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SubjectRe: [PATCH v3 2/6] mm/migrate: correct failure handling if !hugepage_migration_support()
On Fri, Dec 13, 2013 at 03:53:27PM +0900, Joonsoo Kim wrote:
> We should remove the page from the list if we fail with ENOSYS,
> since migrate_pages() consider error cases except -ENOMEM and -EAGAIN
> as permanent failure and it assumes that the page would be removed from
> the list. Without this patch, we could overcount number of failure.
>
> In addition, we should put back the new hugepage if
> !hugepage_migration_support(). If not, we would leak hugepage memory.
>
> Acked-by: Christoph Lameter <cl@linux.com>
> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

Thanks,
Naoya Horiguchi

> diff --git a/mm/migrate.c b/mm/migrate.c
> index c6ac87a..b1cfd01 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1011,7 +1011,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
> {
> int rc = 0;
> int *result = NULL;
> - struct page *new_hpage = get_new_page(hpage, private, &result);
> + struct page *new_hpage;
> struct anon_vma *anon_vma = NULL;
>
> /*
> @@ -1021,9 +1021,12 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
> * tables or check whether the hugepage is pmd-based or not before
> * kicking migration.
> */
> - if (!hugepage_migration_support(page_hstate(hpage)))
> + if (!hugepage_migration_support(page_hstate(hpage))) {
> + putback_active_hugepage(hpage);
> return -ENOSYS;
> + }
>
> + new_hpage = get_new_page(hpage, private, &result);
> if (!new_hpage)
> return -ENOMEM;
>
> --
> 1.7.9.5
>


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