642 lines
14 KiB
C
642 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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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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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/list_lru.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/memcontrol.h>
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#include "slab.h"
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#ifdef CONFIG_MEMCG_KMEM
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static LIST_HEAD(list_lrus);
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static DEFINE_MUTEX(list_lrus_mutex);
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static void list_lru_register(struct list_lru *lru)
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{
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mutex_lock(&list_lrus_mutex);
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list_add(&lru->list, &list_lrus);
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mutex_unlock(&list_lrus_mutex);
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}
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static void list_lru_unregister(struct list_lru *lru)
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{
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mutex_lock(&list_lrus_mutex);
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list_del(&lru->list);
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mutex_unlock(&list_lrus_mutex);
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}
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static int lru_shrinker_id(struct list_lru *lru)
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{
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return lru->shrinker_id;
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}
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static inline bool list_lru_memcg_aware(struct list_lru *lru)
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{
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return lru->memcg_aware;
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}
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static inline struct list_lru_one *
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list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
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{
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struct list_lru_memcg *memcg_lrus;
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/*
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* Either lock or RCU protects the array of per cgroup lists
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* from relocation (see memcg_update_list_lru_node).
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*/
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memcg_lrus = rcu_dereference_check(nlru->memcg_lrus,
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lockdep_is_held(&nlru->lock));
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if (memcg_lrus && idx >= 0)
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return memcg_lrus->lru[idx];
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return &nlru->lru;
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}
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static inline struct list_lru_one *
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list_lru_from_kmem(struct list_lru_node *nlru, void *ptr,
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struct mem_cgroup **memcg_ptr)
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{
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struct list_lru_one *l = &nlru->lru;
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struct mem_cgroup *memcg = NULL;
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if (!nlru->memcg_lrus)
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goto out;
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memcg = mem_cgroup_from_obj(ptr);
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if (!memcg)
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goto out;
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l = list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
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out:
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if (memcg_ptr)
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*memcg_ptr = memcg;
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return l;
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}
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#else
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static void list_lru_register(struct list_lru *lru)
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{
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}
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static void list_lru_unregister(struct list_lru *lru)
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{
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}
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static int lru_shrinker_id(struct list_lru *lru)
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{
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return -1;
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}
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static inline bool list_lru_memcg_aware(struct list_lru *lru)
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{
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return false;
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}
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static inline struct list_lru_one *
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list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
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{
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return &nlru->lru;
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}
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static inline struct list_lru_one *
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list_lru_from_kmem(struct list_lru_node *nlru, void *ptr,
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struct mem_cgroup **memcg_ptr)
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{
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if (memcg_ptr)
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*memcg_ptr = NULL;
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return &nlru->lru;
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}
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#endif /* CONFIG_MEMCG_KMEM */
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bool list_lru_add(struct list_lru *lru, struct list_head *item)
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{
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int nid = page_to_nid(virt_to_page(item));
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struct list_lru_node *nlru = &lru->node[nid];
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struct mem_cgroup *memcg;
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struct list_lru_one *l;
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spin_lock(&nlru->lock);
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if (list_empty(item)) {
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l = list_lru_from_kmem(nlru, item, &memcg);
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list_add_tail(item, &l->list);
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/* Set shrinker bit if the first element was added */
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if (!l->nr_items++)
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set_shrinker_bit(memcg, nid,
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lru_shrinker_id(lru));
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nlru->nr_items++;
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spin_unlock(&nlru->lock);
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return true;
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}
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spin_unlock(&nlru->lock);
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return false;
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}
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EXPORT_SYMBOL_GPL(list_lru_add);
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bool list_lru_del(struct list_lru *lru, struct list_head *item)
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{
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int nid = page_to_nid(virt_to_page(item));
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struct list_lru_node *nlru = &lru->node[nid];
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struct list_lru_one *l;
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spin_lock(&nlru->lock);
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if (!list_empty(item)) {
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l = list_lru_from_kmem(nlru, item, NULL);
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list_del_init(item);
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l->nr_items--;
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nlru->nr_items--;
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spin_unlock(&nlru->lock);
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return true;
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}
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spin_unlock(&nlru->lock);
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return false;
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}
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EXPORT_SYMBOL_GPL(list_lru_del);
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void list_lru_isolate(struct list_lru_one *list, struct list_head *item)
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{
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list_del_init(item);
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list->nr_items--;
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}
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EXPORT_SYMBOL_GPL(list_lru_isolate);
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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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{
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list_move(item, head);
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list->nr_items--;
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}
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EXPORT_SYMBOL_GPL(list_lru_isolate_move);
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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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{
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struct list_lru_node *nlru = &lru->node[nid];
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struct list_lru_one *l;
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unsigned long count;
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rcu_read_lock();
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l = list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
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count = READ_ONCE(l->nr_items);
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rcu_read_unlock();
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return count;
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}
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EXPORT_SYMBOL_GPL(list_lru_count_one);
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unsigned long list_lru_count_node(struct list_lru *lru, int nid)
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{
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struct list_lru_node *nlru;
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nlru = &lru->node[nid];
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return nlru->nr_items;
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}
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EXPORT_SYMBOL_GPL(list_lru_count_node);
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static unsigned long
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__list_lru_walk_one(struct list_lru_node *nlru, int memcg_idx,
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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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struct list_lru_one *l;
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struct list_head *item, *n;
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unsigned long isolated = 0;
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l = list_lru_from_memcg_idx(nlru, memcg_idx);
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restart:
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list_for_each_safe(item, n, &l->list) {
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enum lru_status ret;
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/*
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* decrement nr_to_walk first so that we don't livelock if we
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* get stuck on large numbers of LRU_RETRY items
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*/
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if (!*nr_to_walk)
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break;
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--*nr_to_walk;
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ret = isolate(item, l, &nlru->lock, cb_arg);
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switch (ret) {
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case LRU_REMOVED_RETRY:
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assert_spin_locked(&nlru->lock);
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fallthrough;
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case LRU_REMOVED:
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isolated++;
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nlru->nr_items--;
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/*
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* If the lru lock has been dropped, our list
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* traversal is now invalid and so we have to
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* restart from scratch.
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*/
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if (ret == LRU_REMOVED_RETRY)
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goto restart;
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break;
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case LRU_ROTATE:
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list_move_tail(item, &l->list);
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break;
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case LRU_SKIP:
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break;
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case LRU_RETRY:
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/*
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* The lru lock has been dropped, our list traversal is
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* now invalid and so we have to restart from scratch.
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*/
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assert_spin_locked(&nlru->lock);
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goto restart;
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default:
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BUG();
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}
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}
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return isolated;
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}
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unsigned long
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list_lru_walk_one(struct list_lru *lru, 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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struct list_lru_node *nlru = &lru->node[nid];
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unsigned long ret;
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spin_lock(&nlru->lock);
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ret = __list_lru_walk_one(nlru, memcg_cache_id(memcg), isolate, cb_arg,
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nr_to_walk);
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spin_unlock(&nlru->lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(list_lru_walk_one);
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unsigned long
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list_lru_walk_one_irq(struct list_lru *lru, 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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struct list_lru_node *nlru = &lru->node[nid];
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unsigned long ret;
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spin_lock_irq(&nlru->lock);
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ret = __list_lru_walk_one(nlru, memcg_cache_id(memcg), isolate, cb_arg,
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nr_to_walk);
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spin_unlock_irq(&nlru->lock);
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return ret;
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}
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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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{
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long isolated = 0;
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int memcg_idx;
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isolated += list_lru_walk_one(lru, nid, NULL, isolate, cb_arg,
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nr_to_walk);
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if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) {
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for_each_memcg_cache_index(memcg_idx) {
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struct list_lru_node *nlru = &lru->node[nid];
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spin_lock(&nlru->lock);
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isolated += __list_lru_walk_one(nlru, memcg_idx,
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isolate, cb_arg,
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nr_to_walk);
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spin_unlock(&nlru->lock);
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if (*nr_to_walk <= 0)
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break;
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}
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}
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return isolated;
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}
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EXPORT_SYMBOL_GPL(list_lru_walk_node);
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static void init_one_lru(struct list_lru_one *l)
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{
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INIT_LIST_HEAD(&l->list);
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l->nr_items = 0;
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}
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#ifdef CONFIG_MEMCG_KMEM
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static void __memcg_destroy_list_lru_node(struct list_lru_memcg *memcg_lrus,
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int begin, int end)
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{
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int i;
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for (i = begin; i < end; i++)
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kfree(memcg_lrus->lru[i]);
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}
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static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus,
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int begin, int end)
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{
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int i;
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for (i = begin; i < end; i++) {
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struct list_lru_one *l;
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l = kmalloc(sizeof(struct list_lru_one), GFP_KERNEL);
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if (!l)
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goto fail;
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init_one_lru(l);
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memcg_lrus->lru[i] = l;
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}
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return 0;
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fail:
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__memcg_destroy_list_lru_node(memcg_lrus, begin, i);
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return -ENOMEM;
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}
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static int memcg_init_list_lru_node(struct list_lru_node *nlru)
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{
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struct list_lru_memcg *memcg_lrus;
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int size = memcg_nr_cache_ids;
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memcg_lrus = kvmalloc(sizeof(*memcg_lrus) +
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size * sizeof(void *), GFP_KERNEL);
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if (!memcg_lrus)
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return -ENOMEM;
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if (__memcg_init_list_lru_node(memcg_lrus, 0, size)) {
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kvfree(memcg_lrus);
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return -ENOMEM;
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}
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RCU_INIT_POINTER(nlru->memcg_lrus, memcg_lrus);
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return 0;
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}
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static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
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{
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struct list_lru_memcg *memcg_lrus;
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/*
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* This is called when shrinker has already been unregistered,
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* and nobody can use it. So, there is no need to use kvfree_rcu().
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*/
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memcg_lrus = rcu_dereference_protected(nlru->memcg_lrus, true);
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__memcg_destroy_list_lru_node(memcg_lrus, 0, memcg_nr_cache_ids);
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kvfree(memcg_lrus);
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}
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static int memcg_update_list_lru_node(struct list_lru_node *nlru,
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int old_size, int new_size)
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{
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struct list_lru_memcg *old, *new;
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BUG_ON(old_size > new_size);
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old = rcu_dereference_protected(nlru->memcg_lrus,
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lockdep_is_held(&list_lrus_mutex));
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new = kvmalloc(sizeof(*new) + new_size * sizeof(void *), GFP_KERNEL);
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if (!new)
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return -ENOMEM;
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if (__memcg_init_list_lru_node(new, old_size, new_size)) {
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kvfree(new);
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return -ENOMEM;
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}
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memcpy(&new->lru, &old->lru, old_size * sizeof(void *));
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/*
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* The locking below allows readers that hold nlru->lock avoid taking
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* rcu_read_lock (see list_lru_from_memcg_idx).
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*
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* Since list_lru_{add,del} may be called under an IRQ-safe lock,
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* we have to use IRQ-safe primitives here to avoid deadlock.
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*/
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spin_lock_irq(&nlru->lock);
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rcu_assign_pointer(nlru->memcg_lrus, new);
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spin_unlock_irq(&nlru->lock);
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kvfree_rcu(old, rcu);
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return 0;
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}
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static void memcg_cancel_update_list_lru_node(struct list_lru_node *nlru,
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int old_size, int new_size)
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{
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struct list_lru_memcg *memcg_lrus;
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memcg_lrus = rcu_dereference_protected(nlru->memcg_lrus,
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lockdep_is_held(&list_lrus_mutex));
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/* do not bother shrinking the array back to the old size, because we
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* cannot handle allocation failures here */
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__memcg_destroy_list_lru_node(memcg_lrus, old_size, new_size);
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}
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static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
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{
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int i;
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lru->memcg_aware = memcg_aware;
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if (!memcg_aware)
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return 0;
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for_each_node(i) {
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if (memcg_init_list_lru_node(&lru->node[i]))
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goto fail;
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}
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return 0;
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fail:
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for (i = i - 1; i >= 0; i--) {
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if (!lru->node[i].memcg_lrus)
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continue;
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memcg_destroy_list_lru_node(&lru->node[i]);
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}
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return -ENOMEM;
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}
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static void memcg_destroy_list_lru(struct list_lru *lru)
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{
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int i;
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if (!list_lru_memcg_aware(lru))
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return;
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for_each_node(i)
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memcg_destroy_list_lru_node(&lru->node[i]);
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}
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static int memcg_update_list_lru(struct list_lru *lru,
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int old_size, int new_size)
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{
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int i;
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if (!list_lru_memcg_aware(lru))
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return 0;
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for_each_node(i) {
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if (memcg_update_list_lru_node(&lru->node[i],
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old_size, new_size))
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goto fail;
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}
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return 0;
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fail:
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for (i = i - 1; i >= 0; i--) {
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if (!lru->node[i].memcg_lrus)
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continue;
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memcg_cancel_update_list_lru_node(&lru->node[i],
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old_size, new_size);
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}
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return -ENOMEM;
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}
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static void memcg_cancel_update_list_lru(struct list_lru *lru,
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int old_size, int new_size)
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{
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int i;
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if (!list_lru_memcg_aware(lru))
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return;
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for_each_node(i)
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memcg_cancel_update_list_lru_node(&lru->node[i],
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old_size, new_size);
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}
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int memcg_update_all_list_lrus(int new_size)
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{
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int ret = 0;
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struct list_lru *lru;
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int old_size = memcg_nr_cache_ids;
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mutex_lock(&list_lrus_mutex);
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list_for_each_entry(lru, &list_lrus, list) {
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ret = memcg_update_list_lru(lru, old_size, new_size);
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if (ret)
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goto fail;
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}
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out:
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mutex_unlock(&list_lrus_mutex);
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return ret;
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fail:
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list_for_each_entry_continue_reverse(lru, &list_lrus, list)
|
|
memcg_cancel_update_list_lru(lru, old_size, new_size);
|
|
goto out;
|
|
}
|
|
|
|
static void memcg_drain_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(nlru, src_idx);
|
|
dst = list_lru_from_memcg_idx(nlru, 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;
|
|
}
|
|
|
|
spin_unlock_irq(&nlru->lock);
|
|
}
|
|
|
|
static void memcg_drain_list_lru(struct list_lru *lru,
|
|
int src_idx, struct mem_cgroup *dst_memcg)
|
|
{
|
|
int i;
|
|
|
|
if (!list_lru_memcg_aware(lru))
|
|
return;
|
|
|
|
for_each_node(i)
|
|
memcg_drain_list_lru_node(lru, i, src_idx, dst_memcg);
|
|
}
|
|
|
|
void memcg_drain_all_list_lrus(int src_idx, struct mem_cgroup *dst_memcg)
|
|
{
|
|
struct list_lru *lru;
|
|
|
|
mutex_lock(&list_lrus_mutex);
|
|
list_for_each_entry(lru, &list_lrus, list)
|
|
memcg_drain_list_lru(lru, src_idx, dst_memcg);
|
|
mutex_unlock(&list_lrus_mutex);
|
|
}
|
|
#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, struct shrinker *shrinker)
|
|
{
|
|
int i;
|
|
int err = -ENOMEM;
|
|
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
if (shrinker)
|
|
lru->shrinker_id = shrinker->id;
|
|
else
|
|
lru->shrinker_id = -1;
|
|
#endif
|
|
memcg_get_cache_ids();
|
|
|
|
lru->node = kcalloc(nr_node_ids, sizeof(*lru->node), GFP_KERNEL);
|
|
if (!lru->node)
|
|
goto out;
|
|
|
|
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);
|
|
}
|
|
|
|
err = memcg_init_list_lru(lru, memcg_aware);
|
|
if (err) {
|
|
kfree(lru->node);
|
|
/* Do this so a list_lru_destroy() doesn't crash: */
|
|
lru->node = NULL;
|
|
goto out;
|
|
}
|
|
|
|
list_lru_register(lru);
|
|
out:
|
|
memcg_put_cache_ids();
|
|
return err;
|
|
}
|
|
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;
|
|
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
lru->shrinker_id = -1;
|
|
#endif
|
|
memcg_put_cache_ids();
|
|
}
|
|
EXPORT_SYMBOL_GPL(list_lru_destroy);
|