Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs pile 4 from Al Viro:
 "list_lru pile, mostly"

This came out of Andrew's pile, Al ended up doing the merge work so that
Andrew didn't have to.

Additionally, a few fixes.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (42 commits)
  super: fix for destroy lrus
  list_lru: dynamically adjust node arrays
  shrinker: Kill old ->shrink API.
  shrinker: convert remaining shrinkers to count/scan API
  staging/lustre/libcfs: cleanup linux-mem.h
  staging/lustre/ptlrpc: convert to new shrinker API
  staging/lustre/obdclass: convert lu_object shrinker to count/scan API
  staging/lustre/ldlm: convert to shrinkers to count/scan API
  hugepage: convert huge zero page shrinker to new shrinker API
  i915: bail out earlier when shrinker cannot acquire mutex
  drivers: convert shrinkers to new count/scan API
  fs: convert fs shrinkers to new scan/count API
  xfs: fix dquot isolation hang
  xfs-convert-dquot-cache-lru-to-list_lru-fix
  xfs: convert dquot cache lru to list_lru
  xfs: rework buffer dispose list tracking
  xfs-convert-buftarg-lru-to-generic-code-fix
  xfs: convert buftarg LRU to generic code
  fs: convert inode and dentry shrinking to be node aware
  vmscan: per-node deferred work
  ...

1 files changed, 131 insertions, 0 deletions

diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
new file mode 100644
index 000000000000..3ce541753c88
--- /dev/null
+++ b/include/linux/list_lru.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved.
+ * Authors: David Chinner and Glauber Costa
+ *
+ * Generic LRU infrastructure
+ */
+#ifndef _LRU_LIST_H
+#define _LRU_LIST_H
+
+#include <linux/list.h>
+#include <linux/nodemask.h>
+
+/* list_lru_walk_cb has to always return one of those */
+enum lru_status {
+        LRU_REMOVED,            /* item removed from list */
+        LRU_ROTATE,             /* item referenced, give another pass */
+        LRU_SKIP,               /* item cannot be locked, skip */
+        LRU_RETRY,              /* item not freeable. May drop the lock
+                                   internally, but has to return locked. */
+};
+
+struct list_lru_node {
+        spinlock_t              lock;
+        struct list_head        list;
+        /* kept as signed so we can catch imbalance bugs */
+        long                    nr_items;
+} ____cacheline_aligned_in_smp;
+
+struct list_lru {
+        struct list_lru_node    *node;
+        nodemask_t              active_nodes;
+};
+
+void list_lru_destroy(struct list_lru *lru);
+int list_lru_init(struct list_lru *lru);
+
+/**
+ * list_lru_add: add an element to the lru list's tail
+ * @list_lru: the lru pointer
+ * @item: the item to be added.
+ *
+ * If the element is already part of a list, this function returns doing
+ * nothing. Therefore the caller does not need to keep state about whether or
+ * not the element already belongs in the list and is allowed to lazy update
+ * it. Note however that this is valid for *a* list, not *this* list. If
+ * the caller organize itself in a way that elements can be in more than
+ * one type of list, it is up to the caller to fully remove the item from
+ * the previous list (with list_lru_del() for instance) before moving it
+ * to @list_lru
+ *
+ * Return value: true if the list was updated, false otherwise
+ */
+bool list_lru_add(struct list_lru *lru, struct list_head *item);
+
+/**
+ * list_lru_del: delete an element to the lru list
+ * @list_lru: the lru pointer
+ * @item: the item to be deleted.
+ *
+ * This function works analogously as list_lru_add in terms of list
+ * manipulation. The comments about an element already pertaining to
+ * a list are also valid for list_lru_del.
+ *
+ * Return value: true if the list was updated, false otherwise
+ */
+bool list_lru_del(struct list_lru *lru, struct list_head *item);
+
+/**
+ * list_lru_count_node: return the number of objects currently held by @lru
+ * @lru: the lru pointer.
+ * @nid: the node id to count from.
+ *
+ * Always return a non-negative number, 0 for empty lists. There is no
+ * guarantee that the list is not updated while the count is being computed.
+ * Callers that want such a guarantee need to provide an outer lock.
+ */
+unsigned long list_lru_count_node(struct list_lru *lru, int nid);
+static inline unsigned long list_lru_count(struct list_lru *lru)
+{
+        long count = 0;
+        int nid;
+
+        for_each_node_mask(nid, lru->active_nodes)
+                count += list_lru_count_node(lru, nid);
+
+        return count;
+}
+
+typedef enum lru_status
+(*list_lru_walk_cb)(struct list_head *item, spinlock_t *lock, void *cb_arg);
+/**
+ * list_lru_walk_node: walk a list_lru, isolating and disposing freeable items.
+ * @lru: the lru pointer.
+ * @nid: the node id to scan from.
+ * @isolate: callback function that is resposible for deciding what to do with
+ *  the item currently being scanned
+ * @cb_arg: opaque type that will be passed to @isolate
+ * @nr_to_walk: how many items to scan.
+ *
+ * This function will scan all elements in a particular list_lru, calling the
+ * @isolate callback for each of those items, along with the current list
+ * spinlock and a caller-provided opaque. The @isolate callback can choose to
+ * drop the lock internally, but *must* return with the lock held. The callback
+ * will return an enum lru_status telling the list_lru infrastructure what to
+ * do with the object being scanned.
+ *
+ * Please note that nr_to_walk does not mean how many objects will be freed,
+ * just how many objects will be scanned.
+ *
+ * Return value: the number of objects effectively removed from the LRU.
+ */
+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);
+
+static inline unsigned long
+list_lru_walk(struct list_lru *lru, list_lru_walk_cb isolate,
+              void *cb_arg, unsigned long nr_to_walk)
+{
+        long isolated = 0;
+        int nid;
+
+        for_each_node_mask(nid, lru->active_nodes) {
+                isolated += list_lru_walk_node(lru, nid, isolate,
+                                               cb_arg, &nr_to_walk);
+                if (nr_to_walk <= 0)
+                        break;
+        }
+        return isolated;
+}
+#endif /* _LRU_LIST_H */