From: tip-bot for Valentin Schneider <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: hpa@zytor.com, riel@surriel.com, dave.hansen@linux.intel.com,
bp@alien8.de, valentin.schneider@arm.com, luto@kernel.org,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
peterz@infradead.org, torvalds@linux-foundation.org,
mingo@kernel.org
Subject: [tip:sched/urgent] sched/fair: Comment some nohz_balancer_kick() kick conditions
Date: Tue, 19 Mar 2019 04:12:24 -0700 [thread overview]
Message-ID: <tip-e25a7a944f1936b5134b7ee06bc432fc701e4aa3@git.kernel.org> (raw)
In-Reply-To: <20190211175946.4961-2-valentin.schneider@arm.com>
Commit-ID: e25a7a944f1936b5134b7ee06bc432fc701e4aa3
Gitweb: https://git.kernel.org/tip/e25a7a944f1936b5134b7ee06bc432fc701e4aa3
Author: Valentin Schneider <valentin.schneider@arm.com>
AuthorDate: Mon, 11 Feb 2019 17:59:44 +0000
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 19 Mar 2019 12:06:15 +0100
sched/fair: Comment some nohz_balancer_kick() kick conditions
We now have a comment explaining the first sched_domain based NOHZ kick,
so might as well comment them all.
While at it, unwrap a line that fits under 80 characters.
Co-authored-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dietmar.Eggemann@arm.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: morten.rasmussen@arm.com
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20190211175946.4961-2-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/fair.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8213ff6e365d..e6f7d39d4d45 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9612,8 +9612,12 @@ static void nohz_balancer_kick(struct rq *rq)
sd = rcu_dereference(rq->sd);
if (sd) {
- if ((rq->cfs.h_nr_running >= 1) &&
- check_cpu_capacity(rq, sd)) {
+ /*
+ * If there's a CFS task and the current CPU has reduced
+ * capacity; kick the ILB to see if there's a better CPU to run
+ * on.
+ */
+ if (rq->cfs.h_nr_running >= 1 && check_cpu_capacity(rq, sd)) {
flags = NOHZ_KICK_MASK;
goto unlock;
}
@@ -9621,6 +9625,11 @@ static void nohz_balancer_kick(struct rq *rq)
sd = rcu_dereference(per_cpu(sd_asym_packing, cpu));
if (sd) {
+ /*
+ * When ASYM_PACKING; see if there's a more preferred CPU
+ * currently idle; in which case, kick the ILB to move tasks
+ * around.
+ */
for_each_cpu_and(i, sched_domain_span(sd), nohz.idle_cpus_mask) {
if (sched_asym_prefer(i, cpu)) {
flags = NOHZ_KICK_MASK;
next prev parent reply other threads:[~2019-03-19 11:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-11 17:59 [PATCH v2 0/3] sched/fair: NOHZ cleanups and misfit improvement Valentin Schneider
2019-02-11 17:59 ` [PATCH v2 1/3] sched/fair: Comment some nohz_balancer_kick() kick conditions Valentin Schneider
2019-03-09 14:36 ` [tip:sched/urgent] " tip-bot for Valentin Schneider
2019-03-19 11:12 ` tip-bot for Valentin Schneider [this message]
2019-02-11 17:59 ` [PATCH v2 2/3] sched/fair: Tune down misfit nohz kicks Valentin Schneider
2019-03-09 14:37 ` [tip:sched/urgent] sched/fair: Tune down misfit NOHZ kicks tip-bot for Valentin Schneider
2019-03-19 11:13 ` tip-bot for Valentin Schneider
2019-02-11 17:59 ` [PATCH v2 3/3] sched/fair: Skip LLC nohz logic for asymmetric systems Valentin Schneider
2019-03-09 14:38 ` [tip:sched/urgent] sched/fair: Skip LLC NOHZ " tip-bot for Valentin Schneider
2019-03-19 11:13 ` tip-bot for Valentin Schneider
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