From: Christoph Hellwig <hch@lst.de>
To: Jason Baron <jbaron@akamai.com>
Cc: Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: waitqueue lockdep annotation
Date: Fri, 1 Dec 2017 18:11:02 +0100 [thread overview]
Message-ID: <20171201171102.GA20072@lst.de> (raw)
In-Reply-To: <21c34413-d178-fda0-91b2-6ab02c6d5a06@akamai.com>
On Thu, Nov 30, 2017 at 05:18:07PM -0500, Jason Baron wrote:
> Yes, but for those cases it uses the ep->poll_wait waitqueue not the
> ep->wq, which is guarded by the ep->wq->lock.
True. So it looks like we have one waitqueue in the system that is
special in providing its own synchronization for waitqueues while
entirely ignoring the waitqueue code documentation that states that
waitqueues are internally synchronized.
We could drop the lockdep annotation, updated the documentation and
not add any validation of the assumptions, or just make epoll fit the
scheme used by everyone else. So either we can drop these patches, or
I need to fix up more of the epoll code.
next prev parent reply other threads:[~2017-12-01 17:11 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-30 14:20 waitqueue lockdep annotation Christoph Hellwig
2017-11-30 14:20 ` [PATCH 1/2] sched/wait: assert the wait_queue_head lock is held in __wake_up_common Christoph Hellwig
2017-11-30 14:20 ` [PATCH 2/2] epoll: use proper wake_up variant in ep_poll_callback Christoph Hellwig
2017-11-30 20:50 ` waitqueue lockdep annotation Andrew Morton
2017-11-30 21:38 ` Jason Baron
2017-11-30 22:11 ` Christoph Hellwig
2017-11-30 22:18 ` Jason Baron
2017-12-01 17:11 ` Christoph Hellwig [this message]
2017-12-01 19:00 ` Jason Baron
2017-12-01 22:02 ` Christoph Hellwig
2017-12-01 22:34 ` Jason Baron
2017-12-01 23:03 ` Christoph Hellwig
2017-12-05 15:24 ` Jason Baron
2017-12-05 15:36 ` Davidlohr Bueso
2017-12-06 23:51 ` Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2017-12-06 23:52 Christoph Hellwig
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