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| author | Waiman Long <longman@redhat.com> | 2023-06-27 16:35:00 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2023-07-10 22:59:27 +0200 |
| commit | c8c926200c55454101f072a4b16c9ff5b8c9e56f (patch) | |
| tree | 226839aafe1d519db1140ef22ec6cadc01c190ac | |
| parent | cgroup: fix obsolete comment above for_each_css() (diff) | |
| download | linux-c8c926200c55454101f072a4b16c9ff5b8c9e56f.tar.xz linux-c8c926200c55454101f072a4b16c9ff5b8c9e56f.zip | |
cgroup/cpuset: Inherit parent's load balance state in v2
Since commit f28e22441f35 ("cgroup/cpuset: Add a new isolated
cpus.partition type"), the CS_SCHED_LOAD_BALANCE bit of a v2 cpuset
can be on or off. The child cpusets of a partition root must have the
same setting as its parent or it may screw up the rebuilding of sched
domains. Fix this problem by making sure the a child v2 cpuset will
follows its parent cpuset load balance state unless the child cpuset
is a new partition root itself.
Fixes: f28e22441f35 ("cgroup/cpuset: Add a new isolated cpus.partition type")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | kernel/cgroup/cpuset.c | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index a46deb8a64dd..71e4b5b83614 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1588,11 +1588,16 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, } /* - * Skip the whole subtree if the cpumask remains the same - * and has no partition root state and force flag not set. + * Skip the whole subtree if + * 1) the cpumask remains the same, + * 2) has no partition root state, + * 3) force flag not set, and + * 4) for v2 load balance state same as its parent. */ if (!cp->partition_root_state && !force && - cpumask_equal(tmp->new_cpus, cp->effective_cpus)) { + cpumask_equal(tmp->new_cpus, cp->effective_cpus) && + (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || + (is_sched_load_balance(parent) == is_sched_load_balance(cp)))) { pos_css = css_rightmost_descendant(pos_css); continue; } @@ -1676,6 +1681,20 @@ update_parent_subparts: update_tasks_cpumask(cp, tmp->new_cpus); /* + * On default hierarchy, inherit the CS_SCHED_LOAD_BALANCE + * from parent if current cpuset isn't a valid partition root + * and their load balance states differ. + */ + if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && + !is_partition_valid(cp) && + (is_sched_load_balance(parent) != is_sched_load_balance(cp))) { + if (is_sched_load_balance(parent)) + set_bit(CS_SCHED_LOAD_BALANCE, &cp->flags); + else + clear_bit(CS_SCHED_LOAD_BALANCE, &cp->flags); + } + + /* * 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 @@ -3235,6 +3254,14 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) cs->use_parent_ecpus = true; parent->child_ecpus_count++; } + + /* + * For v2, clear CS_SCHED_LOAD_BALANCE if parent is isolated + */ + if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && + !is_sched_load_balance(parent)) + clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); + spin_unlock_irq(&callback_lock); if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) |