diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/memcontrol.h | 66 | ||||
| -rw-r--r-- | include/trace/events/writeback.h | 5 |
2 files changed, 64 insertions, 7 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 026b62b206b1..a8bd4bb39502 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -379,7 +379,7 @@ static inline bool folio_memcg_kmem(struct folio *folio); * a valid memcg, but can be atomically swapped to the parent memcg. * * The caller must ensure that the returned memcg won't be released: - * e.g. acquire the rcu_read_lock or css_set_lock. + * e.g. acquire the rcu_read_lock or objcg_lock or cgroup_mutex. */ static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg) { @@ -445,8 +445,8 @@ static inline struct obj_cgroup *__folio_objcg(struct folio *folio) * - lock_page_memcg() * - exclusive reference * - * For a kmem folio a caller should hold an rcu read lock to protect memcg - * associated with a kmem folio from being released. + * Note: The caller should hold an rcu read lock to protect memcg associated + * with a folio from being released. */ static inline struct mem_cgroup *folio_memcg(struct folio *folio) { @@ -455,12 +455,48 @@ static inline struct mem_cgroup *folio_memcg(struct folio *folio) return __folio_memcg(folio); } +/* + * page_memcg - Get the memory cgroup associated with a page. + * @page: Pointer to the page. + * + * See the cooments in folio_memcg(). + */ static inline struct mem_cgroup *page_memcg(struct page *page) { return folio_memcg(page_folio(page)); } -/** +/* + * get_mem_cgroup_from_folio - Obtain a reference on the memory cgroup + * associated with a folio. + * @folio: Pointer to the folio. + * + * Returns a pointer to the memory cgroup (and obtain a reference on it) + * associated with the folio, or NULL. This function assumes that the + * folio is known to have a proper memory cgroup pointer. It's not safe + * to call this function against some type of pages, e.g. slab pages or + * ex-slab pages. + */ +static inline struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio) +{ + struct mem_cgroup *memcg; + + rcu_read_lock(); +retry: + memcg = folio_memcg(folio); + if (unlikely(memcg && !css_tryget(&memcg->css))) + goto retry; + rcu_read_unlock(); + + return memcg; +} + +static inline struct mem_cgroup *get_mem_cgroup_from_page(struct page *page) +{ + return get_mem_cgroup_from_folio(page_folio(page)); +} + +/* * folio_memcg_rcu - Locklessly get the memory cgroup associated with a folio. * @folio: Pointer to the folio. * @@ -888,7 +924,7 @@ static inline bool mm_match_cgroup(struct mm_struct *mm, return match; } -struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page); +struct cgroup_subsys_state *get_mem_cgroup_css_from_page(struct page *page); ino_t page_cgroup_ino(struct page *page); static inline bool mem_cgroup_online(struct mem_cgroup *memcg) @@ -1058,19 +1094,25 @@ static inline void count_memcg_events(struct mem_cgroup *memcg, static inline void count_memcg_page_event(struct page *page, enum vm_event_item idx) { - struct mem_cgroup *memcg = page_memcg(page); + struct mem_cgroup *memcg; + rcu_read_lock(); + memcg = page_memcg(page); if (memcg) count_memcg_events(memcg, idx, 1); + rcu_read_unlock(); } static inline void count_memcg_folio_events(struct folio *folio, enum vm_event_item idx, unsigned long nr) { - struct mem_cgroup *memcg = folio_memcg(folio); + struct mem_cgroup *memcg; + rcu_read_lock(); + memcg = folio_memcg(folio); if (memcg) count_memcg_events(memcg, idx, nr); + rcu_read_unlock(); } static inline void count_memcg_event_mm(struct mm_struct *mm, @@ -1149,6 +1191,16 @@ static inline struct mem_cgroup *page_memcg(struct page *page) return NULL; } +static inline struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio) +{ + return NULL; +} + +static inline struct mem_cgroup *get_mem_cgroup_from_page(struct page *page) +{ + return NULL; +} + static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio) { WARN_ON_ONCE(!rcu_read_lock_held()); diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h index 86b2a82da546..cdb822339f13 100644 --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -258,6 +258,11 @@ TRACE_EVENT(track_foreign_dirty, __entry->ino = inode ? inode->i_ino : 0; __entry->memcg_id = wb->memcg_css->id; __entry->cgroup_ino = __trace_wb_assign_cgroup(wb); + /* + * TP_fast_assign() is under preemption disabled which can + * serve as an RCU read-side critical section so that the + * memcg returned by folio_memcg() cannot be freed. + */ __entry->page_cgroup_ino = cgroup_ino(folio_memcg(folio)->css.cgroup); ), |