On Wed, 30 Jul 2014, Fengguang Wu wrote:
> FYI, this commit seems to convert some kernel boot hang bug into
> different BUG messages.
Hmmm. Still a bit confused as to why these messages occur.. Does this
patch do any good?
Subject: vmstat ondemand: Fix online/offline races
Do not allow onlining/offlining while the shepherd task is checking
for vmstat threads.
On offlining a processor do the right thing cancelling the vmstat
worker thread if it exista and also exclude it from the shepherd
process checks.
Signed-off-by: Christoph Lameter <c...@linux.com>
Index: linux/mm/vmstat.c
===================================================================
--- linux.orig/mm/vmstat.c 2014-07-30 09:35:54.602662306 -0500
+++ linux/mm/vmstat.c 2014-07-30 09:43:07.109037043 -0500
@@ -1317,6 +1317,7 @@ static void vmstat_shepherd(struct work_
{
int cpu;
+ get_online_cpus();
/* Check processors whose vmstat worker threads have been disabled */
for_each_cpu(cpu, cpu_stat_off)
if (need_update(cpu) &&
@@ -1325,6 +1326,7 @@ static void vmstat_shepherd(struct work_
schedule_delayed_work_on(cpu, &per_cpu(vmstat_work,
cpu),
__round_jiffies_relative(sysctl_stat_interval,
cpu));
+ put_online_cpus();
schedule_delayed_work(&shepherd,
round_jiffies_relative(sysctl_stat_interval));
@@ -1380,8 +1382,8 @@ static int vmstat_cpuup_callback(struct
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
- if (!cpumask_test_and_set_cpu(cpu, cpu_stat_off))
- cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
+ cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
+ cpumask_clear_cpu(cpu, cpu_stat_off);
break;
case CPU_DOWN_FAILED:
case CPU_DOWN_FAILED_FROZEN:
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
