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Peter Anvin" , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Andy Lutomirski , Frederic Weisbecker , "Paul E. McKenney" , 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 =?iso-8859-1?Q?Wei=DFschuh?= , Juri Lelli , Daniel Bristot de Oliveira , Marcelo Tosatti , Yair Podemsky Subject: Re: [RFC PATCH v2 10/20] jump_label,module: Don't alloc static_key_mod for __ro_after_init keys Message-ID: <20230728220426.GB3934165@hirez.programming.kicks-ass.net> References: <20230720163056.2564824-1-vschneid@redhat.com> <20230720163056.2564824-11-vschneid@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230720163056.2564824-11-vschneid@redhat.com> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 03943140009 X-Stat-Signature: huwrhwr4p44sfr1auxkt5387zsk5yeug X-Rspam-User: X-HE-Tag: 1690581914-677123 X-HE-Meta: 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 ierI2gkq GfPh5H4jGe9D8GUPwE3UAOU75Mh8zi+jpO0f/tgIRzA04RbO55th9FQWz4+BPJyieqYpdoov0yyRxBgEFNrFS/I1AGlKPWfuH37FpkJK9FIAiQpFbVzv/zSUOy1wniXT6Zsx5gMpuobGL0acb1XcjsoAE22mVUcqpuW/6mDO1aMTcP6Jt1zICwxXSf9S1f+ObZvHr8jNKkTMeT8HCoTFajgJb6E4fUMnKn6Gqw1HE4r1pmRqrbC2R131l0wI9remzxZYm6WsBFHoRoxypMI/hYFGf3JxhLZtX9CIViA9LKkOWh/bTt9/P57ROVhbqXmw2XSwiniHW+kofjlRrc3zPJGWNqbdNs326vHuesONE/hqG+GROv2rBI0nU7ytO3cCsVwE8z+zmNt+eu732NILd6Mfc4YexNVj/HwF33Ll/27ZgX2WKrolMntfl3JBSXze4frufGLbLXlpLhH4= 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 Thu, Jul 20, 2023 at 05:30:46PM +0100, Valentin Schneider wrote: > From: Peter Zijlstra > > When a static_key is marked ro_after_init, its state will never change > (after init), therefore jump_label_update() will never need to iterate > the entries, and thus module load won't actually need to track this -- > avoiding the static_key::next write. > > Therefore, mark these keys such that jump_label_add_module() might > recognise them and avoid the modification. > > Use the special state: 'static_key_linked(key) && !static_key_mod(key)' > to denote such keys. > > Link: http://lore.kernel.org/r/20230705204142.GB2813335@hirez.programming.kicks-ass.net > NOT-Signed-off-by: Peter Zijlstra (Intel) > Signed-off-by: Valentin Schneider > --- > @Peter: I've barely touched this patch, it's just been writing a comment > and fixing benign compilation issues, so credit's all yours really! Ah, it works? Excellent! You can remove the NOT from the SoB then ;-)