From: Davidlohr Bueso <dave@stgolabs.net>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jason Low <jason.low2@hpe.com>,
Peter Hurley <peter@hurleysoftware.com>,
jason.low2@hp.com, Waiman Long <waiman.long@hpe.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, Dave Chinner <david@fromorbit.com>,
Scott J Norton <scott.norton@hpe.com>,
Douglas Hatch <doug.hatch@hpe.com>
Subject: Re: [PATCH v4 2/5] locking/rwsem: Protect all writes to owner by WRITE_ONCE
Date: Mon, 23 May 2016 14:04:55 -0700 [thread overview]
Message-ID: <20160523210455.7rycskjo7n5rw73k@linux-uzut.site> (raw)
In-Reply-To: <20160523201502.GN3825@linux.vnet.ibm.com>
On Mon, 23 May 2016, Paul E. McKenney wrote:
>But rcu_read_lock() does not exclude updates, which is one reason why
>pointer reads use rcu_dereference() rather than normal assignments.
Yes, I was referring to readers. With updates, otoh, are done holding a number of locks.
>
>So I do not believe that rcu_read_lock() is helping you in this case.
>
>That said, it is a bit hard to imagine the compiler tearing a load from
>an int...
Oh, right, good point.
Thanks,
Davidlohr
next prev parent reply other threads:[~2016-05-23 21:05 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-18 1:26 [PATCH v4 0/5] [PATCH v3 0/4] locking/rwsem: Add reader-owned state to the owner field Waiman Long
2016-05-18 1:26 ` [PATCH v4 1/5] " Waiman Long
2016-06-06 17:18 ` Davidlohr Bueso
2016-06-06 20:03 ` Waiman Long
2016-06-06 21:02 ` Peter Zijlstra
2016-06-06 21:49 ` Waiman Long
2016-06-08 14:25 ` [tip:locking/core] " tip-bot for Waiman Long
2016-05-18 1:26 ` [PATCH v4 2/5] locking/rwsem: Protect all writes to owner by WRITE_ONCE() Waiman Long
2016-05-18 14:04 ` Davidlohr Bueso
2016-05-18 17:21 ` [PATCH v4 2/5] locking/rwsem: Protect all writes to owner by WRITE_ONCE Jason Low
2016-05-18 18:29 ` Waiman Long
2016-05-18 19:58 ` Jason Low
2016-05-19 22:21 ` Jason Low
2016-05-20 20:26 ` Waiman Long
2016-05-21 16:04 ` Peter Hurley
2016-05-22 10:42 ` Peter Zijlstra
2016-05-23 18:46 ` Jason Low
2016-05-23 19:44 ` Davidlohr Bueso
2016-05-23 20:15 ` Paul E. McKenney
2016-05-23 21:04 ` Davidlohr Bueso [this message]
2016-05-25 1:25 ` Waiman Long
2016-05-18 17:23 ` [PATCH v4 2/5] locking/rwsem: Protect all writes to owner by WRITE_ONCE() Jason Low
2016-06-08 14:25 ` [tip:locking/core] " tip-bot for Waiman Long
2016-05-18 1:26 ` [PATCH v4 3/5] locking/rwsem: Don't wake up one's own task Waiman Long
2016-05-18 10:30 ` Peter Zijlstra
2016-05-18 16:04 ` Waiman Long
2016-05-18 1:26 ` [PATCH v4 4/5] locking/rwsem: Improve reader wakeup code Waiman Long
2016-06-08 14:25 ` [tip:locking/core] " tip-bot for Waiman Long
2016-05-18 1:26 ` [PATCH v4 5/5] locking/rwsem: Streamline the rwsem_optimistic_spin() code Waiman Long
2016-06-08 14:26 ` [tip:locking/core] " tip-bot for Waiman Long
2016-05-18 10:52 ` [PATCH v4 0/5] [PATCH v3 0/4] locking/rwsem: Add reader-owned state to the owner field Peter Zijlstra
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