From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 6 Jun 2001 14:46:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 6 Jun 2001 14:46:04 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:5676 "EHLO flinx.biederman.org") by vger.kernel.org with ESMTP id ; Wed, 6 Jun 2001 14:45:46 -0400 To: Jeff Garzik Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christian Borntrdger , Derek Glidden Subject: Re: Requirement: swap = RAM x 2.5 ?? In-Reply-To: <3B1D5ADE.7FA50CD0@illusionary.com> <991815578.30689.1.camel@nomade> <20010606095431.C15199@dev.sportingbet.com> <0106061316300A.00553@starship> <200106061528.f56FSKa14465@vindaloo.ras.ucalgary.ca> <000701c0ee9f$515fd6a0$3303a8c0@einstein> <3B1E52FC.C17C921F@mandrakesoft.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: 06 Jun 2001 12:42:03 -0600 In-Reply-To: <3B1E52FC.C17C921F@mandrakesoft.com> Message-ID: User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.5 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeff Garzik writes: > I'm sorry but this is a regression, plain and simple. > > Previous versons of Linux have worked great on diskless workstations > with NO swap. > > Swap is "extra space to be used if we have it" and nothing else. Given the slow speed of disks to use them efficiently when you are using swap some additional rules apply. In the worse case when swapping is being used you get: Virtual Memory = RAM + (swap - RAM). That cannot be improved. You can increase your likely hood that that case won't come up, but that is a different matter entirely. I suspect in practice that we are suffering more from lazy reclamation of swap pages than from a more aggressive swap cache. Eric