linux-kernel - [PATCH -next] cgroup/cpuset: remove child_ecpus

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Message-ID: <20240724010803.2195033-1-chenridong@huawei.com>
Date: Wed, 24 Jul 2024 01:08:03 +0000
From: Chen Ridong <chenridong@...wei.com>
To: <tj@...nel.org>, <lizefan.x@...edance.com>, <hannes@...xchg.org>,
	<longman@...hat.com>, <adityakali@...gle.com>, <sergeh@...nel.org>,
	<mkoutny@...e.com>
CC: <cgroups@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH -next] cgroup/cpuset: remove child_ecpus_count

The child_ecpus_count variable was previously used to update
sibling cpumask when parent's effective_cpus is updated. However, it became
obsolete after commit e2ffe502ba45 ("cgroup/cpuset: Add
cpuset.cpus.exclusive for v2"). It should be removed.

Signed-off-by: Chen Ridong <chenridong@...wei.com>
---
 kernel/cgroup/cpuset.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 40ec4abaf440..146bf9258db2 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -188,10 +188,8 @@ struct cpuset {
 	/*
 	 * Default hierarchy only:
 	 * use_parent_ecpus - set if using parent's effective_cpus
-	 * child_ecpus_count - # of children with use_parent_ecpus set
 	 */
 	int use_parent_ecpus;
-	int child_ecpus_count;
 
 	/*
 	 * number of SCHED_DEADLINE tasks attached to this cpuset, so that we
@@ -1512,7 +1510,6 @@ static void reset_partition_data(struct cpuset *cs)
 	if (!cpumask_and(cs->effective_cpus,
 			 parent->effective_cpus, cs->cpus_allowed)) {
 		cs->use_parent_ecpus = true;
-		parent->child_ecpus_count++;
 		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
 	}
 }
@@ -1689,10 +1686,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs,
 	isolcpus_updated = partition_xcpus_add(new_prs, NULL, tmp->new_cpus);
 	list_add(&cs->remote_sibling, &remote_children);
 	if (cs->use_parent_ecpus) {
-		struct cpuset *parent = parent_cs(cs);
-
 		cs->use_parent_ecpus = false;
-		parent->child_ecpus_count--;
 	}
 	spin_unlock_irq(&callback_lock);
 	update_unbound_workqueue_cpumask(isolcpus_updated);
@@ -2320,12 +2314,9 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
 			cpumask_copy(tmp->new_cpus, parent->effective_cpus);
 			if (!cp->use_parent_ecpus) {
 				cp->use_parent_ecpus = true;
-				parent->child_ecpus_count++;
 			}
 		} else if (cp->use_parent_ecpus) {
 			cp->use_parent_ecpus = false;
-			WARN_ON_ONCE(!parent->child_ecpus_count);
-			parent->child_ecpus_count--;
 		}
 
 		if (remote)
@@ -4139,7 +4130,6 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
 		cs->effective_mems = parent->effective_mems;
 		cs->use_parent_ecpus = true;
-		parent->child_ecpus_count++;
 	}
 	spin_unlock_irq(&callback_lock);
 
@@ -4206,10 +4196,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
 		update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
 
 	if (cs->use_parent_ecpus) {
-		struct cpuset *parent = parent_cs(cs);
-
 		cs->use_parent_ecpus = false;
-		parent->child_ecpus_count--;
 	}
 
 	cpuset_dec();
-- 
2.34.1