On Sat, Jul 13, 2002 at 06:05:06PM -0700, William Lee Irwin III wrote:
> On Mon, Jul 01, 2002 at 05:05:55AM +0100, Matthew Wilcox wrote:
> > That doesn't mean that we shouldn't worry about the 38 files which use
> > tq_timer, but they are almost all tty related and are therefore Hard ;-)
> 
> __global_cli(), timer_bh(), and bh_action() are crippling my machines.
> 
> Where do I start?

Even if you replace timemr_bh() with a tasklet, you still need
to take the global_bh_lock to ensure that timers don't race with
single-threaded BH processing in drivers. I wrote this patch [included]
to get rid of timer_bh in Ingo's smptimers, but it acquires
global_bh_lock as well as net_bh_lock, the latter to ensure
that some older protocol code that expected serialization of
NET_BH and timers work correctly (see deliver_to_old_ones()).
They need to be cleaned up too.

My patch of course was experimental to see what is needed to
get rid of timer_bh. It needs some cleanup itself ;-)

Thanks
-- 
Dipankar Sarma  <dipankar@in.ibm.com> http://lse.sourceforge.net
Linux Technology Center, IBM Software Lab, Bangalore, India.