--- /dev/null
+/*
+ * 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 <linux/list.h>
+#include <linux/nodemask.h>
+#include <linux/shrinker.h>
+
+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 */
Code Review / kvmfornfv.git / blobdiff