From owner-cvs-all Fri Apr 12 14: 3:10 2002 Delivered-To: cvs-all@freebsd.org Received: from mail.gmx.net (mail.gmx.net [213.165.64.20]) by hub.freebsd.org (Postfix) with SMTP id 94C4337B404 for ; Fri, 12 Apr 2002 14:02:58 -0700 (PDT) Received: (qmail 13448 invoked by uid 0); 12 Apr 2002 21:02:47 -0000 Received: from pd9538f17.dip.t-dialin.net (HELO forge.local) (217.83.143.23) by mail.gmx.net (mp013-rz3) with SMTP; 12 Apr 2002 21:02:47 -0000 Received: from tmm by forge.local with local (Exim 3.35 #1) id 16w8C0-000103-00; Fri, 12 Apr 2002 23:02:48 +0200 Date: Fri, 12 Apr 2002 23:02:48 +0200 From: Thomas Moestl To: Alan Cox Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern sys_pipe.c Message-ID: <20020412210248.GB290@crow.dom2ip.de> Mail-Followup-To: Alan Cox , cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org References: <200204121938.g3CJcfk69260@freefall.freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.28i Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, 2002/04/12 at 15:42:37 -0500, Alan Cox wrote: > > > On Fri, 12 Apr 2002, Thomas Moestl wrote: > > > tmm 2002/04/12 12:38:41 PDT > > > > Modified files: > > sys/kern sys_pipe.c > > Log: > > Do not use pmap_kextract() to find out the physical address of a user > > belong to a user virtual address; while this happens to work on some > > architectures, it can't on sparc64, since user and kernel virtual > > address spaces overlap there (the distinction between them is done via > > separate address space identifiers). > > > > Why not pmap_extract() on the map->pmap? pmap_extract() is the equivalent > of pmap_kextract() for ordinary pmap's, i.e., not the kernel pmap. Since a pmap module is allowed to drop a mapping at any time, this would unnecessarily open a race between the vm_fault_quick() and the pmap_extract() which might bite us later SMPng-wise. The same is in a way true for the code I committed (a pageout may happen in between), but that should be easy to fix when it is required (by just replacing the vm_fault_quick()/vm_page_wire() sequence with a vm_fault_user_wire()). - thomas -- Thomas Moestl http://www.tu-bs.de/~y0015675/ http://people.FreeBSD.org/~tmm/ PGP fingerprint: 1C97 A604 2BD0 E492 51D0 9C0F 1FE6 4F1D 419C 776C To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message