blk-wbt: Optimize wbt_done() for non-throttled writes

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>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250727173959.160835-2-yizhou.tang@shopee.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index a50d4cd55f419c2c5d104fb1c9b017f52ec7b561..30886d44f6cd253157cb0fa850d1d94fb0322f94 100644 (file)
--- 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));