| Message ID | 1498630044-26724-1-git-send-email-stummala@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jun 28, 2017 at 11:37:23AM +0530, Sahitya Tummala wrote: > list_lru_count_node() iterates over all memcgs to get > the total number of entries on the node but it can race with > memcg_drain_all_list_lrus(), which migrates the entries from > a dead cgroup to another. This can return incorrect number of > entries from list_lru_count_node(). > > Fix this by keeping track of entries per node and simply return > it in list_lru_count_node(). > > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> > --- > include/linux/list_lru.h | 1 + > mm/list_lru.c | 14 ++++++-------- > 2 files changed, 7 insertions(+), 8 deletions(-) > > diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h > index cb0ba9f..eff61bc 100644 > --- a/include/linux/list_lru.h > +++ b/include/linux/list_lru.h > @@ -44,6 +44,7 @@ struct list_lru_node { > /* for cgroup aware lrus points to per cgroup lists, otherwise NULL */ > struct list_lru_memcg *memcg_lrus; > #endif > + long nr_count; 'nr_count' sounds awkward. I think it should be called 'nr_items'. Other than that, looks good to me.
diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h index cb0ba9f..eff61bc 100644 --- a/include/linux/list_lru.h +++ b/include/linux/list_lru.h @@ -44,6 +44,7 @@ struct list_lru_node { /* for cgroup aware lrus points to per cgroup lists, otherwise NULL */ struct list_lru_memcg *memcg_lrus; #endif + long nr_count; } ____cacheline_aligned_in_smp; struct list_lru { diff --git a/mm/list_lru.c b/mm/list_lru.c index 234676e..d417b9f 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -117,6 +117,7 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item) l = list_lru_from_kmem(nlru, item); list_add_tail(item, &l->list); l->nr_items++; + nlru->nr_count++; spin_unlock(&nlru->lock); return true; } @@ -136,6 +137,7 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item) l = list_lru_from_kmem(nlru, item); list_del_init(item); l->nr_items--; + nlru->nr_count--; spin_unlock(&nlru->lock); return true; } @@ -183,15 +185,10 @@ unsigned long list_lru_count_one(struct list_lru *lru, unsigned long list_lru_count_node(struct list_lru *lru, int nid) { - long count = 0; - int memcg_idx; + struct list_lru_node *nlru; - count += __list_lru_count_one(lru, nid, -1); - if (list_lru_memcg_aware(lru)) { - for_each_memcg_cache_index(memcg_idx) - count += __list_lru_count_one(lru, nid, memcg_idx); - } - return count; + nlru = &lru->node[nid]; + return nlru->nr_count; } EXPORT_SYMBOL_GPL(list_lru_count_node); @@ -226,6 +223,7 @@ unsigned long list_lru_count_node(struct list_lru *lru, int nid) assert_spin_locked(&nlru->lock); case LRU_REMOVED: isolated++; + nlru->nr_count--; /* * If the lru lock has been dropped, our list * traversal is now invalid and so we have to
list_lru_count_node() iterates over all memcgs to get the total number of entries on the node but it can race with memcg_drain_all_list_lrus(), which migrates the entries from a dead cgroup to another. This can return incorrect number of entries from list_lru_count_node(). Fix this by keeping track of entries per node and simply return it in list_lru_count_node(). Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> --- include/linux/list_lru.h | 1 + mm/list_lru.c | 14 ++++++-------- 2 files changed, 7 insertions(+), 8 deletions(-)