From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:54658 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753891AbdKIJKy (ORCPT ); Thu, 9 Nov 2017 04:10:54 -0500 Subject: Patch "sched/cputime, powerpc32: Fix stale scaled stime on context switch" has been added to the 4.9-stable tree To: fweisbec@gmail.com, alexander.levin@verizon.com, benh@kernel.crashing.org, borntraeger@de.ibm.com, fenghua.yu@intel.com, gregkh@linuxfoundation.org, heiko.carstens@de.ibm.com, mingo@kernel.org, mpe@ellerman.id.au, paulus@samba.org, peterz@infradead.org, riel@redhat.com, schwidefsky@de.ibm.com, sgruszka@redhat.com, tglx@linutronix.de, tony.luck@intel.com, torvalds@linux-foundation.org, wanpeng.li@hotmail.com Cc: , From: Date: Thu, 09 Nov 2017 10:10:12 +0100 Message-ID: <151021861267136@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled sched/cputime, powerpc32: Fix stale scaled stime on context switch to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sched-cputime-powerpc32-fix-stale-scaled-stime-on-context-switch.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Thu Nov 9 09:48:01 CET 2017 From: Frederic Weisbecker Date: Thu, 5 Jan 2017 18:11:41 +0100 Subject: sched/cputime, powerpc32: Fix stale scaled stime on context switch From: Frederic Weisbecker [ Upstream commit 90d08ba2b9b4be4aeca6a5b5a4b09fbcde30194d ] On context switch with powerpc32, the cputime is accumulated in the thread_info struct. So the switching-in task must move forward its start time snapshot to the current time in order to later compute the delta spent in system mode. This is what we do for the normal cputime by initializing the starttime field to the value of the previous task's starttime which got freshly updated. But we are missing the update of the scaled cputime start time. As a result we may be accounting too much scaled cputime later. Fix this by initializing the scaled cputime the same way we do for normal cputime. Signed-off-by: Frederic Weisbecker Acked-by: Thomas Gleixner Cc: Benjamin Herrenschmidt Cc: Christian Borntraeger Cc: Fenghua Yu Cc: Heiko Carstens Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Rik van Riel Cc: Stanislaw Gruszka Cc: Tony Luck Cc: Wanpeng Li Link: http://lkml.kernel.org/r/1483636310-6557-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/time.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -407,6 +407,7 @@ void arch_vtime_task_switch(struct task_ struct cpu_accounting_data *acct = get_accounting(current); acct->starttime = get_accounting(prev)->starttime; + acct->startspurr = get_accounting(prev)->startspurr; acct->system_time = 0; acct->user_time = 0; } Patches currently in stable-queue which might be from fweisbec@gmail.com are queue-4.9/sched-cputime-powerpc32-fix-stale-scaled-stime-on-context-switch.patch