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Shutemov" , "Hocko, Michal" , Muchun Song , John Hubbard Subject: Re: [PATCH v1 0/2] udmabuf: Add back support for mapping hugetlb pages Message-ID: References: <20230622072710.3707315-1-vivek.kasireddy@intel.com> <6e429fbc-e0e6-53c0-c545-2e2cbbe757de@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MN2PR17CA0008.namprd17.prod.outlook.com (2603:10b6:208:15e::21) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|CH3PR12MB8728:EE_ X-MS-Office365-Filtering-Correlation-Id: bf5c6e95-0696-4c0a-d5f4-08db7644e68f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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yzPCLRsk03VD5Q/tFTLeS+0O1qPkGllGwV1uWiCOa4Cekkq7ul5I9xO+eapjAWejlZ2WHn/oyM1aMA75Dipu1gNdqYHygZRcQjuWswp+KPavLuSLK6F4AcOZSabtSd/w4SpJRRKtwrj9ko+ii5qaOG1fw/5IFFDWOCkFq4JAH32h6J8gCym0HcSXXC+lI9PPbX1X0EJx0z5zm8UN4DRqFUQpPWTydpABmOb58mzRuNq5OXkQqH6avLTUmK7XOSIKVtD+N7rsrq8K/4HZ+O9iBL/rwvtSfttox0nrG9CpwxPqNciaacFtEK3KOAA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jun 23, 2023 at 01:28:24PM -0400, Peter Xu wrote: > On Fri, Jun 23, 2023 at 01:37:58PM -0300, Jason Gunthorpe wrote: > > On Fri, Jun 23, 2023 at 12:35:45PM -0400, Peter Xu wrote: > > > > > It seems the previous concern on using gup was majorly fork(), if this is it: > > > > > > https://patchwork.freedesktop.org/patch/210992/?series=39879&rev=2#comment_414213 > > > > Fork and GUP have been fixed since that comment anyhow there is no > > longer a problem using GUP and fork together. > > Ah, I read it previously as a requirement that the child will also be able > the see the same / coherent page when manipulating the dmabuf later after > fork(), e.g., the udmabuf can be created before fork(). That always worked, just use MAP_SHARED. Jason