From: Robin Holt <holt@sgi.com>
To: Laurent Desnogues <laurent.desnogues@gmail.com>
Cc: Jamie Lokier <jamie@shareable.org>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
David Xiao <dxiao@broadcom.com>, Ben Dooks <ben-linux@fluff.org>,
Hugh Dickins <hugh.dickins@tiscali.co.uk>,
Robin Holt <holt@sgi.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
v4l2_linux <linux-media@vger.kernel.org>,
"linux-arm-kernel@lists.arm.linux.org.uk"
<linux-arm-kernel@lists.arm.linux.org.uk>
Subject: Re: How to efficiently handle DMA and cache on ARMv7 ? (was "Is get_user_pages() enough to prevent pages from being swapped out ?")
Date: Fri, 7 Aug 2009 08:15:01 -0500 [thread overview]
Message-ID: <20090807131501.GD2763@sgi.com> (raw)
In-Reply-To: <761ea48b0908070507n5c580455pb86e5240a7cf6c0c@mail.gmail.com>
On Fri, Aug 07, 2009 at 02:07:43PM +0200, Laurent Desnogues wrote:
> On Fri, Aug 7, 2009 at 11:54 AM, Jamie Lokier<jamie@shareable.org> wrote:
> >
> > 1. Does the architecture not prevent speculative instruction
> > prefetches from crossing a page boundary? It would be handy under the
> > circumstances.
>
> There's no such restriction in ARMv7 architecture.
Doesn't it prevent them for uncached areas? I _THOUGHT_ there was an
alloc_consistent (or something like that) call on ARM which gave you
an uncached mapping where you could do DMA. I also thought there was
a dma_* set of functions which remapped as uncached before DMA begins
and remapped as normal after DMA has been completed.
Sorry for the fuzzy recollection. I am dredging from 2.6.21 timeframe.
Robin
next prev parent reply other threads:[~2009-08-07 13:15 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-06 10:08 How to efficiently handle DMA and cache on ARMv7 ? (was "Is get_user_pages() enough to prevent pages from being swapped out ?") Laurent Pinchart
2009-08-06 11:46 ` Ben Dooks
2009-08-06 13:06 ` Laurent Pinchart
2009-08-06 18:46 ` David Xiao
2009-08-06 19:16 ` Chetan.Loke
2009-08-06 20:15 ` Jamie Lokier
2009-08-06 22:25 ` Russell King - ARM Linux
2009-08-07 5:59 ` David Xiao
2009-08-07 7:58 ` Laurent Pinchart
2009-08-07 8:10 ` Russell King - ARM Linux
2009-08-07 9:54 ` Jamie Lokier
2009-08-07 9:59 ` Russell King - ARM Linux
2009-08-07 12:07 ` Laurent Desnogues
2009-08-07 13:15 ` Robin Holt [this message]
2009-08-07 19:01 ` Russell King - ARM Linux
2009-08-07 20:11 ` Laurent Pinchart
2009-08-07 20:28 ` Russell King - ARM Linux
2009-08-07 22:25 ` David Xiao
2009-08-10 13:49 ` Laurent Pinchart
2009-08-07 8:08 ` Russell King - ARM Linux
2009-08-07 10:23 ` Jamie Lokier
2009-08-07 19:03 ` Russell King - ARM Linux
2009-08-11 9:31 ` Catalin Marinas
2009-08-11 18:23 ` David Xiao
2009-08-07 7:48 ` Laurent Pinchart
2009-08-25 12:53 ` Steven Walter
2009-08-25 22:02 ` David Xiao
2009-08-25 23:17 ` Laurent Pinchart
2009-08-26 17:22 ` David Xiao
2009-09-01 13:31 ` Russell King - ARM Linux
2009-09-01 18:08 ` David Xiao
2009-09-01 13:28 ` Russell King - ARM Linux
2009-09-01 13:43 ` Laurent Pinchart
2009-09-01 14:18 ` Russell King - ARM Linux
2009-09-01 16:53 ` Hugh Dickins
2009-09-02 15:10 ` Imre Deak
2009-09-03 7:31 ` Imre Deak
2009-09-03 8:36 ` Russell King - ARM Linux
2009-09-08 13:05 ` Steven Walter
2009-08-07 7:29 ` Laurent Pinchart
2009-08-07 8:12 ` Matthieu CASTET
2009-08-07 10:13 ` How to efficiently handle DMA and cache on ARMv7 ? (was " Is " Laurent Pinchart
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=20090807131501.GD2763@sgi.com \
--to=holt@sgi.com \
--cc=ben-linux@fluff.org \
--cc=dxiao@broadcom.com \
--cc=hugh.dickins@tiscali.co.uk \
--cc=jamie@shareable.org \
--cc=laurent.desnogues@gmail.com \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-arm-kernel@lists.arm.linux.org.uk \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
/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).