Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756359AbZGMPy4 (ORCPT ); Mon, 13 Jul 2009 11:54:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756274AbZGMPy4 (ORCPT ); Mon, 13 Jul 2009 11:54:56 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:54023 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756243AbZGMPyz (ORCPT ); Mon, 13 Jul 2009 11:54:55 -0400 Date: Mon, 13 Jul 2009 21:24:39 +0530 From: Balbir Singh To: Nikanth Karthikesan Cc: Paul Menage , lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] taskstats: Fix CGROUPSTATS_TYPE_CGROUP_STATS having same value as TASKSTATS_TYPE_PID Message-ID: <20090713155439.GF5051@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <200907131831.12994.knikanth@suse.de> <20090713134158.GD5051@balbir.in.ibm.com> <200907132116.43647.knikanth@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <200907132116.43647.knikanth@suse.de> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2728 Lines: 72 * Nikanth Karthikesan [2009-07-13 21:16:43]: > On Monday 13 July 2009 19:11:58 Balbir Singh wrote: > > * Nikanth Karthikesan [2009-07-13 18:31:12]: > > > Hi > > > > > > Currently we never get message from kernel to userspace of type > > > TASKSTATS_TYPE_PID. Otherwise this could have been spotted earlier. > > > > > > I was trying to add a new taskstat command that would return response of > > > type TASKSTATS_TYPE_PID. > > > > > > Having the same values would restrict one not to use the same netlink > > > socket for a command that would return response of type > > > TASKSTATS_TYPE_PID and the CGROUPSTATS_CMD_GET command. > > > > > > Should we fix it by using values after __TASKSTATS_TYPE_MAX. > > > > > > Changing this now might break pre-built binaries. Or is this intended, > > > and the application is not supposed to use CGROUPSTATS and TASKSTATS on > > > the same socket? > > > > Ideally they are supposed to be on different sockets, but nothing > > really is hard and fast in terms of rules. > > > > > Thanks > > > Nikanth > > > > > > Currently we never get message from kernel to userspace of type > > > TASKSTATS_TYPE_PID. Otherwise this could have been spotted earlier. > > > Having the values in the same range would restrict one not to use the > > > same netlink socket for a command that would return response of type > > > TASKSTATS_TYPE_PID and the CGROUPSTATS_CMD_GET command. Fix it by using > > > values after > > > __TASKSTATS_TYPE_MAX. > > > > > > Signed-off-by: Nikanth Karthikesan > > > > > > --- > > > > > > > > > diff --git a/include/linux/cgroupstats.h b/include/linux/cgroupstats.h > > > index 3753c33..87b31f0 100644 > > > --- a/include/linux/cgroupstats.h > > > +++ b/include/linux/cgroupstats.h > > > @@ -53,7 +53,7 @@ enum { > > > #define CGROUPSTATS_CMD_MAX (__CGROUPSTATS_CMD_MAX - 1) > > > > > > enum { > > > - CGROUPSTATS_TYPE_UNSPEC = 0, /* Reserved */ > > > + CGROUPSTATS_TYPE_UNSPEC = __TASKSTATS_TYPE_MAX, /* Reserved */ > > > CGROUPSTATS_TYPE_CGROUP_STATS, /* contains name + stats */ > > > __CGROUPSTATS_TYPE_MAX, > > > }; > > > > Also this would unnecessarily increase the value of __CGROUPSTATS_TYPE_MAX. > So, please dont take this patch. :) I would send a better fix, soon. > Yes, agreed, but ideally __CGROUPSTATS_TYPE_MAX represents the max of taskstats and cgroupstats so it should be OK in principle, but lets try another approach to fix this. -- Balbir -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/