blkcg: add plugging support for punt bio
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Message ID 1596722082-31817-1-git-send-email-xianting_tian@126.com
State New
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Series
  • blkcg: add plugging support for punt bio
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Commit Message

Aug. 6, 2020, 1:54 p.m. UTC
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(+)

Comments

Jens Axboe Aug. 6, 2020, 3:16 p.m. UTC | #1
On 8/6/20 7:54 AM, Xianting Tian wrote:
> Try to merge continuous bio to current task's plug fisrt.

The patch looks fine to me, but I'd really like to see a bit more
changelog here. The commit message should explain why the change
is made, rather it's a very brief explanation of what it does.

If the bio list is contiguous, then we do the plugging to improve
merging at the lower level. You probably ran into a case where
you saw sub-optimal merging? And now the performance is better
with the patch? How much?
Tejun Heo Sept. 8, 2020, 6:03 p.m. UTC | #2
On Sat, Sep 05, 2020 at 11:25:03AM +0000, Tianxianting wrote:
> Hi jens,tj
> Could you share a couple of  minutes to comment it?
> I really appreciate it

The result looks fine to me but can you please summarize that in the commit
message of the patch?

Thanks.
Xianting Tian Sept. 9, 2020, 1:22 a.m. UTC | #3
Thanks TJ and your previous guide to me.
I will summarize and resubmit the patch.

-----Original Message-----
From: Tejun Heo [mailto:htejun@gmail.com] On Behalf Of Tejun Heo
Sent: Wednesday, September 09, 2020 2:03 AM
To: tianxianting (RD) <tian.xianting@h3c.com>
Cc: axboe@kernel.dk; cgroups@vger.kernel.org; linux-block@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH] blkcg: add plugging support for punt bio

On Sat, Sep 05, 2020 at 11:25:03AM +0000, Tianxianting wrote:
> Hi jens,tj
> Could you share a couple of  minutes to comment it?
> I really appreciate it

The result looks fine to me but can you please summarize that in the commit message of the patch?

Thanks.

--
tejun

Patch
diff mbox series

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);
 }
 
 /**