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[213.44.141.166]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6d43812ab67sm12352206d6.88.2024.11.20.08.15.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Nov 2024 08:15:22 -0800 (PST) From: Valentin Schneider To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org, rcu@vger.kernel.org, linux-kselftest@vger.kernel.org, "Paul E . McKenney" , Steven Rostedt , Masami Hiramatsu , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Andy Lutomirski , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Josh Poimboeuf , Jason Baron , Kees Cook , Sami Tolvanen , Ard Biesheuvel , Nicholas Piggin , Juerg Haefliger , Nicolas Saenz Julienne , "Kirill A. Shutemov" , Nadav Amit , Dan Carpenter , Chuang Wang , Yang Jihong , Petr Mladek , "Jason A. Donenfeld" , Song Liu , Julian Pidancet , Tom Lendacky , Dionna Glaze , Thomas =?utf-8?Q?Wei=C3=9Fschuh?= , Juri Lelli , Marcelo Tosatti , Yair Podemsky , Daniel Wagner , Petr Tesarik Subject: Re: [RFC PATCH v3 04/15] rcu: Add a small-width RCU watching counter debug option In-Reply-To: <20241120145049.GI19989@noisy.programming.kicks-ass.net> References: <20241119153502.41361-1-vschneid@redhat.com> <20241119153502.41361-5-vschneid@redhat.com> <20241120145049.GI19989@noisy.programming.kicks-ass.net> Date: Wed, 20 Nov 2024 17:15:14 +0100 Message-ID: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: mYqMocHHdhpWslgjNuVBowTgcW0PzGAhProuz4j1Ip4_1732119324 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Rspamd-Queue-Id: CCA11A001A X-Stat-Signature: ma1fer9n4w63mpmqm8pfsbtm638hmb3z X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1732119280-858090 X-HE-Meta: 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 fTp0foCo cjw2MW4F6had+e74GqOuOWD6sIjSo6PzVP82w+oTDUZjIHeuSODWAAoawQid+pUiGngn8sBFx6F7odu3gy/580+K1ACLQW30cm21llDSiQVriJau3HHxvxbQInR5N0PmjsROBo8LHKman61kU+punKMm5SDADSh1V/l2Qsn5Mg+tNH8NqckaQ2Ig8hT42in1z5Gx0mZrU6GFoiG/sBvUJhW0mcar/ypEf7FdDjUaDIym78+HmmPTQTOzPtBnwf9knqsQoIQkAVeEsxH4U4E8foYhutrKzdmemGG0VKAlfMWe3vToS64Qi0mNKIjFe1bhEmc//eYtD+2MRbjmLlh9fqskMMe5Q/RrunAMJ/rYxP+joec+7iK50RpHAYRa/kHG3wv35 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: List-Subscribe: List-Unsubscribe: On 20/11/24 15:50, Peter Zijlstra wrote: > On Tue, Nov 19, 2024 at 04:34:51PM +0100, Valentin Schneider wrote: >> A later commit will reduce the size of the RCU watching counter to free up >> some bits for another purpose. Paul suggested adding a config option to >> test the extreme case where the counter is reduced to its minimum usable >> width for rcutorture to poke at, so do that. >> >> Make it only configurable under RCU_EXPERT. While at it, add a comment to >> explain the layout of context_tracking->state. > > Note that this means it will get selected by allyesconfig and the like, > is that desired? > I would say no > If no, depends on !COMPILE_TEST can help here. Noted, thank you!