Git Repo - linux.git/blame_incremental

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Commit	Line	Data
	1	/*
	2	* Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved.
	3	* Authors: David Chinner and Glauber Costa
	4	*
	5	* Generic LRU infrastructure
	6	*/
	7	#include <linux/kernel.h>
	8	#include <linux/module.h>
	9	#include <linux/mm.h>
	10	#include <linux/list_lru.h>
	11	#include <linux/slab.h>
	12
	13	bool list_lru_add(struct list_lru lru, struct list_head item)
	14	{
	15	int nid = page_to_nid(virt_to_page(item));
	16	struct list_lru_node *nlru = &lru->node[nid];
	17
	18	spin_lock(&nlru->lock);
	19	WARN_ON_ONCE(nlru->nr_items < 0);
	20	if (list_empty(item)) {
	21	list_add_tail(item, &nlru->list);
	22	if (nlru->nr_items++ == 0)
	23	node_set(nid, lru->active_nodes);
	24	spin_unlock(&nlru->lock);
	25	return true;
	26	}
	27	spin_unlock(&nlru->lock);
	28	return false;
	29	}
	30	EXPORT_SYMBOL_GPL(list_lru_add);
	31
	32	bool list_lru_del(struct list_lru lru, struct list_head item)
	33	{
	34	int nid = page_to_nid(virt_to_page(item));
	35	struct list_lru_node *nlru = &lru->node[nid];
	36
	37	spin_lock(&nlru->lock);
	38	if (!list_empty(item)) {
	39	list_del_init(item);
	40	if (--nlru->nr_items == 0)
	41	node_clear(nid, lru->active_nodes);
	42	WARN_ON_ONCE(nlru->nr_items < 0);
	43	spin_unlock(&nlru->lock);
	44	return true;
	45	}
	46	spin_unlock(&nlru->lock);
	47	return false;
	48	}
	49	EXPORT_SYMBOL_GPL(list_lru_del);
	50
	51	unsigned long
	52	list_lru_count_node(struct list_lru *lru, int nid)
	53	{
	54	unsigned long count = 0;
	55	struct list_lru_node *nlru = &lru->node[nid];
	56
	57	spin_lock(&nlru->lock);
	58	WARN_ON_ONCE(nlru->nr_items < 0);
	59	count += nlru->nr_items;
	60	spin_unlock(&nlru->lock);
	61
	62	return count;
	63	}
	64	EXPORT_SYMBOL_GPL(list_lru_count_node);
	65
	66	unsigned long
	67	list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate,
	68	void cb_arg, unsigned long nr_to_walk)
	69	{
	70
	71	struct list_lru_node *nlru = &lru->node[nid];
	72	struct list_head item, n;
	73	unsigned long isolated = 0;
	74
	75	spin_lock(&nlru->lock);
	76	restart:
	77	list_for_each_safe(item, n, &nlru->list) {
	78	enum lru_status ret;
	79
	80	/*
	81	* decrement nr_to_walk first so that we don't livelock if we
	82	* get stuck on large numbesr of LRU_RETRY items
	83	*/
	84	if (!*nr_to_walk)
	85	break;
	86	--*nr_to_walk;
	87
	88	ret = isolate(item, &nlru->lock, cb_arg);
	89	switch (ret) {
	90	case LRU_REMOVED_RETRY:
	91	assert_spin_locked(&nlru->lock);
	92	case LRU_REMOVED:
	93	if (--nlru->nr_items == 0)
	94	node_clear(nid, lru->active_nodes);
	95	WARN_ON_ONCE(nlru->nr_items < 0);
	96	isolated++;
	97	/*
	98	* If the lru lock has been dropped, our list
	99	* traversal is now invalid and so we have to
	100	* restart from scratch.
	101	*/
	102	if (ret == LRU_REMOVED_RETRY)
	103	goto restart;
	104	break;
	105	case LRU_ROTATE:
	106	list_move_tail(item, &nlru->list);
	107	break;
	108	case LRU_SKIP:
	109	break;
	110	case LRU_RETRY:
	111	/*
	112	* The lru lock has been dropped, our list traversal is
	113	* now invalid and so we have to restart from scratch.
	114	*/
	115	assert_spin_locked(&nlru->lock);
	116	goto restart;
	117	default:
	118	BUG();
	119	}
	120	}
	121
	122	spin_unlock(&nlru->lock);
	123	return isolated;
	124	}
	125	EXPORT_SYMBOL_GPL(list_lru_walk_node);
	126
	127	int list_lru_init_key(struct list_lru lru, struct lock_class_key key)
	128	{
	129	int i;
	130	size_t size = sizeof(lru->node) nr_node_ids;
	131
	132	lru->node = kzalloc(size, GFP_KERNEL);
	133	if (!lru->node)
	134	return -ENOMEM;
	135
	136	nodes_clear(lru->active_nodes);
	137	for (i = 0; i < nr_node_ids; i++) {
	138	spin_lock_init(&lru->node[i].lock);
	139	if (key)
	140	lockdep_set_class(&lru->node[i].lock, key);
	141	INIT_LIST_HEAD(&lru->node[i].list);
	142	lru->node[i].nr_items = 0;
	143	}
	144	return 0;
	145	}
	146	EXPORT_SYMBOL_GPL(list_lru_init_key);
	147
	148	void list_lru_destroy(struct list_lru *lru)
	149	{
	150	kfree(lru->node);
	151	}
	152	EXPORT_SYMBOL_GPL(list_lru_destroy);