On 12/01/2016 02:16 AM, Anatoly Stepanov wrote:
As memcg array size can be up to:
sizeof(struct memcg_cache_array) + kmemcg_id * sizeof(void *);
where kmemcg_id can be up to MEMCG_CACHES_MAX_SIZE.
When a memcg instance count is large enough it can lead
to high order allocations up to order 7.
The same story with memcg_lrus allocations.
So let's work this around by utilizing vmalloc fallback path.
Signed-off-by: Anatoly Stepanov <astepanov@xxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 16 ++++++++++++++++
mm/list_lru.c | 14 +++++++-------
mm/slab_common.c | 21 ++++++++++++++-------
3 files changed, 37 insertions(+), 14 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 61d20c1..a281622 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -29,6 +29,9 @@
#include <linux/mmzone.h>
#include <linux/writeback.h>
#include <linux/page-flags.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
struct mem_cgroup;
struct page;
@@ -878,4 +881,17 @@ static inline void memcg_kmem_update_page_stat(struct page *page,
}
#endif /* CONFIG_MEMCG && !CONFIG_SLOB */
+static inline void memcg_free(const void *ptr)
+{
+ is_vmalloc_addr(ptr) ? vfree(ptr) : kfree(ptr);
+}
+
+static inline void *memcg_alloc(size_t size)
+{
+ if (likely(size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)))
+ return kzalloc(size, GFP_KERNEL|__GFP_NORETRY);
+
+ return vzalloc(size);
That's not how I imagine a "fallback" to work. You should be trying
kzalloc() and if that fails, call vzalloc(), not distinguish it by
costly order check. Also IIRC __GFP_NORETRY can easily fail even for
non-costly orders.
+}
+
#endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 234676e..8f49339 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -327,12 +327,12 @@ static int memcg_init_list_lru_node(struct list_lru_node *nlru)
{
int size = memcg_nr_cache_ids;
- nlru->memcg_lrus = kmalloc(size * sizeof(void *), GFP_KERNEL);
- if (!nlru->memcg_lrus)
+ nlru->memcg_lrus = memcg_alloc(size * sizeof(void *));
+ if (nlru->memcg_lrus == NULL)
return -ENOMEM;
if (__memcg_init_list_lru_node(nlru->memcg_lrus, 0, size)) {
- kfree(nlru->memcg_lrus);
+ memcg_free(nlru->memcg_lrus);
return -ENOMEM;
}
@@ -342,7 +342,7 @@ static int memcg_init_list_lru_node(struct list_lru_node *nlru)
static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
{
__memcg_destroy_list_lru_node(nlru->memcg_lrus, 0, memcg_nr_cache_ids);
- kfree(nlru->memcg_lrus);
+ memcg_free(nlru->memcg_lrus);
}
static int memcg_update_list_lru_node(struct list_lru_node *nlru,
@@ -353,12 +353,12 @@ static int memcg_update_list_lru_node(struct list_lru_node *nlru,
BUG_ON(old_size > new_size);
old = nlru->memcg_lrus;
- new = kmalloc(new_size * sizeof(void *), GFP_KERNEL);
+ new = memcg_alloc(new_size * sizeof(void *));
if (!new)
return -ENOMEM;
if (__memcg_init_list_lru_node(new, old_size, new_size)) {
- kfree(new);
+ memcg_free(new);
return -ENOMEM;
}
@@ -375,7 +375,7 @@ static int memcg_update_list_lru_node(struct list_lru_node *nlru,
nlru->memcg_lrus = new;
spin_unlock_irq(&nlru->lock);
- kfree(old);
+ memcg_free(old);
return 0;
}
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 329b038..19f8cb5 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -157,9 +157,8 @@ static int init_memcg_params(struct kmem_cache *s,
if (!memcg_nr_cache_ids)
return 0;
- arr = kzalloc(sizeof(struct memcg_cache_array) +
- memcg_nr_cache_ids * sizeof(void *),
- GFP_KERNEL);
+ arr = memcg_alloc(sizeof(struct memcg_cache_array) +
+ memcg_nr_cache_ids * sizeof(void *));
if (!arr)
return -ENOMEM;
@@ -170,7 +169,15 @@ static int init_memcg_params(struct kmem_cache *s,
static void destroy_memcg_params(struct kmem_cache *s)
{
if (is_root_cache(s))
- kfree(rcu_access_pointer(s->memcg_params.memcg_caches));
+ memcg_free(rcu_access_pointer(s->memcg_params.memcg_caches));
+}
+
+static void memcg_rcu_free(struct rcu_head *rcu)
+{
+ struct memcg_cache_array *arr;
+
+ arr = container_of(rcu, struct memcg_cache_array, rcu);
+ memcg_free(arr);
}
static int update_memcg_params(struct kmem_cache *s, int new_array_size)
@@ -180,8 +187,8 @@ static int update_memcg_params(struct kmem_cache *s, int new_array_size)
if (!is_root_cache(s))
return 0;
- new = kzalloc(sizeof(struct memcg_cache_array) +
- new_array_size * sizeof(void *), GFP_KERNEL);
+ new = memcg_alloc(sizeof(struct memcg_cache_array) +
+ new_array_size * sizeof(void *));
if (!new)
return -ENOMEM;
@@ -193,7 +200,7 @@ static int update_memcg_params(struct kmem_cache *s, int new_array_size)
rcu_assign_pointer(s->memcg_params.memcg_caches, new);
if (old)
- kfree_rcu(old, rcu);
+ call_rcu(&old->rcu, memcg_rcu_free);
return 0;
}
--
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