[PATCH] powerpc/pseries: Track LMB nid instead of using device tree

[Michael Ellerman]

Nathan Fontenot <nfont at linux.vnet.ibm.com> writes:

> When removing memory we need to remove the memory from the node
> it was added to instead of looking up the node it should be in
> in the device tree.
>
> During testing we have seen scenarios where the affinity for a
> LMB changes due to a partition migration or PRRN event. In these
> cases the node the LMB exists in may not match the node the device
> tree indicates it belongs in. This can lead to a system crash
> when trying to DLAPR remove the LMB after a migration or PRRN
> event. The current code looks up the node in the device tree to
> remove the LMB from, the crash occurs when we try to offline this
> node and it does not have any data, i.e. node_data[nid] == NULL.

This isn't building for 32-bit etc:

arch/powerpc/mm/drmem.c: In function 'init_drmem_v1_lmbs':
arch/powerpc/mm/drmem.c:371:14: error: implicit declaration of function 'memory_add_physaddr_to_nid' [-Werror=implicit-function-declaration]
   lmb->nid = memory_add_physaddr_to_nid(lmb->base_addr);
              ^
cc1: all warnings being treated as errors
scripts/Makefile.build:317: recipe for target 'arch/powerpc/mm/drmem.o' failed

See the failed checks here:
  https://patchwork.ozlabs.org/patch/969150/


Probably drmem.c should only be compiled for 64-bit NUMA etc.

cheers