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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Jun 14, 2022 at 06:42:14PM +0200, Peter Zijlstra wrote: > On Tue, Jun 14, 2022 at 05:13:16PM +0100, Mark Rutland wrote: > > On Wed, Jun 08, 2022 at 04:27:38PM +0200, Peter Zijlstra wrote: > > > All callers should still have RCU enabled. > > > > IIUC with that true we should be able to drop the RCU_NONIDLE() from > > drivers/perf/arm_pmu.c, as we only needed that for an invocation via a pm > > notifier. > > > > I should be able to give that a spin on some hardware. > > > > > > > > Signed-off-by: Peter Zijlstra (Intel) > > > --- > > > 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. > > > - */ > > > - rcu_irq_enter_irqson(); > > > rcu_read_lock(); > > > ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL); > > > rcu_read_unlock(); > > > - rcu_irq_exit_irqson(); > > > > To make this easier to debug, is it worth adding an assertion that RCU is > > watching here? e.g. > > > > RCU_LOCKDEP_WARN(!rcu_is_watching(), > > "cpu_pm_notify() used illegally from EQS"); > > > > My understanding is that rcu_read_lock() implies something along those > lines when PROVE_RCU. Ah, duh. Given that: Acked-by: Mark Rutland Mark. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv