From: Heiko Carstens Date: Fri, 11 Jul 2008 09:09:22 +0000 (+0200) Subject: nohz: don't stop idle tick if softirqs are pending. X-Git-Tag: v2.6.27-rc1~513^2~3 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=857f3fd7a496ddf4329345af65a4a2b16dd25fe8;p=linux-2.6-omap-h63xx.git nohz: don't stop idle tick if softirqs are pending. In case a cpu goes idle but softirqs are pending only an error message is printed to the console. It may take a very long time until the pending softirqs will finally be executed. Worst case would be a hanging system. With this patch the timer tick just continues and the softirqs will be executed after the next interrupt. Still a delay but better than a hanging system. Currently we have at least two device drivers on s390 which under certain circumstances schedule a tasklet from process context. This is a reason why we can end up with pending softirqs when going idle. Fixing these drivers seems to be non-trivial. However there is no question that the drivers should be fixed. This patch shouldn't be considered as a bug fix. It just is intended to keep a system running even if device drivers are buggy. Signed-off-by: Heiko Carstens Cc: Jan Glauber Cc: Stefan Weinhuber Cc: Andrew Morton Signed-off-by: Ingo Molnar --- diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index cb75394ed00..86baa4f0dfe 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -235,6 +235,7 @@ void tick_nohz_stop_sched_tick(void) local_softirq_pending()); ratelimit++; } + goto end; } ts->idle_calls++;