From 0889eba5b38f66d7d892a167d88284daddd3d43b Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Tue, 16 Oct 2007 01:24:15 -0700 Subject: 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 Signed-off-by: Andy Whitcroft Acked-by: Mel Gorman Cc: Andi Kleen Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/x86_64/mm.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/x86_64/mm.txt b/Documentation/x86_64/mm.txt index f42798ed1c54..b89b6d2bebfa 100644 --- a/Documentation/x86_64/mm.txt +++ b/Documentation/x86_64/mm.txt @@ -9,6 +9,7 @@ ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole ffff810000000000 - ffffc0ffffffffff (=46 bits) direct mapping of all phys. memory ffffc10000000000 - ffffc1ffffffffff (=40 bits) hole ffffc20000000000 - ffffe1ffffffffff (=45 bits) vmalloc/ioremap space +ffffe20000000000 - ffffe2ffffffffff (=40 bits) virtual memory map (1TB) ... unused hole ... ffffffff80000000 - ffffffff82800000 (=40 MB) kernel text mapping, from phys 0 ... unused hole ... -- cgit v1.2.2