在 2026/8/24 22:37, Waiman Long 写道:
> On 8/20/26 8:41 AM, Guopeng Zhang wrote:
>> From: Guopeng Zhang <[email protected]>
>>
>> When a housekeeping check rejects a root-to-isolated or isolated-to-root
>> change, update_prstate() marks the partition invalid but leaves its
>> effective_xcpus allocated. Those CPUs remain missing from the partition
>> which owns the invalidated subtree.
>>
>> Disable a rejected remote partition with remote_partition_disable().
>> For a local partition, return effective_xcpus to its parent before
>> recording the invalid state. Use the complete mask because descendants
>> are invalidated along with the parent and their CPUs return at the same
>> time.
>>
>> Fixes: 103b08709e8a ("cgroup/cpuset: Fail if isolated and nohz_full don't
>> leave any housekeeping")
>> Signed-off-by: Guopeng Zhang <[email protected]>
>> ---
>> kernel/cgroup/cpuset.c | 15 +++++++++++++--
>> 1 file changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
>> index 853942c1afeb..a616012927be 100644
>> --- a/kernel/cgroup/cpuset.c
>> +++ b/kernel/cgroup/cpuset.c
>> @@ -3020,10 +3020,21 @@ static int update_prstate(struct cpuset *cs, int
>> new_prs)
>> compute_partition_owned_cpumask(cs, tmpmask.new_cpus);
>> if (((new_prs == PRS_ISOLATED) &&
>> !isolated_cpus_can_update(tmpmask.new_cpus, NULL)) ||
>> - prstate_housekeeping_conflict(new_prs, tmpmask.new_cpus))
>> + prstate_housekeeping_conflict(new_prs, tmpmask.new_cpus)) {
>> err = PERR_HKEEPING;
>> - else
>> + if (is_remote_partition(cs)) {
>> + WRITE_ONCE(cs->prs_err, err);
> This WRITE_ONCE() is not necessary as it will be done later in the function.
>> + remote_partition_disable(cs, &tmpmask);
>> + } else {
>> + spin_lock_irq(&callback_lock);
>> + partition_xcpus_del(old_prs, parent, cs->effective_xcpus);
>> + spin_unlock_irq(&callback_lock);
>> + cpuset_update_tasks_cpumask(parent, tmpmask.new_cpus);
>> + update_sibling_cpumasks(parent, cs, &tmpmask);
>> + }
>
> This code to disable the partition is duplicating what is being done in the
> last else clause of the outer if, but in a somewhat different way. That is
> not good programming practice. You can either jump to the partition disabling
> code below or separate out the partition disabling code controlled by a
> separate control flag and set the flag to do it.
>
Agreed. I removed the redundant WRITE_ONCE() and used a
disable_partition flag to share the existing partition-disable path in
v2.
Thanks,
Guopeng
> Cheers,
> Longman
>
>> + } else {
>> isolcpus_updated = true;
>> + }
>> } else {
>> /*
>> * Switching back to member is always allowed even if it
>
