From owner-freebsd-current@FreeBSD.ORG Fri Apr 30 07:29:53 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1D67B16A4CE for ; Fri, 30 Apr 2004 07:29:53 -0700 (PDT) Received: from harmony.village.org (rover.bsdimp.com [204.144.255.66]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9693743D5F for ; Fri, 30 Apr 2004 07:29:52 -0700 (PDT) (envelope-from imp@bsdimp.com) Received: from localhost (warner@rover2.village.org [10.0.0.1]) by harmony.village.org (8.12.10/8.12.9) with ESMTP id i3UETaZJ091221; Fri, 30 Apr 2004 08:29:37 -0600 (MDT) (envelope-from imp@bsdimp.com) Date: Fri, 30 Apr 2004 08:30:04 -0600 (MDT) Message-Id: <20040430.083004.116247770.imp@bsdimp.com> To: phk@phk.freebsd.dk From: "M. Warner Losh" In-Reply-To: <7432.1083333726@critter.freebsd.dk> References: <20040430.075448.70646001.imp@bsdimp.com> <7432.1083333726@critter.freebsd.dk> X-Mailer: Mew version 3.3 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: freebsd-current@freebsd.org Subject: Re: DEVFS in a chroot? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 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: Fri, 30 Apr 2004 14:29:53 -0000 In message: <7432.1083333726@critter.freebsd.dk> "Poul-Henning Kamp" writes: : In message <20040430.075448.70646001.imp@bsdimp.com>, "M. Warner Losh" writes: : >In message: <6695.1083331489@critter.freebsd.dk> : > "Poul-Henning Kamp" writes: : >: In message <20040430.070341.26991317.imp@bsdimp.com>, "M. Warner Losh" writes: : >: >In message: <5473.1083327210@critter.freebsd.dk> : >: > "Poul-Henning Kamp" writes: : >: >: >Should I mount /var/chroot/dev as type devfs? : >: >: : >: >: Yes: : >: >: : >: >: mount -t devfs randomargument /var/chroot/dev : >: > : >: >What if I have hundreds of these chroots? We build our product inside : >: >a chroot right now and I'm worried what the overhead of : >: >mounting/unmounting this for every build would be... : >: : >: As far as I recall, our mountlist handling is not optimised for : >: hundreds of simultaneous mountpoints: we basically walk the list. : >: That said, I belive we only do so during the actual mount/unmount : >: operations, so I do not think there is a performance issue as such. : > : >Would the performance issues be mitigated by mounting/unmounting devfs : >all the time? Eg, only mount it while it is actively being used? : : I think you would actually make it worse that way... How would that make it worse? Seems like I'm in a no win situation: if I mount one for everybody, then the system grinds to a halt because the mount lists are too long. If I mount and unmount it all the time, things are also bad in some unspecified way. Warner