mm: memory_hotplug: drop memoryless node from fallback lists

In offline_pages(), if a node becomes memoryless, we will clear its
N_MEMORY state by calling node_states_clear_node().  But we do this
after rebuilding the zonelists by calling build_all_zonelists(), which
will cause this memoryless node to still be in the fallback nodes
(node_order[]) of other nodes.

To drop memoryless nodes from fallback nodes in this case, just call
node_states_clear_node() before calling build_all_zonelists().

In this way, we will not try to allocate pages from memoryless node0,
then the panic mentioned in [1] will also be fixed.  Even though this
problem has been solved by dropping the NODE_MIN_SIZE constrain in x86
[2], it would be better to fix it in the core MM as well.

https://lore.kernel.org/all/[email protected]/ [1]
https://lore.kernel.org/all/[email protected]/ [2]

Link: https://lkml.kernel.org/r/9f1dbe7ee1301c7163b2770e32954ff5e3ecf2c4.1697711415.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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