Commit-ID: 3b9c08ae3dd44201b3a188aef34d6ddf73434015
Gitweb: http://git.kernel.org/tip/3b9c08ae3dd44201b3a188aef34d6ddf73434015
Author: Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Tue, 4 Jul 2017 11:53:40 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 4 Jul 2017 11:58:05 +0200
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 <peterz@xxxxxxxxxxxxx>
Cc: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
Cc: Frans Klaver <fransklaver@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/cputime.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 67c70e2..84a419b 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.
--
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