[PATCH] powerpc/pseries: Don't attempt to acquire drc during memory hot add for assigned lmbs

[Michael Ellerman]

John Allen <jallen at linux.vnet.ibm.com> writes:

> Check if an LMB is assigned before attempting to call dlpar_acquire_drc in
> order to avoid any unnecessary rtas calls. This substantially reduces the
> running time of memory hot add on lpars with large amounts of memory.
>
> Signed-off-by: John Allen <jallen at linux.vnet.ibm.com>

I'll add:

  Fixes: c21f515c7436 ("powerpc/pseries: Make the acquire/release of the drc for memory a seperate step")

?

How bad is the slow down, do we need to backport to stable/distros?

cheers