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From:   Xianting Tian <xianting_tian@126.com>
To:     tj@kernel.org, axboe@kernel.dk
Cc:     cgroups@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] blkcg: add plugging support for punt bio
Date:   Thu,  6 Aug 2020 09:54:42 -0400
Message-Id: <1596722082-31817-1-git-send-email-xianting_tian@126.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Try to merge continuous bio to current task's plug fisrt.

Signed-off-by: Xianting Tian <xianting_tian@126.com>
---
 block/blk-cgroup.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 0ecc897..fe5d361 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -122,6 +122,7 @@ static void blkg_async_bio_workfn(struct work_struct *work)
 					     async_bio_work);
 	struct bio_list bios = BIO_EMPTY_LIST;
 	struct bio *bio;
+	struct blk_plug plug;
 
 	/* as long as there are pending bios, @blkg can't go away */
 	spin_lock_bh(&blkg->async_bio_lock);
@@ -129,8 +130,10 @@ static void blkg_async_bio_workfn(struct work_struct *work)
 	bio_list_init(&blkg->async_bios);
 	spin_unlock_bh(&blkg->async_bio_lock);
 
+	blk_start_plug(&plug);
 	while ((bio = bio_list_pop(&bios)))
 		submit_bio(bio);
+	blk_finish_plug(&plug);
 }
 
 /**
-- 
1.8.3.1