diff mbox

[v5,10/13] mm: Set bit in memcg shrinker bitmap on first list_lru item apearance

Message ID 152594602582.22949.2526776640167844592.stgit@localhost.localdomain (mailing list archive)
State New, archived
Headers show

Commit Message

Kirill Tkhai May 10, 2018, 9:53 a.m. UTC 
Introduce set_shrinker_bit() function to set shrinker-related
bit in memcg shrinker bitmap, and set the bit after the first
item is added and in case of reparenting destroyed memcg's items.

This will allow next patch to make shrinkers be called only,
in case of they have charged objects at the moment, and
to improve shrink_slab() performance.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
 include/linux/memcontrol.h |   15 +++++++++++++++
 mm/list_lru.c              |   22 ++++++++++++++++++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

Comments

Vladimir Davydov May 15, 2018, 4:08 a.m. UTC | #1 
On Thu, May 10, 2018 at 12:53:45PM +0300, Kirill Tkhai wrote:
> Introduce set_shrinker_bit() function to set shrinker-related
> bit in memcg shrinker bitmap, and set the bit after the first
> item is added and in case of reparenting destroyed memcg's items.
> 
> This will allow next patch to make shrinkers be called only,
> in case of they have charged objects at the moment, and
> to improve shrink_slab() performance.
> 
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
> ---
>  include/linux/memcontrol.h |   15 +++++++++++++++
>  mm/list_lru.c              |   22 ++++++++++++++++++++--
>  2 files changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index e5e7e0fc7158..82f892e77637 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -1274,6 +1274,21 @@ static inline void memcg_put_cache_ids(void)
>  
>  extern int memcg_shrinker_nr_max;
>  extern int memcg_expand_shrinker_maps(int old_id, int id);
> +
> +static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int nr)

Nit: too long line (> 80 characters)
Nit: let's rename 'nr' to 'shrinker_id'

> +{
> +	if (nr >= 0 && memcg && memcg != root_mem_cgroup) {
> +		struct memcg_shrinker_map *map;
> +
> +		rcu_read_lock();
> +		map = MEMCG_SHRINKER_MAP(memcg, nid);

Missing rcu_dereference.

> +		set_bit(nr, map->map);
> +		rcu_read_unlock();
> +	}
> +}
> +#else
> +static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
> +					  int node, int id) { }

Nit: please keep the signature (including argument names) the same as in
MEMCG-enabled definition, namely 'node' => 'nid', 'id' => 'shrinker_id'.

Thanks.
diff mbox

Patch

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e5e7e0fc7158..82f892e77637 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1274,6 +1274,21 @@  static inline void memcg_put_cache_ids(void)
 
 extern int memcg_shrinker_nr_max;
 extern int memcg_expand_shrinker_maps(int old_id, int id);
+
+static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int nr)
+{
+	if (nr >= 0 && memcg && memcg != root_mem_cgroup) {
+		struct memcg_shrinker_map *map;
+
+		rcu_read_lock();
+		map = MEMCG_SHRINKER_MAP(memcg, nid);
+		set_bit(nr, map->map);
+		rcu_read_unlock();
+	}
+}
+#else
+static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
+					  int node, int id) { }
 #endif /* CONFIG_MEMCG_SHRINKER */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 7f6cb27aa2f5..6ce52f80f12c 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -30,6 +30,11 @@  static void list_lru_unregister(struct list_lru *lru)
 	list_del(&lru->list);
 	mutex_unlock(&list_lrus_mutex);
 }
+
+static int lru_shrinker_id(struct list_lru *lru)
+{
+	return lru->shrinker_id;
+}
 #else
 static void list_lru_register(struct list_lru *lru)
 {
@@ -38,6 +43,11 @@  static void list_lru_register(struct list_lru *lru)
 static void list_lru_unregister(struct list_lru *lru)
 {
 }
+
+static int lru_shrinker_id(struct list_lru *lru)
+{
+	return -1;
+}
 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */
 
 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
@@ -121,13 +131,17 @@  bool list_lru_add(struct list_lru *lru, struct list_head *item)
 {
 	int nid = page_to_nid(virt_to_page(item));
 	struct list_lru_node *nlru = &lru->node[nid];
+	struct mem_cgroup *memcg;
 	struct list_lru_one *l;
 
 	spin_lock(&nlru->lock);
 	if (list_empty(item)) {
-		l = list_lru_from_kmem(nlru, item, NULL);
+		l = list_lru_from_kmem(nlru, item, &memcg);
 		list_add_tail(item, &l->list);
-		l->nr_items++;
+		/* Set shrinker bit if the first element was added */
+		if (!l->nr_items++)
+			memcg_set_shrinker_bit(memcg, nid,
+					       lru_shrinker_id(lru));
 		nlru->nr_items++;
 		spin_unlock(&nlru->lock);
 		return true;
@@ -522,6 +536,7 @@  static void memcg_drain_list_lru_node(struct list_lru *lru, int nid,
 	struct list_lru_node *nlru = &lru->node[nid];
 	int dst_idx = dst_memcg->kmemcg_id;
 	struct list_lru_one *src, *dst;
+	bool set;
 
 	/*
 	 * Since list_lru_{add,del} may be called under an IRQ-safe lock,
@@ -533,7 +548,10 @@  static void memcg_drain_list_lru_node(struct list_lru *lru, int nid,
 	dst = list_lru_from_memcg_idx(nlru, dst_idx);
 
 	list_splice_init(&src->list, &dst->list);
+	set = (!dst->nr_items && src->nr_items);
 	dst->nr_items += src->nr_items;
+	if (set)
+		memcg_set_shrinker_bit(dst_memcg, nid, lru_shrinker_id(lru));
 	src->nr_items = 0;
 
 	spin_unlock_irq(&nlru->lock);