Re: [PATCH] mm/demotion: Fix kernel error with memory hotplug

[Huang, Ying]

Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> writes:

> On 8/25/22 5:46 PM, David Hildenbrand wrote:
>> On 25.08.22 11:20, Aneesh Kumar K.V wrote:
>>> On memory hot unplug, the kernel removes the node memory type
>>> from the associated memory tier. Use list_del_init instead of
>>> list del such that the same memory type can be added back
>>> to a memory tier on hotplug.
>>>
>>> Without this, we get the below warning and return error on
>>> adding memory type to a new memory tier.
>>>
>>> [   33.596095] ------------[ cut here ]------------
>>> [   33.596099] WARNING: CPU: 3 PID: 667 at mm/memory-tiers.c:115 set_node_memory_tier+0xd6/0x2e0
>>> [   33.596109] Modules linked in: kmem
>>>
>>> ...
>>>
>>> [   33.596126] RIP: 0010:set_node_memory_tier+0xd6/0x2e0
>>>
>>> ....
>>> [   33.596196]  memtier_hotplug_callback+0x48/0x68
>>> [   33.596204]  blocking_notifier_call_chain+0x80/0xc0
>>> [   33.596211]  online_pages+0x25e/0x280
>>> [   33.596218]  memory_block_change_state+0x176/0x1f0
>>> [   33.596225]  memory_subsys_online+0x37/0x40
>>> [   33.596230]  online_store+0x9b/0x130
>>> [   33.596236]  kernfs_fop_write_iter+0x128/0x1b0
>>> [   33.596242]  vfs_write+0x24b/0x2c0
>>> [   33.596249]  ksys_write+0x74/0xe0
>>> [   33.596254]  do_syscall_64+0x43/0x90
>>> [   33.596259]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>>
>>> Fixes: mm/demotion: Add hotplug callbacks to handle new numa node onlined
>> 
>> Do we have a proper 12-digit commit id as well?
>> 
>> Do we have to cc stable?
>> 
>
> That patch is not yet merged upstream. It is in mm-unstable. I guess Andrew can fold the change
> into the original patch?

I think it may better to reply the original patch and name this patch as
fix, for example,

  mm/demotion: Add hotplug callbacks to handle new numa node onlined fix

I found Andrew uses this kind of name before for fixing.

Best Regards,
Huang, Ying