2017-09-08 23:52 ` [PATCH 2/5] scsi: Change the type of the second last argument of scsi_execute() Bart Van Assche
2017-09-08 23:52 ` [PATCH 3/5] block: Introduce REQ_PM and remove RQF_PM Bart Van Assche
2017-09-08 23:52 ` [PATCH 4/5] block: Make SCSI device suspend work reliably Bart Van Assche
2017-09-12  2:29   ` Ming Lei
2017-09-12 15:45     ` Bart Van Assche
2017-09-12 16:10       ` Ming Lei
2017-09-12 16:25   ` Ming Lei
2017-09-08 23:52 ` [PATCH 5/5] blk-mq: Implement power management support Bart Van Assche
2017-09-12  9:14   ` Ming Lei
2017-09-09 10:39 ` [PATCH 0/5] Make SCSI device suspend work reliably Ming Lei
2017-09-11 16:25   ` Bart Van Assche
2017-09-12  2:17     ` Ming Lei

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