Messages in this thread | | | Date | Fri, 27 Jun 2014 10:39:33 -0400 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH 4/5 v2] printk: Add per_cpu printk func to allow printk to be diverted |
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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
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