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222 lines
7.3 KiB
222 lines
7.3 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved. |
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* Authors: David Chinner and Glauber Costa |
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* |
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* Generic LRU infrastructure |
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*/ |
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#ifndef _LRU_LIST_H |
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#define _LRU_LIST_H |
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#include <linux/list.h> |
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#include <linux/nodemask.h> |
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#include <linux/shrinker.h> |
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struct mem_cgroup; |
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/* list_lru_walk_cb has to always return one of those */ |
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enum lru_status { |
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LRU_REMOVED, /* item removed from list */ |
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LRU_REMOVED_RETRY, /* item removed, but lock has been |
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dropped and reacquired */ |
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LRU_ROTATE, /* item referenced, give another pass */ |
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LRU_SKIP, /* item cannot be locked, skip */ |
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LRU_RETRY, /* item not freeable. May drop the lock |
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internally, but has to return locked. */ |
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}; |
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struct list_lru_one { |
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struct list_head list; |
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/* may become negative during memcg reparenting */ |
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long nr_items; |
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}; |
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struct list_lru_memcg { |
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struct rcu_head rcu; |
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/* array of per cgroup lists, indexed by memcg_cache_id */ |
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struct list_lru_one *lru[]; |
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}; |
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struct list_lru_node { |
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/* protects all lists on the node, including per cgroup */ |
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spinlock_t lock; |
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/* global list, used for the root cgroup in cgroup aware lrus */ |
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struct list_lru_one lru; |
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#ifdef CONFIG_MEMCG_KMEM |
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/* for cgroup aware lrus points to per cgroup lists, otherwise NULL */ |
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struct list_lru_memcg __rcu *memcg_lrus; |
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#endif |
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long nr_items; |
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} ____cacheline_aligned_in_smp; |
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struct list_lru { |
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struct list_lru_node *node; |
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#ifdef CONFIG_MEMCG_KMEM |
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struct list_head list; |
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int shrinker_id; |
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bool memcg_aware; |
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#endif |
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}; |
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void list_lru_destroy(struct list_lru *lru); |
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int __list_lru_init(struct list_lru *lru, bool memcg_aware, |
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struct lock_class_key *key, struct shrinker *shrinker); |
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#define list_lru_init(lru) \ |
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__list_lru_init((lru), false, NULL, NULL) |
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#define list_lru_init_key(lru, key) \ |
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__list_lru_init((lru), false, (key), NULL) |
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#define list_lru_init_memcg(lru, shrinker) \ |
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__list_lru_init((lru), true, NULL, shrinker) |
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int memcg_update_all_list_lrus(int num_memcgs); |
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void memcg_drain_all_list_lrus(int src_idx, struct mem_cgroup *dst_memcg); |
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/** |
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* list_lru_add: add an element to the lru list's tail |
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* @list_lru: the lru pointer |
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* @item: the item to be added. |
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* |
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* If the element is already part of a list, this function returns doing |
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* nothing. Therefore the caller does not need to keep state about whether or |
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* not the element already belongs in the list and is allowed to lazy update |
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* it. Note however that this is valid for *a* list, not *this* list. If |
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* the caller organize itself in a way that elements can be in more than |
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* one type of list, it is up to the caller to fully remove the item from |
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* the previous list (with list_lru_del() for instance) before moving it |
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* to @list_lru |
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* |
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* Return value: true if the list was updated, false otherwise |
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*/ |
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bool list_lru_add(struct list_lru *lru, struct list_head *item); |
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/** |
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* list_lru_del: delete an element to the lru list |
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* @list_lru: the lru pointer |
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* @item: the item to be deleted. |
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* |
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* This function works analogously as list_lru_add in terms of list |
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* manipulation. The comments about an element already pertaining to |
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* a list are also valid for list_lru_del. |
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* |
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* Return value: true if the list was updated, false otherwise |
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*/ |
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bool list_lru_del(struct list_lru *lru, struct list_head *item); |
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/** |
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* list_lru_count_one: return the number of objects currently held by @lru |
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* @lru: the lru pointer. |
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* @nid: the node id to count from. |
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* @memcg: the cgroup to count from. |
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* |
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* Always return a non-negative number, 0 for empty lists. There is no |
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* guarantee that the list is not updated while the count is being computed. |
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* Callers that want such a guarantee need to provide an outer lock. |
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*/ |
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unsigned long list_lru_count_one(struct list_lru *lru, |
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int nid, struct mem_cgroup *memcg); |
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unsigned long list_lru_count_node(struct list_lru *lru, int nid); |
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static inline unsigned long list_lru_shrink_count(struct list_lru *lru, |
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struct shrink_control *sc) |
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{ |
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return list_lru_count_one(lru, sc->nid, sc->memcg); |
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} |
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static inline unsigned long list_lru_count(struct list_lru *lru) |
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{ |
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long count = 0; |
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int nid; |
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for_each_node_state(nid, N_NORMAL_MEMORY) |
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count += list_lru_count_node(lru, nid); |
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return count; |
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} |
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void list_lru_isolate(struct list_lru_one *list, struct list_head *item); |
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void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item, |
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struct list_head *head); |
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typedef enum lru_status (*list_lru_walk_cb)(struct list_head *item, |
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struct list_lru_one *list, spinlock_t *lock, void *cb_arg); |
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/** |
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* list_lru_walk_one: walk a list_lru, isolating and disposing freeable items. |
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* @lru: the lru pointer. |
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* @nid: the node id to scan from. |
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* @memcg: the cgroup to scan from. |
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* @isolate: callback function that is resposible for deciding what to do with |
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* the item currently being scanned |
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* @cb_arg: opaque type that will be passed to @isolate |
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* @nr_to_walk: how many items to scan. |
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* |
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* This function will scan all elements in a particular list_lru, calling the |
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* @isolate callback for each of those items, along with the current list |
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* spinlock and a caller-provided opaque. The @isolate callback can choose to |
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* drop the lock internally, but *must* return with the lock held. The callback |
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* will return an enum lru_status telling the list_lru infrastructure what to |
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* do with the object being scanned. |
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* |
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* Please note that nr_to_walk does not mean how many objects will be freed, |
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* just how many objects will be scanned. |
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* |
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* Return value: the number of objects effectively removed from the LRU. |
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*/ |
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unsigned long list_lru_walk_one(struct list_lru *lru, |
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int nid, struct mem_cgroup *memcg, |
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list_lru_walk_cb isolate, void *cb_arg, |
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unsigned long *nr_to_walk); |
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/** |
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* list_lru_walk_one_irq: walk a list_lru, isolating and disposing freeable items. |
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* @lru: the lru pointer. |
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* @nid: the node id to scan from. |
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* @memcg: the cgroup to scan from. |
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* @isolate: callback function that is resposible for deciding what to do with |
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* the item currently being scanned |
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* @cb_arg: opaque type that will be passed to @isolate |
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* @nr_to_walk: how many items to scan. |
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* |
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* Same as @list_lru_walk_one except that the spinlock is acquired with |
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* spin_lock_irq(). |
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*/ |
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unsigned long list_lru_walk_one_irq(struct list_lru *lru, |
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int nid, struct mem_cgroup *memcg, |
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list_lru_walk_cb isolate, void *cb_arg, |
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unsigned long *nr_to_walk); |
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unsigned long list_lru_walk_node(struct list_lru *lru, int nid, |
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list_lru_walk_cb isolate, void *cb_arg, |
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unsigned long *nr_to_walk); |
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static inline unsigned long |
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list_lru_shrink_walk(struct list_lru *lru, struct shrink_control *sc, |
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list_lru_walk_cb isolate, void *cb_arg) |
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{ |
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return list_lru_walk_one(lru, sc->nid, sc->memcg, isolate, cb_arg, |
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&sc->nr_to_scan); |
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} |
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static inline unsigned long |
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list_lru_shrink_walk_irq(struct list_lru *lru, struct shrink_control *sc, |
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list_lru_walk_cb isolate, void *cb_arg) |
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{ |
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return list_lru_walk_one_irq(lru, sc->nid, sc->memcg, isolate, cb_arg, |
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&sc->nr_to_scan); |
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} |
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static inline unsigned long |
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list_lru_walk(struct list_lru *lru, list_lru_walk_cb isolate, |
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void *cb_arg, unsigned long nr_to_walk) |
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{ |
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long isolated = 0; |
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int nid; |
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for_each_node_state(nid, N_NORMAL_MEMORY) { |
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isolated += list_lru_walk_node(lru, nid, isolate, |
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cb_arg, &nr_to_walk); |
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if (nr_to_walk <= 0) |
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break; |
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} |
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return isolated; |
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} |
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#endif /* _LRU_LIST_H */
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