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Miller" , Jakub Kicinski , Jesper Dangaard Brouer , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Magnus Karlsson , Jonathan Lemon , Nathan Chancellor , Nick Desaulniers , Dmitrii Dolgov <9erthalion6@gmail.com>, Quentin Monnet , Tiezhu Yang , Kumar Kartikeya Dwivedi , Chenbo Feng , Willem de Bruijn , Daniel Wagner , Thomas Graf , Ong Boon Leong , "linux-perf-use." , open list , Networking , bpf , llvm@lists.linux.dev References: <20220414223704.341028-1-alobakin@pm.me> <20220414223704.341028-9-alobakin@pm.me> From: Yonghong Song In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SJ0PR03CA0175.namprd03.prod.outlook.com (2603:10b6:a03:338::30) To SN6PR1501MB2064.namprd15.prod.outlook.com (2603:10b6:805:d::27) Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 3a379d6b-d542-44da-5e8a-08da2866476b X-MS-TrafficTypeDiagnostic: DM5PR15MB1851:EE_ X-Microsoft-Antispam-PRVS: X-FB-Source: Internal X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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>> ^ ~~ >> > > long is always 64-bit in BPF, but I suspect this is due to > samples/bpf/Makefile still using this clang + llc combo, where clang > is called with native target and llc for -target bpf. Not sure if we > are ready to ditch that complicated combination. Yonghong, do we still > need that or can we just use -target bpf in samples/bpf? Current most bpf programs in samples/bpf do not use vmlinux.h and CO-RE. They direct use kernel header files. That is why clang C -> IR compilation still needs to be native. We could just use -target bpf for the whole compilation but that needs to change the code to use vmlinux.h and CO-RE. There are already a couple of sample bpf programs did this. > > >> The usual way to avoid this is to shift by 16 two times (see >> upper_32_bits() macro in the kernel). Use it across the BPF sample >> code as well. >> >> Fixes: d822a1926849 ("samples/bpf: Add counting example for kfree_skb() function calls and the write() syscall") >> Fixes: 0fb1170ee68a ("bpf: BPF based latency tracing") >> Fixes: f74599f7c530 ("bpf: Add tests and samples for LWT-BPF") >> Signed-off-by: Alexander Lobakin >> --- >> samples/bpf/lathist_kern.c | 2 +- >> samples/bpf/lwt_len_hist_kern.c | 2 +- >> samples/bpf/tracex2_kern.c | 2 +- >> 3 files changed, 3 insertions(+), 3 deletions(-) >> > > [...]