public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	linux-kernel@vger.kernel.org, mingo@elte.hu,
	laijs@cn.fujitsu.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, josh@joshtriplett.org, niv@us.ibm.com,
	tglx@linutronix.de, dhowells@redhat.com, edumazet@google.com,
	darren@dvhart.com, sbw@mit.edu
Subject: Re: [PATCH] rcu: Is it safe to enter an RCU read-side critical section?
Date: Mon, 9 Sep 2013 13:29:08 -0400	[thread overview]
Message-ID: <20130909172908.GA31239@Krystal> (raw)
In-Reply-To: <20130909165836.GB3966@linux.vnet.ibm.com>

* Paul E. McKenney (paulmck@linux.vnet.ibm.com) wrote:
> On Mon, Sep 09, 2013 at 12:34:22PM -0400, Steven Rostedt wrote:
[...]
> > "rcu_is_ignored()" or "rcu_is_not_active()", "rcu_is_watching_you()"
> 
> You know, I am strongly tempted by "rcu_is_watching_you()", but I have
> this feeling that it is too cute for its own good.  ;-)

Wow, I just got off the plane, and look at what happened to this thread
;-)

Referring to your earlier question Paul, what I meant by my earlier
email on naming has been addressed by Steven: when exposing a new RCU
API, even if it is just for in-kernel use, we should be really cautious
not to tie it to implementation, but rather to concepts. Basically, my
original thought is that we should be able to express the exact same
concept in the kernel RCU implementation and in Userspace RCU. Here,
binding the name on whether the CPU is watching RCU really makes no
sense for urcu, since all the RCU flavors we currently have are watching
threads, not CPUs.

Hence my proposal for "rcu_read_check()". It could be "rcu_is_active()"
too, I don't really mind. It really minds: Is RCU actively watching the
current execution context ? This can be translated to a runtime check
too: is it safe to call rcu_read_lock() form this context ?

Thanks,

Mathieu


-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

  parent reply	other threads:[~2013-09-09 17:29 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-05 19:52 [PATCH] rcu: Is it safe to enter an RCU read-side critical section? Paul E. McKenney
2013-09-05 20:25 ` Steven Rostedt
2013-09-05 20:59   ` Paul E. McKenney
2013-09-05 21:05     ` Paul E. McKenney
2013-09-05 23:40       ` Steven Rostedt
2013-09-06 10:59 ` Frederic Weisbecker
2013-09-06 15:18   ` Paul E. McKenney
2013-09-06 15:33     ` Steven Rostedt
2013-09-06 16:40       ` Frederic Weisbecker
2013-09-06 16:52         ` Steven Rostedt
2013-09-06 16:58           ` Paul E. McKenney
2013-09-06 17:00           ` Frederic Weisbecker
2013-09-06 17:16             ` Steven Rostedt
2013-09-06 17:52               ` Paul E. McKenney
2013-09-06 17:56                 ` Paul E. McKenney
2013-09-06 18:21                 ` Steven Rostedt
2013-09-07  0:49                   ` Paul E. McKenney
2013-09-07  1:19                     ` Mathieu Desnoyers
2013-09-08  1:55                       ` Paul E. McKenney
2013-09-09 10:56                 ` Peter Zijlstra
2013-09-06 17:21     ` Eric Dumazet
2013-09-06 17:41       ` Paul E. McKenney
2013-09-06 18:59         ` Frederic Weisbecker
2013-09-06 20:38           ` Paul E. McKenney
2013-09-09 10:53           ` Peter Zijlstra
2013-09-09 12:13             ` Frederic Weisbecker
2013-09-09 12:39               ` Steven Rostedt
2013-09-09 12:45                 ` Frederic Weisbecker
2013-09-09 12:55                   ` Steven Rostedt
2013-09-09 13:08                     ` Frederic Weisbecker
2013-09-09 13:21                       ` Steven Rostedt
2013-09-09 13:29                         ` Paul E. McKenney
2013-09-09 13:29                         ` Steven Rostedt
2013-09-09 13:37                           ` Peter Zijlstra
2013-09-09 13:48                           ` Paul E. McKenney
2013-09-09 14:40                           ` Frederic Weisbecker
2013-09-09 15:20                             ` Steven Rostedt
2013-09-09 15:39                               ` Steven Rostedt
2013-09-09 16:03                                 ` Frederic Weisbecker
2013-09-09 16:09                               ` Paul E. McKenney
2013-09-09 16:30                                 ` Steven Rostedt
2013-09-09 16:56                                   ` Paul E. McKenney
2013-09-09 16:21                             ` Peter Zijlstra
2013-09-09 13:45                         ` Frederic Weisbecker
2013-09-09 13:56                           ` Paul E. McKenney
2013-09-09 14:16                             ` Steven Rostedt
2013-09-09 16:17                               ` Paul E. McKenney
2013-09-09 16:34                                 ` Steven Rostedt
2013-09-09 16:58                                   ` Paul E. McKenney
2013-09-09 17:06                                     ` Steven Rostedt
2013-09-09 17:45                                       ` Paul E. McKenney
2013-09-09 17:29                                     ` Mathieu Desnoyers [this message]
2013-09-09 17:56                                       ` Paul E. McKenney
2013-09-09 18:36                                         ` Steven Rostedt
2013-09-09 18:50                                           ` Paul E. McKenney
2013-09-09 21:40                                         ` Mathieu Desnoyers
2013-09-09 21:59                                           ` Steven Rostedt
2013-09-09 22:34                                             ` Paul E. McKenney
2013-09-11 14:13                                               ` Paul E. McKenney
2013-09-11 14:26                                                 ` Steven Rostedt
2013-09-11 15:23                                                   ` Paul E. McKenney
2013-09-11 15:49                                                     ` Steven Rostedt
2013-09-11 16:03                                                       ` Paul E. McKenney
2013-09-09 13:14                     ` Peter Zijlstra
2013-09-09 13:29                       ` Frederic Weisbecker
2013-09-09 13:41                         ` Steven Rostedt
2013-09-09 13:49                           ` Frederic Weisbecker
2013-09-09 13:50                           ` Paul E. McKenney
2013-09-09 13:46                       ` Paul E. McKenney
2013-09-09 13:55                         ` Steven Rostedt
2013-09-09 16:22                           ` Paul E. McKenney
2013-09-09 16:40                             ` Steven Rostedt
2013-09-09 17:45                               ` Paul E. McKenney
2013-09-09 13:23             ` Paul E. McKenney
2013-09-09 13:36               ` Peter Zijlstra
2013-09-09 13:53                 ` Paul E. McKenney
2013-09-09 16:18                   ` Peter Zijlstra
2013-09-09 14:49                 ` Christoph Lameter
2013-09-09 15:08                   ` Peter Zijlstra
2013-09-09 15:24                     ` Christoph Lameter
2013-09-09 15:41                       ` Steven Rostedt
2013-09-09 15:47                         ` Steven Rostedt
2013-09-09 16:00                       ` Ingo Molnar
2013-09-09 16:03                         ` Steven Rostedt
2013-09-09 16:11                           ` Ingo Molnar
2013-09-10 21:37                             ` Christoph Lameter
2013-09-12  6:39                               ` Ingo Molnar
2013-09-12 14:20                                 ` Christoph Lameter
2013-09-10 21:28                         ` Christoph Lameter
2013-09-12  6:38                           ` Ingo Molnar
2013-09-12 14:43                             ` Christoph Lameter
2013-09-09 16:15                       ` Peter Zijlstra
2013-09-10  4:07                   ` Mike Galbraith
2013-09-09 13:36               ` Steven Rostedt
2013-09-09 14:21               ` Peter Zijlstra
2013-09-09 16:26                 ` Paul E. McKenney
2013-09-09 16:42                   ` Steven Rostedt
2013-09-09 16:59                     ` Paul E. McKenney

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20130909172908.GA31239@Krystal \
    --to=mathieu.desnoyers@efficios.com \
    --cc=akpm@linux-foundation.org \
    --cc=darren@dvhart.com \
    --cc=dhowells@redhat.com \
    --cc=dipankar@in.ibm.com \
    --cc=edumazet@google.com \
    --cc=eric.dumazet@gmail.com \
    --cc=fweisbec@gmail.com \
    --cc=josh@joshtriplett.org \
    --cc=laijs@cn.fujitsu.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=niv@us.ibm.com \
    --cc=paulmck@linux.vnet.ibm.com \
    --cc=peterz@infradead.org \
    --cc=rostedt@goodmis.org \
    --cc=sbw@mit.edu \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox