From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from www.linux.org.uk (parcelfarce.linux.theplanet.co.uk [195.92.249.252]) by dsl2.external.hp.com (Postfix) with ESMTP id 508E44829 for ; Sun, 9 Mar 2003 18:50:09 -0700 (MST) Received: from willy by www.linux.org.uk with local (Exim 4.12) id 18sCQX-0001jO-00; Mon, 10 Mar 2003 01:50:05 +0000 Date: Mon, 10 Mar 2003 01:50:05 +0000 From: Matthew Wilcox To: "David S. Miller" Cc: willy@debian.org, grundler@dsl2.external.hp.com, jsm@udlkern.fc.hp.com, parisc-linux@lists.parisc-linux.org Subject: Re: [parisc-linux] Re: RFC: mmap patch Message-ID: <20030310015005.GA5278@parcelfarce.linux.theplanet.co.uk> References: <20030308231125.M3865@parcelfarce.linux.theplanet.co.uk> <20030308.150214.30103426.davem@redhat.com> <20030309144225.O3865@parcelfarce.linux.theplanet.co.uk> <20030309.133830.82279538.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20030309.133830.82279538.davem@redhat.com> Sender: parisc-linux-admin@lists.parisc-linux.org Errors-To: parisc-linux-admin@lists.parisc-linux.org List-Help: List-Post: List-Subscribe: , List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: On Sun, Mar 09, 2003 at 01:38:30PM -0800, David S. Miller wrote: > I think the real issue is SHMLBA isn't being honored, right? I don't think so.. according to cachetlb.txt: If your D-cache has this problem, first define asm/shmparam.h SHMLBA properly, it should essentially be the size of your virtually addressed D-cache (or if the size is variable, the largest possible size). This setting will force the SYSv IPC layer to only allow user processes to mmap shared memory at address which are a multiple of this value. That isn't where the problem lies. This missing flush is in shmem_getpage(), round about line 906 in 2.5.64. Really, this should be doing a clear_user_page() -- but not all callers of this routine have a user address to pass on. > The whole purpose of SHMLBA is to ensure a particular alignment > for shared memory anonymous regions, if that isn't happening anymore > that is a bug. I thought this was to deal with user-user coherency problems, not user-kernel? -- "It's not Hollywood. War is real, war is primarily not about defeat or victory, it is about death. I've seen thousands and thousands of dead bodies. Do you think I want to have an academic debate on this subject?" -- Robert Fisk