Messages in this thread | | | Subject | Re: [PATCH v1 05/12] mm/memory_hotplug: remove nid parameter from remove_memory() and friends | From | David Hildenbrand <> | Date | Tue, 8 Jun 2021 13:18:55 +0200 |
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On 08.06.21 13:11, Michael Ellerman wrote: > David Hildenbrand <david@redhat.com> writes: >> There is only a single user remaining. We can simply try to offline all >> online nodes - which is fast, because we usually span pages and can skip >> such nodes right away. > > That makes me slightly nervous, because our big powerpc boxes tend to > trip on these scaling issues before others. > > But the spanned pages check is just: > > void try_offline_node(int nid) > { > pg_data_t *pgdat = NODE_DATA(nid); > ... > if (pgdat->node_spanned_pages) > return; > > So I guess that's pretty cheap, and it's only O(nodes), which should > never get that big.
Exactly. And if it does turn out to be a problem, we can walk all memory blocks before removing them, collecting the nid(s).
-- Thanks,
David / dhildenb
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