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authorJanne Huttunen <janne.huttunen@nokia.com>2018-11-16 15:08:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-18 10:15:10 -0800
commit13c9aaf7fa01cc7600c61981609feadeef3354ec (patch)
parent78179556e7605ba07fd3ddba6ab8891fa457b93e (diff)
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@suse.com: changelog enhancement] Link: http://lkml.kernel.org/r/1541601517-17282-1-git-send-email-janne.huttunen@nokia.com Fixes: 1d90ca897cb0 ("mm: update NUMA counter threshold size") Signed-off-by: Janne Huttunen <janne.huttunen@nokia.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 4 insertions, 3 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 6038ce593ce3..9c624595e904 100644
--- a/mm/vmstat.c
+++ b/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;
- 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;