Re: [PATCH] introduce setup_timer() helper

[Oleg Nesterov <oleg@tv-sign.ru>]

Arjan van de Ven wrote:
> 
> On Sun, Sep 18, 2005 at 07:51:20PM +0400, Oleg Nesterov wrote:
> >
> > I think it does not matter from correctness point of view.
> 
> right now.. it probably doesn't.
> However I think conceptually, touching a timer before init_timer() is just
> wrong.

It is indeed wrong outside timer.{h,c}, but setup_timer() is a
part of timers subsystem, so I hope it's ok.

> For one... it would prevent init_timer() from being able to use
> memset() on the timer. Which it doesn't today but it's the kind of thing
> that you don't want to prevent happening in the future.

Yes, in that case we will have to change setup_timer(). But I
doubt this will happen. init_timer() only needs to set timer's
->base, and to ensure the timer is not pending.

> 
> >       setup_timer(timer, expr1(), expr2())
> >
> > it is better to initialize ->func and ->data first, otherwise
> > the compiler should save the results from expr{1,2}, then call
> > init_timer(), then copy these results to *timer.
> 
> I don't see how that is different....

I think this can save a couple of cpu cycles. The init_timer()
is not inline, gcc can't reorder exprx() and init_timer() calls.

Ok, I do not want to persist very much, I can resend this patch.

Andrew, should I?

Oleg.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/