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From: "Gustavo A. R. Silva" <garsilva@embeddedor.com>
To: Frans Klaver <fransklaver@gmail.com>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] sched/cputime: code refactoring in cputime_adjust()
Date: Thu, 29 Jun 2017 13:41:28 -0500	[thread overview]
Message-ID: <20170629184128.GA5271@embeddedgus> (raw)
In-Reply-To: <20170629125804.Horde.gm62Mi9SrTXYOk8B_t9Srrr@gator4166.hostgator.com>

Value assigned to variable utime at line 619:utime = rtime;
is overwritten at line 642:utime = rtime - stime; before it
can be used. This makes such variable assignment useless.

Remove this variable assignment and refactor the code related.

Addresses-Coverity-ID: 1371643
Cc: Frans Klaver <fransklaver@gmail.com>
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 kernel/sched/cputime.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index aea3135..a83fd9a 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -615,19 +615,13 @@ static void cputime_adjust(struct task_cputime *curr,
 	 * userspace. Once a task gets some ticks, the monotonicy code at
 	 * 'update' will ensure things converge to the observed ratio.
 	 */
-	if (stime == 0) {
-		utime = rtime;
-		goto update;
+	if (stime != 0) {
+		if (utime == 0)
+			stime = rtime;
+		else
+			stime = scale_stime(stime, rtime, stime + utime);
 	}
 
-	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.
-- 
2.5.0

  reply	other threads:[~2017-06-29 18:41 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-27 23:03 [kernel-sched-cputime] question about probable bug in cputime_adjust() Gustavo A. R. Silva
2017-06-28  5:35 ` Frans Klaver
2017-06-28  6:03   ` Frans Klaver
2017-06-28 23:57     ` Gustavo A. R. Silva
2017-06-29  4:51       ` Frans Klaver
2017-06-29 17:58         ` Gustavo A. R. Silva
2017-06-29 18:41           ` Gustavo A. R. Silva [this message]
2017-06-30 13:10             ` [tip:sched/core] sched/cputime: Refactor the cputime_adjust() code tip-bot for Gustavo A. R. Silva
2017-06-30 14:00               ` Rik van Riel
2017-06-30 14:41                 ` Frans Klaver
2017-06-30 15:46                   ` Frederic Weisbecker
2017-06-30 16:17               ` Stanislaw Gruszka
2017-07-04  9:17               ` Peter Zijlstra
2017-07-04 10:01                 ` Ingo Molnar

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