From owner-freebsd-current@FreeBSD.ORG Mon Aug 13 17:03:13 2012 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 14582106566C; Mon, 13 Aug 2012 17:03:13 +0000 (UTC) (envelope-from alan.l.cox@gmail.com) Received: from mail-gh0-f182.google.com (mail-gh0-f182.google.com [209.85.160.182]) by mx1.freebsd.org (Postfix) with ESMTP id A97578FC08; Mon, 13 Aug 2012 17:03:12 +0000 (UTC) Received: by ghrr13 with SMTP id r13so3890590ghr.13 for ; Mon, 13 Aug 2012 10:03:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=fBOeUbPBNA8Ncv35iNOTHPOzGBdwndmXPeL4cRSPav8=; b=gZe9tITD/bDU9VzmmWQvXJSMjWMgxpPPlN1h03ynNXjZx6s58uLLWeB+qhMZYGjqMQ YmLgQt9Ec+y/woP1NXOUyeNNaYptrfAfOfAVvoEV7Ct5s60zKLmCJd+IJBX8Gfrpaim1 LSfMKgmZgrMWfhRTMZVKbnjny+/YSZ9pd8sRFgY8DqXg/us5gNfjRa5GSVXCtA1Idn1E hs4kcNgHauAMNNiDZJry4Pn2lMJuTpNraLpzGFxFdr2BS3FOKQvdYhAqrcc2pdMKe2a+ i4oI7jveOnVYYDO6xHq27B94S0uGKKMYOsSPR//LKXHjGGaYsqs5gbN+fMOjrxpUm038 jShw== MIME-Version: 1.0 Received: by 10.66.75.73 with SMTP id a9mr25805617paw.43.1344877391756; Mon, 13 Aug 2012 10:03:11 -0700 (PDT) Received: by 10.68.203.69 with HTTP; Mon, 13 Aug 2012 10:03:11 -0700 (PDT) In-Reply-To: <502831B7.1080309@freebsd.org> References: <502831B7.1080309@freebsd.org> Date: Mon, 13 Aug 2012 12:03:11 -0500 Message-ID: From: Alan Cox To: Colin Percival Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: FreeBSD current Subject: Re: Time to bump default VM_SWZONE_SIZE_MAX? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: alc@freebsd.org List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Aug 2012 17:03:13 -0000 On Sun, Aug 12, 2012 at 5:44 PM, Colin Percival wrote: > Hi all, > > If I'm understanding things correctly, the "maxswzone" value -- set by the > kern.maxswzone loader tunable or to VM_SWZONE_SIZE_MAX by default -- should > be approximately 9 MiB per GiB of swap space. > > The current default for VM_SWZONE_SIZE_MAX was set in August 2002 to 32 > MiB; > meaning that anyone who wants to use more than ~ 3.5 GB of swap space ought > to set kern.maxswzone in /boot/loader.conf. > > Is it time to increase this default on amd64? (I understand that keeping > the > value low on i386 is important due to KVA limitations, but amd64 has far > more > address space available...) > > The short answer is "Yes." The long answer is that amd64, ia64, etc. shouldn't have this limit at all. The swap zone objects are small objects that could be allocated by uma_small_alloc() and accessed through the direct map. Alan