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Subject: Re: [Patch v2 1/4] mm/migrate.c: not necessary to check start and i
To:     Wei Yang <richardw.yang@linux.intel.com>, akpm@linux-foundation.org
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com,
        yang.shi@linux.alibaba.com, rientjes@google.com
References: <20200122011647.13636-1-richardw.yang@linux.intel.com>
 <20200122011647.13636-2-richardw.yang@linux.intel.com>
From:   David Hildenbrand <david@redhat.com>
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Message-ID: <fa4b94a7-4b70-ab01-e5e5-8eeb18b15c62@redhat.com>
Date:   Tue, 28 Jan 2020 11:04:23 +0100
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On 22.01.20 02:16, Wei Yang wrote:
> Till here, i must no less than start. And if i equals to start,
> store_status() would always return 0.

I'd suggest

"
mm/migrate.c: no need to check for i > start in do_pages_move()

At this point, we always have i >= start. If i == start, store_status()
will return 0. So we can drop the check for i > start.
"

Reviewed-by: David Hildenbrand <david@redhat.com>

> 
> Remove some unnecessary check to make it easy to read and prepare for
> further cleanup.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> ---
>  mm/migrate.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 430fdccc733e..4c2a21856717 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1661,11 +1661,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>  		err = do_move_pages_to_node(mm, &pagelist, current_node);
>  		if (err)
>  			goto out;
> -		if (i > start) {
> -			err = store_status(status, start, current_node, i - start);
> -			if (err)
> -				goto out;
> -		}
> +		err = store_status(status, start, current_node, i - start);
> +		if (err)
> +			goto out;
>  		current_node = NUMA_NO_NODE;
>  	}
>  out_flush:
> 


-- 
Thanks,

David / dhildenb