Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756659Ab1CaGD6 (ORCPT ); Thu, 31 Mar 2011 02:03:58 -0400 Received: from vms173013pub.verizon.net ([206.46.173.13]:49272 "EHLO vms173013pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755853Ab1CaGDy (ORCPT ); Thu, 31 Mar 2011 02:03:54 -0400 From: Len Brown To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, Len Brown Subject: [PATCH 9/9] x86 idle: delete mwait_idle() Date: Thu, 31 Mar 2011 02:03:24 -0400 Message-id: <9797d1edfe558e20297785ce5b4e26339b74ea2c.1301550524.git.len.brown@intel.com> X-Mailer: git-send-email 1.7.4.2.406.gbe91 In-reply-to: <1301551404-8263-1-git-send-email-lenb@kernel.org> References: <1300950508-22746-1-git-send-email-lenb@kernel.org> <1301551404-8263-1-git-send-email-lenb@kernel.org> In-reply-to: <67e90d97e0a77df4acd0c75e1bacc7714e011f3e.1301550524.git.len.brown@intel.com> References: <67e90d97e0a77df4acd0c75e1bacc7714e011f3e.1301550524.git.len.brown@intel.com> X-Patchwork-Hint: ignore Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5233 Lines: 145 From: Len Brown For ACPI mode, mwait_with_hints() in cstate.c is used instead of process.c's mwait_idle(). For INTEL_IDLE mode, the mwait in intel_idle() is used instead of process.c's mwait_idle(). So delete process.c's mwait_idle(). This will change the behaviour of SMP sysgtems that are running !ACPI and !INTEL_IDLE kernels -- they will use HALT instead of MWAIT. This deletes the "idle=mwait" parameter, and thus the boot_option_idle_override == IDLE_FORCE_MWAIT flag. Signed-off-by: Len Brown --- Documentation/kernel-parameters.txt | 7 +------ arch/x86/include/asm/processor.h | 2 +- arch/x86/kernel/process.c | 34 +--------------------------------- drivers/acpi/processor_idle.c | 1 - 4 files changed, 3 insertions(+), 41 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e6b4843..ce9624a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -917,16 +917,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Claim all unknown PCI IDE storage controllers. idle= [X86] - Format: idle=poll, idle=mwait, idle=halt, idle=nomwait + Format: idle=poll, idle=halt, idle=nomwait Poll forces a polling idle loop that can slightly improve the performance of waking up a idle CPU, but will use a lot of power and make the system run hot. Not recommended. - idle=mwait: On systems which support MONITOR/MWAIT but - the kernel chose to not use it because it doesn't save - as much power as a normal idle loop, use the - MONITOR/MWAIT idle loop anyways. Performance should be - the same as idle=poll. idle=halt: Halt is forced to be used for CPU idle. In such case C2/C3 won't be used again. idle=nomwait: Disable mwait for CPU C-states diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 3b288ca..0d8d2a4 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -752,7 +752,7 @@ extern unsigned long boot_option_idle_override; extern bool c1e_detected; enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_NOMWAIT, - IDLE_POLL, IDLE_FORCE_MWAIT}; + IDLE_POLL}; extern void enable_sep_cpu(void); extern int sysenter_setup(void); diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 9f08e7b..4b93d50 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -399,27 +399,6 @@ void cpu_idle_wait(void) } EXPORT_SYMBOL_GPL(cpu_idle_wait); -/* Default MONITOR/MWAIT with no hints, used for default C1 state */ -static void mwait_idle(void) -{ - if (!need_resched()) { - trace_power_start(POWER_CSTATE, 1, smp_processor_id()); - trace_cpu_idle(1, smp_processor_id()); - if (cpu_has(__this_cpu_ptr(&cpu_info), X86_FEATURE_CLFLUSH_MONITOR)) - clflush((void *)¤t_thread_info()->flags); - - __monitor((void *)¤t_thread_info()->flags, 0, 0); - smp_mb(); - if (!need_resched()) - __sti_mwait(0, 0); - else - local_irq_enable(); - trace_power_end(smp_processor_id()); - trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()); - } else - local_irq_enable(); -} - /* * On SMP it's slightly faster (but much more power-consuming!) * to poll the ->work.need_resched flag instead of waiting for the @@ -457,9 +436,6 @@ int mwait_usable(const struct cpuinfo_x86 *c) { u32 eax, ebx, ecx, edx; - if (boot_option_idle_override == IDLE_FORCE_MWAIT) - return 1; - if (c->cpuid_level < MWAIT_INFO) return 0; @@ -548,13 +524,7 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) if (pm_idle) return; - if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) { - /* - * One CPU supports mwait => All CPUs supports mwait - */ - printk(KERN_INFO "using mwait in idle threads.\n"); - pm_idle = mwait_idle; - } else if (cpu_has_amd_erratum(amd_erratum_400)) { + if (cpu_has_amd_erratum(amd_erratum_400)) { /* E400: APIC timer interrupt does not wake up CPU from C1e */ printk(KERN_INFO "using C1E aware idle routine\n"); pm_idle = c1e_idle; @@ -578,8 +548,6 @@ static int __init idle_setup(char *str) printk("using polling idle threads.\n"); pm_idle = poll_idle; boot_option_idle_override = IDLE_POLL; - } else if (!strcmp(str, "mwait")) { - boot_option_idle_override = IDLE_FORCE_MWAIT; } else if (!strcmp(str, "halt")) { /* * When the boot option of idle=halt is added, halt is diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index d615b7d..a15390c 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -82,7 +82,6 @@ module_param(latency_factor, uint, 0644); static int disabled_by_idle_boot_param(void) { return boot_option_idle_override == IDLE_POLL || - boot_option_idle_override == IDLE_FORCE_MWAIT || boot_option_idle_override == IDLE_HALT; } -- 1.7.4.2.406.gbe91 -- 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/