Commit-ID: 7d1a941731fabf27e5fb6edbebb79fe856edb4e5 Gitweb: http://git.kernel.org/tip/7d1a941731fabf27e5fb6edbebb79fe856edb4e5 Author: Thomas Gleixner <t...@linutronix.de> AuthorDate: Thu, 21 Mar 2013 22:50:03 +0100 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Mon, 8 Apr 2013 17:39:29 +0200
x86: Use generic idle loop Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Rusty Russell <ru...@rustcorp.com.au> Cc: Paul McKenney <paul...@linux.vnet.ibm.com> Cc: Peter Zijlstra <pet...@infradead.org> Reviewed-by: Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com> Cc: Magnus Damm <magnus.d...@gmail.com> Link: http://lkml.kernel.org/r/20130321215235.486594...@linutronix.de Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: x...@kernel.org --- arch/x86/Kconfig | 1 + arch/x86/kernel/process.c | 105 ++++++++++++---------------------------------- arch/x86/kernel/smpboot.c | 2 +- arch/x86/xen/smp.c | 2 +- 4 files changed, 30 insertions(+), 80 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 70c0f3d..422a72b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -97,6 +97,7 @@ config X86 select GENERIC_IOMAP select DCACHE_WORD_ACCESS select GENERIC_SMP_IDLE_THREAD + select GENERIC_IDLE_LOOP select ARCH_WANT_IPC_PARSE_VERSION if X86_32 select HAVE_ARCH_SECCOMP_FILTER select BUILDTIME_EXTABLE_SORT diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 14ae100..6833bff 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -301,13 +301,7 @@ void exit_idle(void) } #endif -/* - * The idle thread. There's no useful work to be - * done, so just try to conserve power and have a - * low exit latency (ie sit in a loop waiting for - * somebody to say that they'd like to reschedule) - */ -void cpu_idle(void) +void arch_cpu_idle_prepare(void) { /* * If we're the non-boot CPU, nothing set the stack canary up @@ -317,71 +311,40 @@ void cpu_idle(void) * canaries already on the stack wont ever trigger). */ boot_init_stack_canary(); - current_thread_info()->status |= TS_POLLING; - - while (1) { - tick_nohz_idle_enter(); - - while (!need_resched()) { - rmb(); - - if (cpu_is_offline(smp_processor_id())) - play_dead(); - - /* - * Idle routines should keep interrupts disabled - * from here on, until they go to idle. - * Otherwise, idle callbacks can misfire. - */ - local_touch_nmi(); - local_irq_disable(); - - enter_idle(); - - /* Don't trace irqs off for idle */ - stop_critical_timings(); - - /* enter_idle() needs rcu for notifiers */ - rcu_idle_enter(); +} - if (cpuidle_idle_call()) - x86_idle(); +void arch_cpu_idle_enter(void) +{ + local_touch_nmi(); + enter_idle(); +} - rcu_idle_exit(); - start_critical_timings(); +void arch_cpu_idle_exit(void) +{ + __exit_idle(); +} - /* In many cases the interrupt that ended idle - has already called exit_idle. But some idle - loops can be woken up without interrupt. */ - __exit_idle(); - } +void arch_cpu_idle_dead(void) +{ + play_dead(); +} - tick_nohz_idle_exit(); - preempt_enable_no_resched(); - schedule(); - preempt_disable(); - } +/* + * Called from the generic idle code. + */ +void arch_cpu_idle(void) +{ + if (cpuidle_idle_call()) + x86_idle(); } /* - * We use this if we don't have any better - * idle routine.. + * We use this if we don't have any better idle routine.. */ void default_idle(void) { trace_cpu_idle_rcuidle(1, smp_processor_id()); - current_thread_info()->status &= ~TS_POLLING; - /* - * TS_POLLING-cleared state must be visible before we - * test NEED_RESCHED: - */ - smp_mb(); - - if (!need_resched()) - safe_halt(); /* enables interrupts racelessly */ - else - local_irq_enable(); - current_thread_info()->status |= TS_POLLING; + safe_halt(); trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } #ifdef CONFIG_APM_MODULE @@ -411,20 +374,6 @@ void stop_this_cpu(void *dummy) halt(); } -/* - * On SMP it's slightly faster (but much more power-consuming!) - * to poll the ->work.need_resched flag instead of waiting for the - * cross-CPU IPI to arrive. Use this option with caution. - */ -static void poll_idle(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()); -} - bool amd_e400_c1e_detected; EXPORT_SYMBOL(amd_e400_c1e_detected); @@ -489,10 +438,10 @@ static void amd_e400_idle(void) void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) { #ifdef CONFIG_SMP - if (x86_idle == poll_idle && smp_num_siblings > 1) + if (boot_option_idle_override == IDLE_POLL && smp_num_siblings > 1) pr_warn_once("WARNING: polling idle and HT enabled, performance may degrade\n"); #endif - if (x86_idle) + if (x86_idle || boot_option_idle_override == IDLE_POLL) return; if (cpu_has_amd_erratum(amd_erratum_400)) { @@ -517,8 +466,8 @@ static int __init idle_setup(char *str) if (!strcmp(str, "poll")) { pr_info("using polling idle threads\n"); - x86_idle = poll_idle; boot_option_idle_override = IDLE_POLL; + cpu_idle_poll_ctrl(true); } else if (!strcmp(str, "halt")) { /* * When the boot option of idle=halt is added, halt is diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 9f190a2..9c73b51 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -284,7 +284,7 @@ notrace static void __cpuinit start_secondary(void *unused) x86_cpuinit.setup_percpu_clockev(); wmb(); - cpu_idle(); + cpu_startup_entry(CPUHP_ONLINE); } void __init smp_store_boot_cpu_info(void) diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 09ea61d..73642e9 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -95,7 +95,7 @@ static void __cpuinit cpu_bringup(void) static void __cpuinit cpu_bringup_and_idle(void) { cpu_bringup(); - cpu_idle(); + cpu_startup_entry(CPUHP_ONLINE); } static int xen_smp_intr_init(unsigned int cpu) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
