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mm, memcg: introduce mem_cgroup_kmem_disabled()

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Introduce a new mem_cgroup_kmem_disabled() helper, similar to
mem_cgroup_disabled(), to check whether the kernel memory accounting
is off. A user could disable it using a boot option to eliminate
some associated costs.

The helper can be used outside of memcontrol.c to dynamically disable
the kmem-related code. The returned value is stable after the kernel
initialization is finished.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
This commit is contained in:
Roman Gushchin
2021-06-02 18:09:30 -07:00
committed by Dennis Zhou
parent 0f0cace35f
commit 4d5c8aedc8
2 changed files with 10 additions and 0 deletions
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5
include/linux/memcontrol.h
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@@ -1583,6 +1583,7 @@ static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
#endif #endif
#ifdef CONFIG_MEMCG_KMEM #ifdef CONFIG_MEMCG_KMEM
bool mem_cgroup_kmem_disabled(void);
int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order); int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order);
void __memcg_kmem_uncharge_page(struct page *page, int order); void __memcg_kmem_uncharge_page(struct page *page, int order);
@@ -1636,6 +1637,10 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg)
struct mem_cgroup *mem_cgroup_from_obj(void *p); struct mem_cgroup *mem_cgroup_from_obj(void *p);
#else #else
static inline bool mem_cgroup_kmem_disabled(void)
{
return true;
}
static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp, static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
int order) int order)

5
mm/memcontrol.c
View File

@@ -255,6 +255,11 @@ struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
#ifdef CONFIG_MEMCG_KMEM #ifdef CONFIG_MEMCG_KMEM
extern spinlock_t css_set_lock; extern spinlock_t css_set_lock;
bool mem_cgroup_kmem_disabled(void)
{
return cgroup_memory_nokmem;
}
static int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp, static int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
unsigned int nr_pages); unsigned int nr_pages);
static void __memcg_kmem_uncharge(struct mem_cgroup *memcg, static void __memcg_kmem_uncharge(struct mem_cgroup *memcg,