140 lines
3.1 KiB
C
140 lines
3.1 KiB
C
/*
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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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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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spin_lock(&nlru->lock);
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WARN_ON_ONCE(nlru->nr_items < 0);
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if (list_empty(item)) {
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list_add_tail(item, &nlru->list);
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if (nlru->nr_items++ == 0)
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node_set(nid, lru->active_nodes);
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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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spin_lock(&nlru->lock);
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if (!list_empty(item)) {
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list_del_init(item);
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if (--nlru->nr_items == 0)
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node_clear(nid, lru->active_nodes);
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WARN_ON_ONCE(nlru->nr_items < 0);
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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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unsigned long
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list_lru_count_node(struct list_lru *lru, int nid)
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{
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unsigned long count = 0;
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struct list_lru_node *nlru = &lru->node[nid];
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spin_lock(&nlru->lock);
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WARN_ON_ONCE(nlru->nr_items < 0);
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count += nlru->nr_items;
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spin_unlock(&nlru->lock);
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return count;
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}
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EXPORT_SYMBOL_GPL(list_lru_count_node);
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unsigned long
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list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate,
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void *cb_arg, 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_head *item, *n;
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unsigned long isolated = 0;
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spin_lock(&nlru->lock);
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restart:
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list_for_each_safe(item, n, &nlru->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 numbesr of LRU_RETRY items
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*/
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if (--(*nr_to_walk) == 0)
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break;
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ret = isolate(item, &nlru->lock, cb_arg);
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switch (ret) {
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case LRU_REMOVED:
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if (--nlru->nr_items == 0)
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node_clear(nid, lru->active_nodes);
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WARN_ON_ONCE(nlru->nr_items < 0);
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isolated++;
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break;
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case LRU_ROTATE:
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list_move_tail(item, &nlru->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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goto restart;
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default:
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BUG();
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}
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}
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spin_unlock(&nlru->lock);
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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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int list_lru_init(struct list_lru *lru)
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{
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int i;
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size_t size = sizeof(*lru->node) * nr_node_ids;
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lru->node = kzalloc(size, GFP_KERNEL);
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if (!lru->node)
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return -ENOMEM;
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nodes_clear(lru->active_nodes);
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for (i = 0; i < nr_node_ids; i++) {
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spin_lock_init(&lru->node[i].lock);
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INIT_LIST_HEAD(&lru->node[i].list);
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lru->node[i].nr_items = 0;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(list_lru_init);
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void list_lru_destroy(struct list_lru *lru)
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{
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kfree(lru->node);
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}
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EXPORT_SYMBOL_GPL(list_lru_destroy);
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