On Fri, Apr 29, 2022 at 8:40 AM Miaohe Lin <linmiaohe@xxxxxxxxxx> wrote:
>
> If trylock_page fails, the page won't be non-lru movable page. When this
> page is freed via free_z3fold_page, it will trigger bug on PageMovable
> check in __ClearPageMovable. Throw warning on failure of trylock_page to
> guard against such rare case just as what zsmalloc does.
I don't see how this is better than what we currently have. We can
check if a page is movable before calling __ClearPageMovable instead.
~Vitaly
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/z3fold.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/mm/z3fold.c b/mm/z3fold.c
> index 4e6814c5694f..b3b4e65c107f 100644
> --- a/mm/z3fold.c
> +++ b/mm/z3fold.c
> @@ -1122,10 +1122,9 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
> __SetPageMovable(page, pool->inode->i_mapping);
> unlock_page(page);
> } else {
> - if (trylock_page(page)) {
> - __SetPageMovable(page, pool->inode->i_mapping);
> - unlock_page(page);
> - }
> + WARN_ON(!trylock_page(page));
> + __SetPageMovable(page, pool->inode->i_mapping);
> + unlock_page(page);
> }
> z3fold_page_lock(zhdr);
>
> --
> 2.23.0
>
