From: Koripella Srinivas <talkwithsrinivas@yahoo.co.in>
To: Mark Williamson <mark.williamson@cl.cam.ac.uk>
Cc: derek.murray@cl.cam.ac.uk, xen-devel@lists.xensource.com,
keir@xensource.com
Subject: Re: Grant Tables & mm.c
Date: Sat, 7 Jul 2007 19:14:43 +0530 (IST) [thread overview]
Message-ID: <913023.61596.qm@web94111.mail.in2.yahoo.com> (raw)
[-- Attachment #1.1: Type: text/plain, Size: 1788 bytes --]
I was looking at the user space grant tables but i did not find any code calling the function
"remap_pfn_range" to map the kmalloc ed allocated memory into user space.
What could be the reason?? Or am i missing something
Thanks Mark.
----- Original Message ----
From: Mark Williamson <mark.williamson@cl.cam.ac.uk>
To: Koripella Srinivas <talkwithsrinivas@yahoo.co.in>
Cc: xen-devel@lists.xensource.com
Sent: Friday, 6 July, 2007 9:55:48 AM
Subject: Re: [Xen-devel] Grant Tables & mm.c
> " Linux tends to zap userspace page mappings quite cheerfully
> unless you do something to stop it, could this be your problem?"
>
> What does this mean exactly??
Linux "zaps" mappings when it removes them from pagetables. Really this
corresponds to zeroing a pte corresponding to that mapping.
Unless you do something to stop the Linux mm system from treating the grant
table mappins like "normal" RAM, it will eventually want to simply zero them.
This will break for grant mappings, since it is not a permitted means of
unmapping granted memory.
> Any way i can prevent it from happening?
It depends on what you're trying to do...
Have you looked at the userspace grantables driver in our Linux tree? This
provides a device for mapping granted memory safely into userspace, handling
cleanup correctly. Even if that's not directly useful, maybe you can find
some code in there that'll help you.
Cheers,
Mark
--
Dave: Just a question. What use is a unicyle with no seat? And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!
__________________________________________________________
Yahoo! India Answers: Share what you know. Learn something new
http://in.answers.yahoo.com/
[-- Attachment #1.2: Type: text/html, Size: 2429 bytes --]
[-- Attachment #2: Type: text/plain, Size: 138 bytes --]
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel
next reply other threads:[~2007-07-07 13:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-07 13:44 Koripella Srinivas [this message]
2007-07-07 15:19 ` Grant Tables & mm.c Derek Murray
2007-07-09 9:23 ` question regarding struct xc_dom_image tgh
[not found] <469219.20698.qm@web94111.mail.in2.yahoo.com>
2007-07-06 4:25 ` Grant Tables & mm.c Mark Williamson
-- strict thread matches above, loose matches on Subject: below --
2007-07-04 10:16 Koripella Srinivas
2007-07-04 10:20 ` Keir Fraser
2007-07-04 18:42 ` Jeremy Fitzhardinge
2007-07-04 19:04 ` Keir Fraser
2007-07-04 14:13 ` Mark Williamson
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=913023.61596.qm@web94111.mail.in2.yahoo.com \
--to=talkwithsrinivas@yahoo.co.in \
--cc=derek.murray@cl.cam.ac.uk \
--cc=keir@xensource.com \
--cc=mark.williamson@cl.cam.ac.uk \
--cc=xen-devel@lists.xensource.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 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.