From: Christopher Clark <christopher.w.clark@gmail.com>
To: Xin Zhao <zhaoxin@eecs.umich.edu>
Cc: xen-devel@lists.sourceforge.net
Subject: Re: mapped memory delay?
Date: Fri, 18 Feb 2005 22:14:04 +0000 [thread overview]
Message-ID: <eab087540502181414b60f3f4@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0502181639240.24170@willow.eecs.umich.edu>
Are you running this on a single processor core?
If not, it sounds to me like a cache coherency issue - you'll need a
write memory barrier after writing to the req_prod. If you're using
the ring macros from io/ring.h this should be already taken care of
for you in the push macros.
c.
On Fri, 18 Feb 2005 16:44:30 -0500 (EST), Xin Zhao
<zhaoxin@eecs.umich.edu> wrote:
> I ran into the following problem:
>
> I setup a shared ring page and an event channel between two domains (dom0
> and one domU), DomU increases req_prod by one and notify the dom0 via the
> event channel, dom0 then check req_prod pointer and process the request in
> the shared ring. But I noticed that sometimes dom0 get the irq triggered
> by the notification event, but the req_prod remains the same. This
> situation only happened occasionally. Why? Because the req_prod is saved
> in the shared, mapped page, I suspect that there is a delay of updates
> between two domains. Is that true? If so, how to handle this problem?
>
> Your advice is highly appreciated!
>
> -x
>
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
> http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/xen-devel
>
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
next prev parent reply other threads:[~2005-02-18 22:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-18 21:44 mapped memory delay? Xin Zhao
2005-02-18 22:14 ` Christopher Clark [this message]
2005-02-18 22:41 ` Xin Zhao
2005-02-18 23:58 ` Christopher Clark
2005-02-19 1:46 ` Jacob Gorm Hansen
2005-02-19 1:46 ` Mark Williamson
2005-02-19 2:06 ` Jacob Gorm Hansen
2005-02-19 2:04 ` Mark Williamson
2005-02-19 2:46 ` Anthony Liguori
2005-02-19 3:01 ` Jacob Gorm Hansen
2005-02-19 3:26 ` Jacob Gorm Hansen
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=eab087540502181414b60f3f4@mail.gmail.com \
--to=christopher.w.clark@gmail.com \
--cc=cwc22@cam.ac.uk \
--cc=xen-devel@lists.sourceforge.net \
--cc=zhaoxin@eecs.umich.edu \
/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.