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Date:   Thu, 5 Dec 2019 19:45:49 +0000 (UTC)
From:   Christopher Lameter <cl@linux.com>
X-X-Sender: cl@www.lameter.com
To:     Yang Shi <yang.shi@linux.alibaba.com>
cc:     fabecassis@nvidia.com, jhubbard@nvidia.com, mhocko@suse.com,
        vbabka@suse.cz, mgorman@techsingularity.net,
        akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [v3 PATCH] mm: move_pages: return valid node id in status if
 the page is already on the target node
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On Fri, 6 Dec 2019, Yang Shi wrote:

> Felix Abecassis reports move_pages() would return random status if the
> pages are already on the target node by the below test program:

Looks ok.

Acked-by: Christoph Lameter <cl@linux.com>

Nitpicks:

> @@ -1553,7 +1555,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
>  	if (PageHuge(page)) {
>  		if (PageHead(page)) {
>  			isolate_huge_page(page, pagelist);
> -			err = 0;
> +			err = 1;

Add a meaningful constant instead of 1?

>  out:
>  	up_read(&mm->mmap_sem);
> +
>  	return err;

Dont do that.