Btrfs: allocate prelim_ref with a slab allocater

struct __prelim_ref is allocated and freed frequently when
walking backref tree, using slab allocater can not only
speed up allocating but also detect memory leaks.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 27 insertions, 6 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index f3cb19114c95..0552a599b28f 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -119,6 +119,26 @@ struct __prelim_ref {
         u64 wanted_disk_byte;
 };
 
+static struct kmem_cache *btrfs_prelim_ref_cache;
+
+int __init btrfs_prelim_ref_init(void)
+{
+        btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
+                                        sizeof(struct __prelim_ref),
+                                        0,
+                                        SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+                                        NULL);
+        if (!btrfs_prelim_ref_cache)
+                return -ENOMEM;
+        return 0;
+}
+
+void btrfs_prelim_ref_exit(void)
+{
+        if (btrfs_prelim_ref_cache)
+                kmem_cache_destroy(btrfs_prelim_ref_cache);
+}
+
 /*
  * the rules for all callers of this function are:
  * - obtaining the parent is the goal
@@ -165,7 +185,7 @@ static int __add_prelim_ref(struct list_head *head, u64 root_id,
 {
         struct __prelim_ref *ref;
 
-        ref = kmalloc(sizeof(*ref), gfp_mask);
+        ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
         if (!ref)
                 return -ENOMEM;
 
@@ -368,7 +388,8 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
 
                 /* additional parents require new refs being added here */
                 while ((node = ulist_next(parents, &uiter))) {
-                        new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS);
+                        new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
+                                                   GFP_NOFS);
                         if (!new_ref) {
                                 ret = -ENOMEM;
                                 goto out;
@@ -492,7 +513,7 @@ static void __merge_refs(struct list_head *head, int mode)
                         ref1->count += ref2->count;
 
                         list_del(&ref2->list);
-                        kfree(ref2);
+                        kmem_cache_free(btrfs_prelim_ref_cache, ref2);
                 }
 
         }
@@ -955,7 +976,7 @@ again:
                         }
                 }
                 list_del(&ref->list);
-                kfree(ref);
+                kmem_cache_free(btrfs_prelim_ref_cache, ref);
         }
 
 out:
@@ -963,13 +984,13 @@ out:
         while (!list_empty(&prefs)) {
                 ref = list_first_entry(&prefs, struct __prelim_ref, list);
                 list_del(&ref->list);
-                kfree(ref);
+                kmem_cache_free(btrfs_prelim_ref_cache, ref);
         }
         while (!list_empty(&prefs_delayed)) {
                 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
                                        list);
                 list_del(&ref->list);
-                kfree(ref);
+                kmem_cache_free(btrfs_prelim_ref_cache, ref);
         }
 
         return ret;