linux-btrfs.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] Btrfs: shrink further sizeof(struct extent_buffer)
@ 2014-08-14 11:25 Filipe Manana
  2014-08-26 11:02 ` David Sterba
  0 siblings, 1 reply; 2+ messages in thread
From: Filipe Manana @ 2014-08-14 11:25 UTC (permalink / raw)
  To: linux-btrfs; +Cc: Filipe Manana

The map_start and map_len fields aren't used anywhere, so just remove
them. On a x86_64 system, this reduced sizeof(struct extent_buffer)
from 296 bytes to 280 bytes, and therefore 14 extent_buffer structs can
now fit into a page instead of 13.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/extent_io.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index ce02cc9..5e91fb9 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -125,8 +125,6 @@ struct extent_state {
 struct extent_buffer {
 	u64 start;
 	unsigned long len;
-	unsigned long map_start;
-	unsigned long map_len;
 	unsigned long bflags;
 	struct btrfs_fs_info *fs_info;
 	spinlock_t refs_lock;
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] Btrfs: shrink further sizeof(struct extent_buffer)
  2014-08-14 11:25 [PATCH] Btrfs: shrink further sizeof(struct extent_buffer) Filipe Manana
@ 2014-08-26 11:02 ` David Sterba
  0 siblings, 0 replies; 2+ messages in thread
From: David Sterba @ 2014-08-26 11:02 UTC (permalink / raw)
  To: Filipe Manana; +Cc: linux-btrfs

On Thu, Aug 14, 2014 at 12:25:14PM +0100, Filipe Manana wrote:
> The map_start and map_len fields aren't used anywhere, so just remove
> them. On a x86_64 system, this reduced sizeof(struct extent_buffer)
> from 296 bytes to 280 bytes, and therefore 14 extent_buffer structs can
> now fit into a page instead of 13.
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.cz>

Nice catch.

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2014-08-26 11:02 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-08-14 11:25 [PATCH] Btrfs: shrink further sizeof(struct extent_buffer) Filipe Manana
2014-08-26 11:02 ` David Sterba

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).