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 | 32 ++++++++++--
mm/slub.c | 124 +++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 138 insertions(+), 18 deletions(-)
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 9a8000a..e75efcb 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -13,6 +13,7 @@
#include <linux/kobject.h>
#include <linux/kmemleak.h>
+#include <linux/memcontrol.h>
enum stat_item {
ALLOC_FASTPATH, /* Allocation from cpu slab */
@@ -210,14 +211,21 @@ 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);
@@ -225,13 +233,27 @@ void *kmalloc_no_account(size_t size, 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;
+
+ if (!mem_cgroup_charge_kmem(flags, size))
+ return NULL;
+
+ ret = kmalloc_order_base(size, flags, order);
+ if (!ret)
+ mem_cgroup_uncharge_kmem((1 << order) << PAGE_SHIFT);
+ return ret;
+}
+
/**
* Calling this on allocated memory will check that the memory
* is expected to be in use, and print warnings if not.
@@ -276,7 +298,7 @@ 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;
@@ -309,7 +331,7 @@ 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 d754b06..9b22139 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1283,11 +1283,17 @@ 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;
+}
+
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 +1302,29 @@ 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 +1335,23 @@ 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;
+ }
if (kmemcheck_enabled
&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
@@ -1393,6 +1425,24 @@ out:
return page;
}
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+static unsigned long slab_nr_pages(struct kmem_cache *s)
+{
+ int node;
+ unsigned long nr_slabs = 0;
+
+ for_each_online_node(node) {
+ struct kmem_cache_node *n = get_node(s, node);
+
+ if (!n)
+ continue;
+ nr_slabs += atomic_long_read(&n->nr_slabs);
+ }
+
+ return nr_slabs << oo_order(s->oo);
+}
+#endif
+
static void __free_slab(struct kmem_cache *s, struct page *page)
{
int order = compound_order(page);
@@ -1419,6 +1469,12 @@ 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);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ if (s->memcg_params.memcg && (slab_nr_pages(s) == 0))
+ mem_cgroup_destroy_cache(s);
+#endif
}
#define need_reserve_slab_rcu \
@@ -2300,8 +2356,9 @@ new_slab:
*
* Otherwise we can simply pick the next object from the lockless free list.
*/
-static __always_inline void *slab_alloc(struct kmem_cache *s,
- gfp_t gfpflags, int node, unsigned long addr)
+static __always_inline void *slab_alloc_base(struct kmem_cache *s,
+ gfp_t gfpflags, int node,
+ unsigned long addr)
{
void **object;
struct kmem_cache_cpu *c;
@@ -2369,6 +2426,24 @@ redo:
return object;
}
+static __always_inline void *slab_alloc(struct kmem_cache *s,
+ gfp_t gfpflags, int node, unsigned long addr)
+{
+
+ if (slab_pre_alloc_hook(s, gfpflags))
+ return NULL;
+
+ if (in_interrupt() || (current == NULL) || (gfpflags & __GFP_NOFAIL))
+ goto kernel_alloc;
+
+ rcu_read_lock();
+ s = mem_cgroup_get_kmem_cache(s, gfpflags);
+ rcu_read_unlock();
+
+kernel_alloc:
+ return slab_alloc_base(s, gfpflags, node, addr);
+}
+
void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
{
void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
@@ -3194,6 +3269,13 @@ void kmem_cache_destroy(struct kmem_cache *s)
s->refcount--;
if (!s->refcount) {
list_del(&s->list);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ /* Not a memcg cache */
+ if (s->memcg_params.id != -1) {
+ mem_cgroup_release_cache(s);
+ mem_cgroup_flush_cache_create_queue();
+ }
+#endif
up_write(&slub_lock);
if (kmem_cache_close(s)) {
printk(KERN_ERR "SLUB %s: %s called for cache that "
@@ -3273,6 +3355,7 @@ static struct kmem_cache *__init create_kmalloc_cache(const char *name,
goto panic;
list_add(&s->list, &slab_caches);
+ mem_cgroup_register_cache(NULL, s);
return s;
panic:
@@ -3364,15 +3447,21 @@ void *kmalloc_no_account(size_t size, gfp_t flags)
struct kmem_cache *s;
void *ret;
- if (unlikely(size > SLUB_MAX_SIZE))
- return kmalloc_large(size, flags);
+ if (unlikely(size > SLUB_MAX_SIZE)) {
+ unsigned int order = get_order(size);
+ ret = kmalloc_order_base(size, flags, order);
+#ifdef CONFIG_TRACING
+ trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
+#endif
+ return ret;
+ }
s = get_slab(size, flags);
if (unlikely(ZERO_OR_NULL_PTR(s)))
return s;
- ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
+ ret = slab_alloc_base(s, flags, NUMA_NO_NODE, _RET_IP_);
trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
@@ -3387,10 +3476,17 @@ static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
void *ptr = NULL;
flags |= __GFP_COMP | __GFP_NOTRACK;
+
+ if (!mem_cgroup_charge_kmem(flags, size))
+ goto out;
+
page = alloc_pages_node(node, flags, get_order(size));
if (page)
ptr = page_address(page);
+ else
+ mem_cgroup_uncharge_kmem(size);
+out:
kmemleak_alloc(ptr, size, 1, flags);
return ptr;
}
@@ -3938,8 +4034,10 @@ static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
if (s->size - size >= sizeof(void *))
continue;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
if (memcg && s->memcg_params.memcg != memcg)
continue;
+#endif
return s;
}
--
1.7.7.6
--
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