From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755537Ab0IWOC1 (ORCPT ); Thu, 23 Sep 2010 10:02:27 -0400 Received: from mtagate6.uk.ibm.com ([194.196.100.166]:42975 "EHLO mtagate6.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755403Ab0IWOCZ (ORCPT ); Thu, 23 Sep 2010 10:02:25 -0400 Subject: [RFC][PATCH 09/10] taskstats: Fix exit CPU time accounting From: Michael Holzheu Reply-To: holzheu@linux.vnet.ibm.com To: Shailabh Nagar , Andrew Morton , Venkatesh Pallipadi , Peter Zijlstra , Suresh Siddha , John stultz , Thomas Gleixner , Oleg Nesterov , Balbir Singh , Ingo Molnar , Heiko Carstens , Martin Schwidefsky Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1285249681.1837.28.camel@holzheu-laptop> References: <1285249681.1837.28.camel@holzheu-laptop> Content-Type: text/plain; charset="us-ascii" Organization: IBM Date: Thu, 23 Sep 2010 16:02:21 +0200 Message-ID: <1285250541.1837.95.camel@holzheu-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Subject: [PATCH] taskstats: Fix exit CPU time accounting From: Michael Holzheu Currently there are code pathes (e.g. for kthreads) where the consumed CPU time is not accounted to the parents cumulative counters. Now CPU time is accounted to the parent, if the exit accounting has not been done correctly. Signed-off-by: Michael Holzheu --- include/linux/sched.h | 1 + kernel/exit.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) Index: git-linux-2.6/include/linux/sched.h =================================================================== --- git-linux-2.6.orig/include/linux/sched.h 2010-09-23 14:16:37.000000000 +0200 +++ git-linux-2.6/include/linux/sched.h 2010-09-23 14:17:20.000000000 +0200 @@ -1282,6 +1282,7 @@ cputime_t prev_utime, prev_stime, prev_sttime; #endif unsigned long long acct_time; /* Time for last accounting */ + int exit_accounting_done; unsigned long nvcsw, nivcsw; /* context switch counts */ struct timespec start_time; /* monotonic time */ struct timespec real_start_time; /* boot based time */ Index: git-linux-2.6/kernel/exit.c =================================================================== --- git-linux-2.6.orig/kernel/exit.c 2010-09-23 14:16:37.000000000 +0200 +++ git-linux-2.6/kernel/exit.c 2010-09-23 14:17:20.000000000 +0200 @@ -157,11 +157,45 @@ put_task_struct(tsk); } +static void account_to_parent(struct task_struct *p) +{ + struct signal_struct *psig, *sig; + struct task_struct *tsk_parent; + + read_lock(&tasklist_lock); + tsk_parent = p->real_parent; + if (!tsk_parent) { + read_unlock(&tasklist_lock); + return; + } + get_task_struct(tsk_parent); + read_unlock(&tasklist_lock); + + // printk("XXX Fix accounting: pid=%d ppid=%d\n", p->pid, tsk_parent->pid); + spin_lock_irq(&tsk_parent->sighand->siglock); + psig = tsk_parent->signal; + sig = p->signal; + psig->cutime = cputime_add(psig->cutime, + cputime_add(sig->cutime, p->utime)); + psig->cstime = cputime_add(psig->cstime, + cputime_add(sig->cstime, p->stime)); + psig->csttime = cputime_add(psig->csttime, + cputime_add(sig->csttime, p->sttime)); + psig->cgtime = cputime_add(psig->cgtime, + cputime_add(p->gtime, + cputime_add(sig->gtime, sig->cgtime))); + p->exit_accounting_done = 1; + spin_unlock_irq(&tsk_parent->sighand->siglock); + put_task_struct(tsk_parent); +} void release_task(struct task_struct * p) { struct task_struct *leader; int zap_leader; + + if (!p->exit_accounting_done) + account_to_parent(p); repeat: tracehook_prepare_release_task(p); /* don't need to get the RCU readlock here - the process is dead and @@ -1279,6 +1313,7 @@ psig->cmaxrss = maxrss; task_io_accounting_add(&psig->ioac, &p->ioac); task_io_accounting_add(&psig->ioac, &sig->ioac); + p->exit_accounting_done = 1; spin_unlock_irq(&p->real_parent->sighand->siglock); }