powerpc/pseries/memory-hotplug: Only update DT once per memory DLPAR request

The updates to powerpc numa and memory hotplug code now use the
in-kernel LMB array instead of the device tree. This change allows the
pseries memory DLPAR code to only update the device tree once after
successfully handling a DLPAR request.

Prior to the in-kernel LMB array, the numa code looked up the affinity
for memory being added in the device tree, the code now looks this up
in the LMB array. This change means the memory hotplug code can just
update the affinity for an LMB in the LMB array instead of updating
the device tree.

This also provides a savings in kernel memory. When updating the
device tree old properties are never free'ed since there is no
usecount on properties. This behavior leads to a new copy of the
property being allocated every time a LMB is added or removed (i.e. a
request to add 100 LMBs creates 100 new copies of the property). With
this update only a single new property is created when a DLPAR request
completes successfully.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/drmem.h b/arch/powerpc/include/asm/drmem.h
index ce242b9ea8c6..7c1d8e74b25d 100644
--- a/arch/powerpc/include/asm/drmem.h
+++ b/arch/powerpc/include/asm/drmem.h
@@ -99,4 +99,9 @@ void __init walk_drmem_lmbs_early(unsigned long node,
 			void (*func)(struct drmem_lmb *, const __be32 **));
 #endif
 
+static inline void invalidate_lmb_associativity_index(struct drmem_lmb *lmb)
+{
+	lmb->aa_index = 0xffffffff;
+}
+
 #endif /* _ASM_POWERPC_LMB_H */