Re: Is it possible to implement interrupt time printk's reliably?

[Jon Smirl]

--- Andrew Morton <akpm@xxxxxxxx> wrote:
> Jon Smirl <jonsmirl@xxxxxxxxx> wrote:
> >
> > > If you're in process context you can use acquire_console_sem(), which will
> > > serialise against printk.
> > > 
> > 
> > Won't I deadlock if I have acquire_console_sem(), take an interrupt, and
> then a
> > printk is issued from the interrupt handelr?
> > 
> 
> Nope.  If printk finds the semaphore to be held it queues up the characters
> and returns without printing them.  The console_sem-holding process will
> print the newly buffered characters before releasing the semaphore.

Is this solution sufficient for kernel developers wanting to use printk from
interrupt handlers? I've gotten negative feedback from Linus when I suggested
queuing them before.

=====
Jon Smirl
jonsmirl@xxxxxxxxx


	
		
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