The patch titled
Subject: mm: memcontrol/slab: use helpers to access slab page's memcg_data
has been removed from the -mm tree. Its filename was
mm-memcontrol-slab-use-helpers-to-access-slab-pages-memcg_data.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Roman Gushchin <guro@xxxxxx>
Subject: mm: memcontrol/slab: use helpers to access slab page's memcg_data
To gather all direct accesses to struct page's memcg_data field in one
place, let's introduce 3 new helpers to use in the slab accounting code:
struct obj_cgroup **page_objcgs(struct page *page);
struct obj_cgroup **page_objcgs_check(struct page *page);
bool set_page_objcgs(struct page *page, struct obj_cgroup **objcgs);
They are similar to the corresponding API for generic pages, except that
the setter can return false, indicating that the value has been already
set from a different thread.
Link: https://lkml.kernel.org/r/20201027001657.3398190-3-guro@xxxxxx
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 64 +++++++++++++++++++++++++++++++++++
mm/memcontrol.c | 6 +--
mm/slab.h | 35 ++++---------------
3 files changed, 75 insertions(+), 30 deletions(-)
--- a/include/linux/memcontrol.h~mm-memcontrol-slab-use-helpers-to-access-slab-pages-memcg_data
+++ a/include/linux/memcontrol.h
@@ -410,6 +410,70 @@ static inline struct mem_cgroup *page_me
return (struct mem_cgroup *)memcg_data;
}
+#ifdef CONFIG_MEMCG_KMEM
+/*
+ * page_objcgs - get the object cgroups vector associated with a page
+ * @page: a pointer to the page struct
+ *
+ * Returns a pointer to the object cgroups vector associated with the page,
+ * or NULL. This function assumes that the page is known to have an
+ * associated object cgroups vector. It's not safe to call this function
+ * against pages, which might have an associated memory cgroup: e.g.
+ * kernel stack pages.
+ */
+static inline struct obj_cgroup **page_objcgs(struct page *page)
+{
+ return (struct obj_cgroup **)(READ_ONCE(page->memcg_data) & ~0x1UL);
+}
+
+/*
+ * page_objcgs_check - get the object cgroups vector associated with a page
+ * @page: a pointer to the page struct
+ *
+ * Returns a pointer to the object cgroups vector associated with the page,
+ * or NULL. This function is safe to use if the page can be directly associated
+ * with a memory cgroup.
+ */
+static inline struct obj_cgroup **page_objcgs_check(struct page *page)
+{
+ unsigned long memcg_data = READ_ONCE(page->memcg_data);
+
+ if (memcg_data && (memcg_data & 0x1UL))
+ return (struct obj_cgroup **)(memcg_data & ~0x1UL);
+
+ return NULL;
+}
+
+/*
+ * set_page_objcgs - associate a page with a object cgroups vector
+ * @page: a pointer to the page struct
+ * @objcgs: a pointer to the object cgroups vector
+ *
+ * Atomically associates a page with a vector of object cgroups.
+ */
+static inline bool set_page_objcgs(struct page *page,
+ struct obj_cgroup **objcgs)
+{
+ return !cmpxchg(&page->memcg_data, 0, (unsigned long)objcgs | 0x1UL);
+}
+#else
+static inline struct obj_cgroup **page_objcgs(struct page *page)
+{
+ return NULL;
+}
+
+static inline struct obj_cgroup **page_objcgs_check(struct page *page)
+{
+ return NULL;
+}
+
+static inline bool set_page_objcgs(struct page *page,
+ struct obj_cgroup **objcgs)
+{
+ return true;
+}
+#endif
+
static __always_inline bool memcg_stat_item_in_bytes(int idx)
{
if (idx == MEMCG_PERCPU_B)
--- a/mm/memcontrol.c~mm-memcontrol-slab-use-helpers-to-access-slab-pages-memcg_data
+++ a/mm/memcontrol.c
@@ -3000,7 +3000,7 @@ int memcg_alloc_page_obj_cgroups(struct
if (!vec)
return -ENOMEM;
- if (cmpxchg(&page->memcg_data, 0, (unsigned long)vec | 0x1UL))
+ if (!set_page_objcgs(page, vec))
kfree(vec);
else
kmemleak_not_leak(vec);
@@ -3034,12 +3034,12 @@ struct mem_cgroup *mem_cgroup_from_obj(v
* Memcg membership data for each individual object is saved in
* the page->obj_cgroups.
*/
- if (page_has_obj_cgroups(page)) {
+ if (page_objcgs_check(page)) {
struct obj_cgroup *objcg;
unsigned int off;
off = obj_to_index(page->slab_cache, page, p);
- objcg = page_obj_cgroups(page)[off];
+ objcg = page_objcgs(page)[off];
if (objcg)
return obj_cgroup_memcg(objcg);
--- a/mm/slab.h~mm-memcontrol-slab-use-helpers-to-access-slab-pages-memcg_data
+++ a/mm/slab.h
@@ -239,28 +239,12 @@ static inline bool kmem_cache_debug_flag
}
#ifdef CONFIG_MEMCG_KMEM
-static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
-{
- /*
- * Page's memory cgroup and obj_cgroups vector are sharing the same
- * space. To distinguish between them in case we don't know for sure
- * that the page is a slab page (e.g. page_cgroup_ino()), let's
- * always set the lowest bit of obj_cgroups.
- */
- return (struct obj_cgroup **)(page->memcg_data & ~0x1UL);
-}
-
-static inline bool page_has_obj_cgroups(struct page *page)
-{
- return page->memcg_data & 0x1UL;
-}
-
int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
gfp_t gfp);
static inline void memcg_free_page_obj_cgroups(struct page *page)
{
- kfree(page_obj_cgroups(page));
+ kfree(page_objcgs(page));
page->memcg_data = 0;
}
@@ -332,7 +316,7 @@ static inline void memcg_slab_post_alloc
if (likely(p[i])) {
page = virt_to_head_page(p[i]);
- if (!page_has_obj_cgroups(page) &&
+ if (!page_objcgs(page) &&
memcg_alloc_page_obj_cgroups(page, s, flags)) {
obj_cgroup_uncharge(objcg, obj_full_size(s));
continue;
@@ -340,7 +324,7 @@ static inline void memcg_slab_post_alloc
off = obj_to_index(s, page, p[i]);
obj_cgroup_get(objcg);
- page_obj_cgroups(page)[off] = objcg;
+ page_objcgs(page)[off] = objcg;
mod_objcg_state(objcg, page_pgdat(page),
cache_vmstat_idx(s), obj_full_size(s));
} else {
@@ -354,6 +338,7 @@ static inline void memcg_slab_free_hook(
void **p, int objects)
{
struct kmem_cache *s;
+ struct obj_cgroup **objcgs;
struct obj_cgroup *objcg;
struct page *page;
unsigned int off;
@@ -367,7 +352,8 @@ static inline void memcg_slab_free_hook(
continue;
page = virt_to_head_page(p[i]);
- if (!page_has_obj_cgroups(page))
+ objcgs = page_objcgs(page);
+ if (!objcgs)
continue;
if (!s_orig)
@@ -376,11 +362,11 @@ static inline void memcg_slab_free_hook(
s = s_orig;
off = obj_to_index(s, page, p[i]);
- objcg = page_obj_cgroups(page)[off];
+ objcg = objcgs[off];
if (!objcg)
continue;
- page_obj_cgroups(page)[off] = NULL;
+ objcgs[off] = NULL;
obj_cgroup_uncharge(objcg, obj_full_size(s));
mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s),
-obj_full_size(s));
@@ -389,11 +375,6 @@ static inline void memcg_slab_free_hook(
}
#else /* CONFIG_MEMCG_KMEM */
-static inline bool page_has_obj_cgroups(struct page *page)
-{
- return false;
-}
-
static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
{
return NULL;
_
Patches currently in -mm which might be from guro@xxxxxx are
mm-memcg-slab-fix-obj_cgroup_charge-return-value-handling.patch
mm-memcg-fix-obsolete-code-comments.patch
mm-memcg-deprecate-the-non-hierarchical-mode.patch
docs-cgroup-v1-reflect-the-deprecation-of-the-non-hierarchical-mode.patch
cgroup-remove-obsoleted-broken_hierarchy-and-warned_broken_hierarchy.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings-fix.patch
mm-slub-call-account_slab_page-after-slab-page-initialization.patch
mm-memcg-slab-pre-allocate-obj_cgroups-for-slab-caches-with-slab_account.patch
mm-memcg-slab-pre-allocate-obj_cgroups-for-slab-caches-with-slab_account-v2.patch
