Re: [RFC PATCH 2/2] mm/vmscan.c: Prevent allocating shrinker_info on offlined nodes

[Kirill Tkhai]

On 06.12.2021 13:45, David Hildenbrand wrote:
>> This doesn't seen complete. Slab shrinkers are used in the reclaim
>> context. Previously offline nodes could be onlined later and this would
>> lead to NULL ptr because there is no hook to allocate new shrinker
>> infos. This would be also really impractical because this would have to
>> update all existing memcgs...
> 
> Instead of going through the trouble of updating...
> 
> ...  maybe just keep for_each_node() and check if the target node is
> offline. If it's offline, just allocate from the first online node.
> After all, we're not using __GFP_THISNODE, so there are no guarantees
> either way ...

Hm, can't we add shrinker maps allocation to __try_online_node() in addition
to this patch?