Re: [PATCH] mm: memcontrol: eliminate redundant check in __mem_cgroup_insert_exceeded()

[Michal Hocko]

On Fri 09-10-20 09:51:04, Miaohe Lin wrote:
> The mz->usage_in_excess >= mz_node->usage_in_excess check is exactly the
> else case of mz->usage_in_excess < mz_node->usage_in_excess. So we could
> replace else if (mz->usage_in_excess >= mz_node->usage_in_excess) with else
> equally.
> 
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxxx>

I believe this is a result of a very unreadable code. Resp. the comment
makes it hard to follow. It would be slightly better to simply drop the
comment which doesn't really explain much IMHO.

> ---
>  mm/memcontrol.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 2636f8bad908..f607afd0fcbf 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -629,7 +629,7 @@ static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
>  		 * We can't avoid mem cgroups that are over their soft
>  		 * limit by the same amount
>  		 */
> -		else if (mz->usage_in_excess >= mz_node->usage_in_excess)
> +		else
>  			p = &(*p)->rb_right;
>  	}
>  
> -- 
> 2.19.1

-- 
Michal Hocko
SUSE Labs