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-rw-r--r--mm/list_lru.c139
1 files changed, 139 insertions, 0 deletions
diff --git a/mm/list_lru.c b/mm/list_lru.c
new file mode 100644
index 000000000000..72467914b856
--- /dev/null
+++ b/mm/list_lru.c
@@ -0,0 +1,139 @@
+/*
+ * 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>
+#include <linux/slab.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;
+ size_t size = sizeof(*lru->node) * nr_node_ids;
+
+ lru->node = kzalloc(size, GFP_KERNEL);
+ if (!lru->node)
+ return -ENOMEM;
+
+ nodes_clear(lru->active_nodes);
+ for (i = 0; i < nr_node_ids; 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);
+
+void list_lru_destroy(struct list_lru *lru)
+{
+ kfree(lru->node);
+}
+EXPORT_SYMBOL_GPL(list_lru_destroy);