From: Andrew Morton <akpm@linux-foundation.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Gilad Ben-Yossef <gilad@benyossef.com>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Li Zhong <zhong@linux.vnet.ibm.com>
Subject: Re: [PATCH] context_tracking: Add comments on interface and internals
Date: Thu, 13 Dec 2012 15:00:15 -0800 [thread overview]
Message-ID: <20121213150015.e497a585.akpm@linux-foundation.org> (raw)
In-Reply-To: <CAFTL4hxPAq0pNOAhMc01iOygqdx=Ja=b5u9ozzdRmPLbtxMn+A@mail.gmail.com>
On Thu, 13 Dec 2012 23:50:23 +0100
Frederic Weisbecker <fweisbec@gmail.com> wrote:
> >
> >> + * This call supports re-entrancy.
> >
> > Presumably the explanation for user_exit() applies here.
>
> Not sure what you mean here.
It's unclear what it means to say "user_enter() supports reentrancy".
I mean, zillions of kernel functions are surely reentrant - so what?
It appears that you had something in mind when pointing this out, but
what was it? The comment over user_exit() appears to tell us.
> > It's mainly this bit which makes me wonder why the code is in lib/. Is
> > there any conceivable prospect that any other subsystem will use this
> > code for anything?
>
> So that's because of that cputime accounting on dynticks CPUs which
> will need to know about user/kernel transitions. I'm preparing that
> for the 3.9 merge window.
Oh. That's really the entire reason for the patch and should have been
in the changelog!
next prev parent reply other threads:[~2012-12-13 23:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-13 20:57 [PATCH] context_tracking: Add comments on interface and internals Frederic Weisbecker
2012-12-13 21:18 ` Andrew Morton
2012-12-13 22:50 ` Frederic Weisbecker
2012-12-13 23:00 ` Andrew Morton [this message]
2012-12-13 23:10 ` Frederic Weisbecker
-- strict thread matches above, loose matches on Subject: below --
2013-01-16 12:32 Frederic Weisbecker
2013-01-16 13:04 ` Namhyung Kim
2013-01-16 14:58 ` Frederic Weisbecker
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