From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762134AbXKOGOZ (ORCPT ); Thu, 15 Nov 2007 01:14:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758685AbXKOGK6 (ORCPT ); Thu, 15 Nov 2007 01:10:58 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:36558 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758595AbXKOGKz (ORCPT ); Thu, 15 Nov 2007 01:10:55 -0500 Date: Wed, 14 Nov 2007 22:09:48 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, Greg KH Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Balbir Singh , Peter Zijlstra , Frans Pop Subject: [patch 10/13] sched: keep utime/stime monotonic Message-ID: <20071115060948.GK7602@kroah.com> References: <20071115042610.731859958@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="sched-keep-utime-stime-monotonic.patch" In-Reply-To: <20071115060544.GA7602@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) X-Bad-Reply: References and In-Reply-To but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org -stable review patch. If anyone has any objections, please let us know. ------------------ From: Frans Pop sched: keep utime/stime monotonic cpustats use utime/stime as a ratio against sum_exec_runtime, as a consequence it can happen - when the ratio changes faster than time accumulates - that either can be appear to go backwards. Combined backport for 2.6.23 of the following patches from mainline: commit 73a2bcb0edb9ffb0b007b3546b430e2c6e415eee Author: Peter Zijlstra sched: keep utime/stime monotonic commit 9301899be75b464ef097f0b5af7af6d9bd8f68a7 Author: Balbir Singh sched: fix /proc//stat stime/utime monotonicity, part 2 Signed-off-by: Frans Pop CC: Peter Zijlstra CC: Balbir Singh Signed-off-by: Greg Kroah-Hartman --- fs/proc/array.c | 6 ++++-- include/linux/sched.h | 1 + kernel/fork.c | 2 ++ 3 files changed, 7 insertions(+), 2 deletions(-) --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -351,7 +351,8 @@ static cputime_t task_utime(struct task_ } utime = (clock_t)temp; - return clock_t_to_cputime(utime); + p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime)); + return p->prev_utime; } static cputime_t task_stime(struct task_struct *p) @@ -366,7 +367,8 @@ static cputime_t task_stime(struct task_ stime = nsec_to_clock_t(p->se.sum_exec_runtime) - cputime_to_clock_t(task_utime(p)); - return clock_t_to_cputime(stime); + p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime)); + return p->prev_stime; } #endif --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1022,6 +1022,7 @@ struct task_struct { unsigned int rt_priority; cputime_t utime, stime; + cputime_t prev_utime, prev_stime; unsigned long nvcsw, nivcsw; /* context switch counts */ struct timespec start_time; /* monotonic time */ struct timespec real_start_time; /* boot based time */ --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1045,6 +1045,8 @@ static struct task_struct *copy_process( p->utime = cputime_zero; p->stime = cputime_zero; + p->prev_utime = cputime_zero; + p->prev_stime = cputime_zero; #ifdef CONFIG_TASK_XACCT p->rchar = 0; /* I/O counter: bytes read */ --