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From: Waiman Long <longman@redhat.com>
To: Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org, kernel-team@fb.com, pjt@google.com,
	luto@amacapital.net, Mike Galbraith <efault@gmx.de>,
	torvalds@linux-foundation.org, Roman Gushchin <guro@fb.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Patrick Bellasi <patrick.bellasi@arm.com>,
	Tom Hromatka <tom.hromatka@oracle.com>,
	Waiman Long <longman@redhat.com>
Subject: [PATCH v14 08/12] cpuset: Make generate_sched_domains() work with partition
Date: Mon, 15 Oct 2018 16:29:33 -0400	[thread overview]
Message-ID: <1539635377-22335-9-git-send-email-longman@redhat.com> (raw)
In-Reply-To: <1539635377-22335-1-git-send-email-longman@redhat.com>

The generate_sched_domains() function is modified to make it work
correctly with the newly introduced subparts_cpus mask for scheduling
domains generation.

Signed-off-by: Waiman Long <longman@redhat.com>
---
 kernel/cgroup/cpuset.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 2e9fab21ea57..53dbd473bd7e 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -769,13 +769,14 @@ static int generate_sched_domains(cpumask_var_t **domains,
 	int ndoms = 0;		/* number of sched domains in result */
 	int nslot;		/* next empty doms[] struct cpumask slot */
 	struct cgroup_subsys_state *pos_css;
+	bool root_load_balance = is_sched_load_balance(&top_cpuset);
 
 	doms = NULL;
 	dattr = NULL;
 	csa = NULL;
 
 	/* Special case for the 99% of systems with one, full, sched domain */
-	if (is_sched_load_balance(&top_cpuset)) {
+	if (root_load_balance && !top_cpuset.nr_subparts_cpus) {
 		ndoms = 1;
 		doms = alloc_sched_domains(ndoms);
 		if (!doms)
@@ -798,6 +799,8 @@ static int generate_sched_domains(cpumask_var_t **domains,
 	csn = 0;
 
 	rcu_read_lock();
+	if (root_load_balance)
+		csa[csn++] = &top_cpuset;
 	cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
 		if (cp == &top_cpuset)
 			continue;
@@ -808,6 +811,9 @@ static int generate_sched_domains(cpumask_var_t **domains,
 		 * parent's cpus, so just skip them, and then we call
 		 * update_domain_attr_tree() to calc relax_domain_level of
 		 * the corresponding sched domain.
+		 *
+		 * If root is load-balancing, we can skip @cp if it
+		 * is a subset of the root's effective_cpus.
 		 */
 		if (!cpumask_empty(cp->cpus_allowed) &&
 		    !(is_sched_load_balance(cp) &&
@@ -815,11 +821,16 @@ static int generate_sched_domains(cpumask_var_t **domains,
 					 housekeeping_cpumask(HK_FLAG_DOMAIN))))
 			continue;
 
+		if (root_load_balance &&
+		    cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus))
+			continue;
+
 		if (is_sched_load_balance(cp))
 			csa[csn++] = cp;
 
-		/* skip @cp's subtree */
-		pos_css = css_rightmost_descendant(pos_css);
+		/* skip @cp's subtree if not a partition root */
+		if (!is_partition_root(cp))
+			pos_css = css_rightmost_descendant(pos_css);
 	}
 	rcu_read_unlock();
 
@@ -947,7 +958,12 @@ static void rebuild_sched_domains_locked(void)
 	 * passing doms with offlined cpu to partition_sched_domains().
 	 * Anyways, hotplug work item will rebuild sched domains.
 	 */
-	if (!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
+	if (!top_cpuset.nr_subparts_cpus &&
+	    !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
+		goto out;
+
+	if (top_cpuset.nr_subparts_cpus &&
+	   !cpumask_subset(top_cpuset.effective_cpus, cpu_active_mask))
 		goto out;
 
 	/* Generate domain masks and attrs */
@@ -1362,11 +1378,15 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
 		update_tasks_cpumask(cp);
 
 		/*
-		 * If the effective cpumask of any non-empty cpuset is changed,
-		 * we need to rebuild sched domains.
+		 * On legacy hierarchy, if the effective cpumask of any non-
+		 * empty cpuset is changed, we need to rebuild sched domains.
+		 * On default hierarchy, the cpuset needs to be a partition
+		 * root as well.
 		 */
 		if (!cpumask_empty(cp->cpus_allowed) &&
-		    is_sched_load_balance(cp))
+		    is_sched_load_balance(cp) &&
+		   (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
+		    is_partition_root(cp)))
 			need_rebuild_sched_domains = true;
 
 		rcu_read_lock();
-- 
2.18.0


  parent reply	other threads:[~2018-10-15 20:30 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-15 20:29 [PATCH v14 00/12] Enable cpuset controller in default hierarchy Waiman Long
2018-10-15 20:29 ` [PATCH v14 01/12] cpuset: " Waiman Long
2018-10-15 20:29 ` [PATCH v14 02/12] cpuset: Define data structures to support scheduling partition Waiman Long
2018-10-15 20:29 ` [PATCH v14 03/12] cpuset: Simply allocation and freeing of cpumasks Waiman Long
2018-10-19 15:28   ` Tom Hromatka
2018-10-15 20:29 ` [PATCH v14 04/12] cpuset: Add new v2 cpuset.sched.partition flag Waiman Long
2018-11-06 11:35   ` Peter Zijlstra
2018-10-15 20:29 ` [PATCH v14 05/12] cpuset: Add an error state to cpuset.sched.partition Waiman Long
2018-11-06 11:37   ` Peter Zijlstra
2018-11-06 14:17     ` Waiman Long
2018-11-06 11:40   ` Peter Zijlstra
2018-11-07 23:13     ` Waiman Long
2018-11-06 11:40   ` Peter Zijlstra
2018-10-15 20:29 ` [PATCH v14 06/12] cpuset: Track cpusets that use parent's effective_cpus Waiman Long
2018-10-15 20:29 ` [PATCH v14 07/12] cpuset: Make CPU hotplug work with partition Waiman Long
2018-10-15 20:29 ` Waiman Long [this message]
2018-10-15 20:29 ` [PATCH v14 09/12] cpuset: Expose cpus.effective and mems.effective on cgroup v2 root Waiman Long
2018-10-15 20:29 ` [PATCH v14 10/12] cpuset: Add documentation about the new "cpuset.sched.partition" flag Waiman Long
2018-11-06 11:50   ` Peter Zijlstra
2018-11-06 14:09     ` Waiman Long
2018-11-07 22:58     ` Waiman Long
2018-10-15 20:29 ` [PATCH v14 11/12] cpuset: Expose cpuset.cpus.subpartitions with cgroup_debug Waiman Long
2018-10-15 20:29 ` [PATCH v14 12/12] cpuset: Show descriptive text when reading cpuset.sched.partition Waiman Long
2018-10-17 15:08   ` Tejun Heo
2018-10-17 15:20     ` Waiman Long
2018-10-19 18:56     ` Waiman Long
2018-10-19 19:24       ` Tejun Heo
2018-10-19 19:32         ` Waiman Long
2018-11-02 14:34         ` Waiman Long
2018-11-06 11:52   ` Peter Zijlstra
2018-11-05 16:36 ` [PATCH v14 00/12] Enable cpuset controller in default hierarchy Tejun Heo
2018-11-05 16:57   ` Peter Zijlstra
2018-11-06 11:53   ` Peter Zijlstra
2018-11-06 11:55     ` Peter Zijlstra
2018-11-06 14:06       ` Waiman Long
     [not found]         ` <CAOS58YPye=7Ga+y-ujFsgHqo6vdVnjykmON1z+UjNQLvvM_g4w@mail.gmail.com>
2018-11-06 14:11           ` Tejun Heo
2018-11-07 21:32         ` Tejun Heo
2018-11-07 21:52           ` Waiman Long
2018-11-08  9:41           ` Peter Zijlstra

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