linux-kernel - [Patch v2 2/6] sched/topology: Record number of cores in sched group

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Message-Id: <a8acc91631a1c044ee16081bc80c1b044827c7b2.1686263351.git.tim.c.chen@linux.intel.com>
Date:   Thu,  8 Jun 2023 15:32:28 -0700
From:   Tim Chen <tim.c.chen@...ux.intel.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Tim C Chen <tim.c.chen@...ux.intel.com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Ricardo Neri <ricardo.neri@...el.com>,
        "Ravi V . Shankar" <ravi.v.shankar@...el.com>,
        Ben Segall <bsegall@...gle.com>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Len Brown <len.brown@...el.com>, Mel Gorman <mgorman@...e.de>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Valentin Schneider <vschneid@...hat.com>,
        Ionela Voinescu <ionela.voinescu@....com>, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        Shrikanth Hegde <sshegde@...ux.vnet.ibm.com>,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
        naveen.n.rao@...ux.vnet.ibm.com,
        Yicong Yang <yangyicong@...ilicon.com>,
        Barry Song <v-songbaohua@...o.com>,
        Chen Yu <yu.c.chen@...el.com>, Hillf Danton <hdanton@...a.com>
Subject: [Patch v2 2/6] sched/topology: Record number of cores in sched group

From: Tim C Chen <tim.c.chen@...ux.intel.com>

When balancing sibling domains that have different number of cores,
tasks in respective sibling domain should be proportional to the number
of cores in each domain. In preparation of implementing such a policy,
record the number of tasks in a scheduling group.

Signed-off-by: Tim Chen <tim.c.chen@...ux.intel.com>
---
 kernel/sched/sched.h    |  1 +
 kernel/sched/topology.c | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 3d0eb36350d2..5f7f36e45b87 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1860,6 +1860,7 @@ struct sched_group {
 	atomic_t		ref;
 
 	unsigned int		group_weight;
+	unsigned int		cores;
 	struct sched_group_capacity *sgc;
 	int			asym_prefer_cpu;	/* CPU of highest priority in group */
 	int			flags;
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 6d5628fcebcf..6b099dbdfb39 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1275,14 +1275,22 @@ build_sched_groups(struct sched_domain *sd, int cpu)
 static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
 {
 	struct sched_group *sg = sd->groups;
+	struct cpumask *mask = sched_domains_tmpmask2;
 
 	WARN_ON(!sg);
 
 	do {
-		int cpu, max_cpu = -1;
+		int cpu, cores = 0, max_cpu = -1;
 
 		sg->group_weight = cpumask_weight(sched_group_span(sg));
 
+		cpumask_copy(mask, sched_group_span(sg));
+		for_each_cpu(cpu, mask) {
+			cores++;
+			cpumask_andnot(mask, mask, cpu_smt_mask(cpu));
+		}
+		sg->cores = cores;
+
 		if (!(sd->flags & SD_ASYM_PACKING))
 			goto next;
 
-- 
2.32.0