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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 , Marcelo Tosatti , Yair Podemsky , Daniel Wagner , Petr Tesarik Subject: Re: [RFC PATCH v3 12/15] context_tracking,x86: Defer kernel text patching IPIs Message-ID: <20241120151308.GL19989@noisy.programming.kicks-ass.net> References: <20241119153502.41361-1-vschneid@redhat.com> <20241119153502.41361-13-vschneid@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241119153502.41361-13-vschneid@redhat.com> X-Stat-Signature: oruuiqszu4tyit9rof4aohu38jhgs6qs X-Rspam-User: X-Rspamd-Queue-Id: B2E9E1C001C X-Rspamd-Server: rspam02 X-HE-Tag: 1732115508-798732 X-HE-Meta: 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 sHY7N03N ylXLBSm+d8qylsQvNwV+cFR4B+NUBpu/GnmFFNrRwDz6rN/cVXT18zHi/trVdwKZBqnsk9ckRbI/Z6CqlmzRR6A8h25bAraIpMQkrkA19P4ice8mz/riLDWvIuSd1U+AbyaW27JUljcCc9XAoJNDDg+3wF7d3kAbN05sg0D+fsFy+I4SeYWQ4PHzPGzeM6+bNS7obj9pExwr5+G5TunXdIvREm63v63KmtNdp+Saa04mT/OtAZmoHkjQSmB8M66YYjttdRkOwf6eD+f6lojrTTQY2l6DJiV68gwunRmamRyK1txlNsLEtwPv+kg== 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 Tue, Nov 19, 2024 at 04:34:59PM +0100, Valentin Schneider wrote: > +static void __text_poke_sync(smp_cond_func_t cond_func) > +{ > + on_each_cpu_cond(cond_func, do_sync_core, NULL, 1); > +} > + > void text_poke_sync(void) > { > - on_each_cpu(do_sync_core, NULL, 1); > + __text_poke_sync(NULL); > +} > + > +void text_poke_sync_deferrable(void) > +{ > + __text_poke_sync(do_sync_core_defer_cond); > } How about we unwrap some of that like so: > /* > @@ -2257,6 +2273,8 @@ static int tp_vec_nr; > static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries) > { > unsigned char int3 = INT3_INSN_OPCODE; > + bool force_ipi = false; > + void (*sync_fn)(void); smp_cond_func_t cond = do_sync_core_defer_cond; > unsigned int i; > int do_sync; > > @@ -2291,11 +2309,18 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries > * First step: add a int3 trap to the address that will be patched. > */ > for (i = 0; i < nr_entries; i++) { > + /* > + * Record that we need to send the IPI if at least one location > + * in the batch requires it. > + */ > + force_ipi |= tp[i].force_ipi; if (tp[i].force_ipi) cond = NULL; > tp[i].old = *(u8 *)text_poke_addr(&tp[i]); > text_poke(text_poke_addr(&tp[i]), &int3, INT3_INSN_SIZE); > } > > - text_poke_sync(); > + sync_fn = force_ipi ? text_poke_sync : text_poke_sync_deferrable; > + > + sync_fn(); __text_poke_sync(cond);