599 lines
14 KiB
C
599 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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#include "internal.h"
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#ifdef CONFIG_MEMCG_KMEM
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static LIST_HEAD(memcg_list_lrus);
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static DEFINE_MUTEX(list_lrus_mutex);
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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 void list_lru_register(struct list_lru *lru)
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{
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if (!list_lru_memcg_aware(lru))
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return;
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mutex_lock(&list_lrus_mutex);
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list_add(&lru->list, &memcg_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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if (!list_lru_memcg_aware(lru))
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return;
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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 struct list_lru_one *
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list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx)
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{
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if (list_lru_memcg_aware(lru) && idx >= 0) {
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struct list_lru_memcg *mlru = xa_load(&lru->xa, idx);
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return mlru ? &mlru->node[nid] : NULL;
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}
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return &lru->node[nid].lru;
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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 *lru, int nid, int idx)
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{
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return &lru->node[nid].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, int nid,
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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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spin_lock(&nlru->lock);
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if (list_empty(item)) {
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l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(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, 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_add_obj(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 mem_cgroup *memcg = list_lru_memcg_aware(lru) ?
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mem_cgroup_from_slab_obj(item) : NULL;
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return list_lru_add(lru, item, nid, memcg);
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}
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EXPORT_SYMBOL_GPL(list_lru_add_obj);
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bool list_lru_del(struct list_lru *lru, struct list_head *item, int nid,
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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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spin_lock(&nlru->lock);
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if (!list_empty(item)) {
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l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg));
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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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bool list_lru_del_obj(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 mem_cgroup *memcg = list_lru_memcg_aware(lru) ?
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mem_cgroup_from_slab_obj(item) : NULL;
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return list_lru_del(lru, item, nid, memcg);
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}
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EXPORT_SYMBOL_GPL(list_lru_del_obj);
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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_one *l;
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long count;
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rcu_read_lock();
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l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg));
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count = l ? READ_ONCE(l->nr_items) : 0;
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rcu_read_unlock();
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if (unlikely(count < 0))
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count = 0;
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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 *lru, int nid, 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_node *nlru = &lru->node[nid];
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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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restart:
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l = list_lru_from_memcg_idx(lru, nid, memcg_idx);
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if (!l)
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goto out;
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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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case LRU_STOP:
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assert_spin_locked(&nlru->lock);
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goto out;
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default:
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BUG();
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}
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}
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out:
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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(lru, nid, memcg_kmem_id(memcg), isolate,
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cb_arg, 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(lru, nid, memcg_kmem_id(memcg), isolate,
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cb_arg, 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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isolated += list_lru_walk_one(lru, nid, NULL, isolate, cb_arg,
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nr_to_walk);
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#ifdef CONFIG_MEMCG_KMEM
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if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) {
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struct list_lru_memcg *mlru;
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unsigned long index;
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xa_for_each(&lru->xa, index, mlru) {
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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(lru, nid, index,
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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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#endif
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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 struct list_lru_memcg *memcg_init_list_lru_one(gfp_t gfp)
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{
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int nid;
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struct list_lru_memcg *mlru;
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mlru = kmalloc(struct_size(mlru, node, nr_node_ids), gfp);
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if (!mlru)
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return NULL;
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for_each_node(nid)
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init_one_lru(&mlru->node[nid]);
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return mlru;
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}
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static void memcg_list_lru_free(struct list_lru *lru, int src_idx)
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{
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struct list_lru_memcg *mlru = xa_erase_irq(&lru->xa, src_idx);
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/*
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* The __list_lru_walk_one() can walk the list of this node.
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* We need kvfree_rcu() here. And the walking of the list
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* is under lru->node[nid]->lock, which can serve as a RCU
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* read-side critical section.
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*/
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if (mlru)
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kvfree_rcu(mlru, rcu);
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}
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static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
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{
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if (memcg_aware)
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xa_init_flags(&lru->xa, XA_FLAGS_LOCK_IRQ);
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lru->memcg_aware = memcg_aware;
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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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XA_STATE(xas, &lru->xa, 0);
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struct list_lru_memcg *mlru;
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if (!list_lru_memcg_aware(lru))
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return;
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xas_lock_irq(&xas);
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xas_for_each(&xas, mlru, ULONG_MAX) {
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kfree(mlru);
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xas_store(&xas, NULL);
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}
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xas_unlock_irq(&xas);
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}
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static void memcg_reparent_list_lru_node(struct list_lru *lru, int nid,
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int src_idx, struct mem_cgroup *dst_memcg)
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{
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struct list_lru_node *nlru = &lru->node[nid];
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int dst_idx = dst_memcg->kmemcg_id;
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struct list_lru_one *src, *dst;
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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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src = list_lru_from_memcg_idx(lru, nid, src_idx);
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if (!src)
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goto out;
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dst = list_lru_from_memcg_idx(lru, nid, dst_idx);
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list_splice_init(&src->list, &dst->list);
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if (src->nr_items) {
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dst->nr_items += src->nr_items;
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set_shrinker_bit(dst_memcg, nid, lru_shrinker_id(lru));
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src->nr_items = 0;
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}
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out:
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spin_unlock_irq(&nlru->lock);
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}
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static void memcg_reparent_list_lru(struct list_lru *lru,
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int src_idx, struct mem_cgroup *dst_memcg)
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{
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int i;
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for_each_node(i)
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memcg_reparent_list_lru_node(lru, i, src_idx, dst_memcg);
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memcg_list_lru_free(lru, src_idx);
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}
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void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent)
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{
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struct cgroup_subsys_state *css;
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struct list_lru *lru;
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int src_idx = memcg->kmemcg_id;
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/*
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* Change kmemcg_id of this cgroup and all its descendants to the
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* parent's id, and then move all entries from this cgroup's list_lrus
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* to ones of the parent.
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*
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* After we have finished, all list_lrus corresponding to this cgroup
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* are guaranteed to remain empty. So we can safely free this cgroup's
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* list lrus in memcg_list_lru_free().
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*
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* Changing ->kmemcg_id to the parent can prevent memcg_list_lru_alloc()
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* from allocating list lrus for this cgroup after memcg_list_lru_free()
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* call.
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*/
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rcu_read_lock();
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css_for_each_descendant_pre(css, &memcg->css) {
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struct mem_cgroup *child;
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child = mem_cgroup_from_css(css);
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WRITE_ONCE(child->kmemcg_id, parent->kmemcg_id);
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}
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rcu_read_unlock();
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mutex_lock(&list_lrus_mutex);
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list_for_each_entry(lru, &memcg_list_lrus, list)
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memcg_reparent_list_lru(lru, src_idx, parent);
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mutex_unlock(&list_lrus_mutex);
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}
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static inline bool memcg_list_lru_allocated(struct mem_cgroup *memcg,
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struct list_lru *lru)
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{
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int idx = memcg->kmemcg_id;
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return idx < 0 || xa_load(&lru->xa, idx);
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}
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int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru,
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gfp_t gfp)
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{
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int i;
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unsigned long flags;
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struct list_lru_memcg_table {
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struct list_lru_memcg *mlru;
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struct mem_cgroup *memcg;
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} *table;
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XA_STATE(xas, &lru->xa, 0);
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if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocated(memcg, lru))
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return 0;
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gfp &= GFP_RECLAIM_MASK;
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table = kmalloc_array(memcg->css.cgroup->level, sizeof(*table), gfp);
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if (!table)
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return -ENOMEM;
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/*
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* Because the list_lru can be reparented to the parent cgroup's
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* list_lru, we should make sure that this cgroup and all its
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* ancestors have allocated list_lru_memcg.
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*/
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for (i = 0; memcg; memcg = parent_mem_cgroup(memcg), i++) {
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if (memcg_list_lru_allocated(memcg, lru))
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break;
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table[i].memcg = memcg;
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table[i].mlru = memcg_init_list_lru_one(gfp);
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if (!table[i].mlru) {
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while (i--)
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kfree(table[i].mlru);
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kfree(table);
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return -ENOMEM;
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}
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}
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xas_lock_irqsave(&xas, flags);
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while (i--) {
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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;
|
|
|
|
if (mem_cgroup_kmem_disabled())
|
|
memcg_aware = false;
|
|
#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);
|