btrfs: don't use slab cache for struct btrfs_delalloc_work
Although we prefer to use separate caches for various structs, it seems
better not to do that for struct btrfs_delalloc_work. Objects of this
type are allocated rarely, when transaction commit calls
btrfs_start_delalloc_roots, requesting delayed iputs.
The objects are temporary (with some IO involved) but still allocated
and freed within __start_delalloc_inodes. Memory allocation failure is
handled.
The slab cache is empty most of the time (observed on several systems),
so if we need to allocate a new slab object, the first one has to
allocate a full page. In a potential case of low memory conditions this
might fail with higher probability compared to using the generic slab
caches.
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 255d0f9..0214a81 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -77,7 +77,6 @@
static struct extent_io_ops btrfs_extent_io_ops;
static struct kmem_cache *btrfs_inode_cachep;
-static struct kmem_cache *btrfs_delalloc_work_cachep;
struct kmem_cache *btrfs_trans_handle_cachep;
struct kmem_cache *btrfs_transaction_cachep;
struct kmem_cache *btrfs_path_cachep;
@@ -9159,8 +9158,6 @@
kmem_cache_destroy(btrfs_path_cachep);
if (btrfs_free_space_cachep)
kmem_cache_destroy(btrfs_free_space_cachep);
- if (btrfs_delalloc_work_cachep)
- kmem_cache_destroy(btrfs_delalloc_work_cachep);
}
int btrfs_init_cachep(void)
@@ -9195,13 +9192,6 @@
if (!btrfs_free_space_cachep)
goto fail;
- btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
- sizeof(struct btrfs_delalloc_work), 0,
- SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
- NULL);
- if (!btrfs_delalloc_work_cachep)
- goto fail;
-
return 0;
fail:
btrfs_destroy_cachep();
@@ -9446,7 +9436,7 @@
{
struct btrfs_delalloc_work *work;
- work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
+ work = kmalloc(sizeof(*work), GFP_NOFS);
if (!work)
return NULL;
@@ -9465,7 +9455,7 @@
void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
{
wait_for_completion(&work->completion);
- kmem_cache_free(btrfs_delalloc_work_cachep, work);
+ kfree(work);
}
/*