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Date: Mon, 19 Feb 2024 13:02:09 +0100
From: Michal Hocko <mhocko@suse.com>
To: Donet Tom <donettom@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	Aneesh Kumar <aneesh.kumar@kernel.org>,
	Huang Ying <ying.huang@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Mel Gorman <mgorman@suse.de>, Ben Widawsky <ben.widawsky@intel.com>,
	Feng Tang <feng.tang@intel.com>,
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	Mike Kravetz <mike.kravetz@oracle.com>,
	Vlastimil Babka <vbabka@suse.cz>,
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	Hugh Dickins <hughd@google.com>,
	Kefeng Wang <wangkefeng.wang@huawei.com>,
	Suren Baghdasaryan <surenb@google.com>
Subject: Re: [PATCH 2/3] mm/mempolicy: Avoid the fallthrough with MPOLD_BIND
 in mpol_misplaced.
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References: <9c3f7b743477560d1c5b12b8c111a584a2cc92ee.1708097962.git.donettom@linux.ibm.com>
 <bf7e6779f842fb65cf7bb9b2c617feb2af271cb7.1708097962.git.donettom@linux.ibm.com>
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In-Reply-To: <bf7e6779f842fb65cf7bb9b2c617feb2af271cb7.1708097962.git.donettom@linux.ibm.com>

On Sat 17-02-24 01:31:34, Donet Tom wrote:
> We will update MPOL_PREFERRED_MANY in the follow up patch. This change
> is required for that.

Why is it a separate patch then? Does it make review of the next patch
easier? If so make it explicit in the changelog.

> 
> Signed-off-by: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
> Signed-off-by: Donet Tom <donettom@linux.ibm.com>
> ---
>  mm/mempolicy.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 8478574c000c..73d698e21dae 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -2515,7 +2515,15 @@ int mpol_misplaced(struct folio *folio, struct vm_area_struct *vma,
>  				break;
>  			goto out;
>  		}
> -		fallthrough;
> +
> +		if (node_isset(curnid, pol->nodes))
> +			goto out;
> +		z = first_zones_zonelist(
> +				node_zonelist(thisnid, GFP_HIGHUSER),
> +				gfp_zone(GFP_HIGHUSER),
> +				&pol->nodes);
> +		polnid = zone_to_nid(z->zone);
> +		break;
>  
>  	case MPOL_PREFERRED_MANY:
>  		/*
> -- 
> 2.39.3

-- 
Michal Hocko
SUSE Labs