Re: [PATCH 1/2] mm: always use base address when clear gigantic page

[Kefeng Wang <wangkefeng.wang@huawei.com>]

+cc maillist

On 2024/10/24 20:44, Kefeng Wang wrote:
> When clear gigantic page, it zeros page from the first subpage to
> the last subpage, that is, aligned base address is needed in it,
> and we don't need to aligned down the address in the caller as the
> real address will be passed to process_huge_page().
> 
> Fixes: 78fefd04c123 ("mm: memory: convert clear_huge_page() to folio_zero_user()")
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   fs/hugetlbfs/inode.c | 2 +-
>   mm/memory.c          | 1 +
>   2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index a4441fb77f7c..a5ea006f403e 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -825,7 +825,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
>   			error = PTR_ERR(folio);
>   			goto out;
>   		}
> -		folio_zero_user(folio, ALIGN_DOWN(addr, hpage_size));
> +		folio_zero_user(folio, addr);
>   		__folio_mark_uptodate(folio);
>   		error = hugetlb_add_to_page_cache(folio, mapping, index);
>   		if (unlikely(error)) {
> diff --git a/mm/memory.c b/mm/memory.c
> index 48e534aa939c..934ab5fff537 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -6802,6 +6802,7 @@ static void clear_gigantic_page(struct folio *folio, unsigned long addr,
>   	int i;
>   
>   	might_sleep();
> +	addr = ALIGN_DOWN(addr, folio_size(folio));
>   	for (i = 0; i < nr_pages; i++) {
>   		cond_resched();
>   		clear_user_highpage(folio_page(folio, i), addr + i * PAGE_SIZE);