Date: Fri, 6 Sep 2013 19:00:08 +0200
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, mingo@elte.hu,
        laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org,
        mathieu.desnoyers@efficios.com, josh@joshtriplett.org, niv@us.ibm.com,
        tglx@linutronix.de, peterz@infradead.org, 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?
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On Fri, Sep 06, 2013 at 12:52:38PM -0400, Steven Rostedt wrote:
> On Fri, 6 Sep 2013 18:40:18 +0200
> Frederic Weisbecker <fweisbec@gmail.com> wrote:
>  
> > > I can't use plain preempt_disable() in function tracing.
> > > 
> > > Also, since it's a misnomer to say the cpu is idle in NO_HZ_FULL when
> > > we are coming from userspace, can we rename that?
> > > 
> > > Perhaps we can also have a __rcu_is_cpu_tracking() (or whatever), with
> > > the "__" appended that does not do the preempt disable.
> > 
> > rcu_is_cpu_eqs() is probably better. It refers to other related "eqs" naming
> > in RCU APIs.
> 
> But that will just confuse the heck out of people. When I see "eqs" I
> equate that with "equals". What does the rcu cpu equal?

It's "extended quiescent state". There is already rcu_eqs_enter() and rcu_eqs_exit().
You're right, may be we can rename that to avoid confusion with "equals". I don't mind much.
I'm happy as long as the reader rcu_is_cpu_foo() and the writers rcu_foo_enter() and
rcu_foo_exit() have consistant naming.

> 
> -- Steve
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