Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935954Ab3DHUO0 (ORCPT ); Mon, 8 Apr 2013 16:14:26 -0400 Received: from terminus.zytor.com ([198.137.202.10]:40488 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935890Ab3DHUOY (ORCPT ); Mon, 8 Apr 2013 16:14:24 -0400 Date: Mon, 8 Apr 2013 13:14:03 -0700 From: tip-bot for Thomas Gleixner Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, rusty@rustcorp.com.au, torvalds@linux-foundation.org, peterz@infradead.org, srivatsa.bhat@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, tglx@linutronix.de, magnus.damm@gmail.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, rusty@rustcorp.com.au, peterz@infradead.org, srivatsa.bhat@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, tglx@linutronix.de, magnus.damm@gmail.com In-Reply-To: <20130321215233.646635455@linutronix.de> References: <20130321215233.646635455@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:smp/hotplug] idle: Implement generic idle function Git-Commit-ID: d166991234347215dc23fc9dc15a63a83a1a54e1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Mon, 08 Apr 2013 13:14:09 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4855 Lines: 186 Commit-ID: d166991234347215dc23fc9dc15a63a83a1a54e1 Gitweb: http://git.kernel.org/tip/d166991234347215dc23fc9dc15a63a83a1a54e1 Author: Thomas Gleixner AuthorDate: Thu, 21 Mar 2013 22:49:35 +0100 Committer: Thomas Gleixner CommitDate: Mon, 8 Apr 2013 17:39:23 +0200 idle: Implement generic idle function All idle functions in arch/* are more or less the same, plus minus a few bugs and extra instrumentation, tickless support and other optional items. Implement a generic idle function which resembles the functionality found in arch/. Provide weak arch_cpu_idle_* functions which can be overridden by the architecture code if needed. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Rusty Russell Cc: Paul McKenney Cc: Peter Zijlstra Reviewed-by: Cc: Srivatsa S. Bhat Cc: Magnus Damm Link: http://lkml.kernel.org/r/20130321215233.646635455@linutronix.de Signed-off-by: Thomas Gleixner --- arch/Kconfig | 3 ++ include/linux/cpu.h | 8 ++++ kernel/cpu/idle.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 116 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index 1455579..a699f37 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -216,6 +216,9 @@ config USE_GENERIC_SMP_HELPERS config GENERIC_SMP_IDLE_THREAD bool +config GENERIC_IDLE_LOOP + bool + # Select if arch init_task initializer is different to init/init_task.c config ARCH_INIT_TASK bool diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 7419e30..c6f6e08 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -220,4 +220,12 @@ enum cpuhp_state { void cpu_startup_entry(enum cpuhp_state state); void cpu_idle(void); +void cpu_idle_poll_ctrl(bool enable); + +void arch_cpu_idle(void); +void arch_cpu_idle_prepare(void); +void arch_cpu_idle_enter(void); +void arch_cpu_idle_exit(void); +void arch_cpu_idle_dead(void); + #endif /* _LINUX_CPU_H_ */ diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c index 1908f00..54c3203 100644 --- a/kernel/cpu/idle.c +++ b/kernel/cpu/idle.c @@ -3,8 +3,113 @@ */ #include #include +#include +#include +#include + +#include + +#ifndef CONFIG_GENERIC_IDLE_LOOP void cpu_startup_entry(enum cpuhp_state state) { cpu_idle(); } +#else + +static int __read_mostly cpu_idle_force_poll; + +void cpu_idle_poll_ctrl(bool enable) +{ + if (enable) { + cpu_idle_force_poll++; + } else { + cpu_idle_force_poll--; + WARN_ON_ONCE(cpu_idle_force_poll < 0); + } +} + +#ifdef CONFIG_GENERIC_IDLE_POLL_SETUP +static int __init cpu_idle_poll_setup(char *__unused) +{ + cpu_idle_force_poll = 1; + return 1; +} +__setup("nohlt", cpu_idle_poll_setup); + +static int __init cpu_idle_nopoll_setup(char *__unused) +{ + cpu_idle_force_poll = 0; + return 1; +} +__setup("hlt", cpu_idle_nopoll_setup); +#endif + +static inline int cpu_idle_poll(void) +{ + trace_cpu_idle_rcuidle(0, smp_processor_id()); + local_irq_enable(); + while (!need_resched()) + cpu_relax(); + trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); + return 1; +} + +/* Weak implementations for optional arch specific functions */ +void __weak arch_cpu_idle_prepare(void) { } +void __weak arch_cpu_idle_enter(void) { } +void __weak arch_cpu_idle_exit(void) { } +void __weak arch_cpu_idle_dead(void) { } +void __weak arch_cpu_idle(void) +{ + cpu_idle_force_poll = 1; +} + +/* + * Generic idle loop implementation + */ +static void cpu_idle_loop(void) +{ + while (1) { + tick_nohz_idle_enter(); + + while (!need_resched()) { + check_pgt_cache(); + rmb(); + + if (cpu_is_offline(smp_processor_id())) + arch_cpu_idle_dead(); + + local_irq_disable(); + arch_cpu_idle_enter(); + + if (cpu_idle_force_poll) { + cpu_idle_poll(); + } else { + current_clr_polling(); + if (!need_resched()) { + stop_critical_timings(); + rcu_idle_enter(); + arch_cpu_idle(); + WARN_ON_ONCE(irqs_disabled()); + rcu_idle_exit(); + start_critical_timings(); + } else { + local_irq_enable(); + } + current_set_polling(); + } + arch_cpu_idle_exit(); + } + tick_nohz_idle_exit(); + schedule_preempt_disabled(); + } +} + +void cpu_startup_entry(enum cpuhp_state state) +{ + current_set_polling(); + arch_cpu_idle_prepare(); + cpu_idle_loop(); +} +#endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/