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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1piJbx-00BfMF-56; Fri, 31 Mar 2023 18:36:29 +0000 Date: Fri, 31 Mar 2023 19:36:29 +0100 From: Matthew Wilcox To: Andrii Nakryiko Cc: Arnaldo Carvalho de Melo , Jiri Olsa , Alexei Starovoitov , Andrii Nakryiko , Hao Luo , Andrew Morton , Alexander Viro , Peter Zijlstra , Ingo Molnar , bpf@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-perf-users@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Daniel Borkmann , Namhyung Kim , Dave Chinner Subject: Re: [PATCHv3 bpf-next 0/9] mm/bpf/perf: Store build id in file object Message-ID: References: <20230316170149.4106586-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E780A1C0012 X-Stat-Signature: i6mbgt73rqe5bt9xqkzrdan8k86wnffk X-HE-Tag: 1680287803-102565 X-HE-Meta: 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 cerJ0lml MFQcIq2XPgUnWtekU17V0bps8a9t0D+zRlbuByGJ8grkhATN4BOVYfTXi0bBY6Eav9EmtX714SR/PSmrM9tXrBVBR3rWN5KTJESyhjIMykUSz4mKuZCE6xifUxYsyHyCwWbQWKHCmMdmcp3n91r4bv66bfdNpysz3TV6Y5iud04ONLI+qn3jTaPDYls9dThSDKm+a8DD08PMkRD8qkDmNwGZW4em/M9EDJ0BBKXnxvLz7GsI/XZRBVhbIRHODRU7wLxzST1iC5msMHXcUKzD8NMOZ5SQh89EFvSKj 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, Mar 31, 2023 at 11:19:45AM -0700, Andrii Nakryiko wrote: > On Wed, Mar 22, 2023 at 8:45 AM Arnaldo Carvalho de Melo > wrote: > > Having said that, it seems there will be no extra memory overhead at > > least for a fedora:36 x86_64 kernel: > > Makes sense to me as well. Whatever the solution, as long as it's > usable from NMI contexts would be fine for the purposes of fetching > build ID. It would be good to hear from folks that are opposing adding > a pointer field to struct file whether they prefer this way instead? Still no. While it may not take up any room right now, this will surely not be the last thing added to struct file. When something which is genuinely useful needs to be added, that person should not have to sort out your mess first, NAK now, NAK tomorrow, NAK forever. Al told you how you could do it without trampling on core data structures.