linux-kernel - [PATCH 2/2] sched: topology: Initialize span_weight from sd

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Message-Id: <be1aa0f6c8c5d4cf9a3c35c7bc48be74f60c84e6.1493281605.git.viresh.kumar@linaro.org>
Date:   Thu, 27 Apr 2017 13:59:00 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     linaro-kernel@...ts.linaro.org, linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH 2/2] sched: topology: Initialize span_weight from sd_init()

Most of the sched domain structure gets initialized from sd_init() and
it looks reasonable to initialize span_weight too from it.

Currently it is getting initialized from build_sched_domains(), which
doesn't looks to be the ideal place for doing so.

With this change we need to additionally reset span_weight for a special
error case, but that looks reasonable as span_weight must be updated
every time domain span is updated.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 kernel/sched/topology.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 09a56ca76bd1..691b290a679e 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -892,6 +892,7 @@ sd_init(struct sched_domain_topology_level *tl,
 
 		.last_balance		= jiffies,
 		.balance_interval	= sd_weight,
+		.span_weight		= sd_weight,
 		.smt_gain		= 0,
 		.max_newidle_lb_cost	= 0,
 		.next_decay_max_lb_cost	= jiffies,
@@ -1373,6 +1374,7 @@ static struct sched_domain *build_sched_domain(struct sched_domain_topology_leve
 			cpumask_or(sched_domain_span(sd),
 				   sched_domain_span(sd),
 				   sched_domain_span(child));
+			sd->span_weight = cpumask_weight(sched_domain_span(sd));
 		}
 
 	}
@@ -1417,7 +1419,6 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
 	/* Build the groups for the domains */
 	for_each_cpu(i, cpu_map) {
 		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
-			sd->span_weight = cpumask_weight(sched_domain_span(sd));
 			if (sd->flags & SD_OVERLAP) {
 				if (build_overlap_sched_groups(sd, i))
 					goto error;
-- 
2.12.0.432.g71c3a4f4ba37