Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   "Wang, Haiyue" <haiyue.wang@intel.com>
To:     "Huang, Ying" <ying.huang@intel.com>
CC:     "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "david@redhat.com" <david@redhat.com>,
        "linmiaohe@huawei.com" <linmiaohe@huawei.com>,
        "songmuchun@bytedance.com" <songmuchun@bytedance.com>,
        "naoya.horiguchi@linux.dev" <naoya.horiguchi@linux.dev>,
        "alex.sierra@amd.com" <alex.sierra@amd.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        Alistair Popple <apopple@nvidia.com>
Subject: RE: [PATCH v3 2/2] mm: fix the handling Non-LRU pages returned by
 follow_page
Thread-Topic: [PATCH v3 2/2] mm: fix the handling Non-LRU pages returned by
 follow_page
Thread-Index: AQHYsELgmLPn7hXKS0eClb7ub+l7+62vL4regAABCHA=
Date:   Mon, 15 Aug 2022 01:46:59 +0000
Message-ID: <BYAPR11MB34957681936F3AD544E9BB5DF7689@BYAPR11MB3495.namprd11.prod.outlook.com>
References: <20220812084921.409142-1-haiyue.wang@intel.com>
        <20220815010349.432313-1-haiyue.wang@intel.com>
        <20220815010349.432313-3-haiyue.wang@intel.com>
 <87czd2e13k.fsf@yhuang6-desk2.ccr.corp.intel.com>
In-Reply-To: <87czd2e13k.fsf@yhuang6-desk2.ccr.corp.intel.com>
Accept-Language: zh-CN, en-US
Content-Language: en-US
dlp-product: dlpe-windows
dlp-reaction: no-action
dlp-version: 11.6.500.17
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?HnHquES3r6bskhDercjzc3hon2OK9woyH/zoyZQ7+IrKzmxJAw2Ho0J8tmi8?=
 =?us-ascii?Q?C5hKVkg48lyywhTsqSXIcCvCbHDDZ+6igVnvcLmXyz78H3XHaQ1HrDeu1YIC?=
 =?us-ascii?Q?TRCXS/rQOW2Cezj0B0RRY9aBnJywYGTbSvV25AeSKluVyrWgcDtEGJwgsxfO?=
 =?us-ascii?Q?YXXsyco0DLx4vBzHE5LrxvOLLBBOSrMIr8BhPktP/4vvTSftcjSiQz7gszGw?=
 =?us-ascii?Q?abHtdva8OxHmET9TJdba4EN7kjaZGyKF8fNBhrjgNi/2GbpZkmiQvn2pM/LO?=
 =?us-ascii?Q?WDqUWGZziEm9V57div08K5xJeBHu0TGWPWggrNns++xgj6Ek2qAcGYMrhjFH?=
 =?us-ascii?Q?MmzGb6NCvmXaRrtGJYotOPL1OAs3Jtx5al+Joc0Hy7+lWGBmPN2RfxoymQpq?=
 =?us-ascii?Q?4yf8KOBuORZB6tVRAZeOVIyoYhvame6S+bJ/WogbamXbzNa2VLk6KpZUjijB?=
 =?us-ascii?Q?j38ZhB0ro2eejdUsLPb62cUdhRkREWFw4qMfbobxV7T9QNQyFxDqJMWhV7pd?=
 =?us-ascii?Q?VzowLdPquYpdUDtBwlJKQ/lWqUq8QWfDYGPfMPxprL4vM21LSeFuHwiN7ILg?=
 =?us-ascii?Q?IgVFb9MHRpa+ZODZX6xDbXfyzvBSwk5Zi1Zwrg6CSIP4pcweRHHh3Gog8HqL?=
 =?us-ascii?Q?hPVhhvcrBzDku4Obd5Ox5Id2skNbgC7VjmNwpVA+d4W/xJqAOYukoer0JcK2?=
 =?us-ascii?Q?6EPQSQlI/OEOOrfddmp7q/8JZeWn24u5TrRs1T2EJkajlWD0Gwcx1oYax1g8?=
 =?us-ascii?Q?57uVbp1LK6fzlRSC6kZIvU+w/e07a8NmWFhSyk93V4Lf8BCYNQeXcV3gS6q6?=
 =?us-ascii?Q?dhfV+KGX9OsWE4ZDd2lUAJByCZ4wNWHKqZI6ScTCumeEBtelUnePbHO+6sHk?=
 =?us-ascii?Q?4wbls9lAGnDXl2ICycXz9hsM8C9Ry+G1OH1ERxWISIxL+1Vo5cfODhvHAUFu?=
 =?us-ascii?Q?RfzHkLZ5xMbtLnmLiNUEPRK6yLQ3HWblOV+U9o95KiCq9y+3KS2KxzzsWMmL?=
 =?us-ascii?Q?snykq3bHoYwzhv9nZfOAd/TXreRqPi6O/jNU3nqmEs8Mj+y1ULSvyjBlt1cs?=
 =?us-ascii?Q?6GhNTlu7SAFOaoYT02i4XXvCf0qD2fb+nNmDJkhxgJExbrVuznZcOJTLXl16?=
 =?us-ascii?Q?xq9MnmdD0tIXnmi7fmM+1Ch3U3vVhwDApi7jEAD0B87K2D0wqv5mkMG+B4XR?=
 =?us-ascii?Q?/Sx9fEuWb3tcuiyX0BGiwoNwSRq5TX5Qsq3zgeemNc075f7L+ZOomIifKgQK?=
 =?us-ascii?Q?G/De64rbZpzI5CNZm0ZF4uIWEwyJ6SUmpNXTKrrGrycBWuS6MJ3bA7+edkiE?=
 =?us-ascii?Q?A3FD+oBq/yAlRFQeh3fOEakhZB3uvaK82ra0gK85Pz1iXrjjsCm8TyHe2MdJ?=
 =?us-ascii?Q?CoSDBbUI/b1l5mTnoGSuGrcpoKtJudKd6SFdwcWdKcXzzVOkj4DYOxZratkY?=
 =?us-ascii?Q?4ESoWvFowM6g/am1/QnJnVJFqs5WX868M9F8DY8qnE/Vq2ipz1N4069Pqou1?=
 =?us-ascii?Q?AkeGI1RzUzvMJMe+JmkIxHZUwfDQZxc3cRekLrOAKhq4Ux4Xvdol5PzkGZiY?=
 =?us-ascii?Q?NZbLCGd56JwOr09nSIjTNTKsitZ9rjbzdwn9cdIb?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: BYAPR11MB3495.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: bbd6c9cd-bb97-4aed-5488-08da7e600b1b
X-MS-Exchange-CrossTenant-originalarrivaltime: 15 Aug 2022 01:46:59.4022
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: lu6ftBoHbWCmfB8OJj2g7IP+hzQ4Rr/oxDehaRDL9GvTaqBscpBCoY8Z+kx3uxSAWzSQOW3+B78LYmMucIcxkw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR11MB6770
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-5.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,HK_RANDOM_ENVFROM,
        HK_RANDOM_FROM,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE,
        T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> -----Original Message-----
> From: Huang, Ying <ying.huang@intel.com>
> Sent: Monday, August 15, 2022 09:40
> To: Wang, Haiyue <haiyue.wang@intel.com>
> Cc: linux-mm@kvack.org; linux-kernel@vger.kernel.org; akpm@linux-foundati=
on.org; david@redhat.com;
> linmiaohe@huawei.com; songmuchun@bytedance.com; naoya.horiguchi@linux.dev=
; alex.sierra@amd.com; Felix
> Kuehling <Felix.Kuehling@amd.com>; Alistair Popple <apopple@nvidia.com>
> Subject: Re: [PATCH v3 2/2] mm: fix the handling Non-LRU pages returned b=
y follow_page
>=20
> Haiyue Wang <haiyue.wang@intel.com> writes:
>=20
> > The page returned by follow_page with 'FOLL_GET' has get_page called, s=
o
>=20
> Better to add "()" after function name to improve the readability, for
> example, "follow_page()".

Got it, didn't notice this. ;-)

>=20
> > it needs to call put_page for handling the reference count correctly.
> >
> > And as David reviewed, "device pages are never PageKsm pages". Drop thi=
s
> > zone device page check for break_ksm.
> >
> > Fixes: 3218f8712d6b ("mm: handling Non-LRU pages returned by vm_normal_=
pages")
>=20
> In your patch description, I cannot find how the above commit is related
> to the bug you fixed.  Add some words about that?

The first commit session, but maybe not very clear, will try to add more wo=
rds
In v4.

>=20
> Best Regards,
> Huang, Ying
>=20
> > Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
> > ---
> >  mm/huge_memory.c |  4 ++--
> >  mm/ksm.c         | 12 +++++++++---
> >  mm/migrate.c     | 10 +++++++---
> >  3 files changed, 18 insertions(+), 8 deletions(-)
> >