From: Joel Fernandes <joel@joelfernandes.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com,
dipankar@in.ibm.com, akpm@linux-foundation.org,
mathieu.desnoyers@efficios.com, josh@joshtriplett.org,
tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com,
oleg@redhat.com, linux-mm@kvack.org
Subject: Re: [PATCH tip/core/rcu 02/26] mm/mmap.c: Add cond_resched() for exit_mmap() CPU stalls
Date: Tue, 23 Jun 2020 17:01:11 -0400 [thread overview]
Message-ID: <20200623210111.GA117936@google.com> (raw)
In-Reply-To: <20200623205508.GS9247@paulmck-ThinkPad-P72>
On Tue, Jun 23, 2020 at 01:55:08PM -0700, Paul E. McKenney wrote:
[..]
> > Just for my understanding, cond_resched_tasks_rcu_qs() may not help here
> > because preemption is not disabled right? Still I see no harm in using it
> > here either as it may give a slight speed up for tasks-RCU.
>
> The RCU-tasks stall-warning interval is ten minutes, and I have not yet
> seen evidence that we are getting close to that. If we do, then yes,
> a cond_resched_tasks_rcu_qs() might be in this code's future. But it
> does add overhead, so we need to see the evidence first.
Yes, true about that overhead. Ok, this is fine with me too, thanks :)
- Joel
prev parent reply other threads:[~2020-06-23 21:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200623002128.GA25456@paulmck-ThinkPad-P72>
2020-06-23 0:21 ` [PATCH tip/core/rcu 02/26] mm/mmap.c: Add cond_resched() for exit_mmap() CPU stalls paulmck
2020-06-23 0:47 ` Shakeel Butt
2020-06-23 0:57 ` Paul E. McKenney
2020-06-23 19:34 ` Joel Fernandes
2020-06-23 20:55 ` Paul E. McKenney
2020-06-23 21:01 ` Joel Fernandes [this message]
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