From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264726AbUGZAuT (ORCPT ); Sun, 25 Jul 2004 20:50:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264734AbUGZAuT (ORCPT ); Sun, 25 Jul 2004 20:50:19 -0400 Received: from fw.osdl.org ([65.172.181.6]:42376 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264726AbUGZAuN (ORCPT ); Sun, 25 Jul 2004 20:50:13 -0400 Date: Sun, 25 Jul 2004 17:48:49 -0700 From: Andrew Morton To: Con Kolivas Cc: linux-kernel@vger.kernel.org Subject: Re: Autotune swappiness01 Message-Id: <20040725174849.75f2ecf6.akpm@osdl.org> In-Reply-To: References: <20040725173652.274dcac6.akpm@osdl.org> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Con Kolivas wrote: > > >> It has the effect > >> of being fairly aggressive at avoiding loss of applications to swap under > >> conditions of heavy or sustained file stress while allowing applications to > >> swap out under what would be considered "application" memory stresses on a > >> desktop. > > > > But decreasing /proc/sys/vm/swappiness does that too? > > Low memory boxes and ones that are heavily laden with applications find that > ends up making things slow down trying to keep all applications in physical > ram. Doesn't that mean that swappiness was decreased by too much? > > > >> It has no measurable effect on any known benchmarks. > > > > So how are we to evaluate the desirability of the patch??? > > Get desktop users to report back their experiences which is what I have > currently. Sorry we're in the realm of subjectivity again. Seriously, we've seen placebo effects before... > > Shouldn't mapped_bias be local to refill_inactive_zone()? > > That is so a followup patch can use it elsewhere... erk. I guess it's OK because the thing is derived from global state which changes slowly over time. > > Why is `swappiness' getting squared? AFAICT this will simply make the > > swappiness control behave nonlinearly, which seems undesirable? > > To parallel the nonlinear nature of the mapped bias effect. That doesn't really answer my question? What goes wrong if swappiness is not squared?