dm writecache: remove unused member pointer in writeback_struct

dm writecache: remove unused member pointer in writeback_struct

[Huaisheng Ye]

From: Huaisheng Ye <yehs1@lenovo.com>

The stucture member pointer page in writeback_struct never has been
used actually. Remove it.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
---
 drivers/md/dm-writecache.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 1cb137f..5c7009d 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -190,7 +190,6 @@ struct writeback_struct {
 	struct dm_writecache *wc;
 	struct wc_entry **wc_list;
 	unsigned wc_list_n;
-	struct page *page;
 	struct wc_entry *wc_list_inline[WB_LIST_INLINE];
 	struct bio bio;
 };
-- 
1.8.3.1

dm writecache: add unlikely for getting two block with same LBA

[Huaisheng Ye]

From: Huaisheng Ye <yehs1@lenovo.com>

In function writecache_writeback, entries g and f has same original
sector only happens at entry f has been committed, but entry g has
NOT yet.

The probability of this happening is very low in the following
 256 blocks at most of entry e, so add unlikely for the result.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
---
 drivers/md/dm-writecache.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 5c7009d..3643084 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1628,8 +1628,8 @@ static void writecache_writeback(struct work_struct *work)
 			if (unlikely(!next_node))
 				break;
 			g = container_of(next_node, struct wc_entry, rb_node);
-			if (read_original_sector(wc, g) ==
-			    read_original_sector(wc, f)) {
+			if (unlikely(read_original_sector(wc, g) ==
+			    read_original_sector(wc, f))) {
 				f = g;
 				continue;
 			}
-- 
1.8.3.1

Re: dm writecache: remove unused member pointer in writeback_struct

[Mikulas Patocka]

On Mon, 12 Aug 2019, Huaisheng Ye wrote:

> From: Huaisheng Ye <yehs1@lenovo.com>
> 
> The stucture member pointer page in writeback_struct never has been
> used actually. Remove it.
> 
> Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>

Acked-by: Mikulas Patocka <mpatocka@redhat.com>

> ---
>  drivers/md/dm-writecache.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> index 1cb137f..5c7009d 100644
> --- a/drivers/md/dm-writecache.c
> +++ b/drivers/md/dm-writecache.c
> @@ -190,7 +190,6 @@ struct writeback_struct {
>  	struct dm_writecache *wc;
>  	struct wc_entry **wc_list;
>  	unsigned wc_list_n;
> -	struct page *page;
>  	struct wc_entry *wc_list_inline[WB_LIST_INLINE];
>  	struct bio bio;
>  };
> -- 
> 1.8.3.1
> 
> 

Re: dm writecache: add unlikely for getting two block with same LBA

[Mikulas Patocka]

On Mon, 12 Aug 2019, Huaisheng Ye wrote:

> From: Huaisheng Ye <yehs1@lenovo.com>
> 
> In function writecache_writeback, entries g and f has same original
> sector only happens at entry f has been committed, but entry g has
> NOT yet.
> 
> The probability of this happening is very low in the following
>  256 blocks at most of entry e, so add unlikely for the result.
> 
> Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>

Acked-by: Mikulas Patocka <mpatocka@redhat.com>

> ---
>  drivers/md/dm-writecache.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> index 5c7009d..3643084 100644
> --- a/drivers/md/dm-writecache.c
> +++ b/drivers/md/dm-writecache.c
> @@ -1628,8 +1628,8 @@ static void writecache_writeback(struct work_struct *work)
>  			if (unlikely(!next_node))
>  				break;
>  			g = container_of(next_node, struct wc_entry, rb_node);
> -			if (read_original_sector(wc, g) ==
> -			    read_original_sector(wc, f)) {
> +			if (unlikely(read_original_sector(wc, g) ==
> +			    read_original_sector(wc, f))) {
>  				f = g;
>  				continue;
>  			}
> -- 
> 1.8.3.1
> 
>