Re: [PATCH tip:x86/mm] x86-64, NUMA: Remove custom phys_to_nid() implementation

[Yinghai Lu <yinghai@kernel.org>]

On 03/31/2011 06:57 AM, Tejun Heo wrote:
> phys_to_nid() maps physical address to NUMA node id.  This is
> implemented by building perfect hash in compute_hash_shift() during
> initialization.
>
> However, with SPARSE memory model, the nid is encoded in page flags.
> The perfect hash implementation was for DISCONTIG memory model which
> got removed years ago by b263295dbf (x86: 64-bit, make sparsemem
> vmemmap the only memory model).
>
> So, the perfect hash ends up being used only during initialization
> when the core SPARSE code already provides perfectly acceptable
> generic early_pfn_to_nid() implementation.
>
> Drop phys_to_nid() and use the generic ealry_pfn_to_nid() instead.
>
> Signed-off-by: Tejun Heo<tj@kernel.org>
> Cc: Christoph Lameter<cl@linux-foundation.org>
> Cc: Ingo Molnar<mingo@redhat.com>
> Cc: Yinghai Lu<yinghai@kernel.org>
> Cc: "H. Peter Anvin"<hpa@zytor.com>
> Cc: Thomas Gleixner<tglx@linutronix.de>
> ---
> If no one objects, will route through x86-mm.  Thanks.
>
>   arch/x86/Kconfig                 |    4 -
>   arch/x86/include/asm/mmzone_64.h |   23 -------
>   arch/x86/mm/numa_64.c            |  123 ---------------------------------------
>   3 files changed, 1 insertion(+), 149 deletions(-)

good finding.

Acked-by: Yinghai Lu <yinghai@kernel.org>