linux-kernel - [tip: sched/urgent] sched/fair: Fix -Wunused-but-set-variable warnings

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Message-ID: <156957184180.9866.14215366891982372616.tip-bot2@tip-bot2>
Date:   Fri, 27 Sep 2019 08:10:41 -0000
From:   "tip-bot2 for Qian Cai" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Qian Cai <cai@....pw>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ben Segall <bsegall@...gle.com>,
        Dave Chiluk <chiluk+linux@...eed.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>, pauld@...hat.com,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        linux-kernel@...r.kernel.org
Subject: [tip: sched/urgent] sched/fair: Fix -Wunused-but-set-variable warnings

The following commit has been merged into the sched/urgent branch of tip:

Commit-ID:     763a9ec06c409dcde2a761aac4bb83ff3938e0b3
Gitweb:        https://git.kernel.org/tip/763a9ec06c409dcde2a761aac4bb83ff3938e0b3
Author:        Qian Cai <cai@....pw>
AuthorDate:    Tue, 20 Aug 2019 14:40:55 -04:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Wed, 25 Sep 2019 17:42:31 +02:00

sched/fair: Fix -Wunused-but-set-variable warnings

Commit:

   de53fd7aedb1 ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")

introduced a few compilation warnings:

  kernel/sched/fair.c: In function '__refill_cfs_bandwidth_runtime':
  kernel/sched/fair.c:4365:6: warning: variable 'now' set but not used [-Wunused-but-set-variable]
  kernel/sched/fair.c: In function 'start_cfs_bandwidth':
  kernel/sched/fair.c:4992:6: warning: variable 'overrun' set but not used [-Wunused-but-set-variable]

Also, __refill_cfs_bandwidth_runtime() does no longer update the
expiration time, so fix the comments accordingly.

Signed-off-by: Qian Cai <cai@....pw>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Ben Segall <bsegall@...gle.com>
Reviewed-by: Dave Chiluk <chiluk+linux@...eed.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: pauld@...hat.com
Fixes: de53fd7aedb1 ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")
Link: https://lkml.kernel.org/r/1566326455-8038-1-git-send-email-cai@lca.pw
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 kernel/sched/fair.c | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5bc2399..dfdac90 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4353,21 +4353,16 @@ static inline u64 sched_cfs_bandwidth_slice(void)
 }
 
 /*
- * Replenish runtime according to assigned quota and update expiration time.
- * We use sched_clock_cpu directly instead of rq->clock to avoid adding
- * additional synchronization around rq->lock.
+ * Replenish runtime according to assigned quota. We use sched_clock_cpu
+ * directly instead of rq->clock to avoid adding additional synchronization
+ * around rq->lock.
  *
  * requires cfs_b->lock
  */
 void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
 {
-	u64 now;
-
-	if (cfs_b->quota == RUNTIME_INF)
-		return;
-
-	now = sched_clock_cpu(smp_processor_id());
-	cfs_b->runtime = cfs_b->quota;
+	if (cfs_b->quota != RUNTIME_INF)
+		cfs_b->runtime = cfs_b->quota;
 }
 
 static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
@@ -4983,15 +4978,13 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
 
 void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
 {
-	u64 overrun;
-
 	lockdep_assert_held(&cfs_b->lock);
 
 	if (cfs_b->period_active)
 		return;
 
 	cfs_b->period_active = 1;
-	overrun = hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
+	hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
 	hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
 }