Re: [PATCH] migration/mm: Add WARN_ON to try_offline_node

[Michal Hocko]

On Tue 02-10-18 09:51:40, Michael Bringmann wrote:
[...]
> When the device-tree affinity attributes have changed for memory,
> the 'nid' affinity calculated points to a different node for the
> memory block than the one used to install it, previously on the
> source system.  The newly calculated 'nid' affinity may not yet
> be initialized on the target system.  The current memory tracking
> mechanisms do not record the node to which a memory block was
> associated when it was added.  Nathan is looking at adding this
> feature to the new implementation of LMBs, but it is not there
> yet, and won't be present in earlier kernels without backporting a
> significant number of changes.

Then the patch you have proposed here just papers over a real issue, no?
IIUC then you simply do not remove the memory if you lose the race.
-- 
Michal Hocko
SUSE Labs