[S390] add support for physical memory > 4TB
The kernel address space of a 64 bit kernel currently uses a three level
page table and the vmemmap array has a fixed address and a fixed maximum
size. A three level page table is good enough for systems with less than
3.8TB of memory, for bigger systems four page table levels need to be
used. Each page table level costs a bit of performance, use 3 levels for
normal systems and 4 levels only for the really big systems.
To avoid bloating sparse.o too much set MAX_PHYSMEM_BITS to 46 for a
maximum of 64TB of memory.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/sparsemem.h b/arch/s390/include/asm/sparsemem.h
index 545d219..0fb3402 100644
--- a/arch/s390/include/asm/sparsemem.h
+++ b/arch/s390/include/asm/sparsemem.h
@@ -4,8 +4,8 @@
#ifdef CONFIG_64BIT
#define SECTION_SIZE_BITS 28
-#define MAX_PHYSADDR_BITS 42
-#define MAX_PHYSMEM_BITS 42
+#define MAX_PHYSADDR_BITS 46
+#define MAX_PHYSMEM_BITS 46
#else