The patch titled
Subject: mm: memcontrol: rename memcg_kmem_enabled()
has been added to the -mm mm-unstable branch. Its filename is
mm-memcontrol-rename-memcg_kmem_enabled.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcontrol-rename-memcg_kmem_enabled.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Subject: mm: memcontrol: rename memcg_kmem_enabled()
Date: Mon, 13 Feb 2023 11:29:22 -0800
Currently there are two kmem-related helper functions with a confusing
semantics: memcg_kmem_enabled() and mem_cgroup_kmem_disabled().
The problem is that an obvious expectation
memcg_kmem_enabled() == !mem_cgroup_kmem_disabled(),
can be false.
mem_cgroup_kmem_disabled() is similar to mem_cgroup_disabled(): it returns
true only if CONFIG_MEMCG_KMEM is not set or the kmem accounting is
disabled using a boot time kernel option "cgroup.memory=nokmem". It never
changes the value dynamically.
memcg_kmem_enabled() is different: it always returns false until the first
non-root memory cgroup will get online (assuming the kernel memory
accounting is enabled). It's goal is to improve the performance on
systems without the cgroupfs mounted/memory controller enabled or on the
systems with only the root memory cgroup.
To make things more obvious and avoid potential bugs, let's rename
memcg_kmem_enabled() to memcg_kmem_online().
Link: https://lkml.kernel.org/r/20230213192922.1146370-1-roman.gushchin@xxxxxxxxx
Signed-off-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Acked-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/include/linux/memcontrol.h~mm-memcontrol-rename-memcg_kmem_enabled
+++ a/include/linux/memcontrol.h
@@ -1776,24 +1776,24 @@ struct obj_cgroup *get_obj_cgroup_from_p
int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size);
void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size);
-extern struct static_key_false memcg_kmem_enabled_key;
+extern struct static_key_false memcg_kmem_online_key;
-static inline bool memcg_kmem_enabled(void)
+static inline bool memcg_kmem_online(void)
{
- return static_branch_likely(&memcg_kmem_enabled_key);
+ return static_branch_likely(&memcg_kmem_online_key);
}
static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
int order)
{
- if (memcg_kmem_enabled())
+ if (memcg_kmem_online())
return __memcg_kmem_charge_page(page, gfp, order);
return 0;
}
static inline void memcg_kmem_uncharge_page(struct page *page, int order)
{
- if (memcg_kmem_enabled())
+ if (memcg_kmem_online())
__memcg_kmem_uncharge_page(page, order);
}
@@ -1814,7 +1814,7 @@ static inline void count_objcg_event(str
{
struct mem_cgroup *memcg;
- if (!memcg_kmem_enabled())
+ if (!memcg_kmem_online())
return;
rcu_read_lock();
@@ -1854,7 +1854,7 @@ static inline struct obj_cgroup *get_obj
return NULL;
}
-static inline bool memcg_kmem_enabled(void)
+static inline bool memcg_kmem_online(void)
{
return false;
}
--- a/mm/memcontrol.c~mm-memcontrol-rename-memcg_kmem_enabled
+++ a/mm/memcontrol.c
@@ -345,8 +345,8 @@ static void memcg_reparent_objcgs(struct
* conditional to this static branch, we'll have to allow modules that does
* kmem_cache_alloc and the such to see this symbol as well
*/
-DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key);
-EXPORT_SYMBOL(memcg_kmem_enabled_key);
+DEFINE_STATIC_KEY_FALSE(memcg_kmem_online_key);
+EXPORT_SYMBOL(memcg_kmem_online_key);
#endif
/**
@@ -3034,7 +3034,7 @@ struct obj_cgroup *get_obj_cgroup_from_p
{
struct obj_cgroup *objcg;
- if (!memcg_kmem_enabled())
+ if (!memcg_kmem_online())
return NULL;
if (PageMemcgKmem(page)) {
@@ -3746,7 +3746,7 @@ static int memcg_online_kmem(struct mem_
objcg->memcg = memcg;
rcu_assign_pointer(memcg->objcg, objcg);
- static_branch_enable(&memcg_kmem_enabled_key);
+ static_branch_enable(&memcg_kmem_online_key);
memcg->kmemcg_id = memcg->id.id;
--- a/mm/page_alloc.c~mm-memcontrol-rename-memcg_kmem_enabled
+++ a/mm/page_alloc.c
@@ -1410,7 +1410,7 @@ static __always_inline bool free_pages_p
* Do not let hwpoison pages hit pcplists/buddy
* Untie memcg state and reset page's owner
*/
- if (memcg_kmem_enabled() && PageMemcgKmem(page))
+ if (memcg_kmem_online() && PageMemcgKmem(page))
__memcg_kmem_uncharge_page(page, order);
reset_page_owner(page, order);
page_table_check_free(page, order);
@@ -1441,7 +1441,7 @@ static __always_inline bool free_pages_p
}
if (PageMappingFlags(page))
page->mapping = NULL;
- if (memcg_kmem_enabled() && PageMemcgKmem(page))
+ if (memcg_kmem_online() && PageMemcgKmem(page))
__memcg_kmem_uncharge_page(page, order);
if (check_free && free_page_is_bad(page))
bad++;
@@ -5446,7 +5446,7 @@ unsigned long __alloc_pages_bulk(gfp_t g
goto out;
/* Bulk allocator does not support memcg accounting. */
- if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT))
+ if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT))
goto failed;
/* Use the single page allocator for one page. */
@@ -5618,7 +5618,7 @@ struct page *__alloc_pages(gfp_t gfp, un
page = __alloc_pages_slowpath(alloc_gfp, order, &ac);
out:
- if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT) && page &&
+ if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT) && page &&
unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) {
__free_pages(page, order);
page = NULL;
--- a/mm/percpu.c~mm-memcontrol-rename-memcg_kmem_enabled
+++ a/mm/percpu.c
@@ -1625,7 +1625,7 @@ static bool pcpu_memcg_pre_alloc_hook(si
{
struct obj_cgroup *objcg;
- if (!memcg_kmem_enabled() || !(gfp & __GFP_ACCOUNT))
+ if (!memcg_kmem_online() || !(gfp & __GFP_ACCOUNT))
return true;
objcg = get_obj_cgroup_from_current();
--- a/mm/slab.h~mm-memcontrol-rename-memcg_kmem_enabled
+++ a/mm/slab.h
@@ -494,7 +494,7 @@ static inline bool memcg_slab_pre_alloc_
{
struct obj_cgroup *objcg;
- if (!memcg_kmem_enabled())
+ if (!memcg_kmem_online())
return true;
if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
@@ -535,7 +535,7 @@ static inline void memcg_slab_post_alloc
unsigned long off;
size_t i;
- if (!memcg_kmem_enabled() || !objcg)
+ if (!memcg_kmem_online() || !objcg)
return;
for (i = 0; i < size; i++) {
@@ -567,7 +567,7 @@ static inline void memcg_slab_free_hook(
struct obj_cgroup **objcgs;
int i;
- if (!memcg_kmem_enabled())
+ if (!memcg_kmem_online())
return;
objcgs = slab_objcgs(slab);
@@ -649,7 +649,7 @@ static inline struct kmem_cache *virt_to
static __always_inline void account_slab(struct slab *slab, int order,
struct kmem_cache *s, gfp_t gfp)
{
- if (memcg_kmem_enabled() && (s->flags & SLAB_ACCOUNT))
+ if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
memcg_alloc_slab_cgroups(slab, s, gfp, true);
mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
@@ -659,7 +659,7 @@ static __always_inline void account_slab
static __always_inline void unaccount_slab(struct slab *slab, int order,
struct kmem_cache *s)
{
- if (memcg_kmem_enabled())
+ if (memcg_kmem_online())
memcg_free_slab_cgroups(slab);
mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
--- a/mm/vmscan.c~mm-memcontrol-rename-memcg_kmem_enabled
+++ a/mm/vmscan.c
@@ -915,7 +915,7 @@ static unsigned long shrink_slab_memcg(g
}
/* Call non-slab shrinkers even though kmem is disabled */
- if (!memcg_kmem_enabled() &&
+ if (!memcg_kmem_online() &&
!(shrinker->flags & SHRINKER_NONSLAB))
continue;
_
Patches currently in -mm which might be from roman.gushchin@xxxxxxxxx are
mm-memcontrol-rename-memcg_kmem_enabled.patch
