From: "Paul E. McKenney" <paulmck@us.ibm.com>
To: Oleg Nesterov <oleg@tv-sign.ru>
Cc: linux-kernel@vger.kernel.org,
Dipankar Sarma <dipankar@in.ibm.com>,
Manfred Spraul <manfred@colorfullife.com>,
Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH 2/5] rcu: don't check ->donelist in __rcu_pending()
Date: Sun, 8 Jan 2006 14:00:04 -0800 [thread overview]
Message-ID: <20060108220004.GB11410@us.ibm.com> (raw)
In-Reply-To: <43C165BC.F7C6DCF5@tv-sign.ru>
On Sun, Jan 08, 2006 at 10:19:24PM +0300, Oleg Nesterov wrote:
> ->donelist becomes != NULL only in rcu_process_callbacks().
>
> rcu_process_callbacks() always calls rcu_do_batch() when
> ->donelist != NULL.
>
> rcu_do_batch() schedules rcu_process_callbacks() again if
> ->donelist was not flushed entirely.
>
> So ->donelist != NULL means that rcu_tasklet is either
> TASKLET_STATE_SCHED or TASKLET_STATE_RUN, we don't need to
> check it in __rcu_pending().
>
> [ This patch was tested with rcutorture.ko, I don't understand
> it's output, but it says "End of test: SUCCESS". So if this
> patch incorrect blame Paul, not me! ]
;-)
Did you run the newest version of rcutorture.ko that includes
Vatsa's CPU-hotplug additions?
Thanx, Paul
> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
>
> --- 2.6.15/kernel/rcupdate.c~2_DONE 2006-01-08 21:35:21.000000000 +0300
> +++ 2.6.15/kernel/rcupdate.c 2006-01-08 21:55:45.000000000 +0300
> @@ -454,10 +454,6 @@ static int __rcu_pending(struct rcu_ctrl
> if (!rdp->curlist && rdp->nxtlist)
> return 1;
>
> - /* This cpu has finished callbacks to invoke */
> - if (rdp->donelist)
> - return 1;
> -
> /* The rcu core waits for a quiescent state from the cpu */
> if (rdp->quiescbatch != rcp->cur || rdp->qs_pending)
> return 1;
>
next prev parent reply other threads:[~2006-01-08 21:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-08 19:19 [PATCH 2/5] rcu: don't check ->donelist in __rcu_pending() Oleg Nesterov
2006-01-08 22:00 ` Paul E. McKenney [this message]
2006-01-09 9:31 ` Srivatsa Vaddagiri
2006-01-09 14:51 ` Oleg Nesterov
2006-01-09 13:42 ` Srivatsa Vaddagiri
2006-01-09 15:33 ` Oleg Nesterov
2006-01-09 18:59 ` Paul E. McKenney
2006-01-09 20:31 ` Oleg Nesterov
2006-01-09 19:59 ` Paul E. McKenney
2006-01-10 9:58 ` Srivatsa Vaddagiri
2006-01-10 14:24 ` [PATCH] rcu: fix hotplug-cpu ->donelist leak Oleg Nesterov
2006-01-11 5:01 ` Paul E. McKenney
2006-01-11 16:28 ` Paul E. McKenney
2006-01-11 19:25 ` Oleg Nesterov
2006-01-11 18:21 ` Paul E. McKenney
2006-01-10 14:27 ` [PATCH 2/5] rcu: don't check ->donelist in __rcu_pending() Oleg Nesterov
2006-01-10 18:13 ` Dipankar Sarma
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