From owner-freebsd-questions@FreeBSD.ORG Tue Jun 21 03:01:44 2005 Return-Path: X-Original-To: questions@freebsd.org Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8594816A41F for ; Tue, 21 Jun 2005 03:01:44 +0000 (GMT) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by mx1.FreeBSD.org (Postfix) with ESMTP id B9E7D43D55 for ; Tue, 21 Jun 2005 03:01:42 +0000 (GMT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.13.1/8.13.3) id j5L31gDV053774; Mon, 20 Jun 2005 22:01:42 -0500 (CDT) (envelope-from dan) Date: Mon, 20 Jun 2005 22:01:42 -0500 From: Dan Nelson To: Francisco Reyes Message-ID: <20050621030141.GH8497@dan.emsphone.com> References: <20050620141439.S36309@zoraida.natserv.net> <20050620182430.GE8497@dan.emsphone.com> <20050620144631.F37558@zoraida.natserv.net> <20050620185545.GF8497@dan.emsphone.com> <20050620225204.F41158@zoraida.natserv.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050620225204.F41158@zoraida.natserv.net> X-OS: FreeBSD 5.4-STABLE X-message-flag: Outlook Error User-Agent: Mutt/1.5.9i Cc: FreeBSD Questions List Subject: Re: When does swap decreases X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Jun 2005 03:01:44 -0000 In the last episode (Jun 20), Francisco Reyes said: > On Mon, 20 Jun 2005, Dan Nelson wrote: > > When the system is low on memory, it will force the least used > > blocks of memory to swap. It will not free the swap space until > > the process owning them exits > > Have not found any program to see what programs are using the swap, > but as I think about it, the current method is not very "smart". I > guess any other method is difficult to implement. > > How wonder how the current method affects performance. Basically if > there is a surge of memory usage and processes start that use the > swap and these processes are long lived.. I wonder if performance > will be affected. There may even be a performance gain, since if the system comes under memory pressure again, some of the in-memory pages of those long-lived processes previously copied to swap may still be clean, and the system won't even have to page them out; it can simply free the RAM. I can't think of any way for there to be a performance hit, unless you actually run out of swap. -- Dan Nelson dnelson@allantgroup.com