From 90d08ba2b9b4be4aeca6a5b5a4b09fbcde30194d Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 5 Jan 2017 18:11:41 +0100 Subject: [PATCH] sched/cputime, powerpc32: Fix stale scaled stime on context switch 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 --- arch/powerpc/kernel/time.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index bc2e08d415fa..ce2165089318 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -407,6 +407,7 @@ void arch_vtime_task_switch(struct task_struct *prev) 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; } -- 2.20.1