From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Neeraj Upadhyay <neeraju@codeaurora.org>,
josh@joshtriplett.org, mathieu.desnoyers@efficios.com,
jiangshanlai@gmail.com, linux-kernel@vger.kernel.org,
sramana@codeaurora.org, prsood@codeaurora.org,
pkondeti@codeaurora.org, markivx@codeaurora.org
Subject: Re: Query regarding synchronize_sched_expedited and resched_cpu
Date: Thu, 21 Sep 2017 08:31:34 -0700 [thread overview]
Message-ID: <20170921153134.GG3521@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170921135546.x3q3zeicbo2vtjvk@hirez.programming.kicks-ass.net>
On Thu, Sep 21, 2017 at 03:55:46PM +0200, Peter Zijlstra wrote:
> On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote:
> > On Sun, 17 Sep 2017 11:37:06 +0530
> > Neeraj Upadhyay <neeraju@codeaurora.org> wrote:
> >
> > > Hi Paul, how about replacing raw_spin_trylock_irqsave with
> > > raw_spin_lock_irqsave in resched_cpu()? Are there any paths
> > > in RCU code, which depend on trylock check/spinlock recursion?
> >
> > It looks to me that resched_cpu() was added for nohz full sched
> > balancing, but is not longer used by that. The only user is currently
> > RCU. Perhaps we should change that from a trylock to a lock.
>
> No, regular NOHZ balancing. NOHZ FULL wasn't conceived back then.
>
> 46cb4b7c88fa ("sched: dynticks idle load balancing")
>
> And yeah, its no longer used for that.
>
> And given RCU is the only user of that thing, I suppose we can indeed
> change it to a full lock.
Thank you! May I have your ack?
Thanx, Paul
next prev parent reply other threads:[~2017-09-21 15:31 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-15 11:14 Query regarding synchronize_sched_expedited and resched_cpu Neeraj Upadhyay
2017-09-17 1:00 ` Paul E. McKenney
2017-09-17 6:07 ` Neeraj Upadhyay
2017-09-18 15:11 ` Steven Rostedt
2017-09-18 16:01 ` Paul E. McKenney
2017-09-18 16:12 ` Steven Rostedt
2017-09-18 16:24 ` Paul E. McKenney
2017-09-18 16:29 ` Steven Rostedt
2017-09-18 16:55 ` Paul E. McKenney
2017-09-18 23:53 ` Paul E. McKenney
2017-09-19 1:23 ` Steven Rostedt
2017-09-19 2:26 ` Paul E. McKenney
2017-09-19 1:50 ` Byungchul Park
2017-09-19 2:06 ` Byungchul Park
2017-09-19 2:33 ` Paul E. McKenney
2017-09-19 2:48 ` Byungchul Park
2017-09-19 4:04 ` Paul E. McKenney
2017-09-19 5:37 ` Boqun Feng
2017-09-19 6:11 ` Mike Galbraith
2017-09-19 6:53 ` Byungchul Park
2017-09-19 13:40 ` Paul E. McKenney
2017-09-21 13:57 ` Peter Zijlstra
2017-09-21 15:33 ` Paul E. McKenney
2017-09-19 1:55 ` Byungchul Park
2017-09-19 15:31 ` Paul E. McKenney
2017-09-19 15:58 ` Steven Rostedt
2017-09-19 16:12 ` Paul E. McKenney
2017-09-21 13:59 ` Peter Zijlstra
2017-09-21 16:00 ` Paul E. McKenney
2017-09-21 16:30 ` Peter Zijlstra
2017-09-21 16:47 ` Paul E. McKenney
2017-09-21 13:55 ` Peter Zijlstra
2017-09-21 15:31 ` Paul E. McKenney [this message]
2017-09-21 16:18 ` Peter Zijlstra
2017-09-21 15:46 ` Steven Rostedt
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