From: Ilya Dryomov <idryomov@gmail.com>
To: juncheng bai <baijuncheng@unitedstack.com>
Cc: idryomov@redhat.com, Alex Elder <elder@linaro.org>,
Josh Durgin <josh.durgin@inktank.com>,
lucienchao@gmail.com, jeff@garzik.org, yehuda@hq.newdream.net,
Sage Weil <sage@newdream.net>,
elder@inktank.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ceph Development <ceph-devel@vger.kernel.org>
Subject: Re: [PATCH RFC] storage:rbd: make the size of request is equal to the, size of the object
Date: Mon, 15 Jun 2015 16:03:25 +0300 [thread overview]
Message-ID: <CAOi1vP9iF6LVGrHsORoYGUkx_Ttqr7gsBUMz7EM--b7asOUPCA@mail.gmail.com> (raw)
In-Reply-To: <557EB47F.6090708@unitedstack.com>
On Mon, Jun 15, 2015 at 2:18 PM, juncheng bai
<baijuncheng@unitedstack.com> wrote:
> From 6213215bd19926d1063d4e01a248107dab8a899b Mon Sep 17 00:00:00 2001
> From: juncheng bai <baijuncheng@unitedstack.com>
> Date: Mon, 15 Jun 2015 18:34:00 +0800
> Subject: [PATCH] storage:rbd: make the size of request is equal to the
> size of the object
>
> ensures that the merged size of request can achieve the size of
> the object.
> when merge a bio to request or merge a request to request, the
> sum of the segment number of the current request and the segment
> number of the bio is not greater than the max segments of the request,
> so the max size of request is 512k if the max segments of request is
> BLK_MAX_SEGMENTS.
>
> Signed-off-by: juncheng bai <baijuncheng@unitedstack.com>
> ---
> drivers/block/rbd.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 0a54c58..dec6045 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -3757,6 +3757,8 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
> segment_size = rbd_obj_bytes(&rbd_dev->header);
> blk_queue_max_hw_sectors(q, segment_size / SECTOR_SIZE);
> blk_queue_max_segment_size(q, segment_size);
> + if (segment_size > BLK_MAX_SEGMENTS * PAGE_SIZE)
> + blk_queue_max_segments(q, segment_size / PAGE_SIZE);
> blk_queue_io_min(q, segment_size);
> blk_queue_io_opt(q, segment_size);
I made a similar patch on Friday, investigating blk-mq plugging issue
reported by Nick. My patch sets it to BIO_MAX_PAGES unconditionally -
AFAIU there is no point in setting to anything bigger since the bios
will be clipped to that number of vecs. Given that BIO_MAX_PAGES is
256, this gives is 1M direct I/Os.
Thanks,
Ilya
next prev parent reply other threads:[~2015-06-15 13:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-15 11:18 [PATCH RFC] storage:rbd: make the size of request is equal to the, size of the object juncheng bai
2015-06-15 13:03 ` Ilya Dryomov [this message]
2015-06-15 13:23 ` juncheng bai
2015-06-15 14:27 ` Ilya Dryomov
2015-06-16 3:28 ` juncheng bai
2015-06-16 8:37 ` Ilya Dryomov
2015-06-16 11:57 ` juncheng bai
2015-06-16 13:30 ` Ilya Dryomov
2015-06-16 14:14 ` juncheng bai
2015-06-16 15:51 ` Ilya Dryomov
2015-06-17 3:04 ` juncheng bai
2015-06-17 8:24 ` Ilya Dryomov
2015-06-17 9:47 ` juncheng bai
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