]> git.baikalelectronics.ru Git - kernel.git/commit
sched/cputime: Guarantee stime + utime == rtime
authorPeter Zijlstra <peterz@infradead.org>
Tue, 30 Jun 2015 09:30:54 +0000 (11:30 +0200)
committerIngo Molnar <mingo@kernel.org>
Mon, 3 Aug 2015 10:21:21 +0000 (12:21 +0200)
commit807e8ab6315799ad4e92d53ab5544171e278564a
tree2f6a6d497d0e088bd984876a34845c64afdffdbe
parent0a8660eb0009823736249d0814ac05917bede842
sched/cputime: Guarantee stime + utime == rtime

While the current code guarantees monotonicity for stime and utime
independently of one another, it does not guarantee that the sum of
both is equal to the total time we started out with.

This confuses things (and peoples) who look at this sum, like top, and
will report >100% usage followed by a matching period of 0%.

Rework the code to provide both individual monotonicity and a coherent
sum.

Suggested-by: Fredrik Markstrom <fredrik.markstrom@gmail.com>
Reported-by: Fredrik Markstrom <fredrik.markstrom@gmail.com>
Tested-by: Fredrik Markstrom <fredrik.markstrom@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jason.low2@hp.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
include/linux/init_task.h
include/linux/sched.h
kernel/fork.c
kernel/sched/cputime.c