Re: [PATCH] mm: hugetlb: avoid bogus counter of surplus huge page

From: Michal Hocko
Date: Tue Dec 27 2011 - 07:57:28 EST


On Fri 23-12-11 21:38:38, Hillf Danton wrote:
> From: Hillf Danton <dhillf@xxxxxxxxx>
> Subject: [PATCH] mm: hugetlb: avoid bogus counter of surplus huge page
>
> If we have to hand back the newly allocated huge page to page allocator,
> for any reason, the changed counter should be recovered.
>
> Cc: Michal Hocko <mhocko@xxxxxxx>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx>

Broken since 2.6.27 (caff3a2c: hugetlb: call arch_prepare_hugepage() for
surplus pages) so a stable material

Reviewed-by: Michal Hocko <mhocko@xxxxxxx>

Thanks
> ---
>
> --- a/mm/hugetlb.c Tue Dec 20 21:26:30 2011
> +++ b/mm/hugetlb.c Fri Dec 23 21:18:06 2011
> @@ -800,7 +800,7 @@ static struct page *alloc_buddy_huge_pag
>
> if (page && arch_prepare_hugepage(page)) {
> __free_pages(page, huge_page_order(h));
> - return NULL;
> + page = NULL;
> }
>
> spin_lock(&hugetlb_lock);
> --
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--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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