From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Davidlohr Bueso <dave@stgolabs.net>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
Oleg Nesterov <oleg@redhat.com>,
Amir Goldstein <amir73il@gmail.com>, Jan Kara <jack@suse.cz>
Subject: Re: [RFC PATCH v2 2/2] locking/percpu-rwsem: Mark rwsem as non-spinnable in percpu_rwsem_release()
Date: Tue, 15 May 2018 10:35:25 +0200 [thread overview]
Message-ID: <20180515083525.GV12217@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1526326267-22501-3-git-send-email-longman@redhat.com>
On Mon, May 14, 2018 at 03:31:07PM -0400, Waiman Long wrote:
> The percpu_rwsem_release() is called when the ownership of the embedded
> rwsem is to be transferred to another task. The new owner, however, may
> take a while to get the ownership of the lock via percpu_rwsem_acquire().
> During that period, the rwsem is now marked as writer-owned with no
> optimistic spinning.
This does not explain the problem sufficiently to even begin considering
if the proposed solution is sensible.
next prev parent reply other threads:[~2018-05-15 8:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 19:31 [RFC PATCH v2 0/2] locking/rwsem: Fix DEBUG_RWSEM warning from thaw_sup Waiman Long
2018-05-14 19:31 ` [RFC PATCH v2 1/2] locking/rwsem: Add a new RWSEM_WRITER_OWNED_NOSPIN flag Waiman Long
2018-05-15 6:59 ` Amir Goldstein
2018-05-15 8:25 ` Peter Zijlstra
2018-05-14 19:31 ` [RFC PATCH v2 2/2] locking/percpu-rwsem: Mark rwsem as non-spinnable in percpu_rwsem_release() Waiman Long
2018-05-15 5:42 ` Amir Goldstein
2018-05-15 7:04 ` Amir Goldstein
2018-05-15 13:45 ` Waiman Long
2018-05-15 8:35 ` Peter Zijlstra [this message]
2018-05-15 9:00 ` Jan Kara
2018-05-15 11:33 ` Oleg Nesterov
2018-05-15 8:51 ` Peter Zijlstra
2018-05-15 11:06 ` Oleg Nesterov
2018-05-15 11:51 ` Peter Zijlstra
2018-05-15 12:45 ` Oleg Nesterov
2018-05-15 12:58 ` Peter Zijlstra
2018-05-15 13:57 ` Waiman Long
2018-05-15 14:00 ` Matthew Wilcox
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