linux-block.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Tokunori Ikegami <ikegami.t@gmail.com>
To: Keith Busch <kbusch@kernel.org>
Cc: Ming Lei <tom.leiming@gmail.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Subject: Re: [PATCH] block, nvme: Increase max segments parameter setting value
Date: Wed, 1 Apr 2020 00:24:50 +0900	[thread overview]
Message-ID: <6c35a4f9-af19-feff-6be0-d9c023d6c6b7@gmail.com> (raw)
In-Reply-To: <20200330135323.GA32604@C02WT3WMHTD6>

Hi,

On 2020/03/30 22:53, Keith Busch wrote:
> On Mon, Mar 30, 2020 at 06:15:41PM +0900, Tokunori Ikegami wrote:
>> But there is a case that the command data length is limited by 512KB.
>> I am not sure about this condition so needed more investigation.
> Your memory is too fragmented. You need more physically contiguous
> memory or you'll hit the segment limit before you hit the length
> limit. Try allocating huge pages.

Thank you so much for your advise.
I have confirmed that the 512KB case is limited by the 127 segments 
check below in ll_new_hw_segment().

     if (req->nr_phys_segments + nr_phys_segs > 
queue_max_segments(req->q)) {

Also confirmed that the 4MB limit works correctly with the memory 
condition not fragmented too much.
I will do abandon the patch to increase max segments as limited 4MB now 
by NVMe PCIe driver.

Regards,
Ikegami


  reply	other threads:[~2020-03-31 15:24 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-23 18:23 [PATCH] block, nvme: Increase max segments parameter setting value Tokunori Ikegami
2020-03-23 19:14 ` Chaitanya Kulkarni
2020-03-23 23:09   ` Tokunori Ikegami
2020-03-24  0:02     ` Keith Busch
2020-03-24 16:51       ` Tokunori Ikegami
2020-03-27 17:50         ` Tokunori Ikegami
2020-03-27 18:18           ` Keith Busch
2020-03-28  2:11             ` Ming Lei
2020-03-28  3:13               ` Keith Busch
2020-03-28  8:28                 ` Ming Lei
2020-03-28 12:57               ` Tokunori Ikegami
2020-03-29  3:01                 ` Ming Lei
2020-03-30  9:15                   ` Tokunori Ikegami
2020-03-30 13:53                     ` Keith Busch
2020-03-31 15:24                       ` Tokunori Ikegami [this message]
2020-03-31 14:13                     ` Joshi
2020-03-31 15:37                       ` Tokunori Ikegami
2020-03-24  7:16 ` Hannes Reinecke
2020-03-24 17:17   ` Tokunori Ikegami

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=6c35a4f9-af19-feff-6be0-d9c023d6c6b7@gmail.com \
    --to=ikegami.t@gmail.com \
    --cc=Chaitanya.Kulkarni@wdc.com \
    --cc=kbusch@kernel.org \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=tom.leiming@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).