Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 1 Apr 2001 20:43:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 1 Apr 2001 20:43:19 -0400 Received: from laurin.munich.netsurf.de ([194.64.166.1]:47305 "EHLO laurin.munich.netsurf.de") by vger.kernel.org with ESMTP id ; Sun, 1 Apr 2001 20:43:10 -0400 Date: Mon, 2 Apr 2001 02:42:36 +0200 To: Tim Hockin Cc: linux-kernel@vger.kernel.org Subject: Re: how mmap() works? Message-ID: <20010402024236.A5057@storm.local> Mail-Followup-To: Tim Hockin , linux-kernel@vger.kernel.org In-Reply-To: <20010401184131.A2474@storm.local> <200104012028.PAA05467@isunix.it.ilstu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <200104012028.PAA05467@isunix.it.ilstu.edu>; from thockin@isunix.it.ilstu.edu on Sun, Apr 01, 2001 at 03:28:05PM -0500 From: Andreas Bombe Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 01, 2001 at 03:28:05PM -0500, Tim Hockin wrote: > > Without syncing, Linux writes whenever it thinks it's appropriate, e.g. > > when pages have to be freed (I think also when the bdflush writes back > > data, i.e. every 30 seconds by default). > > what about mmap() on non-filesystem files (/dev/mem, /proc/bus/pci...) ? They map physically present memory directly and do not have to be synced, since all writes go directly to their destination (which is of course not possible with disk files). I'm not that sure if PCI is a bit special case though, since not all architectures can access it like memory. -- Andreas E. Bombe DSA key 0x04880A44 http://home.pages.de/~andreas.bombe/ http://linux1394.sourceforge.net/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/