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-rw-r--r--mm/vmscan.c60
1 files changed, 42 insertions, 18 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d1601163d895..db668c4c78f4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -187,11 +187,17 @@ static DECLARE_RWSEM(shrinker_rwsem);
#ifdef CONFIG_MEMCG
static int shrinker_nr_max;
+/* The shrinker_info is expanded in a batch of BITS_PER_LONG */
static inline int shrinker_map_size(int nr_items)
{
return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long));
}
+static inline int shrinker_defer_size(int nr_items)
+{
+ return (round_up(nr_items, BITS_PER_LONG) * sizeof(atomic_long_t));
+}
+
static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
int nid)
{
@@ -200,11 +206,13 @@ static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
}
static int expand_one_shrinker_info(struct mem_cgroup *memcg,
- int size, int old_size)
+ int map_size, int defer_size,
+ int old_map_size, int old_defer_size)
{
struct shrinker_info *new, *old;
struct mem_cgroup_per_node *pn;
int nid;
+ int size = map_size + defer_size;
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
@@ -217,9 +225,16 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg,
if (!new)
return -ENOMEM;
- /* Set all old bits, clear all new bits */
- memset(new->map, (int)0xff, old_size);
- memset((void *)new->map + old_size, 0, size - old_size);
+ new->nr_deferred = (atomic_long_t *)(new + 1);
+ new->map = (void *)new->nr_deferred + defer_size;
+
+ /* map: set all old bits, clear all new bits */
+ memset(new->map, (int)0xff, old_map_size);
+ memset((void *)new->map + old_map_size, 0, map_size - old_map_size);
+ /* nr_deferred: copy old values, clear all new values */
+ memcpy(new->nr_deferred, old->nr_deferred, old_defer_size);
+ memset((void *)new->nr_deferred + old_defer_size, 0,
+ defer_size - old_defer_size);
rcu_assign_pointer(pn->shrinker_info, new);
kvfree_rcu(old, rcu);
@@ -234,9 +249,6 @@ void free_shrinker_info(struct mem_cgroup *memcg)
struct shrinker_info *info;
int nid;
- if (mem_cgroup_is_root(memcg))
- return;
-
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
info = rcu_dereference_protected(pn->shrinker_info, true);
@@ -249,12 +261,12 @@ int alloc_shrinker_info(struct mem_cgroup *memcg)
{
struct shrinker_info *info;
int nid, size, ret = 0;
-
- if (mem_cgroup_is_root(memcg))
- return 0;
+ int map_size, defer_size = 0;
down_write(&shrinker_rwsem);
- size = shrinker_map_size(shrinker_nr_max);
+ map_size = shrinker_map_size(shrinker_nr_max);
+ defer_size = shrinker_defer_size(shrinker_nr_max);
+ size = map_size + defer_size;
for_each_node(nid) {
info = kvzalloc_node(sizeof(*info) + size, GFP_KERNEL, nid);
if (!info) {
@@ -262,6 +274,8 @@ int alloc_shrinker_info(struct mem_cgroup *memcg)
ret = -ENOMEM;
break;
}
+ info->nr_deferred = (atomic_long_t *)(info + 1);
+ info->map = (void *)info->nr_deferred + defer_size;
rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info);
}
up_write(&shrinker_rwsem);
@@ -269,15 +283,21 @@ int alloc_shrinker_info(struct mem_cgroup *memcg)
return ret;
}
+static inline bool need_expand(int nr_max)
+{
+ return round_up(nr_max, BITS_PER_LONG) >
+ round_up(shrinker_nr_max, BITS_PER_LONG);
+}
+
static int expand_shrinker_info(int new_id)
{
- int size, old_size, ret = 0;
+ int ret = 0;
int new_nr_max = new_id + 1;
+ int map_size, defer_size = 0;
+ int old_map_size, old_defer_size = 0;
struct mem_cgroup *memcg;
- size = shrinker_map_size(new_nr_max);
- old_size = shrinker_map_size(shrinker_nr_max);
- if (size <= old_size)
+ if (!need_expand(new_nr_max))
goto out;
if (!root_mem_cgroup)
@@ -285,11 +305,15 @@ static int expand_shrinker_info(int new_id)
lockdep_assert_held(&shrinker_rwsem);
+ map_size = shrinker_map_size(new_nr_max);
+ defer_size = shrinker_defer_size(new_nr_max);
+ old_map_size = shrinker_map_size(shrinker_nr_max);
+ old_defer_size = shrinker_defer_size(shrinker_nr_max);
+
memcg = mem_cgroup_iter(NULL, NULL, NULL);
do {
- if (mem_cgroup_is_root(memcg))
- continue;
- ret = expand_one_shrinker_info(memcg, size, old_size);
+ ret = expand_one_shrinker_info(memcg, map_size, defer_size,
+ old_map_size, old_defer_size);
if (ret) {
mem_cgroup_iter_break(NULL, memcg);
goto out;