Re: kernel stack size

[Steven Rostedt <rostedt@goodmis.org>]

On Sun, 2005-04-03 at 03:48 +0900, ooyama eiichi wrote:

> > > because my driver hungs the machine by an certain ioctl.  and it
> > > seems to me there is no bad in the code correspond to the ioctl,
> > > except for that it is using large auto variables.  (some functions
> > > are useing ~1KB autos)
> > 
> > don't do that, even if you make it 'apparently' work for you it will
> > just end up being a problem mater on or for someone else
> > 
> 
> I changed these to using kmalloc().
> (but not yet confirmed for my driver to work properly)

You can also use globally static variables too. But this makes for
non-reentry code.

Sometimes I don't feel that a kmalloc is worth it, and if the function
in question for the driver would seldom have problems with reentry, I
use a statically defined global, and protect it with spin_locks. If
these can also be used in interrupt context, you need to use the
spin_lock_irqsave variants.  But don't do this if the critical section
has long latencies.

-- Steve