From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 25BDADDEE3 for ; Thu, 12 Mar 2009 08:39:34 +1100 (EST) Subject: Re: NFS problems on a MPC5200-based board From: Benjamin Herrenschmidt To: =?UTF-8?Q?Bart=C5=82omiej_Si=C4=99ka?= In-Reply-To: <4C4E1899-9086-4DF5-A5BF-832AEBEAA8E9@semihalf.com> References: <4C4E1899-9086-4DF5-A5BF-832AEBEAA8E9@semihalf.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 12 Mar 2009 08:39:26 +1100 Message-Id: <1236807566.7086.51.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2009-03-11 at 16:08 +0100, Bartłomiej Sięka wrote: > Hi, > > This is a follow-up on NFS problems on an MPC5200-based board reported > here a while back: > > http://www.nabble.com/-PATCH--Add-support-for-the-digsy-MTC-board.-to21750004.html#a21792612 > > To recap: while using NFS, especially while mounting the root > filesystem over NFS, the system is really slow and displays a bunch of > "nfs: server 192.168.1.1 not responding, still trying" messages. > Sometimes it is able to get to the login prompt, sometimes not. In > cases where the login is successful, the system is still extremely > sluggish (console hangs for tens of seconds and longer). > > git bisect narrows down the troublesome commit as: Maybe you need to set CPU_FTR_NEED_COHERENT for the 5200 ? Cheers, Ben. > commit 4c456a67f501b8b15542c7c21c28812bf88f484b > Author: Gerhard Pircher > Date: Fri Jan 23 06:51:28 2009 +0000 > > powerpc/mm: Fix handling of _PAGE_COHERENT in BAT setup code > > _PAGE_COHERENT is now always set in _PAGE_RAM resp. PAGE_KERNEL. > Thus it has to be masked out, if the BAT mapping should be non > cacheable or CPU_FTR_NEED_COHERENT is not set. > > This will work on normal SMP setups because we force-set > CPU_FTR_NEED_COHERENT as part of CPU_FTR_COMMON on SMP. > > Signed-off-by: Gerhard Pircher > Signed-off-by: Benjamin Herrenschmidt > > > We have tested recent mainline kernel (past 2.6.29-rc7) with the > 4c456a6... > commit reverted and NFS problems went away. > > Other people have also reported similar problems (original posters on > Cc): > http://www.nabble.com/-PATCH--Add-support-for-the-digsy-MTC-board.-tp21750004p21792825.html > http://www.nabble.com/-PATCH--Add-support-for-the-digsy-MTC-board.-tp21750004p21792612.html > > The commit in question does not look directly related to NFS/ > networking; moreover it is a fix for some other problem, so just > reverting it is not an option, it seems (?). So how do we go about > having NFS operational again? Any comments? > > Regards, > Bartlomiej Sieka