]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
powerpc/pseries: Fix cpu hotplug
authorSebastien Dugue <sebastien.dugue@bull.net>
Thu, 27 Nov 2008 00:59:52 +0000 (00:59 +0000)
committerPaul Mackerras <paulus@samba.org>
Tue, 23 Dec 2008 04:13:27 +0000 (15:13 +1100)
commitb906cfa397fdef8decbd36467b1f63c830a0bf2b
tree1a3fa1f47f82476c8945661ea01e7be8ffb88713
parentfad7b9b51e21a97e9e2662f1b51869ed2d209097
powerpc/pseries: Fix cpu hotplug

Currently, pseries_cpu_die() calls msleep() while polling RTAS for
the status of the dying cpu.

However, if the cpu that is going down also happens to be the one
doing the tick then we're hosed as the tick_do_timer_cpu 'baton' is
only passed later on in tick_shutdown() when _cpu_down() does the
CPU_DEAD notification.  Therefore jiffies won't be updated anymore.

This replaces that msleep() with a cpu_relax() to make sure we're not
going to schedule at that point.

With this patch my test box survives a 100k iterations hotplug stress
test on _all_ cpus, whereas without it, it quickly dies after ~50
iterations.

Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
arch/powerpc/platforms/pseries/hotplug-cpu.c