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banners=-,-,- X-VirusChecked: Checked From: Huaisheng HS1 Ye To: Matthew Wilcox CC: "akpm@linux-foundation.org" , "linux-mm@kvack.org" , "mhocko@suse.com" , "vbabka@suse.cz" , "mgorman@techsingularity.net" , "alexander.levin@verizon.com" , "colyli@suse.de" , NingTing Cheng , "linux-kernel@vger.kernel.org" Subject: RE: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD Thread-Topic: [External] Re: [PATCH v1] include/linux/gfp.h: getting rid of GFP_ZONE_TABLE/BAD Thread-Index: AQHT6HxSRcNgfj0RT02kxPWBEx8Dn6Qp2Qqg Date: Fri, 11 May 2018 03:24:34 +0000 Message-ID: References: <1525968625-40825-1-git-send-email-yehs1@lenovo.com> <20180510163023.GB30442@bombadil.infradead.org> In-Reply-To: <20180510163023.GB30442@bombadil.infradead.org> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [125.33.111.46] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;HK2PR03MB0883;7:0y82vLp9Bq0/CucQDMqX8MmX3zXgtfMqOUBvE1gcNfOunarCh/MvSNegav/A+CYUMkVtHN/uQZO7OkRWktmzIP3acN1lNGvPwIMiQzK0MaIZgj9rxm9A1/UsNHV3SsGf41+SxoFLNydg4isXMb0cd3LwVmo7FDOGDIGxV4LcQrkIz0HuG61db+Y1qh4sftJQ6FoaMkpOKp1G9nsF5JYnWp0B/QcOrp4W6b8CxTyU3mxCvm8sHk+DzEHvIs+o7PTy;20:atn13V+JpYMxyYTqgleB4Hj2wbh6HnAtM1T00P0ggh+jHE6YrLsB4y5I8pnZnWtO6Y/907jR18sU7FxbpZAPatnjyhO8b3vgIAdo6KVAzK6okPkPLYVkVLqVODtaEQVKnwWsTS331goydrR34zNNVmfJsYSbixKm3p65Sv42zQSV1EtXXptrbxmB2Tm8MfGKvRXDLrzBMu0Hhw0Ny57QzZxgR2ffCZlcgEjfSaxLIq+ze/lfWqJaO6hafizb7CGXsoyGaxN0COtbwbB86amNGIoIhvfEyggl39Pg/oWLrwj/dyNiYzA5RSccjject2wpIYt8ZL7jF3dpq3x1+VaqDw== x-ms-exchange-antispam-srfa-diagnostics: SOS;SOR; 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x-ms-exchange-senderadcheck: 1 x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(6040522)(2401047)(8121501046)(5005006)(3002001)(3231254)(944501410)(52105095)(93006095)(93001095)(10201501046)(149027)(150027)(6041310)(20161123562045)(20161123564045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123560045)(20161123558120)(6072148)(201708071742011);SRVR:HK2PR03MB0883;BCL:0;PCL:0;RULEID:;SRVR:HK2PR03MB0883; x-forefront-prvs: 06691A4183 x-microsoft-antispam-message-info: MfwriFbp5kjJwZZjl5FD9VXncWGFdNAnVgN0of+pgBG+uSplLPePHKK3CgFl8z2OR5F9e0/+MS1qlzjDa5a62NrbI1PWQ6Ai1p982liKOts//eFVHrXt6E+btilQcFTQbFOI7tz7QVILInTQ2ynAKacipZOQph+/B4mDVFWs15Q/odEoJo3NCuYKApItmh9w spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 X-MS-Office365-Filtering-Correlation-Id: 926a3db4-35a2-44ca-1d18-08d5b6eeb83f X-MS-Exchange-CrossTenant-Network-Message-Id: 926a3db4-35a2-44ca-1d18-08d5b6eeb83f X-MS-Exchange-CrossTenant-originalarrivaltime: 11 May 2018 03:24:34.9916 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 5c7d0b28-bdf8-410c-aa93-4df372b16203 X-MS-Exchange-Transport-CrossTenantHeadersStamped: HK2PR03MB0883 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id w4B3Otro007504 > From: owner-linux-mm@kvack.org [mailto:owner-linux-mm@kvack.org] On Behalf Of Matthew > Wilcox > On Fri, May 11, 2018 at 12:10:25AM +0800, Huaisheng Ye wrote: > > -#define __GFP_DMA ((__force gfp_t)___GFP_DMA) > > -#define __GFP_HIGHMEM ((__force gfp_t)___GFP_HIGHMEM) > > -#define __GFP_DMA32 ((__force gfp_t)___GFP_DMA32) > > +#define __GFP_DMA ((__force gfp_t)OPT_ZONE_DMA ^ ZONE_NORMAL) > > +#define __GFP_HIGHMEM ((__force gfp_t)ZONE_MOVABLE ^ ZONE_NORMAL) > > +#define __GFP_DMA32 ((__force gfp_t)OPT_ZONE_DMA32 ^ ZONE_NORMAL) > > No, you've made gfp_zone even more complex than it already is. > If you can't use OPT_ZONE_HIGHMEM here, then this is a waste of time. > Dear Matthew, The reason why I don't use OPT_ZONE_HIGHMEM for __GFP_HIGHMEM directly is that, for x86_64 platform there is no CONFIG_HIGHMEM, so OPT_ZONE_HIGHMEM shall always be equal to ZONE_NORMAL. For gfp_zone it is impossible to distinguish the meaning of lowest 3 bits in flags. How can gfp_zone to understand it comes from OPT_ZONE_HIGHMEM or ZONE_NORMAL? And the most pained thing is that, if __GFP_HIGHMEM with movable flag enabled, it means that ZONE_MOVABLE shall be returned. That is different from ZONE_DMA, ZONE_DMA32 and ZONE_NORMAL. I was thinking... Whether it is possible to use other judgement condition to decide OPT_ZONE_HIGHMEM or ZONE_MOVABLE shall be returned from gfp_zone. Sincerely, Huaisheng Ye > > static inline enum zone_type gfp_zone(gfp_t flags) > > { > > enum zone_type z; > > - int bit = (__force int) (flags & GFP_ZONEMASK); > > + z = ((__force unsigned int)flags & ___GFP_ZONE_MASK) ^ ZONE_NORMAL; > > + > > + if (z > OPT_ZONE_HIGHMEM) > > + z = OPT_ZONE_HIGHMEM + > > + !!((__force unsigned int)flags & ___GFP_MOVABLE); > > > > - z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & > > - ((1 << GFP_ZONES_SHIFT) - 1); > > - VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1); > > + VM_BUG_ON(z > ZONE_MOVABLE); > > return z; > > }