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David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 05/47] hugetlb: make hugetlb_vma_lock_alloc return its failure reason Message-ID: References: <20221021163703.3218176-1-jthoughton@google.com> <20221021163703.3218176-6-jthoughton@google.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221021163703.3218176-6-jthoughton@google.com> X-ClientProxiedBy: MW4PR04CA0113.namprd04.prod.outlook.com (2603:10b6:303:83::28) To BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BY5PR10MB4196:EE_|CO6PR10MB5618:EE_ X-MS-Office365-Filtering-Correlation-Id: cbe22106-cd85-4e9c-39e3-08dada35e005 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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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BY5PR10MB4196.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(7916004)(136003)(396003)(376002)(366004)(346002)(39860400002)(451199015)(8936002)(66556008)(66476007)(26005)(66946007)(316002)(83380400001)(41300700001)(4326008)(8676002)(54906003)(6916009)(38100700002)(478600001)(186003)(6666004)(33716001)(53546011)(6512007)(6506007)(9686003)(86362001)(6486002)(2906002)(4744005)(44832011)(5660300002)(7416002);DIR:OUT;SFP:1101; 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However, HGM requires > that the VMA lock exists, so we need to verify that > hugetlb_vma_lock_alloc actually succeeded. If hugetlb_vma_lock_alloc > fails, then we can pass that up to the caller that is attempting to > enable HGM. No serious objections to this change ... However, there are currently only two places today where hugetlb_vma_lock_alloc is called: hugetlb_reserve_pages and hugetlb_vm_op_open. hugetlb_reserve_pages is not an issue. Since hugetlb_vm_op_open (as a defined vm_operation) returns void, I am not sure how you plan to pass up an allocation failure. Suspect this will become evident in subsequent patches. -- Mike Kravetz