Re: [PATCH] kprobes,x86: disable irq durinr optimized callback

From: Ingo Molnar
Date: Tue May 10 2011 - 07:44:33 EST



* Jiri Olsa <jolsa@xxxxxxxxxx> wrote:

> On Tue, May 10, 2011 at 12:40:19PM +0200, Ingo Molnar wrote:
> >
> > * Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> >
> > > + local_irq_save(flags);
> > > preempt_disable();
> > > if (kprobe_running()) {
> > > kprobes_inc_nmissed_count(&op->kp);
> > > @@ -1208,6 +1210,7 @@ static void __kprobes optimized_callback(struct optimized_kprobe *op,
> > > __this_cpu_write(current_kprobe, NULL);
> > > }
> > > preempt_enable_no_resched();
> > > + local_irq_restore(flags);
> >
> > irq-disable is synonymous to preempt disable so the preempt_disable()/enable()
> > pair looks like superfluous overhead.
>
> yes, there's correct patch already in the list here:
> http://marc.info/?l=linux-kernel&m=130382756829695&w=2

It helps to change the subject line when you think another patch should be
considered, to something like:

[PATCH, v2] kprobes, x86: Disable irq during optimized callback

(also note the other changes i made to the title, 3 altogether.)

Thanks,

Ingo
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