| /* |
| * 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> |
| |
| 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]; |
| |
| spin_lock(&nlru->lock); |
| WARN_ON_ONCE(nlru->nr_items < 0); |
| if (list_empty(item)) { |
| list_add_tail(item, &nlru->list); |
| if (nlru->nr_items++ == 0) |
| node_set(nid, lru->active_nodes); |
| 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]; |
| |
| spin_lock(&nlru->lock); |
| if (!list_empty(item)) { |
| list_del_init(item); |
| if (--nlru->nr_items == 0) |
| node_clear(nid, lru->active_nodes); |
| WARN_ON_ONCE(nlru->nr_items < 0); |
| spin_unlock(&nlru->lock); |
| return true; |
| } |
| spin_unlock(&nlru->lock); |
| return false; |
| } |
| EXPORT_SYMBOL_GPL(list_lru_del); |
| |
| unsigned long |
| list_lru_count_node(struct list_lru *lru, int nid) |
| { |
| unsigned long count = 0; |
| struct list_lru_node *nlru = &lru->node[nid]; |
| |
| spin_lock(&nlru->lock); |
| WARN_ON_ONCE(nlru->nr_items < 0); |
| count += nlru->nr_items; |
| spin_unlock(&nlru->lock); |
| |
| return count; |
| } |
| EXPORT_SYMBOL_GPL(list_lru_count_node); |
| |
| 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) |
| { |
| |
| struct list_lru_node *nlru = &lru->node[nid]; |
| struct list_head *item, *n; |
| unsigned long isolated = 0; |
| |
| spin_lock(&nlru->lock); |
| restart: |
| list_for_each_safe(item, n, &nlru->list) { |
| enum lru_status ret; |
| |
| /* |
| * decrement nr_to_walk first so that we don't livelock if we |
| * get stuck on large numbesr of LRU_RETRY items |
| */ |
| if (--(*nr_to_walk) == 0) |
| break; |
| |
| ret = isolate(item, &nlru->lock, cb_arg); |
| switch (ret) { |
| case LRU_REMOVED: |
| if (--nlru->nr_items == 0) |
| node_clear(nid, lru->active_nodes); |
| WARN_ON_ONCE(nlru->nr_items < 0); |
| isolated++; |
| break; |
| case LRU_ROTATE: |
| list_move_tail(item, &nlru->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. |
| */ |
| goto restart; |
| default: |
| BUG(); |
| } |
| } |
| |
| spin_unlock(&nlru->lock); |
| return isolated; |
| } |
| EXPORT_SYMBOL_GPL(list_lru_walk_node); |
| |
| int list_lru_init(struct list_lru *lru) |
| { |
| int i; |
| |
| nodes_clear(lru->active_nodes); |
| for (i = 0; i < MAX_NUMNODES; i++) { |
| spin_lock_init(&lru->node[i].lock); |
| INIT_LIST_HEAD(&lru->node[i].list); |
| lru->node[i].nr_items = 0; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(list_lru_init); |