Re: [PATCH 4/7] x86_64: SPARSEMEM_VMEMMAP 2M page size support

Andrew Morton
2007-07-19T23:25:29Z

On Fri, 13 Jul 2007 14:36:39 +0100
Andy Whitcroft <apw@shadowen.org> wrote:

> 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]
> From: Christoph Lameter <clameter@sgi.com>
> Signed-off-by: Christoph Lameter <clameter@sgi.com>
> Signed-off-by: Andy Whitcroft <apw@shadowen.org>
> Acked-by: Mel Gorman <mel@csn.ul.ie>
> ---
> diff --git a/Documentation/x86_64/mm.txt b/Documentation/x86_64/mm.txt

Please put the From: attribution right at the top of the changelog.

Please alter your scripts to include diffstat output after the ^---

Thanks.