From: Christoph Lameter <cl@linux.com>
To: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org,
m.szyprowski@samsung.com
Subject: Re: how to avoid allocating or freeze MOVABLE memory in userspace
Date: Fri, 13 Apr 2012 13:27:30 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1204131326170.15905@router.home> (raw)
In-Reply-To: <CAN1soZzEuhQQYf7fNqOeMYT3Z-8VMix+1ihD77Bjtf+Do3x3DA@mail.gmail.com>
On Fri, 13 Apr 2012, Haojian Zhuang wrote:
> I have one question on memory migration. As we know, malloc() from
> user app will allocate MIGRATE_MOVABLE pages. But if we want to use
> this memory as DMA usage, we can't accept MIGRATE_MOVABLE type. Could
> we change its behavior before DMA working?
MIGRATE_MOVABLE works fine for DMA. If you keep a reference from a device
driver to user pages then you will have to increase the page refcount
which will in turn pin the page and make it non movable for as long as you
keep the refcount.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2012-04-13 18:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-13 14:35 Haojian Zhuang
2012-04-13 18:27 ` Christoph Lameter [this message]
2012-04-14 2:51 ` Haojian Zhuang
2012-04-16 13:55 ` Christoph Lameter
2012-04-18 7:36 ` Haojian Zhuang
2012-04-18 13:49 ` Christoph Lameter
2012-04-18 15:10 ` Marek Szyprowski
2012-05-11 13:27 ` Marek Szyprowski
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=alpine.DEB.2.00.1204131326170.15905@router.home \
--to=cl@linux.com \
--cc=haojian.zhuang@gmail.com \
--cc=linaro-mm-sig@lists.linaro.org \
--cc=linux-mm@kvack.org \
--cc=m.szyprowski@samsung.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