Re: [PATCH] ARM: ensure all sched_clock() implementations are notrace marked

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Thu, Dec 16, 2010 at 08:42:23PM +0530, Rabin Vincent wrote:
> On Thu, Dec 16, 2010 at 1:48 PM, Russell King - ARM Linux
> <linux@arm.linux.org.uk> wrote:
> > ftrace requires sched_clock() to be notrace.  Ensure that all
> > implementations are so marked.
> >
> > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> 
> It does seem better to have all of them explicity annotated anyway, even
> if it not required in most of the cases because they include
> <linux/sched.h> and the annotation in the declaration takes effect.

Firstly, we shouldn't be relying upon that, and secondly, everywhere which
defines sched_clock() should already be including linux/sched.h to avoid
the sparse error.  It sounds like there's also an exercise to make sure
that is the case.

> Note that in order for this to be fully effective, all functions called
> from sched_clock() need to be notrace too.  OMAP and u300 miss this.

Yes, OMAP still suffers from this.

However, I assume you haven't looked at the u300 sched_clock conversion
patch which is part of a follow-on series on lakml?  It sorts u300 out
in that regard.
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