This patch charges allocation of a slab object to a particular
memcg.
The cache is selected with mem_cgroup_get_kmem_cache(),
which is the biggest overhead we pay here, because
it happens at all allocations. However, other than forcing
a function call, this function is not very expensive, and
try to return as soon as we realize we are not a memcg cache.
The charge/uncharge functions are heavier, but are only called
for new page allocations.
The kmalloc_no_account variant is patched so the base
function is used and we don't even try to do cache
selection.
Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
CC: Christoph Lameter <cl@xxxxxxxxx>
CC: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
CC: Michal Hocko <mhocko@xxxxxxx>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
CC: Johannes Weiner <hannes@xxxxxxxxxxx>
CC: Suleiman Souhlal <suleiman@xxxxxxxxxx>
---
include/linux/slub_def.h | 39 ++++++++++++++++++---
mm/slub.c | 87 +++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 112 insertions(+), 14 deletions(-)
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index f822ca2..ba9c68b 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -13,6 +13,8 @@
#include <linux/kobject.h>
#include <linux/kmemleak.h>
+#include <linux/memcontrol.h>
+#include <linux/mm.h>
enum stat_item {
ALLOC_FASTPATH, /* Allocation from cpu slab */
@@ -228,27 +230,54 @@ static __always_inline int kmalloc_index(size_t size)
* This ought to end up with a global pointer to the right cache
* in kmalloc_caches.
*/
-static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
+static __always_inline struct kmem_cache *kmalloc_slab(gfp_t flags, size_t size)
{
+ struct kmem_cache *s;
int index = kmalloc_index(size);
if (index == 0)
return NULL;
- return kmalloc_caches[index];
+ s = kmalloc_caches[index];
+
+ rcu_read_lock();
+ s = mem_cgroup_get_kmem_cache(s, flags);
+ rcu_read_unlock();
+
+ return s;
}
void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
void *__kmalloc(size_t size, gfp_t flags);
static __always_inline void *
-kmalloc_order(size_t size, gfp_t flags, unsigned int order)
+kmalloc_order_base(size_t size, gfp_t flags, unsigned int order)
{
void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
kmemleak_alloc(ret, size, 1, flags);
return ret;
}
+static __always_inline void *
+kmalloc_order(size_t size, gfp_t flags, unsigned int order)
+{
+ void *ret = NULL;
+ struct page *page;
+
+ ret = kmalloc_order_base(size, flags, order);
+ if (!ret)
+ return ret;
+
+ page = virt_to_head_page(ret);
+
+ if (!mem_cgroup_new_kmem_page(page, flags)) {
+ put_page(page);
+ return NULL;
+ }
+
+ return ret;
+}
+
/**
* Calling this on allocated memory will check that the memory
* is expected to be in use, and print warnings if not.
@@ -293,7 +322,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
return kmalloc_large(size, flags);
if (!(flags & SLUB_DMA)) {
- struct kmem_cache *s = kmalloc_slab(size);
+ struct kmem_cache *s = kmalloc_slab(flags, size);
if (!s)
return ZERO_SIZE_PTR;
@@ -326,7 +355,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
if (__builtin_constant_p(size) &&
size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
- struct kmem_cache *s = kmalloc_slab(size);
+ struct kmem_cache *s = kmalloc_slab(flags, size);
if (!s)
return ZERO_SIZE_PTR;
diff --git a/mm/slub.c b/mm/slub.c
index 640872f..730e69f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1283,11 +1283,39 @@ static inline struct page *alloc_slab_page(gfp_t flags, int node,
return alloc_pages_exact_node(node, flags, order);
}
+static inline unsigned long size_in_bytes(unsigned int order)
+{
+ return (1 << order) << PAGE_SHIFT;
+}
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+static void kmem_cache_inc_ref(struct kmem_cache *s)
+{
+ if (s->memcg_params.memcg)
+ atomic_inc(&s->memcg_params.refcnt);
+}
+static void kmem_cache_drop_ref(struct kmem_cache *s)
+{
+ if (s->memcg_params.memcg)
+ atomic_dec(&s->memcg_params.refcnt);
+}
+#else
+static inline void kmem_cache_inc_ref(struct kmem_cache *s)
+{
+}
+static inline void kmem_cache_drop_ref(struct kmem_cache *s)
+{
+}
+#endif
+
+
+
static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
{
- struct page *page;
+ struct page *page = NULL;
struct kmem_cache_order_objects oo = s->oo;
gfp_t alloc_gfp;
+ unsigned int memcg_allowed = oo_order(oo);
flags &= gfp_allowed_mask;
@@ -1296,13 +1324,29 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
flags |= s->allocflags;
- /*
- * Let the initial higher-order allocation fail under memory pressure
- * so we fall-back to the minimum order allocation.
- */
- alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
+ memcg_allowed = oo_order(oo);
+ if (!mem_cgroup_charge_slab(s, flags, size_in_bytes(memcg_allowed))) {
+
+ memcg_allowed = oo_order(s->min);
+ if (!mem_cgroup_charge_slab(s, flags,
+ size_in_bytes(memcg_allowed))) {
+ if (flags & __GFP_WAIT)
+ local_irq_disable();
+ return NULL;
+ }
+ }
+
+ if (memcg_allowed == oo_order(oo)) {
+ /*
+ * Let the initial higher-order allocation fail under memory
+ * pressure so we fall-back to the minimum order allocation.
+ */
+ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) &
+ ~__GFP_NOFAIL;
+
+ page = alloc_slab_page(alloc_gfp, node, oo);
+ }
- page = alloc_slab_page(alloc_gfp, node, oo);
if (unlikely(!page)) {
oo = s->min;
/*
@@ -1313,13 +1357,25 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
if (page)
stat(s, ORDER_FALLBACK);
+ /*
+ * We reserved more than we used, time to give it back
+ */
+ if (page && memcg_allowed != oo_order(oo)) {
+ unsigned long delta;
+ delta = memcg_allowed - oo_order(oo);
+ mem_cgroup_uncharge_slab(s, size_in_bytes(delta));
+ }
}
if (flags & __GFP_WAIT)
local_irq_disable();
- if (!page)
+ if (!page) {
+ mem_cgroup_uncharge_slab(s, size_in_bytes(memcg_allowed));
return NULL;
+ }
+
+ kmem_cache_inc_ref(s);
if (kmemcheck_enabled
&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
@@ -1419,6 +1475,9 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += pages;
__free_pages(page, order);
+
+ mem_cgroup_uncharge_slab(s, (1 << order) << PAGE_SHIFT);
+ kmem_cache_drop_ref(s);
}
#define need_reserve_slab_rcu \
@@ -2310,6 +2369,9 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
if (slab_pre_alloc_hook(s, gfpflags))
return NULL;
+ rcu_read_lock();
+ s = mem_cgroup_get_kmem_cache(s, gfpflags);
+ rcu_read_unlock();
redo:
/*
@@ -3372,9 +3434,15 @@ static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
flags |= __GFP_COMP | __GFP_NOTRACK;
page = alloc_pages_node(node, flags, get_order(size));
- if (page)
+ if (!page)
+ goto out;
+
+ if (!mem_cgroup_new_kmem_page(page, flags))
+ put_page(page);
+ else
ptr = page_address(page);
+out:
kmemleak_alloc(ptr, size, 1, flags);
return ptr;
}
@@ -3476,6 +3544,7 @@ void kfree(const void *x)
if (unlikely(!PageSlab(page))) {
BUG_ON(!PageCompound(page));
kmemleak_free(x);
+ mem_cgroup_free_kmem_page(page);
put_page(page);
return;
}
--
1.7.7.6
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