lkml.org 
[lkml]   [2014]   [Jun]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC][PATCH 4/5 v2] printk: Add per_cpu printk func to allow printk to be diverted
On Fri, 27 Jun 2014 16:20:25 +0200
Petr Mládek <pmladek@suse.cz> wrote:


> > va_start(args, fmt);
> > - r = vprintk_emit(0, -1, NULL, 0, fmt, args);
> > + preempt_disable();
>
> I think that it is too late to disable the preemption here.
> It has to be done by the printk() caller if it wants to be sure
> that the requested function is used.

That's only if the printk() caller cares. But it would be nice that we
run the printk_func for the CPU that vprintk_func() is on, thus the
preempt_disable() is required. (in -rt, this would turn into a
migrate_disable()).

-- Steve

>
> > + vprintk_func = this_cpu_read(printk_func);
> > + r = vprintk_func(fmt, args);
> > + preempt_enable();
> > va_end(args);
> >
> > return r;
>
> Best Regards,
> Petr

--
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/

\
 
 \ /
  Last update: 2014-06-27 17:41    [W:0.257 / U:0.592 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site