From owner-freebsd-hackers@FreeBSD.ORG Sun May 30 00:34:15 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 56D8D16A4CE for ; Sun, 30 May 2004 00:34:15 -0700 (PDT) Received: from VARK.homeunix.com (ar59.lsanca2-4.27.98.47.lsanca2.dsl-verizon.net [4.27.98.47]) by mx1.FreeBSD.org (Postfix) with ESMTP id DAB2B43D2F for ; Sun, 30 May 2004 00:34:14 -0700 (PDT) (envelope-from das@FreeBSD.ORG) Received: from VARK.homeunix.com (localhost [127.0.0.1]) by VARK.homeunix.com (8.12.10/8.12.10) with ESMTP id i4U7YDaG034931; Sun, 30 May 2004 00:34:13 -0700 (PDT) (envelope-from das@FreeBSD.ORG) Received: (from das@localhost) by VARK.homeunix.com (8.12.10/8.12.10/Submit) id i4U7YDdb034930; Sun, 30 May 2004 00:34:13 -0700 (PDT) (envelope-from das@FreeBSD.ORG) Date: Sun, 30 May 2004 00:34:13 -0700 From: David Schultz To: Geert Hendrickx Message-ID: <20040530073413.GA34869@VARK.homeunix.com> Mail-Followup-To: Geert Hendrickx , freebsd-hackers@FreeBSD.ORG References: <20040529200748.GA87145@lori.mine.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040529200748.GA87145@lori.mine.nu> cc: freebsd-hackers@FreeBSD.ORG Subject: Re: documentation on sysctl vm.defer_swapspace_pageouts? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 May 2004 07:34:15 -0000 On Sat, May 29, 2004, Geert Hendrickx wrote: > where can I find documentation on the vm.defer_swapspace_pageouts > sysctl? LINT only mentions it, without explaining, man sysctl doesn't > mention it at all, and even Google yields very few useful results... vm.defer_swapspace_pageouts causes the system to avoid using swap, if possible. With the option enabled, the VM system will still evict clean pages and read them in again from the filesystem when necessary, but it will only write dirty pages to the swap partition as a last resort. > I was looking for a way to tune swap-usage a bit, I heard Linux has a > "swappiness" setting (telling the kernel how easy it should go with > paging out), and I hoped FreeBSD would have something similar. > vm.defer_swapspace_pageouts might do the trick, but so it seems to be > poorly documented... Take a look at vm.swap_idle_enabled. With that option enabled, the VM system is more proactive in swapping out idle processes, rather than waiting for a low-memory situation to materialize before taking action.