powerpc/numa: Add ability to disable and debug topology updates
authorNishanth Aravamudan <nacc@linux.vnet.ibm.com>
Fri, 10 Oct 2014 16:04:49 +0000 (09:04 -0700)
committerMichael Ellerman <mpe@ellerman.id.au>
Mon, 13 Oct 2014 07:16:17 +0000 (18:16 +1100)
commit2d73bae12b26db6eba074b70406c707961b6cda9
tree99ac1885683491bdeeb0dfb88195580cecddff62
parent2d15b9b479512f05680541acffd9acbbc831a47c
powerpc/numa: Add ability to disable and debug topology updates

We have hit a few customer issues with the topology update code (VPHN
and PRRN). It would be nice to be able to debug the notifications coming
from the hypervisor in both cases to the LPAR, as well as to disable
responding to the notifications at boot-time, to narrow down the source
of the problems. Add a basic level of such functionality, similar to the
numa= command-line parameter. We already have a toggle in
/proc/powerpc/topology_updates that allows run-time enabling/disabling,
so the updates can be started at run-time if desired. But the bugs we've
run into have occured during boot or very shortly after coming to login,
and have resulted in a broken NUMA topology.

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Documentation/kernel-parameters.txt
arch/powerpc/mm/numa.c