Btrfs: use a slab for the free space entries

Since we alloc/free free space entries a whole lot, lets use a slab to keep
track of them.  This makes some of my tests slightly faster.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>

3 files changed, 29 insertions, 16 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7f78cc78fdd0..2c98d209e6ac 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -40,6 +40,7 @@ extern struct kmem_cache *btrfs_trans_handle_cachep;
 extern struct kmem_cache *btrfs_transaction_cachep;
 extern struct kmem_cache *btrfs_bit_radix_cachep;
 extern struct kmem_cache *btrfs_path_cachep;
+extern struct kmem_cache *btrfs_free_space_cachep;
 struct btrfs_ordered_sum;
 
 #define BTRFS_MAGIC "_BHRfS_M"
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index a0390657451b..0282033041e1 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -393,7 +393,8 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
                                 break;
 
                         need_loop = 1;
-                        e = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
+                        e = kmem_cache_zalloc(btrfs_free_space_cachep,
+                                              GFP_NOFS);
                         if (!e) {
                                 kunmap(page);
                                 unlock_page(page);
@@ -405,7 +406,7 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
                         e->bytes = le64_to_cpu(entry->bytes);
                         if (!e->bytes) {
                                 kunmap(page);
-                                kfree(e);
+                                kmem_cache_free(btrfs_free_space_cachep, e);
                                 unlock_page(page);
                                 page_cache_release(page);
                                 goto free_cache;
@@ -420,7 +421,8 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
                                 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
                                 if (!e->bitmap) {
                                         kunmap(page);
-                                        kfree(e);
+                                        kmem_cache_free(
+                                                btrfs_free_space_cachep, e);
                                         unlock_page(page);
                                         page_cache_release(page);
                                         goto free_cache;
@@ -1187,7 +1189,7 @@ static void free_bitmap(struct btrfs_block_group_cache *block_group,
 {
         unlink_free_space(block_group, bitmap_info);
         kfree(bitmap_info->bitmap);
-        kfree(bitmap_info);
+        kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
         block_group->total_bitmaps--;
         recalculate_thresholds(block_group);
 }
@@ -1342,8 +1344,8 @@ new_bitmap:
 
                 /* no pre-allocated info, allocate a new one */
                 if (!info) {
-                        info = kzalloc(sizeof(struct btrfs_free_space),
-                                       GFP_NOFS);
+                        info = kmem_cache_zalloc(btrfs_free_space_cachep,
+                                                 GFP_NOFS);
                         if (!info) {
                                 spin_lock(&block_group->tree_lock);
                                 ret = -ENOMEM;
@@ -1365,7 +1367,7 @@ out:
         if (info) {
                 if (info->bitmap)
                         kfree(info->bitmap);
-                kfree(info);
+                kmem_cache_free(btrfs_free_space_cachep, info);
         }
 
         return ret;
@@ -1398,7 +1400,7 @@ bool try_merge_free_space(struct btrfs_block_group_cache *block_group,
                 else
                         __unlink_free_space(block_group, right_info);
                 info->bytes += right_info->bytes;
-                kfree(right_info);
+                kmem_cache_free(btrfs_free_space_cachep, right_info);
                 merged = true;
         }
 
@@ -1410,7 +1412,7 @@ bool try_merge_free_space(struct btrfs_block_group_cache *block_group,
                         __unlink_free_space(block_group, left_info);
                 info->offset = left_info->offset;
                 info->bytes += left_info->bytes;
-                kfree(left_info);
+                kmem_cache_free(btrfs_free_space_cachep, left_info);
                 merged = true;
         }
 
@@ -1423,7 +1425,7 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
         struct btrfs_free_space *info;
         int ret = 0;
 
-        info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
+        info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
         if (!info)
                 return -ENOMEM;
 
@@ -1450,7 +1452,7 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
 link:
         ret = link_free_space(block_group, info);
         if (ret)
-                kfree(info);
+                kmem_cache_free(btrfs_free_space_cachep, info);
 out:
         spin_unlock(&block_group->tree_lock);
 
@@ -1520,7 +1522,7 @@ again:
                         kfree(info->bitmap);
                         block_group->total_bitmaps--;
                 }
-                kfree(info);
+                kmem_cache_free(btrfs_free_space_cachep, info);
                 goto out_lock;
         }
 
@@ -1556,7 +1558,7 @@ again:
                         /* the hole we're creating ends at the end
                          * of the info struct, just free the info
                          */
-                        kfree(info);
+                        kmem_cache_free(btrfs_free_space_cachep, info);
                 }
                 spin_unlock(&block_group->tree_lock);
 
@@ -1689,7 +1691,7 @@ void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
                 unlink_free_space(block_group, info);
                 if (info->bitmap)
                         kfree(info->bitmap);
-                kfree(info);
+                kmem_cache_free(btrfs_free_space_cachep, info);
                 if (need_resched()) {
                         spin_unlock(&block_group->tree_lock);
                         cond_resched();
@@ -1722,7 +1724,7 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
                 entry->offset += bytes;
                 entry->bytes -= bytes;
                 if (!entry->bytes)
-                        kfree(entry);
+                        kmem_cache_free(btrfs_free_space_cachep, entry);
                 else
                         link_free_space(block_group, entry);
         }
@@ -1884,7 +1886,7 @@ out:
         block_group->free_space -= bytes;
         if (entry->bytes == 0) {
                 block_group->free_extents--;
-                kfree(entry);
+                kmem_cache_free(btrfs_free_space_cachep, entry);
         }
 
         spin_unlock(&block_group->tree_lock);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d97b69afbbfb..2d2e079713d7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -50,6 +50,7 @@
 #include "tree-log.h"
 #include "compression.h"
 #include "locking.h"
+#include "free-space-cache.h"
 
 struct btrfs_iget_args {
         u64 ino;
@@ -70,6 +71,7 @@ static struct kmem_cache *btrfs_inode_cachep;
 struct kmem_cache *btrfs_trans_handle_cachep;
 struct kmem_cache *btrfs_transaction_cachep;
 struct kmem_cache *btrfs_path_cachep;
+struct kmem_cache *btrfs_free_space_cachep;
 
 #define S_SHIFT 12
 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
@@ -6761,6 +6763,8 @@ void btrfs_destroy_cachep(void)
                 kmem_cache_destroy(btrfs_transaction_cachep);
         if (btrfs_path_cachep)
                 kmem_cache_destroy(btrfs_path_cachep);
+        if (btrfs_free_space_cachep)
+                kmem_cache_destroy(btrfs_free_space_cachep);
 }
 
 int btrfs_init_cachep(void)
@@ -6789,6 +6793,12 @@ int btrfs_init_cachep(void)
         if (!btrfs_path_cachep)
                 goto fail;
 
+        btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space_cache",
+                        sizeof(struct btrfs_free_space), 0,
+                        SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
+        if (!btrfs_free_space_cachep)
+                goto fail;
+
         return 0;
 fail:
         btrfs_destroy_cachep();