btrfs: merge ordered work callbacks in btrfs_work into one

There are two callbacks defined in btrfs_work but only two actually make
use of them, otherwise there are NULLs. We can get rid of the freeing
callback making it a special case of the normal work. This reduces the
size of btrfs_work by 8 bytes, final layout:

struct btrfs_work {
        btrfs_func_t               func;                 /*     0     8 */
        btrfs_ordered_func_t       ordered_func;         /*     8     8 */
        struct work_struct         normal_work;          /*    16    32 */
        struct list_head           ordered_list;         /*    48    16 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        struct btrfs_workqueue *   wq;                   /*    64     8 */
        long unsigned int          flags;                /*    72     8 */

        /* size: 80, cachelines: 2, members: 6 */
        /* last cacheline: 16 bytes */
};

This in turn reduces size of other structures (on a release config):

- async_chunk			 160 ->  152
- async_submit_bio		 152 ->  144
- btrfs_async_delayed_work	 104 ->   96
- btrfs_caching_control		 176 ->  168
- btrfs_delalloc_work		 144 ->  136
- btrfs_fs_info			3608 -> 3600
- btrfs_ordered_extent		 440 ->  424
- btrfs_writepage_fixup		 104 ->   96

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 638412ab090d..279a7a0c90c0 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1561,7 +1561,6 @@ DECLARE_EVENT_CLASS(btrfs__work,
 		__field(	const void *,	wq			)
 		__field(	const void *,	func			)
 		__field(	const void *,	ordered_func		)
-		__field(	const void *,	ordered_free		)
 		__field(	const void *,	normal_work		)
 	),
 
@@ -1570,14 +1569,12 @@ DECLARE_EVENT_CLASS(btrfs__work,
 		__entry->wq		= work->wq;
 		__entry->func		= work->func;
 		__entry->ordered_func	= work->ordered_func;
-		__entry->ordered_free	= work->ordered_free;
 		__entry->normal_work	= &work->normal_work;
 	),
 
-	TP_printk_btrfs("work=%p (normal_work=%p) wq=%p func=%ps ordered_func=%p "
-		  "ordered_free=%p",
+	TP_printk_btrfs("work=%p (normal_work=%p) wq=%p func=%ps ordered_func=%p",
 		  __entry->work, __entry->normal_work, __entry->wq,
-		   __entry->func, __entry->ordered_func, __entry->ordered_free)
+		   __entry->func, __entry->ordered_func)
 );
 
 /*