IA64: SPARSEMEM_VMEMMAP 16K page size support

Equip IA64 sparsemem with a virtual memmap.  This is similar to the existing
CONFIG_VIRTUAL_MEM_MAP functionality for DISCONTIGMEM.  It uses a PAGE_SIZE
mapping.

This is provided as a minimally intrusive solution.  We split the 128TB
VMALLOC area into two 64TB areas and use one for the virtual memmap.

This should replace CONFIG_VIRTUAL_MEM_MAP long term.

[apw@shadowen.org: convert to new helper based initialisation]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/asm-ia64/pgtable.h b/include/asm-ia64/pgtable.h
index de6d01e24dd0..6b4216edbb9c 100644
--- a/include/asm-ia64/pgtable.h
+++ b/include/asm-ia64/pgtable.h
@@ -236,8 +236,14 @@ ia64_phys_addr_valid (unsigned long addr)
 # define VMALLOC_END            vmalloc_end
   extern unsigned long vmalloc_end;
 #else
+#if defined(CONFIG_SPARSEMEM) && defined(CONFIG_SPARSEMEM_VMEMMAP)
+/* SPARSEMEM_VMEMMAP uses half of vmalloc... */
+# define VMALLOC_END            (RGN_BASE(RGN_GATE) + (1UL << (4*PAGE_SHIFT - 10)))
+# define vmemmap                ((struct page *)VMALLOC_END)
+#else
 # define VMALLOC_END            (RGN_BASE(RGN_GATE) + (1UL << (4*PAGE_SHIFT - 9)))
 #endif
+#endif
 
 /* fs/proc/kcore.c */
 #define kc_vaddr_to_offset(v) ((v) - RGN_BASE(RGN_GATE))