From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [PATCH] rcu: Only pin GP kthread when full dynticks is actually used
Date: Fri, 13 Jun 2014 09:23:23 -0700 [thread overview]
Message-ID: <20140613162323.GS4581@linux.vnet.ibm.com> (raw)
In-Reply-To: <20140613160933.GN6635@localhost.localdomain>
On Fri, Jun 13, 2014 at 06:09:35PM +0200, Frederic Weisbecker wrote:
> On Fri, Jun 13, 2014 at 08:58:12AM -0700, Paul E. McKenney wrote:
> > > Maybe what we should do instead is to have something like this on RCU kthread init:
> > >
> > > cpumask_var_t gp_kthread_mask;
> > >
> > > if (alloc_cpumask_var(gp_kthread_mask, GFP_KERNEL))
> > > return -EFAULT;
> > >
> > > cpumask_andnot(gp_kthread_mask, cpu_possible_mask, tick_nohz_full_mask);
> > >
> > > set_cpus_allowed_ptr(current, gp_kthread_mask);
> > >
> > > free_cpumask_var(gp_kthread_mask);
> >
> > I was guessing that RCU's kthreads would not be the only ones that wanted
> > similar binding. But if you feel strongly about this, we could at least
> > start by placing it local to RCU as above.
>
> Hmm, I don't feel well creating mirrored cpumasks (nor solely negation cpumasks in general).
> Also exposing that nohz gut is probably not a good idea either, except for RCU due to
> the sysidle stuff.
>
> Now you're right that we can expect that this non-nohz affinity stuff is going to be reused.
>
> Could it be housekeeping_affine(struct task_struct *tsk) maybe?
Now that you mention it, that does sound better. I will do that.
Thanx, Paul
prev parent reply other threads:[~2014-06-13 16:23 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-13 0:16 [PATCH] rcu: Only pin GP kthread when full dynticks is actually used Frederic Weisbecker
2014-06-13 1:24 ` Paul E. McKenney
2014-06-13 1:35 ` Paul E. McKenney
2014-06-13 12:47 ` Frederic Weisbecker
2014-06-13 15:52 ` Paul E. McKenney
2014-06-13 16:00 ` Frederic Weisbecker
2014-06-13 16:16 ` Paul E. McKenney
2014-06-13 16:21 ` Frederic Weisbecker
2014-06-13 16:44 ` Josh Triplett
2014-06-13 20:48 ` Paul E. McKenney
2014-06-13 21:10 ` Josh Triplett
2014-06-13 22:49 ` Paul E. McKenney
2014-06-13 23:10 ` Frederic Weisbecker
2014-06-13 23:27 ` Paul E. McKenney
2014-06-13 23:39 ` Frederic Weisbecker
2014-06-14 5:06 ` Paul E. McKenney
2014-06-14 11:26 ` Paul E. McKenney
2014-06-14 13:10 ` Frederic Weisbecker
2014-06-14 14:29 ` Paul E. McKenney
2014-06-14 13:05 ` Frederic Weisbecker
2014-06-13 20:49 ` Paul E. McKenney
2014-06-13 23:13 ` Frederic Weisbecker
2014-06-13 23:22 ` Paul E. McKenney
2014-06-13 2:05 ` Paul E. McKenney
2014-06-13 12:55 ` Frederic Weisbecker
2014-06-13 15:55 ` Paul E. McKenney
2014-06-13 16:03 ` Frederic Weisbecker
2014-06-13 16:20 ` Paul E. McKenney
2014-06-13 16:10 ` Paul E. McKenney
2014-06-13 12:42 ` Frederic Weisbecker
2014-06-13 15:58 ` Paul E. McKenney
2014-06-13 16:09 ` Frederic Weisbecker
2014-06-13 16:23 ` Paul E. McKenney [this message]
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