diff mbox series

[15/21] ext4: use best found when complex scan of group finishs

Message ID 20230209194825.511043-16-shikemeng@huaweicloud.com
State New
Headers
Series Some bugfix and cleanup to mballoc |

Commit Message

Kemeng Shi Feb. 9, 2023, 7:48 p.m. UTC 
  If any bex which meets bex->fe_len >= gex->fe_len is found, then it will
always be used when complex scan of group that bex belongs to finishs.
So there will not be any lock-unlock period.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/ext4/mballoc.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

Comments

Ojaswin Mujoo Feb. 13, 2023, 7:53 p.m. UTC | #1 
On Fri, Feb 10, 2023 at 03:48:19AM +0800, Kemeng Shi wrote:
> If any bex which meets bex->fe_len >= gex->fe_len is found, then it will
> always be used when complex scan of group that bex belongs to finishs.
> So there will not be any lock-unlock period.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> ---
>  fs/ext4/mballoc.c | 14 ++------------
>  1 file changed, 2 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index e53f84de5018..c684758d6dbb 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2019,8 +2019,6 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
>  	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
>  	struct ext4_free_extent *bex = &ac->ac_b_ex;
>  	struct ext4_free_extent *gex = &ac->ac_g_ex;
> -	struct ext4_free_extent ex;
> -	int max;
>  
>  	if (ac->ac_status == AC_STATUS_FOUND)
>  		return;
> @@ -2039,16 +2037,8 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
>  	if (bex->fe_len < gex->fe_len)
>  		return;
>  
> -	if (finish_group && bex->fe_group == e4b->bd_group) {
> -		/* recheck chunk's availability - we don't know
> -		 * when it was found (within this lock-unlock
> -		 * period or not) */
> -		max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
> -		if (max >= gex->fe_len) {
> -			ext4_mb_use_best_found(ac, e4b);
> -			return;
> -		}
> -	}
> +	if (finish_group)
> +		ext4_mb_use_best_found(ac, e4b);
>  }
>  
>  /*
> -- 
> 2.30.0
> 
Looks good. So when we have found bex > gex, then we wont have a lock
unlock period since we always allocate the bex when we reach the end of
group. 

Just a small typo in the commit message (finshs -> finishes), but other
than that feel free to add:

Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
diff mbox series

Patch

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index e53f84de5018..c684758d6dbb 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2019,8 +2019,6 @@  static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
 	struct ext4_free_extent *bex = &ac->ac_b_ex;
 	struct ext4_free_extent *gex = &ac->ac_g_ex;
-	struct ext4_free_extent ex;
-	int max;
 
 	if (ac->ac_status == AC_STATUS_FOUND)
 		return;
@@ -2039,16 +2037,8 @@  static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
 	if (bex->fe_len < gex->fe_len)
 		return;
 
-	if (finish_group && bex->fe_group == e4b->bd_group) {
-		/* recheck chunk's availability - we don't know
-		 * when it was found (within this lock-unlock
-		 * period or not) */
-		max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
-		if (max >= gex->fe_len) {
-			ext4_mb_use_best_found(ac, e4b);
-			return;
-		}
-	}
+	if (finish_group)
+		ext4_mb_use_best_found(ac, e4b);
 }
 
 /*