From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Joe Lawrence <joe.lawrence@stratus.com>
Cc: Jiri Pirko <jiri@resnulli.us>, Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v2 1/2] workqueue: add quiescent state between work items
Date: Tue, 7 Oct 2014 20:24:11 -0700 [thread overview]
Message-ID: <20141008032411.GG4880@linux.vnet.ibm.com> (raw)
In-Reply-To: <20141007134528.1a59f31b@jlaw-desktop.mno.stratus.com>
On Tue, Oct 07, 2014 at 01:45:28PM -0400, Joe Lawrence wrote:
> On Tue, 7 Oct 2014 06:43:29 -0700
> "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
>
> > On Tue, Oct 07, 2014 at 09:29:42AM +0200, Jiri Pirko wrote:
> [ ... snip ... ]
> > >
> > > Paul, Tehun, how do you propose to fix this on older kernels which do
> > > not have rcu_note_voluntary_context_switch? I'm particullary interested
> > > in 3.10.
> >
> > Hello, Jiri,
> >
> > Older kernels can instead use rcu_note_context_switch().
>
> Hi Paul,
>
> Does 4a81e8328d37 ("rcu: Reduce overhead of cond_resched() checks for
> RCU") affect a backport to 3.10?
>
> I noticed that rcu_note_context_switch added a call to
> rcu_momentary_dyntick_idle in that change, which is only present in
> v3.16+.
>
> Would rcu_note_context_switch be effective by itself on a 3.10 kernel?
Should be fine. There is more overhead than current mainline, but that
should not be in the noise compared to executing a work-queue item.
Thanx, Paul
next prev parent reply other threads:[~2014-10-08 3:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-05 17:24 [PATCH v2 0/2] workqueue: add RCU quiescent state between items Joe Lawrence
2014-10-05 17:24 ` [PATCH v2 1/2] workqueue: add quiescent state between work items Joe Lawrence
2014-10-05 19:21 ` Tejun Heo
2014-10-05 19:47 ` Tejun Heo
2014-10-06 4:21 ` Paul E. McKenney
2014-10-07 7:29 ` Jiri Pirko
2014-10-07 13:43 ` Paul E. McKenney
2014-10-07 17:45 ` Joe Lawrence
2014-10-08 3:24 ` Paul E. McKenney [this message]
2014-10-08 11:54 ` Jiri Pirko
2014-10-08 12:19 ` Paul E. McKenney
2014-10-05 17:24 ` [PATCH v2 2/2] workqueue: use cond_resched_rcu_qs macro Joe Lawrence
2014-10-05 18:47 ` Paul E. McKenney
2014-10-05 19:48 ` Tejun Heo
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