From owner-freebsd-stable@FreeBSD.ORG Wed Mar 22 18:13:22 2006 Return-Path: X-Original-To: stable@freebsd.org Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 265A416A41F; Wed, 22 Mar 2006 18:13:22 +0000 (UTC) (envelope-from mi+mx@aldan.algebra.com) Received: from aldan.algebra.com (aldan.algebra.com [216.254.65.224]) by mx1.FreeBSD.org (Postfix) with ESMTP id A5C1943D7C; Wed, 22 Mar 2006 18:12:56 +0000 (GMT) (envelope-from mi+mx@aldan.algebra.com) Received: from corbulon.video-collage.com (static-151-204-231-237.bos.east.verizon.net [151.204.231.237]) by aldan.algebra.com (8.13.4/8.13.4) with ESMTP id k2MICpSw031842 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 22 Mar 2006 13:12:55 -0500 (EST) (envelope-from mi+mx@aldan.algebra.com) Received: from mteterin.us.murex.com (195-11.customer.cloud9.net [168.100.195.11]) by corbulon.video-collage.com (8.13.4/8.13.1) with ESMTP id k2MICjGr044235 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 22 Mar 2006 13:12:46 -0500 (EST) (envelope-from mi+mx@aldan.algebra.com) Received: from mteterin.us.murex.com (mteterin@localhost [127.0.0.1]) by mteterin.us.murex.com (8.13.4/8.13.4) with ESMTP id k2MICeZD005598; Wed, 22 Mar 2006 13:12:40 -0500 (EST) (envelope-from mi+mx@aldan.algebra.com) Received: from localhost (localhost [[UNIX: localhost]]) by mteterin.us.murex.com (8.13.4/8.13.4/Submit) id k2MICc4O005597; Wed, 22 Mar 2006 13:12:38 -0500 (EST) (envelope-from mi+mx@aldan.algebra.com) X-Authentication-Warning: mteterin.us.murex.com: mteterin set sender to mi+mx@aldan.algebra.com using -f From: Mikhail Teterin Organization: Virtual Estates, Inc. To: Matthew Dillon Date: Wed, 22 Mar 2006 13:12:34 -0500 User-Agent: KMail/1.8.3 References: <200603211607.30372.mi+mx@aldan.algebra.com> <20060322091010.GA20929@deviant.kiev.zoral.com.ua> <200603221723.k2MHNmu0012943@apollo.backplane.com> In-Reply-To: <200603221723.k2MHNmu0012943@apollo.backplane.com> MIME-Version: 1.0 Content-Type: text/plain; charset="koi8-u" Content-Transfer-Encoding: 8bit Content-Disposition: inline Message-Id: <200603221312.38502.mi+mx@aldan.algebra.com> X-Virus-Scanned: ClamAV devel-20050525/1349/Tue Mar 21 17:54:43 2006 on corbulon.video-collage.com X-Virus-Status: Clean X-Scanned-By: MIMEDefang 2.43 Cc: Kostik Belousov , alc@freebsd.org, stable@freebsd.org Subject: Re: more weird bugs with mmap-ing via NFS X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Mar 2006 18:13:22 -0000 ÓÅÒÅÄÁ 22 ÂÅÒÅÚÅÎØ 2006 12:23, Matthew Dillon ÷É ÎÁÐÉÓÁÌÉ: > My guess is that you are exporting the filesystem as a particular > user id that is not root (i.e. you do not have -maproot=root: in the > exports line on the server). Yes, indeed, re-exporting with -maproot=0 leads to normal behavior. Thanks for the workaround! Here are the stats: As the program is working hard, the incoming traffic on the client is about 200Kb/s (I guess, all those not yet existant pages being faulted in) and the outgoing -- about 7Kb/s with occasional spikes to 8Mb/s (I guess, this is when the flushing takes place). > š š What is likely happening is that the NFS client is trying to push out > š š the pages using the root uid rather then the user uid. šThis is a > highly probable circumstance for VM pages because once they get > disassociated from the related buffer cache buffer, the cred information > for the last process to modify the related VM pages is lost. šWhen the > kernel tries to flush the pages out it winds up using root creds. So mmap is just a more "reliable" way to trigger this problem, right? Is not this, like, a major bug? A file can be opened, written to for a while, and then -- at a semi-random moment -- the log will drop across the road? Ouch... Thanks a lot to all concerned for helping solve this problem. Yours, -mi