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From: Keith Busch <kbusch@kernel.org>
To: Tokunori Ikegami <ikegami.t@gmail.com>
Cc: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: Re: [PATCH] block, nvme: Increase max segments parameter setting value
Date: Sat, 28 Mar 2020 03:18:25 +0900	[thread overview]
Message-ID: <20200327181825.GA8356@redsun51.ssa.fujisawa.hgst.com> (raw)
In-Reply-To: <dc3a3e88-f062-b7df-dd18-18fb76e68e0c@gmail.com>

On Sat, Mar 28, 2020 at 02:50:43AM +0900, Tokunori Ikegami wrote:
> On 2020/03/25 1:51, Tokunori Ikegami wrote:
> > On 2020/03/24 9:02, Keith Busch wrote:
> > > We didn't have 32-bit max segments before, though. Why was 16-bits
> > > enough in older kernels? Which kernel did this stop working?
> > Now I am asking the detail information to the reporter so let me
> > update later.  That was able to use the same command script with the
> > large data length in the past.
> 
> I have just confirmed the detail so let me update below.
> 
> The data length 20,531,712 (0x1394A00) is used on kernel 3.10.0 (CentOS
> 64bit).
> Also it is failed on kernel 10 4.10.0 (Ubuntu 32bit).
> But just confirmed it as succeeded on both 4.15.0 (Ubuntu 32bit) and 4.15.1
> (Ubuntu 64bit).
> So the original 20,531,712 length failure issue seems already resolved.
> 
> I tested the data length 0x10000000 (268,435,456) and it is failed
> But now confirmed it as failed on all the above kernel versions.
> Also the patch fixes only this 0x10000000 length failure issue.

This is actually even more confusing. We do not support 256MB transfers
within a single command in the pci nvme driver anymore. The max is 4MB,
so I don't see how increasing the max segments will help: you should be
hitting the 'max_sectors' limit if you don't hit the segment limit first.

WARNING: multiple messages have this Message-ID (diff)
From: Keith Busch <kbusch@kernel.org>
To: Tokunori Ikegami <ikegami.t@gmail.com>
Cc: "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: Sat, 28 Mar 2020 03:18:25 +0900	[thread overview]
Message-ID: <20200327181825.GA8356@redsun51.ssa.fujisawa.hgst.com> (raw)
In-Reply-To: <dc3a3e88-f062-b7df-dd18-18fb76e68e0c@gmail.com>

On Sat, Mar 28, 2020 at 02:50:43AM +0900, Tokunori Ikegami wrote:
> On 2020/03/25 1:51, Tokunori Ikegami wrote:
> > On 2020/03/24 9:02, Keith Busch wrote:
> > > We didn't have 32-bit max segments before, though. Why was 16-bits
> > > enough in older kernels? Which kernel did this stop working?
> > Now I am asking the detail information to the reporter so let me
> > update later.  That was able to use the same command script with the
> > large data length in the past.
> 
> I have just confirmed the detail so let me update below.
> 
> The data length 20,531,712 (0x1394A00) is used on kernel 3.10.0 (CentOS
> 64bit).
> Also it is failed on kernel 10 4.10.0 (Ubuntu 32bit).
> But just confirmed it as succeeded on both 4.15.0 (Ubuntu 32bit) and 4.15.1
> (Ubuntu 64bit).
> So the original 20,531,712 length failure issue seems already resolved.
> 
> I tested the data length 0x10000000 (268,435,456) and it is failed
> But now confirmed it as failed on all the above kernel versions.
> Also the patch fixes only this 0x10000000 length failure issue.

This is actually even more confusing. We do not support 256MB transfers
within a single command in the pci nvme driver anymore. The max is 4MB,
so I don't see how increasing the max segments will help: you should be
hitting the 'max_sectors' limit if you don't hit the segment limit first.

_______________________________________________
linux-nvme mailing list
linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2020-03-27 18:18 UTC|newest]

Thread overview: 38+ 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 18:23 ` Tokunori Ikegami
2020-03-23 19:14 ` Chaitanya Kulkarni
2020-03-23 19:14   ` Chaitanya Kulkarni
2020-03-23 23:09   ` Tokunori Ikegami
2020-03-23 23:09     ` Tokunori Ikegami
2020-03-24  0:02     ` Keith Busch
2020-03-24  0:02       ` Keith Busch
2020-03-24 16:51       ` Tokunori Ikegami
2020-03-24 16:51         ` Tokunori Ikegami
2020-03-27 17:50         ` Tokunori Ikegami
2020-03-27 17:50           ` Tokunori Ikegami
2020-03-27 18:18           ` Keith Busch [this message]
2020-03-27 18:18             ` Keith Busch
2020-03-28  2:11             ` Ming Lei
2020-03-28  2:11               ` Ming Lei
2020-03-28  3:13               ` Keith Busch
2020-03-28  3:13                 ` Keith Busch
2020-03-28  8:28                 ` Ming Lei
2020-03-28  8:28                   ` Ming Lei
2020-03-28 12:57               ` Tokunori Ikegami
2020-03-28 12:57                 ` Tokunori Ikegami
2020-03-29  3:01                 ` Ming Lei
2020-03-29  3:01                   ` Ming Lei
2020-03-30  9:15                   ` Tokunori Ikegami
2020-03-30  9:15                     ` Tokunori Ikegami
2020-03-30 13:53                     ` Keith Busch
2020-03-30 13:53                       ` Keith Busch
2020-03-31 15:24                       ` Tokunori Ikegami
2020-03-31 15:24                         ` Tokunori Ikegami
2020-03-31 14:13                     ` Joshi
2020-03-31 14:13                       ` Joshi
2020-03-31 15:37                       ` Tokunori Ikegami
2020-03-31 15:37                         ` Tokunori Ikegami
2020-03-24  7:16 ` Hannes Reinecke
2020-03-24  7:16   ` Hannes Reinecke
2020-03-24 17:17   ` Tokunori Ikegami
2020-03-24 17:17     ` Tokunori Ikegami

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