On 08/23/22 11:02, Miaohe Lin wrote:
> When huge_add_to_page_cache() fails, the page is freed directly without
> calling restore_reserve_on_error() to restore reserve for newly allocated
> pages not in page cache. Fix this by calling restore_reserve_on_error()
> when huge_add_to_page_cache fails.
>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/hugetlb.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index d46dfe5ba62c..8e62da153c64 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -5576,7 +5576,6 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
> if (idx >= size)
> goto out;
>
> -retry:
> new_page = false;
> page = find_lock_page(mapping, idx);
> if (!page) {
> @@ -5616,9 +5615,15 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
> if (vma->vm_flags & VM_MAYSHARE) {
> int err = huge_add_to_page_cache(page, mapping, idx);
> if (err) {
> + /*
> + * err can't be -EEXIST which implies someone
> + * else consumed the reservation since hugetlb
> + * fault mutex is held when add a hugetlb page
> + * to the page cache. So it's safe to call
> + * restore_reserve_on_error() here.
> + */
> + restore_reserve_on_error(h, vma, haddr, page);
> put_page(page);
> - if (err == -EEXIST)
> - goto retry;
Thanks for removing this check and adding the comment.
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
--
Mike Kravetz
> goto out;
> }
> new_pagecache_page = true;
> --
> 2.23.0
>
