* [PATCH] Btrfs: remove unused wait queue in struct extent_buffer
@ 2014-06-16 12:14 Filipe David Borba Manana
2014-06-17 5:02 ` Satoru Takeuchi
0 siblings, 1 reply; 2+ messages in thread
From: Filipe David Borba Manana @ 2014-06-16 12:14 UTC (permalink / raw)
To: linux-btrfs; +Cc: Filipe David Borba Manana
The lock_wq wait queue is not used anywhere, therefore just remove it.
On a x86_64 system, this reduced sizeof(struct extent_buffer) from 320
bytes down to 296 bytes, which means a 4Kb page can now be used for
13 extent buffers instead of 12.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
fs/btrfs/extent_io.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 8b63f2d..dbbea4f 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -158,7 +158,6 @@ struct extent_buffer {
* to unlock
*/
wait_queue_head_t read_lock_wq;
- wait_queue_head_t lock_wq;
struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
#ifdef CONFIG_BTRFS_DEBUG
struct list_head leak_list;
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] Btrfs: remove unused wait queue in struct extent_buffer
2014-06-16 12:14 [PATCH] Btrfs: remove unused wait queue in struct extent_buffer Filipe David Borba Manana
@ 2014-06-17 5:02 ` Satoru Takeuchi
0 siblings, 0 replies; 2+ messages in thread
From: Satoru Takeuchi @ 2014-06-17 5:02 UTC (permalink / raw)
To: Filipe David Borba Manana, linux-btrfs; +Cc: Chris Mason
Hi Filipe,
(2014/06/16 21:14), Filipe David Borba Manana wrote:
> The lock_wq wait queue is not used anywhere, therefore just remove it.
> On a x86_64 system, this reduced sizeof(struct extent_buffer) from 320
> bytes down to 296 bytes, which means a 4Kb page can now be used for
> 13 extent buffers instead of 12.
>
> Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
It looks good to me. This field was once removed by bd681513.
However, re-introduced in error by 727011e07c
(both are Chris's patch).
I consider it's better to fix the following comment too.
===
$ cat -n fs/btrfs/extent_io.h | grep -B 3 write_lock_wq
152 /* readers use lock_wq while they wait for the write
153 * lock holders to unlock
154 */
155 wait_queue_head_t write_lock_wq;
===
We should "s/ lock_wq / write_lock_wq /" here.
Thanks,
Satoru
> ---
> fs/btrfs/extent_io.h | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
> index 8b63f2d..dbbea4f 100644
> --- a/fs/btrfs/extent_io.h
> +++ b/fs/btrfs/extent_io.h
> @@ -158,7 +158,6 @@ struct extent_buffer {
> * to unlock
> */
> wait_queue_head_t read_lock_wq;
> - wait_queue_head_t lock_wq;
> struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
> #ifdef CONFIG_BTRFS_DEBUG
> struct list_head leak_list;
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2014-06-16 12:14 [PATCH] Btrfs: remove unused wait queue in struct extent_buffer Filipe David Borba Manana
2014-06-17 5:02 ` Satoru Takeuchi
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