The current scheme of maintaining per-node per-memcg lru lists looks like:
struct list_lru {
struct list_lru_node *node; (for each node)
struct list_lru_memcg *memcg_lrus;
struct list_lru_one *lru[]; (for each memcg)
}
By effectively transposing the two-dimension array of list_lru_one's structures
(per-node per-memcg => per-memcg per-node) it's possible to save some memory
and simplify alloc/dealloc paths. The new scheme looks like:
struct list_lru {
struct list_lru_memcg *mlrus;
struct list_lru_per_memcg *mlru[]; (for each memcg)
struct list_lru_one node[0]; (for each node)
}
Memory savings are coming from not only 'struct rcu_head' but also some
pointer arrays used to store the pointer to 'struct list_lru_one'. The
array is per node and its size is 8 (a pointer) * num_memcgs. So the total
size of the arrays is 8 * num_nodes * memcg_nr_cache_ids. After this patch,
the size becomes 8 * memcg_nr_cache_ids.
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
include/linux/list_lru.h | 17 ++--
mm/list_lru.c | 206 +++++++++++++++++------------------------------
2 files changed, 86 insertions(+), 137 deletions(-)
diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
index 1b5fceb565df..729a27b6ff53 100644
--- a/include/linux/list_lru.h
+++ b/include/linux/list_lru.h
@@ -31,10 +31,15 @@ struct list_lru_one {
long nr_items;
};
+struct list_lru_per_memcg {
+ /* array of per cgroup per node lists, indexed by node id */
+ struct list_lru_one node[0];
+};
+
struct list_lru_memcg {
- struct rcu_head rcu;
+ struct rcu_head rcu;
/* array of per cgroup lists, indexed by memcg_cache_id */
- struct list_lru_one *lru[];
+ struct list_lru_per_memcg *mlru[];
};
struct list_lru_node {
@@ -42,11 +47,7 @@ struct list_lru_node {
spinlock_t lock;
/* global list, used for the root cgroup in cgroup aware lrus */
struct list_lru_one lru;
-#ifdef CONFIG_MEMCG_KMEM
- /* for cgroup aware lrus points to per cgroup lists, otherwise NULL */
- struct list_lru_memcg __rcu *memcg_lrus;
-#endif
- long nr_items;
+ long nr_items;
} ____cacheline_aligned_in_smp;
struct list_lru {
@@ -55,6 +56,8 @@ struct list_lru {
struct list_head list;
int shrinker_id;
bool memcg_aware;
+ /* for cgroup aware lrus points to per cgroup lists, otherwise NULL */
+ struct list_lru_memcg __rcu *mlrus;
#endif
};
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 0cd5e89ca063..7d1356241aa8 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -49,35 +49,37 @@ static int lru_shrinker_id(struct list_lru *lru)
}
static inline struct list_lru_one *
-list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
+list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx)
{
- struct list_lru_memcg *memcg_lrus;
+ struct list_lru_memcg *mlrus;
+ struct list_lru_node *nlru = &lru->node[nid];
+
/*
* Either lock or RCU protects the array of per cgroup lists
- * from relocation (see memcg_update_list_lru_node).
+ * from relocation (see memcg_update_list_lru).
*/
- memcg_lrus = rcu_dereference_check(nlru->memcg_lrus,
- lockdep_is_held(&nlru->lock));
- if (memcg_lrus && idx >= 0)
- return memcg_lrus->lru[idx];
+ mlrus = rcu_dereference_check(lru->mlrus, lockdep_is_held(&nlru->lock));
+ if (mlrus && idx >= 0)
+ return &mlrus->mlru[idx]->node[nid];
return &nlru->lru;
}
static inline struct list_lru_one *
-list_lru_from_kmem(struct list_lru_node *nlru, void *ptr,
+list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr,
struct mem_cgroup **memcg_ptr)
{
+ struct list_lru_node *nlru = &lru->node[nid];
struct list_lru_one *l = &nlru->lru;
struct mem_cgroup *memcg = NULL;
- if (!nlru->memcg_lrus)
+ if (!lru->mlrus)
goto out;
memcg = mem_cgroup_from_obj(ptr);
if (!memcg)
goto out;
- l = list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
+ l = list_lru_from_memcg_idx(lru, nid, memcg_cache_id(memcg));
out:
if (memcg_ptr)
*memcg_ptr = memcg;
@@ -103,18 +105,18 @@ static inline bool list_lru_memcg_aware(struct list_lru *lru)
}
static inline struct list_lru_one *
-list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
+list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx)
{
- return &nlru->lru;
+ return &lru->node[nid].lru;
}
static inline struct list_lru_one *
-list_lru_from_kmem(struct list_lru_node *nlru, void *ptr,
+list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr,
struct mem_cgroup **memcg_ptr)
{
if (memcg_ptr)
*memcg_ptr = NULL;
- return &nlru->lru;
+ return &lru->node[nid].lru;
}
#endif /* CONFIG_MEMCG_KMEM */
@@ -127,7 +129,7 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item)
spin_lock(&nlru->lock);
if (list_empty(item)) {
- l = list_lru_from_kmem(nlru, item, &memcg);
+ l = list_lru_from_kmem(lru, nid, item, &memcg);
list_add_tail(item, &l->list);
/* Set shrinker bit if the first element was added */
if (!l->nr_items++)
@@ -150,7 +152,7 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item)
spin_lock(&nlru->lock);
if (!list_empty(item)) {
- l = list_lru_from_kmem(nlru, item, NULL);
+ l = list_lru_from_kmem(lru, nid, item, NULL);
list_del_init(item);
l->nr_items--;
nlru->nr_items--;
@@ -180,12 +182,11 @@ EXPORT_SYMBOL_GPL(list_lru_isolate_move);
unsigned long list_lru_count_one(struct list_lru *lru,
int nid, struct mem_cgroup *memcg)
{
- struct list_lru_node *nlru = &lru->node[nid];
struct list_lru_one *l;
long count;
rcu_read_lock();
- l = list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
+ l = list_lru_from_memcg_idx(lru, nid, memcg_cache_id(memcg));
count = READ_ONCE(l->nr_items);
rcu_read_unlock();
@@ -206,16 +207,16 @@ unsigned long list_lru_count_node(struct list_lru *lru, int nid)
EXPORT_SYMBOL_GPL(list_lru_count_node);
static unsigned long
-__list_lru_walk_one(struct list_lru_node *nlru, int memcg_idx,
+__list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
list_lru_walk_cb isolate, void *cb_arg,
unsigned long *nr_to_walk)
{
-
+ struct list_lru_node *nlru = &lru->node[nid];
struct list_lru_one *l;
struct list_head *item, *n;
unsigned long isolated = 0;
- l = list_lru_from_memcg_idx(nlru, memcg_idx);
+ l = list_lru_from_memcg_idx(lru, nid, memcg_idx);
restart:
list_for_each_safe(item, n, &l->list) {
enum lru_status ret;
@@ -272,8 +273,8 @@ list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
unsigned long ret;
spin_lock(&nlru->lock);
- ret = __list_lru_walk_one(nlru, memcg_cache_id(memcg), isolate, cb_arg,
- nr_to_walk);
+ ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), isolate,
+ cb_arg, nr_to_walk);
spin_unlock(&nlru->lock);
return ret;
}
@@ -288,8 +289,8 @@ list_lru_walk_one_irq(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
unsigned long ret;
spin_lock_irq(&nlru->lock);
- ret = __list_lru_walk_one(nlru, memcg_cache_id(memcg), isolate, cb_arg,
- nr_to_walk);
+ ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), isolate,
+ cb_arg, nr_to_walk);
spin_unlock_irq(&nlru->lock);
return ret;
}
@@ -308,7 +309,7 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
struct list_lru_node *nlru = &lru->node[nid];
spin_lock(&nlru->lock);
- isolated += __list_lru_walk_one(nlru, memcg_idx,
+ isolated += __list_lru_walk_one(lru, nid, memcg_idx,
isolate, cb_arg,
nr_to_walk);
spin_unlock(&nlru->lock);
@@ -328,166 +329,111 @@ static void init_one_lru(struct list_lru_one *l)
}
#ifdef CONFIG_MEMCG_KMEM
-static void __memcg_destroy_list_lru_node(struct list_lru_memcg *memcg_lrus,
- int begin, int end)
+static void memcg_destroy_list_lru_range(struct list_lru_memcg *mlrus,
+ int begin, int end)
{
int i;
for (i = begin; i < end; i++)
- kfree(memcg_lrus->lru[i]);
+ kfree(mlrus->mlru[i]);
}
-static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus,
- int begin, int end)
+static int memcg_init_list_lru_range(struct list_lru_memcg *mlrus,
+ int begin, int end)
{
int i;
for (i = begin; i < end; i++) {
- struct list_lru_one *l;
+ int nid;
+ struct list_lru_per_memcg *mlru;
- l = kmalloc(sizeof(struct list_lru_one), GFP_KERNEL);
- if (!l)
+ mlru = kmalloc(struct_size(mlru, node, nr_node_ids), GFP_KERNEL);
+ if (!mlru)
goto fail;
- init_one_lru(l);
- memcg_lrus->lru[i] = l;
+ for_each_node(nid)
+ init_one_lru(&mlru->node[nid]);
+ mlrus->mlru[i] = mlru;
}
return 0;
fail:
- __memcg_destroy_list_lru_node(memcg_lrus, begin, i);
+ memcg_destroy_list_lru_range(mlrus, begin, i);
return -ENOMEM;
}
-static int memcg_init_list_lru_node(struct list_lru_node *nlru)
+static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
{
- struct list_lru_memcg *memcg_lrus;
+ struct list_lru_memcg *mlrus;
int size = memcg_nr_cache_ids;
- memcg_lrus = kvmalloc(struct_size(memcg_lrus, lru, size), GFP_KERNEL);
- if (!memcg_lrus)
+ lru->memcg_aware = memcg_aware;
+ if (!memcg_aware)
+ return 0;
+
+ mlrus = kvmalloc(struct_size(mlrus, mlru, size), GFP_KERNEL);
+ if (!mlrus)
return -ENOMEM;
- if (__memcg_init_list_lru_node(memcg_lrus, 0, size)) {
- kvfree(memcg_lrus);
+ if (memcg_init_list_lru_range(mlrus, 0, size)) {
+ kvfree(mlrus);
return -ENOMEM;
}
- RCU_INIT_POINTER(nlru->memcg_lrus, memcg_lrus);
+ RCU_INIT_POINTER(lru->mlrus, mlrus);
return 0;
}
-static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
+static void memcg_destroy_list_lru(struct list_lru *lru)
{
- struct list_lru_memcg *memcg_lrus;
+ struct list_lru_memcg *mlrus;
+
+ if (!list_lru_memcg_aware(lru))
+ return;
+
/*
* This is called when shrinker has already been unregistered,
* and nobody can use it. So, there is no need to use kvfree_rcu().
*/
- memcg_lrus = rcu_dereference_protected(nlru->memcg_lrus, true);
- __memcg_destroy_list_lru_node(memcg_lrus, 0, memcg_nr_cache_ids);
- kvfree(memcg_lrus);
+ mlrus = rcu_dereference_protected(lru->mlrus, true);
+ memcg_destroy_list_lru_range(mlrus, 0, memcg_nr_cache_ids);
+ kvfree(mlrus);
}
-static int memcg_update_list_lru_node(struct list_lru_node *nlru,
- int old_size, int new_size)
+static int memcg_update_list_lru(struct list_lru *lru, int old_size, int new_size)
{
struct list_lru_memcg *old, *new;
BUG_ON(old_size > new_size);
- old = rcu_dereference_protected(nlru->memcg_lrus,
+ old = rcu_dereference_protected(lru->mlrus,
lockdep_is_held(&list_lrus_mutex));
- new = kvmalloc(struct_size(new, lru, new_size), GFP_KERNEL);
+ new = kvmalloc(struct_size(new, mlru, new_size), GFP_KERNEL);
if (!new)
return -ENOMEM;
- if (__memcg_init_list_lru_node(new, old_size, new_size)) {
+ if (memcg_init_list_lru_range(new, old_size, new_size)) {
kvfree(new);
return -ENOMEM;
}
- memcpy(&new->lru, &old->lru, flex_array_size(new, lru, old_size));
- rcu_assign_pointer(nlru->memcg_lrus, new);
+ memcpy(&new->mlru, &old->mlru, flex_array_size(new, mlru, old_size));
+ rcu_assign_pointer(lru->mlrus, new);
kvfree_rcu(old, rcu);
return 0;
}
-static void memcg_cancel_update_list_lru_node(struct list_lru_node *nlru,
- int old_size, int new_size)
-{
- struct list_lru_memcg *memcg_lrus;
-
- memcg_lrus = rcu_dereference_protected(nlru->memcg_lrus,
- lockdep_is_held(&list_lrus_mutex));
- /* do not bother shrinking the array back to the old size, because we
- * cannot handle allocation failures here */
- __memcg_destroy_list_lru_node(memcg_lrus, old_size, new_size);
-}
-
-static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
-{
- int i;
-
- lru->memcg_aware = memcg_aware;
-
- if (!memcg_aware)
- return 0;
-
- for_each_node(i) {
- if (memcg_init_list_lru_node(&lru->node[i]))
- goto fail;
- }
- return 0;
-fail:
- for (i = i - 1; i >= 0; i--) {
- if (!lru->node[i].memcg_lrus)
- continue;
- memcg_destroy_list_lru_node(&lru->node[i]);
- }
- return -ENOMEM;
-}
-
-static void memcg_destroy_list_lru(struct list_lru *lru)
-{
- int i;
-
- if (!list_lru_memcg_aware(lru))
- return;
-
- for_each_node(i)
- memcg_destroy_list_lru_node(&lru->node[i]);
-}
-
-static int memcg_update_list_lru(struct list_lru *lru,
- int old_size, int new_size)
-{
- int i;
-
- for_each_node(i) {
- if (memcg_update_list_lru_node(&lru->node[i],
- old_size, new_size))
- goto fail;
- }
- return 0;
-fail:
- for (i = i - 1; i >= 0; i--) {
- if (!lru->node[i].memcg_lrus)
- continue;
-
- memcg_cancel_update_list_lru_node(&lru->node[i],
- old_size, new_size);
- }
- return -ENOMEM;
-}
-
static void memcg_cancel_update_list_lru(struct list_lru *lru,
int old_size, int new_size)
{
- int i;
+ struct list_lru_memcg *mlrus;
- for_each_node(i)
- memcg_cancel_update_list_lru_node(&lru->node[i],
- old_size, new_size);
+ mlrus = rcu_dereference_protected(lru->mlrus,
+ lockdep_is_held(&list_lrus_mutex));
+ /*
+ * Do not bother shrinking the array back to the old size, because we
+ * cannot handle allocation failures here.
+ */
+ memcg_destroy_list_lru_range(mlrus, old_size, new_size);
}
int memcg_update_all_list_lrus(int new_size)
@@ -524,8 +470,8 @@ static void memcg_drain_list_lru_node(struct list_lru *lru, int nid,
*/
spin_lock_irq(&nlru->lock);
- src = list_lru_from_memcg_idx(nlru, src_idx);
- dst = list_lru_from_memcg_idx(nlru, dst_idx);
+ src = list_lru_from_memcg_idx(lru, nid, src_idx);
+ dst = list_lru_from_memcg_idx(lru, nid, dst_idx);
list_splice_init(&src->list, &dst->list);
--
2.11.0
