Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx12.netapp.com ([216.240.18.77]:21371 "EHLO mx12.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762372Ab3JQVHb convert rfc822-to-8bit (ORCPT ); Thu, 17 Oct 2013 17:07:31 -0400 From: "Myklebust, Trond" To: Helge Deller CC: Linux Kernel Development , NFS list , list parisc-linux Subject: Re: 3.12-rcX - NFS regression - kswapd0 / kswapd1 stays using 100% CPU? Date: Thu, 17 Oct 2013 21:07:30 +0000 Message-ID: <1382044045.3216.44.camel@leira.trondhjem.org> References: <52604BA9.20104@gmx.de> In-Reply-To: <52604BA9.20104@gmx.de> Content-Type: text/plain; charset="utf-7" MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, 2013-10-17 at 22:42 +-0200, Helge Deller wrote: +AD4- I'm seeing a regression with current kernel git head when using NFS-mounts. +AD4- Architecture in my case is parisc, although I don't think that this is relevant. +AD4- At least kernel 3.10 (and I think 3.11) didn't showed that problem. +AD4- +AD4- The symtom is, that +ACI-top+ACI- shows high usage of either kswapd0 or kswapd1. +AD4- Here is an output with kswapd1: +AD4- PID USER PR NI VIRT RES SHR S +ACU-CPU +ACU-MEM TIME+- COMMAND +AD4- 37 root 20 0 0 0 0 R 91.8 0.0 63:00.40 kswapd1 +AD4- 28448 root 20 0 3252 1428 1060 R 15.3 0.0 0:00.09 top +AD4- 1 root 20 0 2784 988 852 S 0.0 0.0 0:09.95 init +AD4- +AD4- This is what ps shows: +AD4- lsXXXX:+AH4AIw- ps -ef +AHw- grep mount +AD4- root 1181 1 0 14:51 ? 00:00:18 /usr/sbin/automount --pid-file /var/run/autofs.pid +AD4- root 25331 1181 0 21:25 ? 00:00:00 /bin/mount -n -t nfs -s -o nolock,rw,hard,intr homes:/unixhome1 /net/home1 +AD4- root 25332 25331 0 21:25 ? 00:00:00 /sbin/mount.nfs homes:/unixhome1 /net/home1 -s -n -o rw,nolock,hard,intr +AD4- +AD4- And using sysrq to show the blocked tasks I get in syslog: +AD4- SysRq : Show Blocked State +AD4- mount.nfs D 00000000401040c0 0 25332 25331 0x00000010 +AD4- Backtrace: +AD4- +AFsAPA-0000000040113a68+AD4AXQ- +AF8AXw-schedule+-0x500/0x810 +AD4- +AD4- I know it's not a problem of the NFS server, since the same mount is still ok on other machines. +AD4- The NFS directory was already mounted and in use when this mount happened again (called by cron-job). +AD4- +AD4- Any ideas? If the NFS directory is already mounted, then why is the automounter trying to mount it a second time? -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust+AEA-netapp.com www.netapp.com