From 100d57025cce6bf568a10660c0d884bcc64c580e Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 8 Dec 2015 14:39:32 +0100 Subject: [PATCH] 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 --- fs/btrfs/inode.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 255d0f966b9f..0214a812fc0e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -77,7 +77,6 @@ static const struct file_operations btrfs_dir_file_operations; 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 @@ void btrfs_destroy_cachep(void) 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 @@ int btrfs_init_cachep(void) 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 *btrfs_alloc_delalloc_work(struct inode *inode, { 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 @@ struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode, 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); } /* -- 2.20.1