Messages in this thread Patch in this message | | | Date | Tue, 29 Jul 2014 10:39:03 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: vmstat: On demand vmstat workers V8 |
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On Tue, 29 Jul 2014, Tejun Heo wrote:
> Hmmm, well, then it's something else. Either a bug in workqueue or in > the caller. Given the track record, the latter is more likely. > e.g. it looks kinda suspicious that the work func is cleared after > cancel_delayed_work_sync() is called. What happens if somebody tries > to schedule it inbetween?
Here is yet another patch to also address this idea:
Subject: vmstat: Clear the work.func before cancelling delayed work
Looks strange to me but Tejun thinks this could do some good. If this really is the right thing to do then cancel_delayed_work should zap the work func itselt I think.
Signed-off-by: Christoph Lameter <cl@linux.com>
Index: linux/mm/vmstat.c =================================================================== --- linux.orig/mm/vmstat.c 2014-07-29 10:22:45.073884943 -0500 +++ linux/mm/vmstat.c 2014-07-29 10:34:45.083369228 -0500 @@ -1277,8 +1277,8 @@ static int vmstat_cpuup_callback(struct break; case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: - cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu)); per_cpu(vmstat_work, cpu).work.func = NULL; + cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu)); break; case CPU_DOWN_FAILED: case CPU_DOWN_FAILED_FROZEN:
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