From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965774AbXCPRgg (ORCPT ); Fri, 16 Mar 2007 13:36:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965777AbXCPRgf (ORCPT ); Fri, 16 Mar 2007 13:36:35 -0400 Received: from mail.screens.ru ([213.234.233.54]:51049 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965756AbXCPRge (ORCPT ); Fri, 16 Mar 2007 13:36:34 -0400 Date: Fri, 16 Mar 2007 20:40:28 +0300 From: Oleg Nesterov To: Eric Dumazet Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: + getrusage-fill-ru_inblock-and-ru_oublock-fields-if-possible.patch added to -mm tree Message-ID: <20070316174028.GA233@tv-sign.ru> References: <20070316171023.GA218@tv-sign.ru> <200703161823.57858.dada1@cosmosbay.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200703161823.57858.dada1@cosmosbay.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 03/16, Eric Dumazet wrote: > > On Friday 16 March 2007 18:10, Oleg Nesterov wrote: > > Eric Dumazet wrote: > > > @@ -2021,6 +2022,8 @@ static void k_getrusage(struct task_stru > > > r->ru_nivcsw = p->signal->cnivcsw; > > > r->ru_minflt = p->signal->cmin_flt; > > > r->ru_majflt = p->signal->cmaj_flt; > > > + r->ru_inblock = task_io_get_inblock(p); > > > + r->ru_oublock = task_io_get_oublock(p); > > > > > > if (who == RUSAGE_CHILDREN) > > > break; > > > @@ -2032,6 +2035,8 @@ static void k_getrusage(struct task_stru > > > r->ru_nivcsw += p->signal->nivcsw; > > > r->ru_minflt += p->signal->min_flt; > > > r->ru_majflt += p->signal->maj_flt; > > > + r->ru_inblock += task_io_get_inblock(p); > > > + r->ru_oublock += task_io_get_oublock(p); > > > t = p; > > > do { > > > utime = cputime_add(utime, t->utime); > > > @@ -2040,6 +2045,8 @@ static void k_getrusage(struct task_stru > > > r->ru_nivcsw += t->nivcsw; > > > r->ru_minflt += t->min_flt; > > > r->ru_majflt += t->maj_flt; > > > + r->ru_inblock += task_io_get_inblock(t); > > > + r->ru_oublock += task_io_get_oublock(t); > > > > I can't understand this. Consider k_getrusage(RUSAGE_BOTH). The end result > > is that r->ru_inblock == 3 * task_io_get_inblock(p). > > > > No? > > Yes :) > > Very good point, you found a bug in k_getrusage(). No, no, please check the code. > So not only ru_inblock/ru_oublock are multiplied by 3 : others fields as well > are wrong. > > Also the definition of RUSAGE_CHILDREN is not conformant to standard > > http://www.opengroup.org/onlinepubs/009695399/functions/getrusage.html > > "If the value of the who argument is RUSAGE_CHILDREN, information shall be > "returned about resources used by the terminated and waited-for children of > "the current process This exactly happens. We are reading ->signal->*, see wait_task_zombie(). > We currently do a sum of rusage stats of still alive children.. thats totally > wrong... I hope not :) Oleg.