cpusets: Rebuild root domain deadline accounting information
When the topology of root domains is modified by CPUset or CPUhotplug operations information about the current deadline bandwidth held in the root domain is lost. This patch addresses the issue by recalculating the lost deadline bandwidth information by circling through the deadline tasks held in CPUsets and adding their current load to the root domain they are associated with. Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Juri Lelli <juri.lelli@redhat.com> [ Various additional modifications. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bristot@redhat.com Cc: claudio@evidence.eu.com Cc: lizefan@huawei.com Cc: longman@redhat.com Cc: luca.abeni@santannapisa.it Cc: rostedt@goodmis.org Cc: tj@kernel.org Cc: tommaso.cucinotta@santannapisa.it Link: https://lkml.kernel.org/r/20190719140000.31694-4-juri.lelli@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:

committed by
Ingo Molnar

parent
4b211f2b12
commit
f9a25f776d
@@ -45,6 +45,7 @@
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#include <linux/proc_fs.h>
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#include <linux/rcupdate.h>
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#include <linux/sched.h>
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#include <linux/sched/deadline.h>
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#include <linux/sched/mm.h>
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#include <linux/sched/task.h>
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#include <linux/seq_file.h>
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@@ -894,6 +895,67 @@ done:
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return ndoms;
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}
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static void update_tasks_root_domain(struct cpuset *cs)
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{
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struct css_task_iter it;
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struct task_struct *task;
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css_task_iter_start(&cs->css, 0, &it);
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while ((task = css_task_iter_next(&it)))
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dl_add_task_root_domain(task);
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css_task_iter_end(&it);
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}
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static void rebuild_root_domains(void)
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{
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struct cpuset *cs = NULL;
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struct cgroup_subsys_state *pos_css;
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lockdep_assert_held(&cpuset_mutex);
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lockdep_assert_cpus_held();
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lockdep_assert_held(&sched_domains_mutex);
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cgroup_enable_task_cg_lists();
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rcu_read_lock();
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/*
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* Clear default root domain DL accounting, it will be computed again
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* if a task belongs to it.
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*/
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dl_clear_root_domain(&def_root_domain);
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cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
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if (cpumask_empty(cs->effective_cpus)) {
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pos_css = css_rightmost_descendant(pos_css);
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continue;
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}
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css_get(&cs->css);
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rcu_read_unlock();
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update_tasks_root_domain(cs);
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rcu_read_lock();
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css_put(&cs->css);
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}
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rcu_read_unlock();
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}
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static void
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partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
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struct sched_domain_attr *dattr_new)
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{
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mutex_lock(&sched_domains_mutex);
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partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
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rebuild_root_domains();
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mutex_unlock(&sched_domains_mutex);
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}
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/*
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* Rebuild scheduler domains.
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*
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@@ -931,7 +993,7 @@ static void rebuild_sched_domains_locked(void)
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ndoms = generate_sched_domains(&doms, &attr);
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/* Have scheduler rebuild the domains */
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partition_sched_domains(ndoms, doms, attr);
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partition_and_rebuild_sched_domains(ndoms, doms, attr);
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out:
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put_online_cpus();
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}
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