Re: [PATCH v4 1/2] mm/migration: make isolate_movable_page always defined

[Michal Hocko <mhocko@kernel.org>]

On Wed 25-01-17 23:05:37, ysxie@foxmail.com wrote:
> From: Yisheng Xie <xieyisheng1@huawei.com>
> 
> Define isolate_movable_page as a static inline function when
> CONFIG_MIGRATION is not enable. It should return false
> here which means failed to isolate movable pages.
> 
> This patch do not have any functional change but prepare for
> later patch.

I think it would make more sense to make isolate_movable_page return int
and have the same semantic as __isolate_lru_page. This would be a better
preparatory patch for the later work.

> Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> CC: Vlastimil Babka <vbabka@suse.cz>
> ---
>  include/linux/migrate.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index ae8d475..631a8c8 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -56,6 +56,8 @@ static inline int migrate_pages(struct list_head *l, new_page_t new,
>  		free_page_t free, unsigned long private, enum migrate_mode mode,
>  		int reason)
>  	{ return -ENOSYS; }
> +static inline bool isolate_movable_page(struct page *page, isolate_mode_t mode)
> +	{ return false; }
>  
>  static inline int migrate_prep(void) { return -ENOSYS; }
>  static inline int migrate_prep_local(void) { return -ENOSYS; }
> -- 
> 1.9.1
> 
> 
> 

-- 
Michal Hocko
SUSE Labs