tree 7bd1b0de6e82363beba60097529b72ac7de923f5
parent 7a14ce1d8c1d3a6118d406e64eaf9aa70375e085
author Heiko Carstens <heiko.carstens@de.ibm.com> 1215767362 +0200
committer Ingo Molnar <mingo@elte.hu> 1215767824 +0200

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 <heiko.carstens@de.ibm.com>
Cc: Jan Glauber <jan.glauber@de.ibm.com>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>