| Message ID | 20210802143834.30578-1-longman@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] mm/memcg: Fix incorrect flushing of lruvec data in obj_stock | expand |
On Mon, Aug 2, 2021 at 7:38 AM Waiman Long <longman@redhat.com> wrote: > > When mod_objcg_state() is called with a pgdat that is different from > that in the obj_stock, the old lruvec data cached in obj_stock are > flushed out. Unfortunately, they were flushed to the new pgdat and > so the data go to the wrong node. This will screw up the slab data > reported in /sys/devices/system/node/node*/meminfo. > > Fix that by flushing the data to the cached pgdat instead. > > Fixes: 68ac5b3c8db2 ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp") > Signed-off-by: Waiman Long <longman@redhat.com> > Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Shakeel Butt <shakeelb@google.com>
On Mon, Aug 02, 2021 at 10:38:34AM -0400, Waiman Long wrote: > When mod_objcg_state() is called with a pgdat that is different from > that in the obj_stock, the old lruvec data cached in obj_stock are > flushed out. Unfortunately, they were flushed to the new pgdat and > so the data go to the wrong node. This will screw up the slab data > reported in /sys/devices/system/node/node*/meminfo. > > Fix that by flushing the data to the cached pgdat instead. > > Fixes: 68ac5b3c8db2 ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp") > Signed-off-by: Waiman Long <longman@redhat.com> > Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Thanks!
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ae1f5d0cb581..87c883227f90 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3106,13 +3106,15 @@ void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat, stock->cached_pgdat = pgdat; } else if (stock->cached_pgdat != pgdat) { /* Flush the existing cached vmstat data */ + struct pglist_data *oldpg = stock->cached_pgdat; + if (stock->nr_slab_reclaimable_b) { - mod_objcg_mlstate(objcg, pgdat, NR_SLAB_RECLAIMABLE_B, + mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B, stock->nr_slab_reclaimable_b); stock->nr_slab_reclaimable_b = 0; } if (stock->nr_slab_unreclaimable_b) { - mod_objcg_mlstate(objcg, pgdat, NR_SLAB_UNRECLAIMABLE_B, + mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B, stock->nr_slab_unreclaimable_b); stock->nr_slab_unreclaimable_b = 0; }
When mod_objcg_state() is called with a pgdat that is different from that in the obj_stock, the old lruvec data cached in obj_stock are flushed out. Unfortunately, they were flushed to the new pgdat and so the data go to the wrong node. This will screw up the slab data reported in /sys/devices/system/node/node*/meminfo. Fix that by flushing the data to the cached pgdat instead. Fixes: 68ac5b3c8db2 ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp") Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> --- mm/memcontrol.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)