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Thread-Topic: [RFC PATCH V2 1/10] mm/resource: Move child to new resource when release mem region. Thread-Index: AQHVxVvKIEcG+CpTJkitsskMuv0x06fz8zSA Date: Mon, 20 Jan 2020 18:34:00 +0000 Message-ID: References: <20200107130950.2983-1-Tianyu.Lan@microsoft.com> <20200107130950.2983-2-Tianyu.Lan@microsoft.com> In-Reply-To: <20200107130950.2983-2-Tianyu.Lan@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Enabled=True; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SiteId=72f988bf-86f1-41af-91ab-2d7cd011db47; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Owner=mikelley@ntdev.microsoft.com; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SetDate=2020-01-20T18:33:58.8724560Z; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Name=General; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Application=Microsoft Azure Information Protection; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_ActionId=b8500966-b3db-4344-8270-1a70d94c770c; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Extended_MSFT_Method=Automatic authentication-results: spf=none (sender IP is ) smtp.mailfrom=mikelley@microsoft.com; x-originating-ip: [24.22.167.197] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: c8d6a88e-ec8e-435b-e12e-08d79dd751b2 x-ms-traffictypediagnostic: MW2PR2101MB0940:|MW2PR2101MB0940:|MW2PR2101MB0940: x-ms-exchange-transport-forked: True x-ld-processed: 72f988bf-86f1-41af-91ab-2d7cd011db47,ExtAddr x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8273; x-forefront-prvs: 0288CD37D9 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(4636009)(39860400002)(346002)(396003)(366004)(136003)(376002)(189003)(199004)(316002)(4326008)(8990500004)(7696005)(6506007)(26005)(478600001)(71200400001)(10290500003)(8936002)(7416002)(186003)(54906003)(110136005)(2906002)(55016002)(86362001)(81156014)(81166006)(8676002)(9686003)(66446008)(52536014)(5660300002)(64756008)(66476007)(66556008)(33656002)(76116006)(66946007)(921003)(1121003);DIR:OUT;SFP:1102;SCL:1;SRVR:MW2PR2101MB0940;H:MW2PR2101MB1052.namprd21.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-ms-exchange-antispam-messagedata: HLZsGufKc8QWGB9oy1VWaoDduf3iN72UKpwjpoGGdUO76XwJCyxXe8j2tjGxBn+MJYOLXm1liFFCvRuQkWqS4C28ysv4jSEBSA4c2gFqczpQheCLeXIU21EbK4CUbwLBcdbz6vXISMcMv8LCLd3OWQ== Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: c8d6a88e-ec8e-435b-e12e-08d79dd751b2 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Jan 2020 18:34:00.8742 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: UeZXdiE5DccVttGWtDGIs5qVsQxE861TqqJBff7MXiz0J2O0bmz0lxGXAwQ/q5RXNuYw3MVy0Vc/DA+cazJoFB0nb4FmsEklrlOJn8IWcVE= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW2PR2101MB0940 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tianyu Lan Sent: Tuesday, January 7, 2020 = 5:10 AM >=20 > When release mem region, old mem region may be splited to > two regions. Current allocate new struct resource for high > end mem region but not move child resources whose ranges are > in the high end range to new resource. When adjust old mem > region's range, adjust_resource() detects child region's range > is out of new range and return error. Move child resources to > high end resource before adjusting old mem range. >=20 > Signed-off-by: Tianyu Lan > --- > kernel/resource.c | 38 ++++++++++++++++++++++++++++++++++---- > 1 file changed, 34 insertions(+), 4 deletions(-) >=20 > diff --git a/kernel/resource.c b/kernel/resource.c > index 76036a41143b..1c7362825134 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -181,6 +181,38 @@ static struct resource *alloc_resource(gfp_t flags) > return res; > } >=20 > +static void move_child_to_newresource(struct resource *old, > + struct resource *new) > +{ > + struct resource *tmp, **p, **np; > + > + if (!old->child) > + return; I don't think the above test is needed. This case is handled by the first three lines of the "for" loop. > + > + p =3D &old->child; > + np =3D &new->child; > + > + for (;;) { > + tmp =3D *p; > + if (!tmp) > + break; > + > + if (tmp->start >=3D new->start && tmp->end <=3D new->end) { > + tmp->parent =3D new; > + *np =3D tmp; > + np =3D &tmp->sibling; > + *p =3D tmp->sibling; > + > + if (!tmp->sibling) > + *np =3D NULL; I don't think the above two lines are right. They seem tautological. If t= he ! were removed it would be clearing the sibling link for the child as it exists un= der its new parent, which should be done. But the child that is moved to the new paren= t always becomes the last entry in the new parent's child list. So could you just u= nconditionally do tmp->sibling =3D NULL? That link will get fixed up if another child is= moved. Michael > + continue; > + } > + > + p =3D &tmp->sibling; > + } > +} > + > + > /* Return the conflict entry if you can't request it */ > static struct resource * __request_resource(struct resource *root, struc= t resource *new) > { > @@ -1246,9 +1278,6 @@ EXPORT_SYMBOL(__release_region); > * Note: > * - Additional release conditions, such as overlapping region, can be > * supported after they are confirmed as valid cases. > - * - When a busy memory resource gets split into two entries, the code > - * assumes that all children remain in the lower address entry for > - * simplicity. Enhance this logic when necessary. > */ > int release_mem_region_adjustable(struct resource *parent, > resource_size_t start, resource_size_t size) > @@ -1331,11 +1360,12 @@ int release_mem_region_adjustable(struct resource= *parent, > new_res->sibling =3D res->sibling; > new_res->child =3D NULL; >=20 > + move_child_to_newresource(res, new_res); > + res->sibling =3D new_res; > ret =3D __adjust_resource(res, res->start, > start - res->start); > if (ret) > break; > - res->sibling =3D new_res; > new_res =3D NULL; > } >=20 > -- > 2.14.5