Re: [PATCH v3 3/4] locking/rwsem: Improve reader wakeup code

From	Peter Hurley <peter@hurleysoftware.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 3/4] locking/rwsem: Improve reader wakeup code
Date	2016-05-17 19:40 +0200
Message-ID	<rzR8l-7vF-3@gated-at.bofh.it> (permalink)
References	<ry7Kh-7bF-5@gated-at.bofh.it> <ry7Kh-7bF-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 05/12/2016 03:56 PM, Waiman Long wrote:
> In __rwsem_do_wake(), the reader wakeup code will assume a writer
> has stolen the lock if the active reader/writer count is not 0.
> However, this is not as reliable an indicator as the original
> "< RWSEM_WAITING_BIAS" check. If another reader is present, the code
> will still break out and exit even if the writer is gone. This patch
> changes it to check the same "< RWSEM_WAITING_BIAS" condition to
> reduce the chance of false positive.

Nice.

Reviewed-by: Peter Hurley <peter@hurleysoftware.com>

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[PATCH v3 3/4] locking/rwsem: Improve reader wakeup code Waiman Long <Waiman.Long@hpe.com> - 2016-05-13 01:00 +0200
  Re: [PATCH v3 3/4] locking/rwsem: Improve reader wakeup code Peter Hurley <peter@hurleysoftware.com> - 2016-05-17 19:40 +0200

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