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Miller" Subject: Re: [RFC PATCH 2/6] cpumask: Purify cpumask_next() Thread-Topic: [RFC PATCH 2/6] cpumask: Purify cpumask_next() Thread-Index: AQHVEtL01bbPeKZ8oUGZpk8eFnzdaKZ+p1cAgACX3YA= Date: Mon, 27 May 2019 17:34:26 +0000 Message-ID: <5EE58FF7-FDAA-4C4E-8A61-B8BECC29CDD3@vmware.com> References: <20190525082203.6531-1-namit@vmware.com> <20190525082203.6531-3-namit@vmware.com> <20190527083052.GR2623@hirez.programming.kicks-ass.net> In-Reply-To: <20190527083052.GR2623@hirez.programming.kicks-ass.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=namit@vmware.com; x-originating-ip: [66.170.99.2] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 69896ef2-9984-4269-8959-08d6e2c990fb x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600148)(711020)(4605104)(1401327)(2017052603328)(7193020);SRVR:BYAPR05MB4885; x-ms-traffictypediagnostic: BYAPR05MB4885: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8273; x-forefront-prvs: 0050CEFE70 x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(396003)(366004)(39860400002)(346002)(136003)(376002)(199004)(189003)(6506007)(54906003)(53546011)(6916009)(316002)(76176011)(446003)(256004)(82746002)(36756003)(102836004)(26005)(2616005)(14454004)(476003)(486006)(3846002)(6116002)(86362001)(305945005)(73956011)(7736002)(66446008)(64756008)(66556008)(66476007)(478600001)(66946007)(76116006)(83716004)(71200400001)(71190400001)(8676002)(8936002)(99286004)(81156014)(81166006)(11346002)(2906002)(6486002)(5660300002)(6436002)(4744005)(25786009)(229853002)(4326008)(68736007)(6246003)(186003)(6512007)(33656002)(53936002)(66066001);DIR:OUT;SFP:1101;SCL:1;SRVR:BYAPR05MB4885;H:BYAPR05MB4776.namprd05.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; received-spf: None (protection.outlook.com: vmware.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: /gqBA8eO+dMhXEHIyeJ3dnQS7loqyaChbTMfVVGneV2D4DvKGbru1GBrybrvfh7lidw24LGMzqaLFQ9t2Hd3Z9Zgl2veRe9n8sVebeS1DzX/0dwrURzXIdCOuudbG7MjjJ1fDQHC+wN1ciDpxwrSandZPPwVCDAgxqVf0m9h2eHksJTxsKsaVS2Kgwm02za72wKmeg5nrBCIZC+dJMQ7lBBe5OuslK6AkYxTrMz46uYV17IfwOeKwePCVrCSKNXZXLG6PC1IrNP9HMT0qhnu63Lk7FJULFkT4VNduXR3im5LSyWNtZPrJNvWmYM5qWIA54Qadkd6c0p0XhawZYXlTEte0jZ3iunLq88vVqS47V3FkiEe3/dkPPI2KFisxKuql6x3/0eR3Ed5juDSr8265Ms0dgbam9lGJpjeQrVsKKQ= Content-Type: text/plain; charset="us-ascii" Content-ID: <590182A5FF348047B747D164DCFDB8C7@namprd05.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: vmware.com X-MS-Exchange-CrossTenant-Network-Message-Id: 69896ef2-9984-4269-8959-08d6e2c990fb X-MS-Exchange-CrossTenant-originalarrivaltime: 27 May 2019 17:34:26.6702 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b39138ca-3cee-4b4a-a4d6-cd83d9dd62f0 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: namit@vmware.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR05MB4885 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On May 27, 2019, at 1:30 AM, Peter Zijlstra wrote: >=20 > On Sat, May 25, 2019 at 01:21:59AM -0700, Nadav Amit wrote: >> cpumask_next() has no side-effects. Mark it as pure. >=20 > It would be good to have a few word on why... because apparently you > found this makes a difference. I see that eventually it did not make any difference. I saw in the past tha= t some instances of the kernel are affected by it, but I will remove it from this patch-set in the next iteration.