From: Vladimir Davydov Date: Thu, 12 Feb 2015 22:59:10 +0000 (-0800) Subject: list_lru: introduce per-memcg lists X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=60d3fd32a7a9da4c8c93a9f89cfda22a0b4c65ce;p=openwrt%2Fstaging%2Fblogic.git list_lru: introduce per-memcg lists There are several FS shrinkers, including super_block::s_shrink, that keep reclaimable objects in the list_lru structure. Hence to turn them to memcg-aware shrinkers, it is enough to make list_lru per-memcg. This patch does the trick. It adds an array of lru lists to the list_lru_node structure (per-node part of the list_lru), one for each kmem-active memcg, and dispatches every item addition or removal to the list corresponding to the memcg which the item is accounted to. So now the list_lru structure is not just per node, but per node and per memcg. Not all list_lrus need this feature, so this patch also adds a new method, list_lru_init_memcg, which initializes a list_lru as memcg aware. Otherwise (i.e. if initialized with old list_lru_init), the list_lru won't have per memcg lists. Just like per memcg caches arrays, the arrays of per-memcg lists are indexed by memcg_cache_id, so we must grow them whenever memcg_nr_cache_ids is increased. So we introduce a callback, memcg_update_all_list_lrus, invoked by memcg_alloc_cache_id if the id space is full. The locking is implemented in a manner similar to lruvecs, i.e. we have one lock per node that protects all lists (both global and per cgroup) on the node. Signed-off-by: Vladimir Davydov Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Cc: Greg Thelen Cc: Glauber Costa Cc: Alexander Viro Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h index ee9486ac0621..305b598abac2 100644 --- a/include/linux/list_lru.h +++ b/include/linux/list_lru.h @@ -11,6 +11,8 @@ #include #include +struct mem_cgroup; + /* list_lru_walk_cb has to always return one of those */ enum lru_status { LRU_REMOVED, /* item removed from list */ @@ -22,11 +24,26 @@ enum lru_status { internally, but has to return locked. */ }; -struct list_lru_node { - spinlock_t lock; +struct list_lru_one { struct list_head list; /* kept as signed so we can catch imbalance bugs */ long nr_items; +}; + +struct list_lru_memcg { + /* array of per cgroup lists, indexed by memcg_cache_id */ + struct list_lru_one *lru[0]; +}; + +struct list_lru_node { + /* protects all lists on the node, including per cgroup */ + spinlock_t lock; + /* global list, used for the root cgroup in cgroup aware lrus */ + struct list_lru_one lru; +#ifdef CONFIG_MEMCG_KMEM + /* for cgroup aware lrus points to per cgroup lists, otherwise NULL */ + struct list_lru_memcg *memcg_lrus; +#endif } ____cacheline_aligned_in_smp; struct list_lru { @@ -37,11 +54,14 @@ struct list_lru { }; void list_lru_destroy(struct list_lru *lru); -int list_lru_init_key(struct list_lru *lru, struct lock_class_key *key); -static inline int list_lru_init(struct list_lru *lru) -{ - return list_lru_init_key(lru, NULL); -} +int __list_lru_init(struct list_lru *lru, bool memcg_aware, + struct lock_class_key *key); + +#define list_lru_init(lru) __list_lru_init((lru), false, NULL) +#define list_lru_init_key(lru, key) __list_lru_init((lru), false, (key)) +#define list_lru_init_memcg(lru) __list_lru_init((lru), true, NULL) + +int memcg_update_all_list_lrus(int num_memcgs); /** * list_lru_add: add an element to the lru list's tail @@ -75,20 +95,23 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item); bool list_lru_del(struct list_lru *lru, struct list_head *item); /** - * list_lru_count_node: return the number of objects currently held by @lru + * list_lru_count_one: return the number of objects currently held by @lru * @lru: the lru pointer. * @nid: the node id to count from. + * @memcg: the cgroup to count from. * * Always return a non-negative number, 0 for empty lists. There is no * guarantee that the list is not updated while the count is being computed. * Callers that want such a guarantee need to provide an outer lock. */ +unsigned long list_lru_count_one(struct list_lru *lru, + int nid, struct mem_cgroup *memcg); unsigned long list_lru_count_node(struct list_lru *lru, int nid); static inline unsigned long list_lru_shrink_count(struct list_lru *lru, struct shrink_control *sc) { - return list_lru_count_node(lru, sc->nid); + return list_lru_count_one(lru, sc->nid, sc->memcg); } static inline unsigned long list_lru_count(struct list_lru *lru) @@ -105,9 +128,10 @@ static inline unsigned long list_lru_count(struct list_lru *lru) typedef enum lru_status (*list_lru_walk_cb)(struct list_head *item, spinlock_t *lock, void *cb_arg); /** - * list_lru_walk_node: walk a list_lru, isolating and disposing freeable items. + * list_lru_walk_one: walk a list_lru, isolating and disposing freeable items. * @lru: the lru pointer. * @nid: the node id to scan from. + * @memcg: the cgroup to scan from. * @isolate: callback function that is resposible for deciding what to do with * the item currently being scanned * @cb_arg: opaque type that will be passed to @isolate @@ -125,6 +149,10 @@ typedef enum lru_status * * Return value: the number of objects effectively removed from the LRU. */ +unsigned long list_lru_walk_one(struct list_lru *lru, + int nid, struct mem_cgroup *memcg, + list_lru_walk_cb isolate, void *cb_arg, + unsigned long *nr_to_walk); unsigned long list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate, void *cb_arg, unsigned long *nr_to_walk); @@ -133,8 +161,8 @@ static inline unsigned long list_lru_shrink_walk(struct list_lru *lru, struct shrink_control *sc, list_lru_walk_cb isolate, void *cb_arg) { - return list_lru_walk_node(lru, sc->nid, isolate, cb_arg, - &sc->nr_to_scan); + return list_lru_walk_one(lru, sc->nid, sc->memcg, isolate, cb_arg, + &sc->nr_to_scan); } static inline unsigned long diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index dbc4baa3619c..72dff5fb0d0c 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -439,6 +439,8 @@ int memcg_cache_id(struct mem_cgroup *memcg); struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep); void __memcg_kmem_put_cache(struct kmem_cache *cachep); +struct mem_cgroup *__mem_cgroup_from_kmem(void *ptr); + int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, unsigned long nr_pages); void memcg_uncharge_kmem(struct mem_cgroup *memcg, unsigned long nr_pages); @@ -535,6 +537,13 @@ static __always_inline void memcg_kmem_put_cache(struct kmem_cache *cachep) if (memcg_kmem_enabled()) __memcg_kmem_put_cache(cachep); } + +static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr) +{ + if (!memcg_kmem_enabled()) + return NULL; + return __mem_cgroup_from_kmem(ptr); +} #else #define for_each_memcg_cache_index(_idx) \ for (; NULL; ) @@ -586,6 +595,11 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp) static inline void memcg_kmem_put_cache(struct kmem_cache *cachep) { } + +static inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr) +{ + return NULL; +} #endif /* CONFIG_MEMCG_KMEM */ #endif /* _LINUX_MEMCONTROL_H */ diff --git a/mm/list_lru.c b/mm/list_lru.c index a9021cb3ccde..79aee70c3b9d 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -10,6 +10,7 @@ #include #include #include +#include #ifdef CONFIG_MEMCG_KMEM static LIST_HEAD(list_lrus); @@ -38,16 +39,71 @@ static void list_lru_unregister(struct list_lru *lru) } #endif /* CONFIG_MEMCG_KMEM */ +#ifdef CONFIG_MEMCG_KMEM +static inline bool list_lru_memcg_aware(struct list_lru *lru) +{ + return !!lru->node[0].memcg_lrus; +} + +static inline struct list_lru_one * +list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx) +{ + /* + * The lock protects the array of per cgroup lists from relocation + * (see memcg_update_list_lru_node). + */ + lockdep_assert_held(&nlru->lock); + if (nlru->memcg_lrus && idx >= 0) + return nlru->memcg_lrus->lru[idx]; + + return &nlru->lru; +} + +static inline struct list_lru_one * +list_lru_from_kmem(struct list_lru_node *nlru, void *ptr) +{ + struct mem_cgroup *memcg; + + if (!nlru->memcg_lrus) + return &nlru->lru; + + memcg = mem_cgroup_from_kmem(ptr); + if (!memcg) + return &nlru->lru; + + return list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg)); +} +#else +static inline bool list_lru_memcg_aware(struct list_lru *lru) +{ + return false; +} + +static inline struct list_lru_one * +list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx) +{ + return &nlru->lru; +} + +static inline struct list_lru_one * +list_lru_from_kmem(struct list_lru_node *nlru, void *ptr) +{ + return &nlru->lru; +} +#endif /* CONFIG_MEMCG_KMEM */ + bool list_lru_add(struct list_lru *lru, struct list_head *item) { int nid = page_to_nid(virt_to_page(item)); struct list_lru_node *nlru = &lru->node[nid]; + struct list_lru_one *l; spin_lock(&nlru->lock); - WARN_ON_ONCE(nlru->nr_items < 0); + l = list_lru_from_kmem(nlru, item); + WARN_ON_ONCE(l->nr_items < 0); if (list_empty(item)) { - list_add_tail(item, &nlru->list); - nlru->nr_items++; + list_add_tail(item, &l->list); + l->nr_items++; spin_unlock(&nlru->lock); return true; } @@ -60,12 +116,14 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item) { int nid = page_to_nid(virt_to_page(item)); struct list_lru_node *nlru = &lru->node[nid]; + struct list_lru_one *l; spin_lock(&nlru->lock); + l = list_lru_from_kmem(nlru, item); if (!list_empty(item)) { list_del_init(item); - nlru->nr_items--; - WARN_ON_ONCE(nlru->nr_items < 0); + l->nr_items--; + WARN_ON_ONCE(l->nr_items < 0); spin_unlock(&nlru->lock); return true; } @@ -74,33 +132,58 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item) } EXPORT_SYMBOL_GPL(list_lru_del); -unsigned long -list_lru_count_node(struct list_lru *lru, int nid) +static unsigned long __list_lru_count_one(struct list_lru *lru, + int nid, int memcg_idx) { - unsigned long count = 0; struct list_lru_node *nlru = &lru->node[nid]; + struct list_lru_one *l; + unsigned long count; spin_lock(&nlru->lock); - WARN_ON_ONCE(nlru->nr_items < 0); - count += nlru->nr_items; + l = list_lru_from_memcg_idx(nlru, memcg_idx); + WARN_ON_ONCE(l->nr_items < 0); + count = l->nr_items; spin_unlock(&nlru->lock); return count; } + +unsigned long list_lru_count_one(struct list_lru *lru, + int nid, struct mem_cgroup *memcg) +{ + return __list_lru_count_one(lru, nid, memcg_cache_id(memcg)); +} +EXPORT_SYMBOL_GPL(list_lru_count_one); + +unsigned long list_lru_count_node(struct list_lru *lru, int nid) +{ + long count = 0; + int memcg_idx; + + count += __list_lru_count_one(lru, nid, -1); + if (list_lru_memcg_aware(lru)) { + for_each_memcg_cache_index(memcg_idx) + count += __list_lru_count_one(lru, nid, memcg_idx); + } + return count; +} EXPORT_SYMBOL_GPL(list_lru_count_node); -unsigned long -list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate, - void *cb_arg, unsigned long *nr_to_walk) +static unsigned long +__list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx, + list_lru_walk_cb isolate, void *cb_arg, + unsigned long *nr_to_walk) { - struct list_lru_node *nlru = &lru->node[nid]; + struct list_lru_node *nlru = &lru->node[nid]; + struct list_lru_one *l; struct list_head *item, *n; unsigned long isolated = 0; spin_lock(&nlru->lock); + l = list_lru_from_memcg_idx(nlru, memcg_idx); restart: - list_for_each_safe(item, n, &nlru->list) { + list_for_each_safe(item, n, &l->list) { enum lru_status ret; /* @@ -116,8 +199,8 @@ restart: case LRU_REMOVED_RETRY: assert_spin_locked(&nlru->lock); case LRU_REMOVED: - nlru->nr_items--; - WARN_ON_ONCE(nlru->nr_items < 0); + l->nr_items--; + WARN_ON_ONCE(l->nr_items < 0); isolated++; /* * If the lru lock has been dropped, our list @@ -128,7 +211,7 @@ restart: goto restart; break; case LRU_ROTATE: - list_move_tail(item, &nlru->list); + list_move_tail(item, &l->list); break; case LRU_SKIP: break; @@ -147,36 +230,279 @@ restart: spin_unlock(&nlru->lock); return isolated; } + +unsigned long +list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg, + list_lru_walk_cb isolate, void *cb_arg, + unsigned long *nr_to_walk) +{ + return __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), + isolate, cb_arg, nr_to_walk); +} +EXPORT_SYMBOL_GPL(list_lru_walk_one); + +unsigned long list_lru_walk_node(struct list_lru *lru, int nid, + list_lru_walk_cb isolate, void *cb_arg, + unsigned long *nr_to_walk) +{ + long isolated = 0; + int memcg_idx; + + isolated += __list_lru_walk_one(lru, nid, -1, isolate, cb_arg, + nr_to_walk); + if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) { + for_each_memcg_cache_index(memcg_idx) { + isolated += __list_lru_walk_one(lru, nid, memcg_idx, + isolate, cb_arg, nr_to_walk); + if (*nr_to_walk <= 0) + break; + } + } + return isolated; +} EXPORT_SYMBOL_GPL(list_lru_walk_node); -int list_lru_init_key(struct list_lru *lru, struct lock_class_key *key) +static void init_one_lru(struct list_lru_one *l) +{ + INIT_LIST_HEAD(&l->list); + l->nr_items = 0; +} + +#ifdef CONFIG_MEMCG_KMEM +static void __memcg_destroy_list_lru_node(struct list_lru_memcg *memcg_lrus, + int begin, int end) +{ + int i; + + for (i = begin; i < end; i++) + kfree(memcg_lrus->lru[i]); +} + +static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus, + int begin, int end) +{ + int i; + + for (i = begin; i < end; i++) { + struct list_lru_one *l; + + l = kmalloc(sizeof(struct list_lru_one), GFP_KERNEL); + if (!l) + goto fail; + + init_one_lru(l); + memcg_lrus->lru[i] = l; + } + return 0; +fail: + __memcg_destroy_list_lru_node(memcg_lrus, begin, i - 1); + return -ENOMEM; +} + +static int memcg_init_list_lru_node(struct list_lru_node *nlru) +{ + int size = memcg_nr_cache_ids; + + nlru->memcg_lrus = kmalloc(size * sizeof(void *), GFP_KERNEL); + if (!nlru->memcg_lrus) + return -ENOMEM; + + if (__memcg_init_list_lru_node(nlru->memcg_lrus, 0, size)) { + kfree(nlru->memcg_lrus); + return -ENOMEM; + } + + return 0; +} + +static void memcg_destroy_list_lru_node(struct list_lru_node *nlru) +{ + __memcg_destroy_list_lru_node(nlru->memcg_lrus, 0, memcg_nr_cache_ids); + kfree(nlru->memcg_lrus); +} + +static int memcg_update_list_lru_node(struct list_lru_node *nlru, + int old_size, int new_size) +{ + struct list_lru_memcg *old, *new; + + BUG_ON(old_size > new_size); + + old = nlru->memcg_lrus; + new = kmalloc(new_size * sizeof(void *), GFP_KERNEL); + if (!new) + return -ENOMEM; + + if (__memcg_init_list_lru_node(new, old_size, new_size)) { + kfree(new); + return -ENOMEM; + } + + memcpy(new, old, old_size * sizeof(void *)); + + /* + * The lock guarantees that we won't race with a reader + * (see list_lru_from_memcg_idx). + * + * Since list_lru_{add,del} may be called under an IRQ-safe lock, + * we have to use IRQ-safe primitives here to avoid deadlock. + */ + spin_lock_irq(&nlru->lock); + nlru->memcg_lrus = new; + spin_unlock_irq(&nlru->lock); + + kfree(old); + return 0; +} + +static void memcg_cancel_update_list_lru_node(struct list_lru_node *nlru, + int old_size, int new_size) +{ + /* do not bother shrinking the array back to the old size, because we + * cannot handle allocation failures here */ + __memcg_destroy_list_lru_node(nlru->memcg_lrus, old_size, new_size); +} + +static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) +{ + int i; + + for (i = 0; i < nr_node_ids; i++) { + if (!memcg_aware) + lru->node[i].memcg_lrus = NULL; + else if (memcg_init_list_lru_node(&lru->node[i])) + goto fail; + } + return 0; +fail: + for (i = i - 1; i >= 0; i--) + memcg_destroy_list_lru_node(&lru->node[i]); + return -ENOMEM; +} + +static void memcg_destroy_list_lru(struct list_lru *lru) +{ + int i; + + if (!list_lru_memcg_aware(lru)) + return; + + for (i = 0; i < nr_node_ids; i++) + memcg_destroy_list_lru_node(&lru->node[i]); +} + +static int memcg_update_list_lru(struct list_lru *lru, + int old_size, int new_size) +{ + int i; + + if (!list_lru_memcg_aware(lru)) + return 0; + + for (i = 0; i < nr_node_ids; i++) { + if (memcg_update_list_lru_node(&lru->node[i], + old_size, new_size)) + goto fail; + } + return 0; +fail: + for (i = i - 1; i >= 0; i--) + memcg_cancel_update_list_lru_node(&lru->node[i], + old_size, new_size); + return -ENOMEM; +} + +static void memcg_cancel_update_list_lru(struct list_lru *lru, + int old_size, int new_size) +{ + int i; + + if (!list_lru_memcg_aware(lru)) + return; + + for (i = 0; i < nr_node_ids; i++) + memcg_cancel_update_list_lru_node(&lru->node[i], + old_size, new_size); +} + +int memcg_update_all_list_lrus(int new_size) +{ + int ret = 0; + struct list_lru *lru; + int old_size = memcg_nr_cache_ids; + + mutex_lock(&list_lrus_mutex); + list_for_each_entry(lru, &list_lrus, list) { + ret = memcg_update_list_lru(lru, old_size, new_size); + if (ret) + goto fail; + } +out: + mutex_unlock(&list_lrus_mutex); + return ret; +fail: + list_for_each_entry_continue_reverse(lru, &list_lrus, list) + memcg_cancel_update_list_lru(lru, old_size, new_size); + goto out; +} +#else +static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) +{ + return 0; +} + +static void memcg_destroy_list_lru(struct list_lru *lru) +{ +} +#endif /* CONFIG_MEMCG_KMEM */ + +int __list_lru_init(struct list_lru *lru, bool memcg_aware, + struct lock_class_key *key) { int i; size_t size = sizeof(*lru->node) * nr_node_ids; + int err = -ENOMEM; + + memcg_get_cache_ids(); lru->node = kzalloc(size, GFP_KERNEL); if (!lru->node) - return -ENOMEM; + goto out; for (i = 0; i < nr_node_ids; i++) { spin_lock_init(&lru->node[i].lock); if (key) lockdep_set_class(&lru->node[i].lock, key); - INIT_LIST_HEAD(&lru->node[i].list); - lru->node[i].nr_items = 0; + init_one_lru(&lru->node[i].lru); + } + + err = memcg_init_list_lru(lru, memcg_aware); + if (err) { + kfree(lru->node); + goto out; } + list_lru_register(lru); - return 0; +out: + memcg_put_cache_ids(); + return err; } -EXPORT_SYMBOL_GPL(list_lru_init_key); +EXPORT_SYMBOL_GPL(__list_lru_init); void list_lru_destroy(struct list_lru *lru) { /* Already destroyed or not yet initialized? */ if (!lru->node) return; + + memcg_get_cache_ids(); + list_lru_unregister(lru); + + memcg_destroy_list_lru(lru); kfree(lru->node); lru->node = NULL; + + memcg_put_cache_ids(); } EXPORT_SYMBOL_GPL(list_lru_destroy); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6706e5fa5ac0..afa55bb38cbd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2571,6 +2571,8 @@ static int memcg_alloc_cache_id(void) size = MEMCG_CACHES_MAX_SIZE; err = memcg_update_all_caches(size); + if (!err) + err = memcg_update_all_list_lrus(size); if (!err) memcg_nr_cache_ids = size; @@ -2765,6 +2767,24 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order) memcg_uncharge_kmem(memcg, 1 << order); page->mem_cgroup = NULL; } + +struct mem_cgroup *__mem_cgroup_from_kmem(void *ptr) +{ + struct mem_cgroup *memcg = NULL; + struct kmem_cache *cachep; + struct page *page; + + page = virt_to_head_page(ptr); + if (PageSlab(page)) { + cachep = page->slab_cache; + if (!is_root_cache(cachep)) + memcg = cachep->memcg_params->memcg; + } else + /* page allocated by alloc_kmem_pages */ + memcg = page->mem_cgroup; + + return memcg; +} #endif /* CONFIG_MEMCG_KMEM */ #ifdef CONFIG_TRANSPARENT_HUGEPAGE