It works fine with this patch. Thank you so much!
18.07.2020 07:25, Kent Gibson пишет:
On Fri, Jul 17, 2020 at 06:07:04PM +0300, Andy Shevchenko wrote:
On Fri, Jul 17, 2020 at 5:17 PM Maxim Kochetkov <fido_max@xxxxxxxx> wrote:
I need a small userspace program to do some GPIO magic to communicate
other hardware like devmem. This program takes about 2,5 seconds just to
find GPIO lines by name.
replacing synchronize_rcu to synchronize_rcu_expedited in
atomic_notifier_chain_unregister gives the same boost as removing
synchronize_rcu
Have you tried to replace an atomic notifier call with a regular one?
IIRC it's still not clear why atomic is used there.
Indeed, I recently submitted a patch to switch the
atomic_notifier_call_chain to blocking_notifier_call_chain, as some of
the chained calls can sleep.
Not sure if that is related, or if the change would make this case better
or worse, but it would be interesting to find out.
The patch is in the current gpio/devel, btw.
Cheers,
Kent.
