From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- include/linux/list_lru.h | 189 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 189 insertions(+) create mode 100644 include/linux/list_lru.h (limited to 'include/linux/list_lru.h') diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h new file mode 100644 index 000000000..2a6b9947a --- /dev/null +++ b/include/linux/list_lru.h @@ -0,0 +1,189 @@ +/* + * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved. + * Authors: David Chinner and Glauber Costa + * + * Generic LRU infrastructure + */ +#ifndef _LRU_LIST_H +#define _LRU_LIST_H + +#include +#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 */ + LRU_REMOVED_RETRY, /* item removed, but lock has been + dropped and reacquired */ + LRU_ROTATE, /* item referenced, give another pass */ + LRU_SKIP, /* item cannot be locked, skip */ + LRU_RETRY, /* item not freeable. May drop the lock + internally, but has to return locked. */ +}; + +struct list_lru_one { + struct list_head list; + /* may become negative during memcg reparenting */ + 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 { + struct list_lru_node *node; +#ifdef CONFIG_MEMCG_KMEM + struct list_head list; +#endif +}; + +void list_lru_destroy(struct list_lru *lru); +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); +void memcg_drain_all_list_lrus(int src_idx, int dst_idx); + +/** + * list_lru_add: add an element to the lru list's tail + * @list_lru: the lru pointer + * @item: the item to be added. + * + * If the element is already part of a list, this function returns doing + * nothing. Therefore the caller does not need to keep state about whether or + * not the element already belongs in the list and is allowed to lazy update + * it. Note however that this is valid for *a* list, not *this* list. If + * the caller organize itself in a way that elements can be in more than + * one type of list, it is up to the caller to fully remove the item from + * the previous list (with list_lru_del() for instance) before moving it + * to @list_lru + * + * Return value: true if the list was updated, false otherwise + */ +bool list_lru_add(struct list_lru *lru, struct list_head *item); + +/** + * list_lru_del: delete an element to the lru list + * @list_lru: the lru pointer + * @item: the item to be deleted. + * + * This function works analogously as list_lru_add in terms of list + * manipulation. The comments about an element already pertaining to + * a list are also valid for list_lru_del. + * + * Return value: true if the list was updated, false otherwise + */ +bool list_lru_del(struct list_lru *lru, struct list_head *item); + +/** + * 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_one(lru, sc->nid, sc->memcg); +} + +static inline unsigned long list_lru_count(struct list_lru *lru) +{ + long count = 0; + int nid; + + for_each_node_state(nid, N_NORMAL_MEMORY) + count += list_lru_count_node(lru, nid); + + return count; +} + +void list_lru_isolate(struct list_lru_one *list, struct list_head *item); +void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item, + struct list_head *head); + +typedef enum lru_status (*list_lru_walk_cb)(struct list_head *item, + struct list_lru_one *list, spinlock_t *lock, void *cb_arg); + +/** + * 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 + * @nr_to_walk: how many items to scan. + * + * This function will scan all elements in a particular list_lru, calling the + * @isolate callback for each of those items, along with the current list + * spinlock and a caller-provided opaque. The @isolate callback can choose to + * drop the lock internally, but *must* return with the lock held. The callback + * will return an enum lru_status telling the list_lru infrastructure what to + * do with the object being scanned. + * + * Please note that nr_to_walk does not mean how many objects will be freed, + * just how many objects will be scanned. + * + * 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); + +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_one(lru, sc->nid, sc->memcg, isolate, cb_arg, + &sc->nr_to_scan); +} + +static inline unsigned long +list_lru_walk(struct list_lru *lru, list_lru_walk_cb isolate, + void *cb_arg, unsigned long nr_to_walk) +{ + long isolated = 0; + int nid; + + for_each_node_state(nid, N_NORMAL_MEMORY) { + isolated += list_lru_walk_node(lru, nid, isolate, + cb_arg, &nr_to_walk); + if (nr_to_walk <= 0) + break; + } + return isolated; +} +#endif /* _LRU_LIST_H */ -- cgit v1.2.3-54-g00ecf