Re: [PATCH] mm/page_alloc: let the highest memory node recover from hopeless state

[Zi Yan]

On 19 Oct 2026, at 16:16, Gregory Price wrote:

> On Mon, Oct 19, 2026 at 03:51:27PM -0400, Zi Yan wrote:
>> On Mon Oct 19, 2026 at 2:48 PM EDT, Gregory Price (Meta) wrote:
>>>  		if (kswapd_test_hopeless(pgdat) &&
>>> -		    next_memory_node(pgdat->node_id) < MAX_NUMNODES)
>>> +		    num_node_state(N_MEMORY) > 1)
>>
>> Why does a runtime behavior, clearing kswapd hopeless state, depend on a
>> static memory topology (excluding memory hotadd/hotremove in this
>> context)? There is nothing telling us if a fallback node has available memory.
>>
>> Just reset it regardless. kswapd can go hopeless later if the node
>> cannot be reclaimed.
>>
>
> I mostly agree, but this was more of behavioral change than i was
> outright willing to commit to in a stable backport.
>
> I can send a follow up commit to drop the check altogether if you
> prefer - but I'm not sure we want to drop it outright in the backport.

Yeah, for that specific Fixes, your patch works. Feel free to add

Acked-by: Zi Yan <ziy@xxxxxxxxxx>

>
>> BTW, LLM also points out that kswapd_try_clear_hopeless(), called by
>> direct reclaim, only clears hopeless when the node is balanced, but that
>> rarely happens. So hopeless state can stay much longer if there is only
>> one node. Adding Jiayuna, who added kswapd_try_clear_hopeless(), to gvie
>> some insight.
>>
>
> Yeah I have some additional things in my pile on the hopeless flag, but
> i haven't gotten around to them.

Got it. The above issue will have a separate fix I guess.


Best Regards,
Yan, Zi