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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Menglong Dong Subject: Re: [PATCH net-next 01/17] net: Copy slab data for sendmsg(MSG_SPLICE_PAGES) Message-ID: References: <20230616161301.622169-1-dhowells@redhat.com> <20230616161301.622169-2-dhowells@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230616161301.622169-2-dhowells@redhat.com> X-ClientProxiedBy: AM4PR0302CA0011.eurprd03.prod.outlook.com (2603:10a6:205:2::24) To PH0PR13MB4842.namprd13.prod.outlook.com (2603:10b6:510:78::6) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR13MB4842:EE_|MN2PR13MB4037:EE_ X-MS-Office365-Filtering-Correlation-Id: bce14373-aea6-43b4-ae89-08db6ea2da70 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: ETsZMFkyS7j3I9hQxVsRv+Okmyy6oEpYBmphs7dyhIUPMLmYaLtBcpVBITM1Afh7xUM6sU9kTiCQKWamJ/CBEYsNYRyxEu8KCViENnfO5up3JFD5IcLB/arLEah6HI9Mgnxg4gaF78pOFZBHSAho608/ciwcWH4thmJCRG7iDZNrua7bdIGKQvF6Ctsh+ytktNxZObSaf4Sa4PO26zPmPb5V+OFjPJJeYRZBtSKRB7y4RL+TRpJWlhOhOEsiPJhFtzdPV+1tAxWzSE0JQQpvs2xz4qFMOCW608PxPUMyKyJOJAAahTzVkG5G4Jya6ghvTsqmbDFAcepfKfNDuMM1TtiRBSG5mIJTI5aYorYXa2CiYxaQmwnFzF2nCwNVL9MMW6pFYOspWWbwdFNhHgB/TrXGoS9oP/QWX8h2dvNBH7z0vFTpovbk8fhIuKRBNlv4NwfNUkXs7JuirOiCX072H7Epg55QfVkRdz30bmRIEUgClU7Wtgxqv1iKGFnHeOZOlSZMx2i0VkllAgLH9qgvqR1xtV47p7YDXFRO843MfJHFJ6DWzdmyuWHw7uEF9zz2sNjbO8+n4hRgpSvUsi0r04QD736CKj+UQ5herZPdwZE= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH0PR13MB4842.namprd13.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(4636009)(376002)(396003)(39840400004)(346002)(366004)(136003)(451199021)(6512007)(478600001)(36756003)(6506007)(186003)(6666004)(6486002)(4744005)(2906002)(316002)(41300700001)(44832011)(86362001)(5660300002)(8676002)(8936002)(7416002)(38100700002)(2616005)(54906003)(4326008)(66946007)(66556008)(66476007)(6916009);DIR:OUT;SFP:1102; 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> + struct folio *folio, *spare = NULL; > + size_t offset, fsize; > + void *p; > + > + if (WARN_ON_ONCE(fragsz == 0)) > + fragsz = 1; > + > + cache = get_cpu_ptr(&skb_splice_frag_cache); > +reload: > + folio = cache->folio; > + offset = cache->offset; > +try_again: > + if (fragsz > offset) > + goto insufficient_space; > + > + /* Make the allocation. */ > + cache->pagecnt_bias--; > + offset = ALIGN_DOWN(offset - fragsz, SMP_CACHE_BYTES); > + cache->offset = offset; > + p = cache->virt + offset; > + put_cpu_ptr(skb_splice_frag_cache); Hi David, I don't think it makes any difference at run-time. But to keep Sparse happy, perhaps this ought to be put_cpu_var() ...