On 01/12/2018 08:33 PM, Michael Ellerman wrote: > Nathan Fontenot <nf...@linux.vnet.ibm.com> writes: ... >> >> One thing I don't see addressed in the comments or in the code is >> migration support. I think we need to update the thread group mask >> post-migration to reflect the threads per core on the new system. > > Normally I'd agree with you, but I don't see any prospect of the kernel > surviving if the threads per core changes across a migration. We'll have > data structures allocated based on the old value and things will > definitely crash if the value increases. If it shrinks maybe we'd get > away with it, but either way is dicey. > > If there's an expectation that we'll be able to migrate between systems > with different settings then we have a much bigger problem. > > cheers > >
>From what I recall of my tests a few months ago, the device-tree is read in and flattened before the kernel starts processing the migration state. I am trying to get access to a couple of P9 systems on which I may test migration to verify the ordering of events between initializing the kernel and post-migration processing. Regards, -- Michael W. Bringmann Linux Technology Center IBM Corporation Tie-Line 363-5196 External: (512) 286-5196 Cell: (512) 466-0650 m...@linux.vnet.ibm.com
