On 1/19/21 11:15 PM, Miaohe Lin wrote:
> The variable avoid_reserve is meaningless because we never changed its
> value and just passed it to alloc_huge_page(). So remove it to make code
> more clear that in hugetlbfs_fallocate, we never avoid reserve when alloc
> hugepage yet. Also add a comment offered by Mike Kravetz to explain this.
>
> Reviewed-by: David Hildenbrand <da...@redhat.com>
> Signed-off-by: Miaohe Lin <linmia...@huawei.com>
> Cc: Mike Kravetz <mike.krav...@oracle.com>
> ---
> fs/hugetlbfs/inode.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
Reviewed-by: Mike Kravetz <mike.krav...@oracle.com>
>
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 4bbfd78a7ccb..14df2f73b8ef 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -680,7 +680,6 @@ static long hugetlbfs_fallocate(struct file *file, int
> mode, loff_t offset,
> */
> struct page *page;
> unsigned long addr;
> - int avoid_reserve = 0;
>
> cond_resched();
>
> @@ -716,8 +715,15 @@ static long hugetlbfs_fallocate(struct file *file, int
> mode, loff_t offset,
> continue;
> }
>
> - /* Allocate page and add to page cache */
> - page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
> + /*
> + * Allocate page without setting the avoid_reserve argument.
> + * There certainly are no reserves associated with the
> + * pseudo_vma. However, there could be shared mappings with
> + * reserves for the file at the inode level. If we fallocate
> + * pages in these areas, we need to consume the reserves
> + * to keep reservation accounting consistent.
> + */
> + page = alloc_huge_page(&pseudo_vma, addr, 0);
> hugetlb_drop_vma_policy(&pseudo_vma);
> if (IS_ERR(page)) {
> mutex_unlock(&hugetlb_fault_mutex_table[hash]);
>
--
Mike Kravetz
