From owner-freebsd-questions@FreeBSD.ORG Fri Apr 10 18:20:14 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 730151065675 for ; Fri, 10 Apr 2009 18:20:14 +0000 (UTC) (envelope-from ipfreak@yahoo.com) Received: from web52106.mail.re2.yahoo.com (web52106.mail.re2.yahoo.com [206.190.48.109]) by mx1.freebsd.org (Postfix) with SMTP id 1BCCB8FC14 for ; Fri, 10 Apr 2009 18:20:13 +0000 (UTC) (envelope-from ipfreak@yahoo.com) Received: (qmail 93421 invoked by uid 60001); 10 Apr 2009 18:20:13 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1239387613; bh=1qYZ+dS4NhVPRQxe1+3EJAvMewZKjZr5dxV3gEWP3oI=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type; b=mVV5c5+zargtlHmJU1NRFaS4uoGdBZPowaO7JYwRNgIxABt2SL+hNfiPZwDHnRzDOfEMuwrdOxIyda4NsG0k0YxSJMGGVdSucFz3/a6viJFG70ICubN2yCwN0biCMDdnoeQo4a/ZrsnvndlBVAS+CSoV7QzV4JLmQXE+ud+cV9U= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type; b=V/Dyrf6OYLjborEX8Sh8626jyTRbzd4KDyzCyTWhho3rrFG634cJd/25huKoqtvXuFLmfxNcBaNnhTfQWeuCi1x4xG2s9K1xT3oF3TLP+QR7TMdoSn72kahvx5VkZ3CjqUC0jysr2rQppxwa5chq5l6A1YPy6qNs88r1BmJbXQ8=; Message-ID: <352228.61716.qm@web52106.mail.re2.yahoo.com> X-YMail-OSG: qllax4MVM1mMaJpv4aLRwzkf.Wb5x.g77LAf0kq0za_yByfTm7BZdpzCz1eS2GqcP4GGqiE_GgEHnHxTrKJYx0ds5BOOnYdMqwHPXijNG4gWl_vtT6H71pgnJh8YrlEHmwDgQqnsGwiwHwFIWE02kWjYzUP_1ebSilq8_VCoVTW79NEqnW2ShEJf4j_dn5YFacEXdE0adSCF2CAl2s5SSlgQiXWX3JqA6GNgDgkK5icC7mtIdAUWhignqsv7v6sYEt1Na9upa19FQfLSfwcUlnLwUKTNU.eNotJEsY9nkqFm6zE_r3.vv5hYtWIzilJ88p5XltXRALyPCseKn.t3cyI2WkaRrXOjaAGK Received: from [134.207.53.14] by web52106.mail.re2.yahoo.com via HTTP; Fri, 10 Apr 2009 11:20:12 PDT X-Mailer: YahooMailWebService/0.7.289.1 Date: Fri, 10 Apr 2009 11:20:12 -0700 (PDT) From: gahn To: Matthew Seaman In-Reply-To: <49DF6DEC.7010706@infracaninophile.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: freebsd general questions Subject: Re: loader.conf X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: ipfreak@yahoo.com List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 Apr 2009 18:20:14 -0000 Thanks for the detailed information. Best --- On Fri, 4/10/09, Matthew Seaman wrote: > From: Matthew Seaman > Subject: Re: loader.conf > To: ipfreak@yahoo.com > Cc: "freebsd general questions" > Date: Friday, April 10, 2009, 9:03 AM > gahn wrote: > > Hi all: > > > > I have a machine with 2GB memory. in the file > loader.conf, there is a line: > > > > #hw.physmem="1G" # Limit > physical memory. See loader(8) > > > > Could I remove the "#" and change that to > "2G"? > > > > Interestingly, the sysctl indicates the parameter of > "hw.physmem" is not changeable. > > > > Any guru here give me some enlightenment? > > hw.physmem is a loader tunable: ie. you can only set it > from the boot > loader before the kernel is fully operational. Once the > kernel is running > it can't be altered. > > hw.physmem is designed to let you test running a kernel > with less RAM > than is physically installed in a machine. Not having to > pop the case > and physically pull memory sticks out can be pretty useful. > It's not of > general interest -- only for kernel and various other > software developers > in the main -- as the usual thing is to make use of all the > RAM you have > available or (in the case of 32bit machines) that the > system is capable of > addressing. > If hw.physmem is unset in loader.conf the kernel will > automatically use all > the memory available to it: this is the correct and > desirable behaviour for > the vast majority of systems. For a 2GB machine, that > means the system will > use all the RAM that's installed. > > Cheers, > > Matthew > > -- Dr Matthew J Seaman MA, D.Phil. 7 > Priory Courtyard > Flat 3 > PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate > Kent, CT11 > 9PW