public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: "Leon Woestenberg" <leon.woestenberg@gmail.com>
To: "FUJITA Tomonori" <fujita.tomonori@lab.ntt.co.jp>
Cc: jens.axboe@oracle.com, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org,
	James.Bottomley@hansenpartnership.com, tj@kernel.org
Subject: Re: pci_map_sg() does not coalesce adjacent physical memory? x86
Date: Wed, 19 Nov 2008 10:45:09 +0100	[thread overview]
Message-ID: <c384c5ea0811190145y78803fbboecfcf6ebd652ee03@mail.gmail.com> (raw)
In-Reply-To: <20081119165915A.fujita.tomonori@lab.ntt.co.jp>

Hello,

On Wed, Nov 19, 2008 at 8:58 AM, FUJITA Tomonori
<fujita.tomonori@lab.ntt.co.jp> wrote:
> On Wed, 19 Nov 2008 15:58:12 +0900
> FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:
>> On Wed, 19 Nov 2008 07:22:31 +0100
>
> - pci_map_sg/dma_map_sg are used with a scatter gather list that
> doesn't come from the block layer (e.g. some network drivers do).
>
This is the point I then want to make: we have pci_map_sg() users in
other system than the block layer, the network and v4l2 subsystems,
why cannot they benefit from coalescing?

Should they copy the block layer coalescing implementation, or should
that implementation be made more generic and live outside the block
sub system?

My intended use case is as follows. See the sg_write() call for the code flow.

http://www.sidebranch.com/leon/user_dma_sg.c


Thanks,
-- 
Leon

  reply	other threads:[~2008-11-19  9:45 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-17 21:54 pci_map_sg() does not coalesce adjacent physical memory? x86 Leon Woestenberg
2008-11-18  3:15 ` Andrew Morton
2008-11-18  5:21   ` James Bottomley
2008-11-18  9:37     ` Leon Woestenberg
2008-11-19  5:19   ` FUJITA Tomonori
2008-11-19  6:22     ` Leon Woestenberg
2008-11-19  6:58       ` FUJITA Tomonori
2008-11-19  7:05         ` FUJITA Tomonori
2008-11-19  7:58         ` FUJITA Tomonori
2008-11-19  9:45           ` Leon Woestenberg [this message]
2008-11-19 10:05             ` Tejun Heo

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=c384c5ea0811190145y78803fbboecfcf6ebd652ee03@mail.gmail.com \
    --to=leon.woestenberg@gmail.com \
    --cc=James.Bottomley@hansenpartnership.com \
    --cc=akpm@linux-foundation.org \
    --cc=fujita.tomonori@lab.ntt.co.jp \
    --cc=jens.axboe@oracle.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=tj@kernel.org \
    /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