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Tue, 04 Oct 2022 04:05:33 -0700 (PDT) MIME-Version: 1.0 References: <20220919095939.761690562@infradead.org> <20220919101521.274051658@infradead.org> In-Reply-To: <20220919101521.274051658@infradead.org> From: Ulf Hansson Date: Tue, 4 Oct 2022 13:04:57 +0200 Message-ID: Subject: Re: [PATCH v2 14/44] cpuidle,cpu_pm: Remove RCU fiddling from cpu_pm_{enter,exit}() To: Peter Zijlstra Cc: richard.henderson@linaro.org, ink@jurassic.park.msu.ru, mattst88@gmail.com, vgupta@kernel.org, linux@armlinux.org.uk, ulli.kroll@googlemail.com, linus.walleij@linaro.org, shawnguo@kernel.org, Sascha Hauer , kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, tony@atomide.com, khilman@kernel.org, catalin.marinas@arm.com, will@kernel.org, guoren@kernel.org, bcain@quicinc.com, chenhuacai@kernel.org, kernel@xen0n.name, geert@linux-m68k.org, sammy@sammy.net, monstr@monstr.eu, tsbogend@alpha.franken.de, dinguyen@kernel.org, jonas@southpole.se, stefan.kristiansson@saunalahti.fi, shorne@gmail.com, James.Bottomley@hansenpartnership.com, deller@gmx.de, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, richard@nod.at, anton.ivanov@cambridgegreys.com, johannes@sipsolutions.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, jgross@suse.com, srivatsa@csail.mit.edu, amakhalov@vmware.com, pv-drivers@vmware.com, boris.ostrovsky@oracle.com, chris@zankel.net, jcmvbkbc@gmail.com, rafael@kernel.org, lenb@kernel.org, pavel@ucw.cz, gregkh@linuxfoundation.org, mturquette@baylibre.com, sboyd@kernel.org, daniel.lezcano@linaro.org, lpieralisi@kernel.org, sudeep.holla@arm.com, agross@kernel.org, bjorn.andersson@linaro.org, konrad.dybcio@somainline.org, anup@brainfault.org, thierry.reding@gmail.com, jonathanh@nvidia.com, jacob.jun.pan@linux.intel.com, atishp@atishpatra.org, Arnd Bergmann , yury.norov@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, dennis@kernel.org, tj@kernel.org, cl@linux.com, rostedt@goodmis.org, pmladek@suse.com, senozhatsky@chromium.org, john.ogness@linutronix.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, fweisbec@gmail.com, ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, Andrew Morton , jpoimboe@kernel.org, linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-omap@vger.kernel.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-perf-users@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-xtensa@linux-xtensa.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-arch@vger.kernel.org, kasan-dev@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Mon, 19 Sept 2022 at 12:17, Peter Zijlstra wrote: > > All callers should still have RCU enabled. > > Signed-off-by: Peter Zijlstra (Intel) > Acked-by: Mark Rutland Reviewed-by: Ulf Hansson Kind regards Uffe > --- > kernel/cpu_pm.c | 9 --------- > 1 file changed, 9 deletions(-) > > --- a/kernel/cpu_pm.c > +++ b/kernel/cpu_pm.c > @@ -30,16 +30,9 @@ static int cpu_pm_notify(enum cpu_pm_eve > { > int ret; > > - /* > - * This introduces a RCU read critical section, which could be > - * disfunctional in cpu idle. Copy RCU_NONIDLE code to let RCU know > - * this. > - */ > - ct_irq_enter_irqson(); > rcu_read_lock(); > ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL); > rcu_read_unlock(); > - ct_irq_exit_irqson(); > > return notifier_to_errno(ret); > } > @@ -49,11 +42,9 @@ static int cpu_pm_notify_robust(enum cpu > unsigned long flags; > int ret; > > - ct_irq_enter_irqson(); > raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags); > ret = raw_notifier_call_chain_robust(&cpu_pm_notifier.chain, event_up, event_down, NULL); > raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags); > - ct_irq_exit_irqson(); > > return notifier_to_errno(ret); > } > >