Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264082AbUD2Scc (ORCPT ); Thu, 29 Apr 2004 14:32:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264914AbUD2Scc (ORCPT ); Thu, 29 Apr 2004 14:32:32 -0400 Received: from holomorphy.com ([207.189.100.168]:30080 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S264082AbUD2Scb (ORCPT ); Thu, 29 Apr 2004 14:32:31 -0400 Date: Thu, 29 Apr 2004 11:32:26 -0700 From: William Lee Irwin III To: "Brett E." Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: ~500 megs cached yet 2.6.5 goes into swap hell Message-ID: <20040429183226.GA783@holomorphy.com> Mail-Followup-To: William Lee Irwin III , "Brett E." , Andrew Morton , linux-kernel@vger.kernel.org References: <409021D3.4060305@fastclick.com> <20040428170106.122fd94e.akpm@osdl.org> <40904FD8.7020208@fastclick.com> <20040428181319.601decfc.akpm@osdl.org> <40905A5E.5000807@fastclick.com> <409143F6.3050300@fastclick.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <409143F6.3050300@fastclick.com> User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1530 Lines: 31 On Thu, Apr 29, 2004 at 11:05:42AM -0700, Brett E. wrote: > Anyone know what I should believe? Sar's pgpgin/s and pgpgout/s tell me > that it is paging in/out from/to disk. Yet pswpin/s and pswpout/s are > both 0. Swapping and paging are the same thing I believe. pgpgin/out > refer to paging, pswpin/out refer to swapping. So I for one am confused. > I guess I could dig through the source but I figured someone might have > encountered this disrepency in the past. Both are to be believed. They merely describe different things. Pagein/pageout are counts of VM-initiated IO, regardless of whether this IO is done on filesystem-backed pages or swap-backed pages. Pagein and pageout are used more generally to describe VM-initiated IO and don't exclusively refer to swap IO, but also include IO to filesystems to/from filesystem-backed memory. Swapin/swapout are counts of swap IO only, and are considered to apply only to IO done to swap files/devices to/from swap-backed anonymous memory. Pagein/pageout are both proper and necessary to have. In fact, you were requesting that filesystem IO be done preferentially to swap IO, and the pagein/pageout indicators showing IO while swapin/swapout indicators show none mean you are getting exactly what you asked for. -- wli - 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/