From: Christoph Hellwig <hch@infradead.org>
To: Christopher Lameter <cl@linux.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
"Luis R. Rodriguez" <mcgrof@kernel.org>,
linux-mm@kvack.org, Jan Kara <jack@suse.cz>,
matthew@wil.cx, x86@kernel.org, luto@amacapital.net,
martin.petersen@oracle.com, jthumshirn@suse.de,
broonie@kernel.org, linux-spi@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
"lsf-pc@lists.linux-foundation.org"
<lsf-pc@lists.linux-foundation.org>
Subject: Re: [LSF/MM TOPIC NOTES] x86 ZONE_DMA love
Date: Sat, 28 Apr 2018 01:33:47 -0700 [thread overview]
Message-ID: <20180428083347.GC31684@infradead.org> (raw)
In-Reply-To: <alpine.DEB.2.20.1804271136030.11686@nuc-kabylake>
On Fri, Apr 27, 2018 at 11:36:23AM -0500, Christopher Lameter wrote:
> On Fri, 27 Apr 2018, Matthew Wilcox wrote:
>
> > Some devices have incredibly bogus hardware like 28 bit addressing
> > or 39 bit addressing. We don't have a good way to allocate memory by
> > physical address other than than saying "GFP_DMA for anything less than
> > 32, GFP_DMA32 (or GFP_KERNEL on 32-bit) for anything less than 64 bit".
> >
> > Even CMA doesn't have a "cma_alloc_phys()". Maybe that's the right place
> > to put such an allocation API.
>
> The other way out of this would be to require a IOMMU?
Which on many systems doesn't exist. And even if it exists might not
be usable.
next prev parent reply other threads:[~2018-04-28 8:33 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-26 21:54 [LSF/MM TOPIC NOTES] x86 ZONE_DMA love Luis R. Rodriguez
2018-04-27 1:09 ` [Lsf-pc] " Rik van Riel
2018-04-27 5:35 ` Christoph Hellwig
2018-04-27 7:18 ` Michal Hocko
2018-04-27 16:07 ` Christopher Lameter
2018-04-27 16:18 ` Matthew Wilcox
2018-04-27 16:36 ` Christopher Lameter
2018-04-28 8:33 ` Christoph Hellwig [this message]
2018-04-27 16:37 ` Michal Hocko
2018-04-28 8:33 ` Christoph Hellwig
2018-04-28 8:30 ` Christoph Hellwig
2018-04-27 16:14 ` Luis R. Rodriguez
2018-04-27 16:28 ` Matthew Wilcox
2018-04-28 8:42 ` Christoph Hellwig
2018-04-28 18:55 ` Luis R. Rodriguez
2018-04-28 19:10 ` Matthew Wilcox
2018-05-03 12:03 ` Michal Hocko
2018-05-03 12:13 ` Christoph Hellwig
2018-04-28 19:46 ` Julia Lawall
2018-04-28 20:41 ` Matthew Wilcox
2018-04-29 14:34 ` Julia Lawall
2018-05-03 8:20 ` Geert Uytterhoeven
2018-05-05 16:08 ` Are media drivers abusing of GFP_DMA? - was: " Mauro Carvalho Chehab
2018-05-07 13:26 ` Laurent Pinchart
2018-05-07 15:19 ` Mauro Carvalho Chehab
2018-05-14 8:00 ` Fabien DESSENNE
2018-05-14 10:35 ` Mauro Carvalho Chehab
2018-05-14 10:39 ` Mauro Carvalho Chehab
2018-05-15 7:30 ` Fabien DESSENNE
2018-05-15 8:27 ` Laurent Pinchart
2018-05-15 10:30 ` Mauro Carvalho Chehab
2018-05-15 16:24 ` Luis R. Rodriguez
2018-05-10 4:39 ` Yasunari.Takiguchi
2018-05-10 4:39 ` Yasunari.Takiguchi
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=20180428083347.GC31684@infradead.org \
--to=hch@infradead.org \
--cc=broonie@kernel.org \
--cc=cl@linux.com \
--cc=jack@suse.cz \
--cc=jthumshirn@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-scsi@vger.kernel.org \
--cc=linux-spi@vger.kernel.org \
--cc=lsf-pc@lists.linux-foundation.org \
--cc=luto@amacapital.net \
--cc=martin.petersen@oracle.com \
--cc=matthew@wil.cx \
--cc=mcgrof@kernel.org \
--cc=mhocko@kernel.org \
--cc=willy@infradead.org \
--cc=x86@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.