]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
sched: fix cpupri hotplug support
authorGregory Haskins <ghaskins@novell.com>
Wed, 4 Jun 2008 19:04:05 +0000 (15:04 -0400)
committerIngo Molnar <mingo@elte.hu>
Fri, 6 Jun 2008 13:19:42 +0000 (15:19 +0200)
commit1f11eb6a8bc92536d9e93ead48fa3ffbd1478571
tree40a123bd566bab8ddc726303e2725bae55b1a499
parent099f98c8a1f13501a98afbfff4756395a610581c
sched: fix cpupri hotplug support

The RT folks over at RedHat found an issue w.r.t. hotplug support which
was traced to problems with the cpupri infrastructure in the scheduler:

https://bugzilla.redhat.com/show_bug.cgi?id=449676

This bug affects 23-rt12+, 24-rtX, 25-rtX, and sched-devel.  This patch
applies to 25.4-rt4, though it should trivially apply to most cpupri enabled
kernels mentioned above.

It turned out that the issue was that offline cpus could get inadvertently
registered with cpupri so that they were erroneously selected during
migration decisions.  The end result would be an OOPS as the offline cpu
had tasks routed to it.

This patch generalizes the old join/leave domain interface into an
online/offline interface, and adjusts the root-domain/hotplug code to
utilize it.

I was able to easily reproduce the issue prior to this patch, and am no
longer able to reproduce it after this patch.  I can offline cpus
indefinately and everything seems to be in working order.

Thanks to Arnaldo (acme), Thomas, and Peter for doing the legwork to point
me in the right direction.  Also thank you to Peter for reviewing the
early iterations of this patch.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
include/linux/sched.h
kernel/sched.c
kernel/sched_rt.c