From: James Simmons <jsimmons@edgeglobal.com>
To: "Stephen C. Tweedie" <sct@redhat.com>
Cc: Linux MM <linux-mm@kvack.org>
Subject: Re: MMIO regions
Date: Mon, 4 Oct 1999 11:52:50 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.10.9910041146560.8080-100000@imperial.edgeglobal.com> (raw)
In-Reply-To: <14328.51304.207897.182095@dukat.scot.redhat.com>
On Mon, 4 Oct 1999, Stephen C. Tweedie wrote:
> Hi,
>
> On Mon, 4 Oct 1999 10:38:13 -0400 (EDT), James Simmons
> <jsimmons@edgeglobal.com> said:
>
> > I noticed something for SMP machines with all the dicussion about
> > concurrent access to memory regions. What happens when you have two
> > processes that have both mmapped the same MMIO region for some card.
>
> The kernel doesn't impose any limits against this. If you want to make
> this impossible, then you need to add locking to the driver itself to
> prevent multiple processes from conflicting.
And if the process holding the locks dies then no other process can access
this resource. Also if the program forgets to release the lock you end up
with other process never being able to access this piece of hardware.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://humbolt.geo.uu.nl/Linux-MM/
next prev parent reply other threads:[~1999-10-04 15:52 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-10-04 14:38 James Simmons
1999-10-04 15:31 ` Stephen C. Tweedie
1999-10-04 15:52 ` James Simmons [this message]
1999-10-04 16:02 ` Benjamin C.R. LaHaise
1999-10-04 17:27 ` James Simmons
1999-10-04 17:56 ` Benjamin C.R. LaHaise
1999-10-04 18:26 ` James Simmons
1999-10-04 19:19 ` Stephen C. Tweedie
1999-10-06 20:15 ` James Simmons
1999-10-11 17:09 ` Stephen C. Tweedie
1999-10-11 17:26 ` Jeff Garzik
1999-10-11 23:14 ` James Simmons
1999-10-11 17:57 ` James Simmons
1999-10-04 16:11 ` Stephen C. Tweedie
1999-10-04 18:29 ` James Simmons
1999-10-04 19:35 ` Stephen C. Tweedie
1999-10-07 19:40 ` James Simmons
1999-10-10 11:24 ` Rik Faith
1999-10-10 14:03 ` Eric W. Biederman
1999-10-10 18:46 ` Rik Faith
1999-10-11 0:21 ` James Simmons
1999-10-11 10:59 ` Rik Faith
1999-10-11 3:38 ` Eric W. Biederman
1999-10-10 14:21 ` James Simmons
1999-10-11 17:22 ` Stephen C. Tweedie
1999-10-04 16:58 ` Marcus Sundberg
1999-10-04 18:27 ` James Simmons
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=Pine.LNX.4.10.9910041146560.8080-100000@imperial.edgeglobal.com \
--to=jsimmons@edgeglobal.com \
--cc=linux-mm@kvack.org \
--cc=sct@redhat.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