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From: Steven Rostedt <rostedt@goodmis.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Byungchul Park <byungchul.park@lge.com>,
	jiangshanlai@gmail.com, josh@joshtriplett.org,
	mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org,
	kernel-team@lge.com, joel@joelfernandes.org
Subject: Re: [RFC 1/2] rcu: Do prepare and cleanup idle depending on in_nmi()
Date: Wed, 20 Jun 2018 12:11:56 -0400	[thread overview]
Message-ID: <20180620121156.4da98db2@gandalf.local.home> (raw)
In-Reply-To: <20180620155658.GU3593@linux.vnet.ibm.com>

On Wed, 20 Jun 2018 08:56:58 -0700
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:

> OK, so in theory this change is safe from a tracing perspective.  But
> it does add conditionals to a fastpath.

Does it?

I see it replacing two conditions from both rcu_irq_enter/exit() with a
single one in rcu_nmi_enter/exit(). Sure it adds one to rcu_nmi_enter()
but that's a far less fast path than rcu_irq_enter(), which this patch
removes a conditional from.

-- Steve

  parent reply	other threads:[~2018-06-20 16:12 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-20  8:47 [RFC 1/2] rcu: Do prepare and cleanup idle depending on in_nmi() Byungchul Park
2018-06-20  8:47 ` [RFC 2/2] rcu: Remove ->dynticks_nmi_nesting from struct rcu_dynticks Byungchul Park
2018-06-20 14:58   ` Paul E. McKenney
2018-06-20 16:05     ` Byungchul Park
2018-06-20 16:49       ` Paul E. McKenney
2018-06-20 17:15         ` Byungchul Park
2018-06-20 17:40           ` Paul E. McKenney
2018-06-21  6:39             ` Byungchul Park
2018-06-21  6:48               ` Byungchul Park
2018-06-21 10:08               ` Byungchul Park
2018-06-21 15:05                 ` Paul E. McKenney
2018-06-21 15:04               ` Paul E. McKenney
2018-06-22  3:00                 ` Byungchul Park
2018-06-22 13:36                   ` Paul E. McKenney
2018-06-22  5:56         ` Joel Fernandes
2018-06-22 13:28           ` Paul E. McKenney
2018-06-22 14:19             ` Andy Lutomirski
2018-06-22 16:12               ` Paul E. McKenney
2018-06-22 16:01             ` Steven Rostedt
2018-06-22 18:14               ` Paul E. McKenney
2018-06-22 18:19             ` Joel Fernandes
2018-06-22 18:32               ` Steven Rostedt
2018-06-22 20:05                 ` Joel Fernandes
2018-06-25  8:28                   ` Byungchul Park
2018-06-25 16:39                     ` Joel Fernandes
2018-06-25 17:19                       ` Paul E. McKenney
2018-06-25 19:15                         ` Joel Fernandes
2018-06-25 20:25                       ` Steven Rostedt
2018-06-25 20:47                         ` Paul E. McKenney
2018-06-25 20:47                           ` Andy Lutomirski
2018-06-25 22:16                             ` Steven Rostedt
2018-06-25 23:30                               ` Andy Lutomirski
2018-06-25 22:15                           ` Steven Rostedt
2018-06-25 23:32                             ` Andy Lutomirski
2018-06-25 21:25                         ` Joel Fernandes
2018-06-22 20:58                 ` Paul E. McKenney
2018-06-22 20:58               ` Paul E. McKenney
2018-06-22 21:00                 ` Steven Rostedt
2018-06-22 21:16                   ` Paul E. McKenney
2018-06-22 22:03                     ` Andy Lutomirski
2018-06-23 17:53                       ` Paul E. McKenney
2018-06-28 20:02                         ` Paul E. McKenney
2018-06-28 21:13                           ` Joel Fernandes
2018-06-28 21:41                             ` Paul E. McKenney
2018-06-23 15:48                     ` Joel Fernandes
2018-06-23 17:56                       ` Paul E. McKenney
2018-06-24  3:02                         ` Joel Fernandes
2018-06-20 13:33 ` [RFC 1/2] rcu: Do prepare and cleanup idle depending on in_nmi() Steven Rostedt
2018-06-20 14:58   ` Paul E. McKenney
2018-06-20 15:25   ` Byungchul Park
2018-06-20 14:50 ` Paul E. McKenney
2018-06-20 15:43   ` Steven Rostedt
2018-06-20 15:56     ` Paul E. McKenney
2018-06-20 16:11       ` Byungchul Park
2018-06-20 16:14         ` Steven Rostedt
2018-06-20 16:37           ` Byungchul Park
2018-06-20 16:11       ` Steven Rostedt [this message]
2018-06-20 16:30         ` Paul E. McKenney

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