[PATCH RFC 5/5] sched/fair: remove impossible condition from find_idlest_group_cpu

From: Joel Fernandes <joelaf@google.com>
To: linux-kernel@vger.kernel.org
Cc: Joel Fernandes <joelaf@google.com>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Brendan Jackman <brendan.jackman@arm.com>,
	Dietmar <dietmar.eggemann@arm.com>,
	"Cc: Srinivas Pandruvada" <srinivas.pandruvada@linux.intel.com>,
	"Cc: Len Brown" <lenb@kernel.org>,
	"Cc: Rafael J. Wysocki" <rjw@rjwysocki.net>,
	"Cc: Viresh Kumar" <viresh.kumar@linaro.org>,
	"Cc: Juri Lelli" <juri.lelli@arm.com>,
	"Cc: Patrick Bellasi" <patrick.bellasi@arm.com>,
	"Cc: Steve Muckle" <smuckle@google.com>,
	"Cc: Chris Redpath" <Chris.Redpath@arm.com>,
	"Cc: Atish Patra" <atish.patra@oracle.com>,
	"Cc: Vincent Guittot" <vincent.guittot@linaro.org>,
	"Cc: Morten Ramussen" <morten.rasmussen@arm.com>,
	"Cc: Frederic Weisbecker" <fweisbec@gmail.com>,
	"Cc: Thomas Gleixner" <tglx@linutronix.de>,
	"Cc: EAS Dev" <eas-dev@lists.linaro.org>,
	"Cc: Android Kernel" <kernel-team@android.com>
Subject: [PATCH RFC 5/5] sched/fair: remove impossible condition from find_idlest_group_cpu
Date: Sat, 28 Oct 2017 02:59:41 -0700	[thread overview]
Message-ID: <20171028095941.4773-6-joelaf@google.com> (raw)
In-Reply-To: <20171028095941.4773-1-joelaf@google.com>

find_idlest_group_cpu goes through CPUs of a group previous selected by
find_idlest_group. find_idlest_group returns NULL if the local group is the
selected one and doesn't execute find_idlest_group_cpu if the group to which
'cpu' belongs to is chosen. So we're always guaranteed to call
find_idlest_group_cpu with a group to which cpu is non-local. This makes one of
the conditions in find_idlest_group_cpu an impossible one, which we can get rid
off.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Brendan Jackman <brendan.jackman@arm.com>
Cc: Dietmar <dietmar.eggemann@arm.com>
Signed-off-by: Joel Fernandes <joelaf@google.com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5c49fdb4c508..740602ce799f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5922,7 +5922,7 @@ find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this
 			}
 		} else if (shallowest_idle_cpu == -1) {
 			load = weighted_cpuload(cpu_rq(i));
-			if (load < min_load || (load == min_load && i == this_cpu)) {
+			if (load < min_load) {
 				min_load = load;
 				least_loaded_cpu = i;
 			}
-- 
2.15.0.rc2.357.g7e34df9404-goog
