From owner-freebsd-current@FreeBSD.ORG Sat Aug 25 00:10:38 2012 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id AD419106564A for ; Sat, 25 Aug 2012 00:10:38 +0000 (UTC) (envelope-from bounces+73574-dfb6-freebsd-current=freebsd.org@sendgrid.me) Received: from o3.shared.sendgrid.net (o3.shared.sendgrid.net [208.117.48.85]) by mx1.freebsd.org (Postfix) with SMTP id 50A8E8FC15 for ; Sat, 25 Aug 2012 00:10:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sendgrid.info; h= message-id:date:from:mime-version:to:cc:subject:references :in-reply-to:content-type:content-transfer-encoding; s=smtpapi; bh=m9d/6ER/aud4RdznOPWPYffXPyE=; b=RNG4vGaKObvfQX3oXkS6lT4+C6lb CJwvRt8+AREVdoTUoYf/mvzuw7iMZqWaeK8KSr0RhTFg4PGURTlYejFGwOcZIUzK jRjAMhtfEzIRCTz02/NzDdPsx8GVDHoe0lHWJpznX5bzKUvCDArIBgmZmL4XPxV/ 6AzuY2avFws1BQ4= Received: by 10.4.35.250 with SMTP id mf55.28113.503817FD3 Fri, 24 Aug 2012 19:10:37 -0500 (CDT) Received: from mail.tarsnap.com (unknown [10.41.44.5]) by mi20 (SG) with ESMTP id 503817fd.761a.2d1ed89 for ; Fri, 24 Aug 2012 19:10:37 -0500 (CST) Received: (qmail 7267 invoked from network); 25 Aug 2012 00:10:36 -0000 Received: from unknown (HELO clamshell.daemonology.net) (127.0.0.1) by ec2-107-20-205-189.compute-1.amazonaws.com with ESMTP; 25 Aug 2012 00:10:36 -0000 Received: (qmail 38522 invoked from network); 25 Aug 2012 00:10:01 -0000 Received: from unknown (HELO clamshell.daemonology.net) (127.0.0.1) by clamshell.daemonology.net with SMTP; 25 Aug 2012 00:10:01 -0000 Message-ID: <503817D9.3070006@freebsd.org> Date: Fri, 24 Aug 2012 17:10:01 -0700 From: Colin Percival User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:14.0) Gecko/20120731 Thunderbird/14.0 MIME-Version: 1.0 To: John Baldwin References: <502831B7.1080309@freebsd.org> <201208240748.19737.jhb@freebsd.org> <866288laq0.fsf@ds4.des.no> <201208241013.48805.jhb@freebsd.org> In-Reply-To: <201208241013.48805.jhb@freebsd.org> X-Enigmail-Version: 1.4.3 Content-Type: text/plain; charset=UTF-8 content-transfer-encoding: quoted-printable X-Sendgrid-EID: XhyBwObMhraAR+zdwMupjQ6BIqbhdEfc+6p+uBxS7S9KLomxXxSYkRSDZk/EixPQ+rialnK7iSV4kdm/aZrj7zejpTcS58nMXoMCjIdHUCnyrePMVsg82pzUOZlRyW517V4OVbws+hTOqUnzfEFEtUJYyGjVojrCGgyzLvopIl4= Cc: alc@freebsd.org, =?UTF-8?B?RGFnLUVybGluZyBTbcO4cmdyYXY=?= , freebsd-current@freebsd.org Subject: Re: Time to bump default VM_SWZONE_SIZE_MAX? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 25 Aug 2012 00:10:38 -0000 On 08/24/12 07:13, John Baldwin wrote:=0D > On Friday, August 24, 2012 8:45:43 am Dag-Erling Sm=C3=B8rgrav wrote:=0D >> John Baldwin writes:=0D >>> Note that on i386 you can't get more than 4GB of RAM without PAE, and i= f you=0D >>> have any modern x86 box with > 4GB of RAM, you are most likely running = amd64=0D >>> on it, not i386. I think i386 would be fine to just keep the limit it = had.=0D >>=0D >> The limit we had was insufficient for 8 GB of swap.=0D > =0D > In absolute or practical terms? Not all swap blocks are fully utilized. = At=0D > Y! the install script we used would compute the maximum theoretical swap = zone=0D > needed and then cut it in half, and this worked quite well. Also, keep i= n mind,=0D > this is for i386, not amd64. At this point i386 is going to be used on s= maller=0D > systems (e.g. netbooks, etc.), not servers that have lots of swap.=0D =0D I'd like to see i386 bumped slightly, just so that the rule of "allocate sw= ap=0D space equal to max(RAM, min(2*RAM, 8 GB))" (which I've seen in lots of plac= es)=0D is more likely to be safe. If I'm understanding things correctly, bumping = from=0D 32 MB up to 34.5 MB should give us a theoretical 16 GiB or a "safe" 8 GiB l= imit=0D on swap usage (2^17 structures which are 276 bytes each on i386).=0D =0D But I agree that the real issue was with amd64, not i386.=0D =0D -- =0D Colin Percival=0D Security Officer Emeritus, FreeBSD | The power to serve=0D Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid= =0D