From 3b9c08ae3dd44201b3a188aef34d6ddf73434015 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 4 Jul 2017 11:53:40 +0200 Subject: Revert "sched/cputime: Refactor the cputime_adjust() code" This reverts commit 72298e5c92c50edd8cb7cfda4519483ce65fa166. As Peter explains: > Argh, no... That code was perfectly fine. The new code otoh is > convoluted. > > The old code had the following form: > > if (exception1) > deal with exception1 > > if (execption2) > deal with exception2 > > do normal stuff > > Which is as simple and straight forward as it gets. > > The new code otoh reads like: > > if (!exception1) { > if (exception2) > deal with exception 2 > else > do normal stuff > } So restore the old form. Also fix the comment describing the logic, as it was confusing. Requested-by: Peter Zijlstra Cc: Gustavo A. R. Silva Cc: Frans Klaver Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Rik van Riel Cc: Stanislaw Gruszka Cc: Thomas Gleixner Cc: Wanpeng Li Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/cputime.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 67c70e287647..84a419bdf5aa 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -611,17 +611,23 @@ static void cputime_adjust(struct task_cputime *curr, utime = curr->utime; /* - * If either stime or both stime and utime are 0, assume all runtime is - * userspace. Once a task gets some ticks, the monotonicy code at - * 'update' will ensure things converge to the observed ratio. + * If either stime or utime are 0, assume all runtime is userspace. + * Once a task gets some ticks, the monotonicy code at 'update:' + * will ensure things converge to the observed ratio. */ - if (stime != 0) { - if (utime == 0) - stime = rtime; - else - stime = scale_stime(stime, rtime, stime + utime); + if (stime == 0) { + utime = rtime; + goto update; } + if (utime == 0) { + stime = rtime; + goto update; + } + + stime = scale_stime(stime, rtime, stime + utime); + +update: /* * Make sure stime doesn't go backwards; this preserves monotonicity * for utime because rtime is monotonic. -- cgit