From: Tang Yizhou <yizhou.tang@shopee.com>

In the current implementation, the sync_cookie and last_cookie members of
struct rq_wb are used only by read requests and not by non-throttled write
requests. Based on this, we can optimize wbt_done() by removing one if
condition check for non-throttled write requests.

Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com>
---
 block/blk-wbt.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index a50d4cd55f41..30886d44f6cd 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -248,13 +248,14 @@ static void wbt_done(struct rq_qos *rqos, struct request *rq)
 	struct rq_wb *rwb = RQWB(rqos);
 
 	if (!wbt_is_tracked(rq)) {
-		if (rwb->sync_cookie == rq) {
-			rwb->sync_issue = 0;
-			rwb->sync_cookie = NULL;
-		}
+		if (wbt_is_read(rq)) {
+			if (rwb->sync_cookie == rq) {
+				rwb->sync_issue = 0;
+				rwb->sync_cookie = NULL;
+			}
 
-		if (wbt_is_read(rq))
 			wb_timestamp(rwb, &rwb->last_comp);
+		}
 	} else {
 		WARN_ON_ONCE(rq == rwb->sync_cookie);
 		__wbt_done(rqos, wbt_flags(rq));
-- 
2.25.1

Hi,

在 2025/7/24 16:29, Tang Yizhou 写道:
> From: Tang Yizhou <yizhou.tang@shopee.com>
>
> In the current implementation, the sync_cookie and last_cookie members of
> struct rq_wb are used only by read requests and not by non-throttled write
> requests. Based on this, we can optimize wbt_done() by removing one if
> condition check for non-throttled write requests.
>
> Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com>
> ---
>   block/blk-wbt.c | 11 ++++++-----
>   1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-wbt.c b/block/blk-wbt.c
> index a50d4cd55f41..30886d44f6cd 100644
> --- a/block/blk-wbt.c
> +++ b/block/blk-wbt.c
> @@ -248,13 +248,14 @@ static void wbt_done(struct rq_qos *rqos, struct request *rq)
>   	struct rq_wb *rwb = RQWB(rqos);
>   
>   	if (!wbt_is_tracked(rq)) {
> -		if (rwb->sync_cookie == rq) {
> -			rwb->sync_issue = 0;
> -			rwb->sync_cookie = NULL;
> -		}
> +		if (wbt_is_read(rq)) {
> +			if (rwb->sync_cookie == rq) {
> +				rwb->sync_issue = 0;
> +				rwb->sync_cookie = NULL;
> +			}
>   
> -		if (wbt_is_read(rq))
>   			wb_timestamp(rwb, &rwb->last_comp);
> +		}
>   	} else {
>   		WARN_ON_ONCE(rq == rwb->sync_cookie);
>   		__wbt_done(rqos, wbt_flags(rq));
At lease this is correct logically.

Reviewed-by: Yu Kuai <yukuai3@huawei.com>

On Thu 24-07-25 16:29:59, Tang Yizhou wrote:
> From: Tang Yizhou <yizhou.tang@shopee.com>
> 
> In the current implementation, the sync_cookie and last_cookie members of
> struct rq_wb are used only by read requests and not by non-throttled write
> requests. Based on this, we can optimize wbt_done() by removing one if
> condition check for non-throttled write requests.
> 
> Signed-off-by: Tang Yizhou <yizhou.tang@shopee.com>

Nah, I'm undecided if this is actually worth it. But it looks correct and
doesn't make the code harder to follow so I guess feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  block/blk-wbt.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/block/blk-wbt.c b/block/blk-wbt.c
> index a50d4cd55f41..30886d44f6cd 100644
> --- a/block/blk-wbt.c
> +++ b/block/blk-wbt.c
> @@ -248,13 +248,14 @@ static void wbt_done(struct rq_qos *rqos, struct request *rq)
>  	struct rq_wb *rwb = RQWB(rqos);
>  
>  	if (!wbt_is_tracked(rq)) {
> -		if (rwb->sync_cookie == rq) {
> -			rwb->sync_issue = 0;
> -			rwb->sync_cookie = NULL;
> -		}
> +		if (wbt_is_read(rq)) {
> +			if (rwb->sync_cookie == rq) {
> +				rwb->sync_issue = 0;
> +				rwb->sync_cookie = NULL;
> +			}
>  
> -		if (wbt_is_read(rq))
>  			wb_timestamp(rwb, &rwb->last_comp);
> +		}
>  	} else {
>  		WARN_ON_ONCE(rq == rwb->sync_cookie);
>  		__wbt_done(rqos, wbt_flags(rq));
> -- 
> 2.25.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR