powerpc/pseries: Increase cpu die timeout

In testing SMT disable, we have been regularly seeing the following
message:

Querying DEAD? cpu %i (%i) shows %i

This indicates the current delay in pseries_cpu_die where we wait
for the specified CPU to die, is insufficient. Usually, this does
not cause a problem, but we've seen this result in BUG_ON's going
off in the timer code when we try to migrate the timers off the
dead cpu while a timer is still running. Increasing this delay,
as is done in this patch, seems to resolve this issue.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index bbe5076..fd50ccd 100644 (file)
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -193,12 +193,12 @@ static void pseries_cpu_die(unsigned int cpu)
 
        if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
                cpu_status = 1;
-               for (tries = 0; tries < 1000; tries++) {
+               for (tries = 0; tries < 5000; tries++) {
                        if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) {
                                cpu_status = 0;
                                break;
                        }
-                       cpu_relax();
+                       msleep(1);
                }
        } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {