cc'ing Waiman and copying the whole body.
Waiman, can you please take a look?
Thanks.
On Tue, Apr 19, 2022 at 10:09:58AM +0800, Feng Tang wrote:
> We got report that setting cpuset.mems failed when the nodemask
> contains a newly onlined memory node (not enumerated during boot)
> for cgroup v2, while the binding succeeded for cgroup v1.
>
> The root cause is, for cgroup v2, when a new memory node is onlined,
> top_cpuset's 'mem_allowed' is not updated with the new nodemask of
> memory nodes, and the following setting memory nodemask will fail,
> if the nodemask contains a new node.
>
> Fix it by updating top_cpuset.mems_allowed right after the
> new memory node is onlined, just like v1.
>
> Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
> ---
> Very likely I missed some details here, but it looks strange that
> the top_cpuset.mem_allowed is not updatd even after we onlined
> several memory nodes after boot.
>
> kernel/cgroup/cpuset.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index 9390bfd9f1cd..b97caaf16374 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -3314,8 +3314,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
> /* synchronize mems_allowed to N_MEMORY */
> if (mems_updated) {
> spin_lock_irq(&callback_lock);
> - if (!on_dfl)
> - top_cpuset.mems_allowed = new_mems;
> + top_cpuset.mems_allowed = new_mems;
> top_cpuset.effective_mems = new_mems;
> spin_unlock_irq(&callback_lock);
> update_tasks_nodemask(&top_cpuset);
> --
> 2.27.0
>
--
tejun
