On Mon, Jul 29, 2013 at 02:32:06PM +0900, Joonsoo Kim wrote:
> If we fail with a allocated hugepage, it is hard to recover properly.
> One such example is reserve count. We don't have any method to recover
> reserve count. Although, I will introduce a function to recover reserve
> count in following patch, it is better not to allocate a hugepage
> as much as possible. So move up anon_vma_prepare() which can be failed
> in OOM situation.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 683fd38..bb8a45f 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2536,6 +2536,15 @@ retry_avoidcopy:
> /* Drop page_table_lock as buddy allocator may be called */
> spin_unlock(&mm->page_table_lock);
>
> + /*
> + * When the original hugepage is shared one, it does not have
> + * anon_vma prepared.
> + */
> + if (unlikely(anon_vma_prepare(vma))) {
> + ret = VM_FAULT_OOM;
> + goto out_old_page;
> + }
> +
> use_reserve = vma_has_reserves(h, vma, address);
> if (use_reserve == -ENOMEM) {
> ret = VM_FAULT_OOM;
> @@ -2590,15 +2599,6 @@ retry_avoidcopy:
> goto out_lock;
> }
>
> - /*
> - * When the original hugepage is shared one, it does not have
> - * anon_vma prepared.
> - */
> - if (unlikely(anon_vma_prepare(vma))) {
> - ret = VM_FAULT_OOM;
> - goto out_new_page;
> - }
> -
> copy_user_huge_page(new_page, old_page, address, vma,
> pages_per_huge_page(h));
> __SetPageUptodate(new_page);
> @@ -2625,7 +2625,6 @@ retry_avoidcopy:
> spin_unlock(&mm->page_table_lock);
> mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
>
> -out_new_page:
> page_cache_release(new_page);
> out_old_page:
> page_cache_release(old_page);
> --
> 1.7.9.5
>
> --
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