Re: [PATCH 3/6] change alloc function in alloc_slab_page

[Minchan Kim]

On Wed, Apr 14, 2010 at 6:37 AM, David Rientjes <rientjes@xxxxxxxxxx> wrote:
> On Wed, 14 Apr 2010, Minchan Kim wrote:
>
>> alloc_slab_page never calls alloc_pages_node with -1.
>> It means node's validity check is unnecessary.
>> So we can use alloc_pages_exact_node instead of alloc_pages_node.
>> It could avoid comparison and branch as 6484eb3e2a81807722 tried.
>>
>> Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
>> ---
>> Âmm/slub.c | Â Â2 +-
>> Â1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/mm/slub.c b/mm/slub.c
>> index b364844..9984165 100644
>> --- a/mm/slub.c
>> +++ b/mm/slub.c
>> @@ -1084,7 +1084,7 @@ static inline struct page *alloc_slab_page(gfp_t flags, int node,
>> Â Â Â if (node == -1)
>> Â Â Â Â Â Â Â return alloc_pages(flags, order);
>> Â Â Â else
>> - Â Â Â Â Â Â return alloc_pages_node(node, flags, order);
>> + Â Â Â Â Â Â return alloc_pages_exact_node(node, flags, order);
>> Â}
>>
>> Âstatic struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
>
> Slub changes need to go through its maintainer, Pekka Enberg
> <penberg@xxxxxxxxxxxxxx>.

Thanks, David. It was by mistake.

Pekka.

This changlog is bad.
I will change it with following as when I send v2.

"alloc_slab_page always checks nid == -1, so alloc_page_node can't be
called with -1.
 It means node's validity check in alloc_pages_node is unnecessary.
 So we can use alloc_pages_exact_node instead of alloc_pages_node.
 It could avoid comparison and branch as 6484eb3e2a81807722 tried."

Thanks.


-- 
Kind regards,
Minchan Kim
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/