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authorWaiman Long <longman@redhat.com>2021-07-20 10:18:27 -0400
committerTejun Heo <tj@kernel.org>2021-07-26 12:59:05 -1000
commit15d428e6fe77fffc3f4fff923336036f5496ef17 (patch)
treefeee2b28339093b7f3a76d762080d22d7c243716 /kernel/cgroup/cpuset.c
parent0f3adb8a1e5f36e792598c1d77a2cfac9c90a4f9 (diff)
downloadlinux-15d428e6fe77fffc3f4fff923336036f5496ef17.tar.bz2
cgroup/cpuset: Fix a partition bug with hotplug
In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case. Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup/cpuset.c')
-rw-r--r--kernel/cgroup/cpuset.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index f5fef5516d99..28a784bf64b1 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -3166,6 +3166,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
+ /*
+ * In the rare case that hotplug removes all the cpus in subparts_cpus,
+ * we assumed that cpus are updated.
+ */
+ if (!cpus_updated && top_cpuset.nr_subparts_cpus)
+ cpus_updated = true;
+
/* synchronize cpus_allowed to cpu_active_mask */
if (cpus_updated) {
spin_lock_irq(&callback_lock);