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Subject: Re: [PATCH v3] mm/page_owner: fix for deferred struct page init
From:   William Kucharski <william.kucharski@oracle.com>
In-Reply-To: <20181220203156.43441-1-cai@lca.pw>
Date:   Thu, 20 Dec 2018 14:00:10 -0700
Cc:     akpm@linux-foundation.org, mhocko@suse.com,
        Pavel.Tatashin@microsoft.com, mingo@kernel.org, hpa@zytor.com,
        mgorman@techsingularity.net, iamjoonsoo.kim@lge.com,
        yang.shi@linaro.org, tglx@linutronix.de, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
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References: <20181220185031.43146-1-cai@lca.pw>
 <20181220203156.43441-1-cai@lca.pw>
To:     Qian Cai <cai@lca.pw>
Sender: linux-kernel-owner@vger.kernel.org
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> On Dec 20, 2018, at 1:31 PM, Qian Cai <cai@lca.pw> wrote:
>=20
> diff --git a/mm/page_ext.c b/mm/page_ext.c
> index ae44f7adbe07..d76fd51e312a 100644
> --- a/mm/page_ext.c
> +++ b/mm/page_ext.c
> @@ -399,9 +399,8 @@ void __init page_ext_init(void)
> 			 * -------------pfn-------------->
> 			 * N0 | N1 | N2 | N0 | N1 | N2|....
> 			 *
> -			 * Take into account DEFERRED_STRUCT_PAGE_INIT.
> 			 */
> -			if (early_pfn_to_nid(pfn) !=3D nid)
> +			if (pfn_to_nid(pfn) !=3D nid)
> 				continue;
> 			if (init_section_page_ext(pfn, nid))
> 				goto oom;
> --=20
> 2.17.2 (Apple Git-113)
>=20

Is there any danger in the fact that in the CONFIG_NUMA case in mmzone.h =
(around line 1261), pfn_to_nid() calls page_to_nid(), possibly causing =
the same issue seen in v2?