diff options
Diffstat (limited to 'mm/list_lru.c')
| -rw-r--r-- | mm/list_lru.c | 605 |
1 files changed, 605 insertions, 0 deletions
diff --git a/mm/list_lru.c b/mm/list_lru.c new file mode 100644 index 000000000..a05e5bef3 --- /dev/null +++ b/mm/list_lru.c @@ -0,0 +1,605 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved. + * Authors: David Chinner and Glauber Costa + * + * Generic LRU infrastructure + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mm.h> +#include <linux/list_lru.h> +#include <linux/slab.h> +#include <linux/mutex.h> +#include <linux/memcontrol.h> +#include "slab.h" +#include "internal.h" + +#ifdef CONFIG_MEMCG_KMEM +static LIST_HEAD(memcg_list_lrus); +static DEFINE_MUTEX(list_lrus_mutex); + +static inline bool list_lru_memcg_aware(struct list_lru *lru) +{ + return lru->memcg_aware; +} + +static void list_lru_register(struct list_lru *lru) +{ + if (!list_lru_memcg_aware(lru)) + return; + + mutex_lock(&list_lrus_mutex); + list_add(&lru->list, &memcg_list_lrus); + mutex_unlock(&list_lrus_mutex); +} + +static void list_lru_unregister(struct list_lru *lru) +{ + if (!list_lru_memcg_aware(lru)) + return; + + mutex_lock(&list_lrus_mutex); + list_del(&lru->list); + mutex_unlock(&list_lrus_mutex); +} + +static int lru_shrinker_id(struct list_lru *lru) +{ + return lru->shrinker_id; +} + +static inline struct list_lru_one * +list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx) +{ + if (list_lru_memcg_aware(lru) && idx >= 0) { + struct list_lru_memcg *mlru = xa_load(&lru->xa, idx); + + return mlru ? &mlru->node[nid] : NULL; + } + return &lru->node[nid].lru; +} + +static inline struct list_lru_one * +list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr, + struct mem_cgroup **memcg_ptr) +{ + struct list_lru_node *nlru = &lru->node[nid]; + struct list_lru_one *l = &nlru->lru; + struct mem_cgroup *memcg = NULL; + + if (!list_lru_memcg_aware(lru)) + goto out; + + memcg = mem_cgroup_from_slab_obj(ptr); + if (!memcg) + goto out; + + l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg)); +out: + if (memcg_ptr) + *memcg_ptr = memcg; + return l; +} +#else +static void list_lru_register(struct list_lru *lru) +{ +} + +static void list_lru_unregister(struct list_lru *lru) +{ +} + +static int lru_shrinker_id(struct list_lru *lru) +{ + return -1; +} + +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 *lru, int nid, int idx) +{ + return &lru->node[nid].lru; +} + +static inline struct list_lru_one * +list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr, + struct mem_cgroup **memcg_ptr) +{ + if (memcg_ptr) + *memcg_ptr = NULL; + return &lru->node[nid].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 mem_cgroup *memcg; + struct list_lru_one *l; + + spin_lock(&nlru->lock); + if (list_empty(item)) { + l = list_lru_from_kmem(lru, nid, item, &memcg); + list_add_tail(item, &l->list); + /* Set shrinker bit if the first element was added */ + if (!l->nr_items++) + set_shrinker_bit(memcg, nid, + lru_shrinker_id(lru)); + nlru->nr_items++; + spin_unlock(&nlru->lock); + return true; + } + spin_unlock(&nlru->lock); + return false; +} +EXPORT_SYMBOL_GPL(list_lru_add); + +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); + if (!list_empty(item)) { + l = list_lru_from_kmem(lru, nid, item, NULL); + list_del_init(item); + l->nr_items--; + nlru->nr_items--; + spin_unlock(&nlru->lock); + return true; + } + spin_unlock(&nlru->lock); + return false; +} +EXPORT_SYMBOL_GPL(list_lru_del); + +void list_lru_isolate(struct list_lru_one *list, struct list_head *item) +{ + list_del_init(item); + list->nr_items--; +} +EXPORT_SYMBOL_GPL(list_lru_isolate); + +void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item, + struct list_head *head) +{ + list_move(item, head); + list->nr_items--; +} +EXPORT_SYMBOL_GPL(list_lru_isolate_move); + +unsigned long list_lru_count_one(struct list_lru *lru, + int nid, struct mem_cgroup *memcg) +{ + struct list_lru_one *l; + long count; + + rcu_read_lock(); + l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg)); + count = l ? READ_ONCE(l->nr_items) : 0; + rcu_read_unlock(); + + if (unlikely(count < 0)) + count = 0; + + return count; +} +EXPORT_SYMBOL_GPL(list_lru_count_one); + +unsigned long list_lru_count_node(struct list_lru *lru, int nid) +{ + struct list_lru_node *nlru; + + nlru = &lru->node[nid]; + return nlru->nr_items; +} +EXPORT_SYMBOL_GPL(list_lru_count_node); + +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_one *l; + struct list_head *item, *n; + unsigned long isolated = 0; + +restart: + l = list_lru_from_memcg_idx(lru, nid, memcg_idx); + if (!l) + goto out; + + list_for_each_safe(item, n, &l->list) { + enum lru_status ret; + + /* + * decrement nr_to_walk first so that we don't livelock if we + * get stuck on large numbers of LRU_RETRY items + */ + if (!*nr_to_walk) + break; + --*nr_to_walk; + + ret = isolate(item, l, &nlru->lock, cb_arg); + switch (ret) { + case LRU_REMOVED_RETRY: + assert_spin_locked(&nlru->lock); + fallthrough; + case LRU_REMOVED: + isolated++; + nlru->nr_items--; + /* + * If the lru lock has been dropped, our list + * traversal is now invalid and so we have to + * restart from scratch. + */ + if (ret == LRU_REMOVED_RETRY) + goto restart; + break; + case LRU_ROTATE: + list_move_tail(item, &l->list); + break; + case LRU_SKIP: + break; + case LRU_RETRY: + /* + * The lru lock has been dropped, our list traversal is + * now invalid and so we have to restart from scratch. + */ + assert_spin_locked(&nlru->lock); + goto restart; + default: + BUG(); + } + } +out: + 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) +{ + struct list_lru_node *nlru = &lru->node[nid]; + unsigned long ret; + + spin_lock(&nlru->lock); + ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate, + cb_arg, nr_to_walk); + spin_unlock(&nlru->lock); + return ret; +} +EXPORT_SYMBOL_GPL(list_lru_walk_one); + +unsigned long +list_lru_walk_one_irq(struct list_lru *lru, int nid, struct mem_cgroup *memcg, + list_lru_walk_cb isolate, void *cb_arg, + unsigned long *nr_to_walk) +{ + struct list_lru_node *nlru = &lru->node[nid]; + unsigned long ret; + + spin_lock_irq(&nlru->lock); + ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate, + cb_arg, nr_to_walk); + spin_unlock_irq(&nlru->lock); + return ret; +} + +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; + + isolated += list_lru_walk_one(lru, nid, NULL, isolate, cb_arg, + nr_to_walk); + +#ifdef CONFIG_MEMCG_KMEM + if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) { + struct list_lru_memcg *mlru; + unsigned long index; + + xa_for_each(&lru->xa, index, mlru) { + struct list_lru_node *nlru = &lru->node[nid]; + + spin_lock(&nlru->lock); + isolated += __list_lru_walk_one(lru, nid, index, + isolate, cb_arg, + nr_to_walk); + spin_unlock(&nlru->lock); + + if (*nr_to_walk <= 0) + break; + } + } +#endif + + return isolated; +} +EXPORT_SYMBOL_GPL(list_lru_walk_node); + +static void init_one_lru(struct list_lru_one *l) +{ + INIT_LIST_HEAD(&l->list); + l->nr_items = 0; +} + +#ifdef CONFIG_MEMCG_KMEM +static struct list_lru_memcg *memcg_init_list_lru_one(gfp_t gfp) +{ + int nid; + struct list_lru_memcg *mlru; + + mlru = kmalloc(struct_size(mlru, node, nr_node_ids), gfp); + if (!mlru) + return NULL; + + for_each_node(nid) + init_one_lru(&mlru->node[nid]); + + return mlru; +} + +static void memcg_list_lru_free(struct list_lru *lru, int src_idx) +{ + struct list_lru_memcg *mlru = xa_erase_irq(&lru->xa, src_idx); + + /* + * The __list_lru_walk_one() can walk the list of this node. + * We need kvfree_rcu() here. And the walking of the list + * is under lru->node[nid]->lock, which can serve as a RCU + * read-side critical section. + */ + if (mlru) + kvfree_rcu(mlru, rcu); +} + +static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) +{ + if (memcg_aware) + xa_init_flags(&lru->xa, XA_FLAGS_LOCK_IRQ); + lru->memcg_aware = memcg_aware; +} + +static void memcg_destroy_list_lru(struct list_lru *lru) +{ + XA_STATE(xas, &lru->xa, 0); + struct list_lru_memcg *mlru; + + if (!list_lru_memcg_aware(lru)) + return; + + xas_lock_irq(&xas); + xas_for_each(&xas, mlru, ULONG_MAX) { + kfree(mlru); + xas_store(&xas, NULL); + } + xas_unlock_irq(&xas); +} + +static void memcg_reparent_list_lru_node(struct list_lru *lru, int nid, + int src_idx, struct mem_cgroup *dst_memcg) +{ + struct list_lru_node *nlru = &lru->node[nid]; + int dst_idx = dst_memcg->kmemcg_id; + struct list_lru_one *src, *dst; + + /* + * 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); + + src = list_lru_from_memcg_idx(lru, nid, src_idx); + if (!src) + goto out; + dst = list_lru_from_memcg_idx(lru, nid, dst_idx); + + list_splice_init(&src->list, &dst->list); + + if (src->nr_items) { + dst->nr_items += src->nr_items; + set_shrinker_bit(dst_memcg, nid, lru_shrinker_id(lru)); + src->nr_items = 0; + } +out: + spin_unlock_irq(&nlru->lock); +} + +static void memcg_reparent_list_lru(struct list_lru *lru, + int src_idx, struct mem_cgroup *dst_memcg) +{ + int i; + + for_each_node(i) + memcg_reparent_list_lru_node(lru, i, src_idx, dst_memcg); + + memcg_list_lru_free(lru, src_idx); +} + +void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent) +{ + struct cgroup_subsys_state *css; + struct list_lru *lru; + int src_idx = memcg->kmemcg_id; + + /* + * Change kmemcg_id of this cgroup and all its descendants to the + * parent's id, and then move all entries from this cgroup's list_lrus + * to ones of the parent. + * + * After we have finished, all list_lrus corresponding to this cgroup + * are guaranteed to remain empty. So we can safely free this cgroup's + * list lrus in memcg_list_lru_free(). + * + * Changing ->kmemcg_id to the parent can prevent memcg_list_lru_alloc() + * from allocating list lrus for this cgroup after memcg_list_lru_free() + * call. + */ + rcu_read_lock(); + css_for_each_descendant_pre(css, &memcg->css) { + struct mem_cgroup *child; + + child = mem_cgroup_from_css(css); + WRITE_ONCE(child->kmemcg_id, parent->kmemcg_id); + } + rcu_read_unlock(); + + mutex_lock(&list_lrus_mutex); + list_for_each_entry(lru, &memcg_list_lrus, list) + memcg_reparent_list_lru(lru, src_idx, parent); + mutex_unlock(&list_lrus_mutex); +} + +static inline bool memcg_list_lru_allocated(struct mem_cgroup *memcg, + struct list_lru *lru) +{ + int idx = memcg->kmemcg_id; + + return idx < 0 || xa_load(&lru->xa, idx); +} + +int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, + gfp_t gfp) +{ + int i; + unsigned long flags; + struct list_lru_memcg_table { + struct list_lru_memcg *mlru; + struct mem_cgroup *memcg; + } *table; + XA_STATE(xas, &lru->xa, 0); + + if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocated(memcg, lru)) + return 0; + + gfp &= GFP_RECLAIM_MASK; + table = kmalloc_array(memcg->css.cgroup->level, sizeof(*table), gfp); + if (!table) + return -ENOMEM; + + /* + * Because the list_lru can be reparented to the parent cgroup's + * list_lru, we should make sure that this cgroup and all its + * ancestors have allocated list_lru_memcg. + */ + for (i = 0; memcg; memcg = parent_mem_cgroup(memcg), i++) { + if (memcg_list_lru_allocated(memcg, lru)) + break; + + table[i].memcg = memcg; + table[i].mlru = memcg_init_list_lru_one(gfp); + if (!table[i].mlru) { + while (i--) + kfree(table[i].mlru); + kfree(table); + return -ENOMEM; + } + } + + xas_lock_irqsave(&xas, flags); + while (i--) { + int index = READ_ONCE(table[i].memcg->kmemcg_id); + struct list_lru_memcg *mlru = table[i].mlru; + + xas_set(&xas, index); +retry: + if (unlikely(index < 0 || xas_error(&xas) || xas_load(&xas))) { + kfree(mlru); + } else { + xas_store(&xas, mlru); + if (xas_error(&xas) == -ENOMEM) { + xas_unlock_irqrestore(&xas, flags); + if (xas_nomem(&xas, gfp)) + xas_set_err(&xas, 0); + xas_lock_irqsave(&xas, flags); + /* + * The xas lock has been released, this memcg + * can be reparented before us. So reload + * memcg id. More details see the comments + * in memcg_reparent_list_lrus(). + */ + index = READ_ONCE(table[i].memcg->kmemcg_id); + if (index < 0) + xas_set_err(&xas, 0); + else if (!xas_error(&xas) && index != xas.xa_index) + xas_set(&xas, index); + goto retry; + } + } + } + /* xas_nomem() is used to free memory instead of memory allocation. */ + if (xas.xa_alloc) + xas_nomem(&xas, gfp); + xas_unlock_irqrestore(&xas, flags); + kfree(table); + + return xas_error(&xas); +} +#else +static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) +{ +} + +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, struct shrinker *shrinker) +{ + int i; + +#ifdef CONFIG_MEMCG_KMEM + if (shrinker) + lru->shrinker_id = shrinker->id; + else + lru->shrinker_id = -1; +#endif + + lru->node = kcalloc(nr_node_ids, sizeof(*lru->node), GFP_KERNEL); + if (!lru->node) + return -ENOMEM; + + for_each_node(i) { + spin_lock_init(&lru->node[i].lock); + if (key) + lockdep_set_class(&lru->node[i].lock, key); + init_one_lru(&lru->node[i].lru); + } + + memcg_init_list_lru(lru, memcg_aware); + list_lru_register(lru); + + return 0; +} +EXPORT_SYMBOL_GPL(__list_lru_init); + +void list_lru_destroy(struct list_lru *lru) +{ + /* Already destroyed or not yet initialized? */ + if (!lru->node) + return; + + list_lru_unregister(lru); + + memcg_destroy_list_lru(lru); + kfree(lru->node); + lru->node = NULL; + +#ifdef CONFIG_MEMCG_KMEM + lru->shrinker_id = -1; +#endif +} +EXPORT_SYMBOL_GPL(list_lru_destroy); |