From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pizda.ninka.net (pizda.ninka.net [216.101.162.242]) by dsl2.external.hp.com (Postfix) with ESMTP id B6FCF4829 for ; Sun, 9 Mar 2003 15:00:15 -0700 (MST) Date: Sun, 09 Mar 2003 13:38:30 -0800 (PST) Message-Id: <20030309.133830.82279538.davem@redhat.com> To: willy@debian.org Cc: grundler@dsl2.external.hp.com, jsm@udlkern.fc.hp.com, parisc-linux@lists.parisc-linux.org Subject: Re: [parisc-linux] Re: RFC: mmap patch From: "David S. Miller" In-Reply-To: <20030309144225.O3865@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> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii 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: From: Matthew Wilcox Date: Sun, 9 Mar 2003 14:42:25 +0000 Well.. one patch which affected us, but wouldn't affect a writethrough cache is: http://ftp.linux.org.uk/pub/linux/willy/patches/applied/shmem.diff In that situation, the user has no view of that page currently so they will read from memory. With a writethrough cache it works without the flush_dcache_page(), with writeback it does not. I think the real issue is SHMLBA isn't being honored, right? 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. This is why SHMLBA is set to the virtual cache size on sparc32 for certain cpus and on sparc64 for all cpus.