From owner-freebsd-hackers@FreeBSD.ORG  Sat Dec  3 09:31:59 2011
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 32879106566C
	for <freebsd-hackers@freebsd.org>; Sat,  3 Dec 2011 09:31:59 +0000 (UTC)
	(envelope-from phk@phk.freebsd.dk)
Received: from phk.freebsd.dk (phk.freebsd.dk [130.225.244.222])
	by mx1.freebsd.org (Postfix) with ESMTP id E64328FC0C
	for <freebsd-hackers@freebsd.org>; Sat,  3 Dec 2011 09:31:58 +0000 (UTC)
Received: from critter.freebsd.dk (critter.freebsd.dk [192.168.61.3])
	by phk.freebsd.dk (Postfix) with ESMTP id CCB8F5DAA;
	Sat,  3 Dec 2011 09:16:24 +0000 (UTC)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.14.5/8.14.5) with ESMTP id pB39GOZb010965;
	Sat, 3 Dec 2011 09:16:24 GMT (envelope-from phk@phk.freebsd.dk)
To: Filippo Sironi <filippo.sironi@gmail.com>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Sat, 03 Dec 2011 09:42:44 +0100."
	<A51F9B30-A71A-49A5-B684-16EC3C127BC9@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Date: Sat, 03 Dec 2011 09:16:24 +0000
Message-ID: <10964.1322903784@critter.freebsd.dk>
X-Mailman-Approved-At: Sat, 03 Dec 2011 12:14:16 +0000
Cc: freebsd-hackers@freebsd.org
Subject: Re: mmap implementation for cdev
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 03 Dec 2011 09:31:59 -0000

In message <A51F9B30-A71A-49A5-B684-16EC3C127BC9@gmail.com>, Filippo Sironi wri
tes:

>The problem is that when I come =
>back to user space all the threads write in memory page mapped by the =
>first thread that called the mmap leaving their memory pages untouched.

That's how cdev->mmap works, it is global rather than per-thread.


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.