From: Waiman Long <waiman.long@hpe.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, <linux-kernel@vger.kernel.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Jason Low <jason.low2@hp.com>,
Scott J Norton <scott.norton@hpe.com>,
Douglas Hatch <doug.hatch@hpe.com>
Subject: Re: [PATCH v2] locking/rwsem: Add reader-owned state to the owner field
Date: Fri, 20 May 2016 18:56:53 -0400 [thread overview]
Message-ID: <573F9635.7080006@hpe.com> (raw)
In-Reply-To: <20160519013753.GF21200@dastard>
On 05/18/2016 09:37 PM, Dave Chinner wrote:
> On Fri, May 06, 2016 at 08:20:24PM -0400, Waiman Long wrote:
>> Currently, it is not possible to determine for sure if a reader
>> owns a rwsem by looking at the content of the rwsem data structure.
>> This patch adds a new state RWSEM_READER_OWNED to the owner field
>> to indicate that readers currently own the lock.
> Oh, yes please. This will enable us to get rid of the remaining
> mrlock rwsem abstraction we've carried since the days of Irix in
> XFS. The only reason the abstraction still exists is that we track
> write locks for the purposes of checking for correct inode locking
> contexts via ASSERT(xfs_isilocked()) calls....
I think we could add code to export this read/write ownership
information. However, that will only work when both
CONFIG_RWSEM_XCHGADD_ALGORITHM and CONFIG_RWSEM_SPIN_ON_OWNER are set.
So this functionality may not be available in some architectures that
use CONFIG_RWSEM_GENERIC_SPINLOCK.
Cheers,
Longman
prev parent reply other threads:[~2016-05-20 22:57 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-07 0:20 [PATCH v2] locking/rwsem: Add reader-owned state to the owner field Waiman Long
2016-05-07 4:56 ` Ingo Molnar
2016-05-08 3:04 ` Waiman Long
2016-05-09 8:27 ` Peter Zijlstra
2016-05-10 2:24 ` Waiman Long
2016-05-10 7:02 ` Peter Zijlstra
2016-05-09 18:44 ` Jason Low
2016-05-10 13:03 ` Davidlohr Bueso
2016-05-11 22:04 ` Peter Hurley
2016-05-12 20:15 ` Waiman Long
2016-05-12 21:27 ` Peter Hurley
2016-05-12 23:13 ` Waiman Long
2016-05-13 15:07 ` Peter Zijlstra
2016-05-13 17:58 ` Peter Hurley
2016-05-15 14:47 ` Waiman Long
2016-05-16 11:09 ` Peter Zijlstra
2016-05-16 12:17 ` Paul E. McKenney
2016-05-16 14:17 ` Peter Hurley
2016-05-16 17:22 ` Paul E. McKenney
2016-05-17 19:46 ` Peter Hurley
2016-05-17 19:53 ` Peter Hurley
2016-05-16 17:50 ` Peter Zijlstra
2016-05-17 19:15 ` Peter Hurley
2016-05-17 19:46 ` Paul E. McKenney
2016-05-18 11:05 ` Peter Zijlstra
2016-05-18 15:56 ` Waiman Long
2016-05-18 17:28 ` Paul E. McKenney
2016-05-18 17:26 ` Paul E. McKenney
2016-05-19 9:00 ` Peter Zijlstra
2016-05-19 13:43 ` Paul E. McKenney
2016-05-19 1:37 ` Dave Chinner
2016-05-19 8:32 ` Peter Zijlstra
2016-05-20 22:56 ` Waiman Long [this message]
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