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>,
"tom.leiming@gmail.com" <tom.leiming@gmail.com>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"jthumshirn@suse.de" <jthumshirn@suse.de>,
"axboe@kernel.dk" <axboe@kernel.dk>
Subject: Re: [PATCH 2/3] block, scsi: Rework runtime power management
Date: Thu, 19 Jul 2018 15:54:53 +0000 [thread overview]
Message-ID: <c15e8f2b15b734284a983102e8e91a8f28cd2686.camel@wdc.com> (raw)
In-Reply-To: <20180718224545.GA15589@ming.t460p>
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On Thu, 2018-07-19 at 06:45 +-0800, Ming Lei wrote:
+AD4- So once blk+AF8-freeze+AF8-queue+AF8-start() returns, percpu+AF8-ref+=
AF8-is+AF8-zero() won't
+AD4- return true only until the rcu confirmation is done. That means this
+AD4- approach may not put device down.
Hello Ming,
I agree with your conclusion that it is not guaranteed that q-+AD4-q+AF8-us=
age+AF8-counter
is in atomic mode when percpu+AF8-ref+AF8-is+AF8-zero() is called. However,=
I think that's
fine: if blk+AF8-pre+AF8-runtime+AF8-suspend() returns -EBUSY then the runt=
ime core will
try again at a later time to perform runtime suspend.
Bart.=
next prev parent reply other threads:[~2018-07-19 15:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-17 23:49 [PATCH 0/3] blk-mq: Enable runtime power management Bart Van Assche
2018-07-17 23:49 ` [PATCH 1/3] block: Fix a comment in a header file Bart Van Assche
2018-07-18 6:47 ` Johannes Thumshirn
2018-07-17 23:49 ` [PATCH 2/3] block, scsi: Rework runtime power management Bart Van Assche
2018-07-18 12:16 ` Ming Lei
2018-07-18 15:45 ` Bart Van Assche
2018-07-18 22:45 ` Ming Lei
2018-07-19 15:54 ` Bart Van Assche [this message]
2018-07-19 23:26 ` Ming Lei
2018-07-17 23:49 ` [PATCH 3/3] blk-mq: Enable support for " Bart Van Assche
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