This is a note to let you know that I've just added the patch titled
vmstat: do not use deferrable delayed work for vmstat_update
to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vmstat-do-not-use-deferrable-delayed-work-for-vmstat_update.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ba4877b9ca51f80b5d30f304a46762f0509e1635 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@xxxxxxx>
Date: Wed, 11 Feb 2015 15:28:24 -0800
Subject: vmstat: do not use deferrable delayed work for vmstat_update
From: Michal Hocko <mhocko@xxxxxxx>
commit ba4877b9ca51f80b5d30f304a46762f0509e1635 upstream.
Vinayak Menon has reported that an excessive number of tasks was throttled
in the direct reclaim inside too_many_isolated() because NR_ISOLATED_FILE
was relatively high compared to NR_INACTIVE_FILE. However it turned out
that the real number of NR_ISOLATED_FILE was 0 and the per-cpu
vm_stat_diff wasn't transferred into the global counter.
vmstat_work which is responsible for the sync is defined as deferrable
delayed work which means that the defined timeout doesn't wake up an idle
CPU. A CPU might stay in an idle state for a long time and general effort
is to keep such a CPU in this state as long as possible which might lead
to all sorts of troubles for vmstat consumers as can be seen with the
excessive direct reclaim throttling.
This patch basically reverts 39bf6270f524 ("VM statistics: Make timer
deferrable") but it shouldn't cause any problems for idle CPUs because
only CPUs with an active per-cpu drift are woken up since 7cc36bbddde5
("vmstat: on-demand vmstat workers v8") and CPUs which are idle for a
longer time shouldn't have per-cpu drift.
Fixes: 39bf6270f524 (VM statistics: Make timer deferrable)
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Reported-by: Vinayak Menon <vinmenon@xxxxxxxxxxxxxx>
Acked-by: Christoph Lameter <cl@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/vmstat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1450,7 +1450,7 @@ static void __init start_shepherd_timer(
int cpu;
for_each_possible_cpu(cpu)
- INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
+ INIT_DELAYED_WORK(per_cpu_ptr(&vmstat_work, cpu),
vmstat_update);
if (!alloc_cpumask_var(&cpu_stat_off, GFP_KERNEL))
Patches currently in stable-queue which might be from mhocko@xxxxxxx are
queue-3.19/mm-page_alloc-revert-inadvertent-__gfp_fs-retry-behavior-change.patch
queue-3.19/mm-hugetlb-add-migration-hwpoisoned-entry-check-in-hugetlb_change_protection.patch
queue-3.19/mm-when-stealing-freepages-also-take-pages-created-by-splitting-buddy-page.patch
queue-3.19/mm-mmap.c-fix-arithmetic-overflow-in-__vm_enough_memory.patch
queue-3.19/mm-hugetlb-fix-getting-refcount-0-page-in-hugetlb_fault.patch
queue-3.19/vmstat-do-not-use-deferrable-delayed-work-for-vmstat_update.patch
queue-3.19/mm-hugetlb-add-migration-entry-check-in-__unmap_hugepage_range.patch
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