The patch titled
Subject: mm/vmstat.c: fix NUMA statistics updates
has been added to the -mm tree. Its filename is
mm-fix-numa-statistics-updates.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-numa-statistics-updates.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-numa-statistics-updates.patch
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------------------------------------------------------
From: Janne Huttunen <janne.huttunen@xxxxxxxxx>
Subject: mm/vmstat.c: fix NUMA statistics updates
Scan through the whole array to see if an update is needed. While we're
at it, use sizeof() to be safe against any possible type changes in the
future.
The bug here is that we wouldn't sync per-cpu counters into global ones if
there was an update of numa_stats for higher cpus. Highly theoretical one
though because it is much more probable that zone_stats are updated so we
would refresh anyway. So I wouldn't bother to mark this for stable, yet
something nice to fix.
[mhocko@xxxxxxxx: changelog enhancement]
Link: http://lkml.kernel.org/r/1541601517-17282-1-git-send-email-janne.huttunen@xxxxxxxxx
Fixes: 1d90ca897cb0 ("mm: update NUMA counter threshold size")
Signed-off-by: Janne Huttunen <janne.huttunen@xxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmstat.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/mm/vmstat.c~mm-fix-numa-statistics-updates
+++ a/mm/vmstat.c
@@ -1827,12 +1827,13 @@ static bool need_update(int cpu)
/*
* The fast way of checking if there are any vmstat diffs.
- * This works because the diffs are byte sized items.
*/
- if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS))
+ if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS *
+ sizeof(p->vm_stat_diff[0])))
return true;
#ifdef CONFIG_NUMA
- if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS))
+ if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS *
+ sizeof(p->vm_numa_stat_diff[0])))
return true;
#endif
}
_
Patches currently in -mm which might be from janne.huttunen@xxxxxxxxx are
mm-fix-numa-statistics-updates.patch
