Re: [PATCH 02/10] x86: Change size of node ids from u8 to u16 V3

Eric Dumazet
2008-01-16T17:54:12Z

On Wed, 16 Jan 2008 09:09:04 -0800
travis@sgi.com wrote:

> Change the size of node ids from 8 bits to 16 bits to
> accomodate more than 256 nodes.
>
> Signed-off-by: Mike Travis <travis@sgi.com>
> Reviewed-by: Christoph Lameter <clameter@sgi.com>
> ---
> V1->V2:
> - changed pxm_to_node_map to u16
> - changed memnode map entries to u16
> V2->V3:
> - changed memnode.embedded_map from [64-16] to [64-8]
> (and size comment to 128 bytes)
> ---
> arch/x86/mm/numa_64.c | 9 ++++++---
> arch/x86/mm/srat_64.c | 2 +-
> drivers/acpi/numa.c | 2 +-
> include/asm-x86/mmzone_64.h | 6 +++---
> include/asm-x86/numa_64.h | 4 ++--
> include/asm-x86/topology.h | 2 +-
> 6 files changed, 14 insertions(+), 11 deletions(-)

I know new typedefs are not welcome, but in this case, it could be nice
to define a fundamental type node_t (like pte_t, pmd_t, pgd_t, ...).

Clean NUMA code deserves it.

#if MAX_NUMNODES > 256
typedef u16 node_t;
#else
typedef u8 node_t;
#endif

In 2016, we can add u32 for MAX_NUMNODES > 65536

Another point: you want this change, sorry if my previous mail was not detailed enough :

--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -78,7 +78,7 @@ static int __init allocate_cachealigned_memnodemap(void)
unsigned long pad, pad_addr;

memnodemap = memnode.embedded_map;
- if (memnodemapsize <= 48)
+ if (memnodemapsize <= ARRAY_SIZE(memnode.embedded_map))
return 0;

pad = L1_CACHE_BYTES - 1;

Thanks