x86_64: SPARSEMEM_VMEMMAP 2M page size support
authorChristoph Lameter <clameter@sgi.com>
Tue, 16 Oct 2007 08:24:15 +0000 (01:24 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Tue, 16 Oct 2007 16:42:51 +0000 (09:42 -0700)
commit0889eba5b38f66d7d892a167d88284daddd3d43b
treeadb578bb92cc18dbf842a9bde67e3861db030557
parent29c71111d0557385328211b130246a90f9223b46
x86_64: SPARSEMEM_VMEMMAP 2M page size support

x86_64 uses 2M page table entries to map its 1-1 kernel space.  We also
implement the virtual memmap using 2M page table entries.  So there is no
additional runtime overhead over FLATMEM, initialisation is slightly more
complex.  As FLATMEM still references memory to obtain the mem_map pointer and
SPARSEMEM_VMEMMAP uses a compile time constant, SPARSEMEM_VMEMMAP should be
superior.

With this SPARSEMEM becomes the most efficient way of handling virt_to_page,
pfn_to_page and friends for UP, SMP and NUMA on x86_64.

[apw@shadowen.org: code resplit, style fixups]
[apw@shadowen.org: vmemmap x86_64: ensure end of section memmap is initialised]
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: Andi Kleen <ak@suse.de>
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>
Documentation/x86_64/mm.txt
arch/x86/mm/init_64.c
arch/x86_64/Kconfig
include/asm-x86/page_64.h
include/asm-x86/pgtable_64.h