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Date: Mon, 8 Apr 2013 13:47:44 -0700
From: tip-bot for Thomas Gleixner <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
rusty@...tcorp.com.au, torvalds@...ux-foundation.org,
peterz@...radead.org, srivatsa.bhat@...ux.vnet.ibm.com,
paulmck@...ux.vnet.ibm.com, tglx@...utronix.de,
magnus.damm@...il.com
Subject: [tip:smp/hotplug] x86: Use generic idle loop
Commit-ID: 7d1a941731fabf27e5fb6edbebb79fe856edb4e5
Gitweb: http://git.kernel.org/tip/7d1a941731fabf27e5fb6edbebb79fe856edb4e5
Author: Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Thu, 21 Mar 2013 22:50:03 +0100
Committer: Thomas Gleixner <tglx@...utronix.de>
CommitDate: Mon, 8 Apr 2013 17:39:29 +0200
x86: Use generic idle loop
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Rusty Russell <rusty@...tcorp.com.au>
Cc: Paul McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@...il.com>
Link: http://lkml.kernel.org/r/20130321215235.486594473@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: x86@...nel.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)
--
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