From: Tejun Heo <tj@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: jack@suse.cz, axboe@kernel.dk, clm@fb.com, jbacik@fb.com,
kernel-team@fb.com, linux-kernel@vger.kernel.org,
linux-btrfs@vger.kernel.org, peterz@infradead.org,
jianchao.w.wang@oracle.com, Bart.VanAssche@wdc.com
Subject: Re: [PATCH 1/7] blk-mq: protect completion path with RCU
Date: Mon, 8 Jan 2018 09:12:34 -0800 [thread overview]
Message-ID: <20180108171234.GX3668920@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20171229100418.GB4020@infradead.org>
Hello, Christoph.
On Fri, Dec 29, 2017 at 02:04:18AM -0800, Christoph Hellwig wrote:
> Why do you need the srcu protection? The completion path can never
> sleep.
>
> If there is a good reason to keep it please add commment, and
> make the srcu variant a separate function only used by drivers that
> need it instead of adding the conditional.
It's either that or adding protection against both srcu and rcu in the
counterpart. It's easier / cleaner to just use single rcu construct
for a given queue. Will add a comment. Jens already has a patch
which factors out the conditionals.
Thanks.
--
tejun
next prev parent reply other threads:[~2018-01-08 17:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171216120726.517153-1-tj@kernel.org>
[not found] ` <20171229100239.GA4020@infradead.org>
2018-01-08 17:03 ` [PATCHSET v3] blk-mq: reimplement timeout handling Tejun Heo
[not found] ` <20171216120726.517153-2-tj@kernel.org>
[not found] ` <20171229100418.GB4020@infradead.org>
2018-01-08 17:12 ` Tejun Heo [this message]
[not found] ` <20171216120726.517153-6-tj@kernel.org>
[not found] ` <64dfa760-d433-1537-9bc6-b12cda3c9dc6@oracle.com>
[not found] ` <20171221135051.GE1084507@devbig577.frc2.facebook.com>
[not found] ` <4e5aa629-f341-d077-961b-c778ceb31154@oracle.com>
2018-01-08 17:27 ` [PATCH 5/7] blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mq Tejun Heo
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