]> err.no Git - linux-2.6/commitdiff
fix idle (arch, acpi and apm) and lockdep
authorPeter Zijlstra <peterz@infradead.org>
Fri, 25 Apr 2008 15:39:01 +0000 (17:39 +0200)
committerIngo Molnar <mingo@elte.hu>
Sat, 26 Apr 2008 22:01:45 +0000 (00:01 +0200)
OK, so 25-mm1 gave a lockdep error which made me look into this.

The first thing that I noticed was the horrible mess; the second thing I
saw was hacks like: 71e93d15612c61c2e26a169567becf088e71b8ff

The problem is that arch idle routines are somewhat inconsitent with
their IRQ state handling and instead of fixing _that_, we go paper over
the problem.

So the thing I've tried to do is set a standard for idle routines and
fix them all up to adhere to that. So the rules are:

  idle routines are entered with IRQs disabled
  idle routines will exit with IRQs enabled

Nearly all already did this in one form or another.

Merge the 32 and 64 bit bits so they no longer have different bugs.

As for the actual lockdep warning; __sti_mwait() did a plainly un-annotated
irq-enable.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/apm_32.c
arch/x86/kernel/process.c
arch/x86/kernel/process_32.c
arch/x86/kernel/process_64.c
drivers/acpi/processor_idle.c
include/asm-x86/processor.h

index f0030a0999c74f01785c4acd7a499778de58a4ff..e4ea362e84800a6c28bf8056ec340aff5fea4bad 100644 (file)
@@ -904,6 +904,7 @@ recalc:
                        original_pm_idle();
                else
                        default_idle();
+               local_irq_disable();
                jiffies_since_last_check = jiffies - last_jiffies;
                if (jiffies_since_last_check > idle_period)
                        goto recalc;
@@ -911,6 +912,8 @@ recalc:
 
        if (apm_idle_done)
                apm_do_busy();
+
+       local_irq_enable();
 }
 
 /**
index 3004d716539dde2b882acd4e0576676531382965..67e9b4a1e89d5a1ac3a3851beaab9d48bbe22c0b 100644 (file)
@@ -4,6 +4,8 @@
 #include <linux/smp.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/pm.h>
 
 struct kmem_cache *task_xstate_cachep;
 
@@ -42,3 +44,118 @@ void arch_task_cache_init(void)
                                  __alignof__(union thread_xstate),
                                  SLAB_PANIC, NULL);
 }
+
+static void do_nothing(void *unused)
+{
+}
+
+/*
+ * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
+ * pm_idle and update to new pm_idle value. Required while changing pm_idle
+ * handler on SMP systems.
+ *
+ * Caller must have changed pm_idle to the new value before the call. Old
+ * pm_idle value will not be used by any CPU after the return of this function.
+ */
+void cpu_idle_wait(void)
+{
+       smp_mb();
+       /* kick all the CPUs so that they exit out of pm_idle */
+       smp_call_function(do_nothing, NULL, 0, 1);
+}
+EXPORT_SYMBOL_GPL(cpu_idle_wait);
+
+/*
+ * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
+ * which can obviate IPI to trigger checking of need_resched.
+ * We execute MONITOR against need_resched and enter optimized wait state
+ * through MWAIT. Whenever someone changes need_resched, we would be woken
+ * up from MWAIT (without an IPI).
+ *
+ * New with Core Duo processors, MWAIT can take some hints based on CPU
+ * capability.
+ */
+void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
+{
+       if (!need_resched()) {
+               __monitor((void *)&current_thread_info()->flags, 0, 0);
+               smp_mb();
+               if (!need_resched())
+                       __mwait(ax, cx);
+       }
+}
+
+/* Default MONITOR/MWAIT with no hints, used for default C1 state */
+static void mwait_idle(void)
+{
+       if (!need_resched()) {
+               __monitor((void *)&current_thread_info()->flags, 0, 0);
+               smp_mb();
+               if (!need_resched())
+                       __sti_mwait(0, 0);
+               else
+                       local_irq_enable();
+       } else
+               local_irq_enable();
+}
+
+
+static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
+{
+       if (force_mwait)
+               return 1;
+       /* Any C1 states supported? */
+       return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0;
+}
+
+/*
+ * 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)
+{
+       local_irq_enable();
+       cpu_relax();
+}
+
+void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
+{
+       static int selected;
+
+       if (selected)
+               return;
+#ifdef CONFIG_X86_SMP
+       if (pm_idle == poll_idle && smp_num_siblings > 1) {
+               printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
+                       " performance may degrade.\n");
+       }
+#endif
+       if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
+               /*
+                * Skip, if setup has overridden idle.
+                * One CPU supports mwait => All CPUs supports mwait
+                */
+               if (!pm_idle) {
+                       printk(KERN_INFO "using mwait in idle threads.\n");
+                       pm_idle = mwait_idle;
+               }
+       }
+       selected = 1;
+}
+
+static int __init idle_setup(char *str)
+{
+       if (!strcmp(str, "poll")) {
+               printk("using polling idle threads.\n");
+               pm_idle = poll_idle;
+       } else if (!strcmp(str, "mwait"))
+               force_mwait = 1;
+       else
+               return -1;
+
+       boot_option_idle_override = 1;
+       return 0;
+}
+early_param("idle", idle_setup);
+
index 77de848bd1fbbca9d498a07f4c0fbc65cf05c43b..f8476dfbb60d9818f5da08d3a5b95a223930964f 100644 (file)
@@ -111,12 +111,10 @@ void default_idle(void)
                 */
                smp_mb();
 
-               local_irq_disable();
-               if (!need_resched()) {
+               if (!need_resched())
                        safe_halt();    /* enables interrupts racelessly */
-                       local_irq_disable();
-               }
-               local_irq_enable();
+               else
+                       local_irq_enable();
                current_thread_info()->status |= TS_POLLING;
        } else {
                local_irq_enable();
@@ -128,17 +126,6 @@ void default_idle(void)
 EXPORT_SYMBOL(default_idle);
 #endif
 
-/*
- * 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)
-{
-       local_irq_enable();
-       cpu_relax();
-}
-
 #ifdef CONFIG_HOTPLUG_CPU
 #include <asm/nmi.h>
 /* We don't actually take CPU down, just spin without interrupts. */
@@ -196,6 +183,7 @@ void cpu_idle(void)
                        if (cpu_is_offline(cpu))
                                play_dead();
 
+                       local_irq_disable();
                        __get_cpu_var(irq_stat).idle_timestamp = jiffies;
                        idle();
                }
@@ -206,104 +194,6 @@ void cpu_idle(void)
        }
 }
 
-static void do_nothing(void *unused)
-{
-}
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-       smp_mb();
-       /* kick all the CPUs so that they exit out of pm_idle */
-       smp_call_function(do_nothing, NULL, 0, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
-
-/*
- * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
- * which can obviate IPI to trigger checking of need_resched.
- * We execute MONITOR against need_resched and enter optimized wait state
- * through MWAIT. Whenever someone changes need_resched, we would be woken
- * up from MWAIT (without an IPI).
- *
- * New with Core Duo processors, MWAIT can take some hints based on CPU
- * capability.
- */
-void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
-{
-       if (!need_resched()) {
-               __monitor((void *)&current_thread_info()->flags, 0, 0);
-               smp_mb();
-               if (!need_resched())
-                       __sti_mwait(ax, cx);
-               else
-                       local_irq_enable();
-       } else
-               local_irq_enable();
-}
-
-/* Default MONITOR/MWAIT with no hints, used for default C1 state */
-static void mwait_idle(void)
-{
-       local_irq_enable();
-       mwait_idle_with_hints(0, 0);
-}
-
-static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
-{
-       if (force_mwait)
-               return 1;
-       /* Any C1 states supported? */
-       return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0;
-}
-
-void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
-{
-       static int selected;
-
-       if (selected)
-               return;
-#ifdef CONFIG_X86_SMP
-       if (pm_idle == poll_idle && smp_num_siblings > 1) {
-               printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
-                       " performance may degrade.\n");
-       }
-#endif
-       if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
-               /*
-                * Skip, if setup has overridden idle.
-                * One CPU supports mwait => All CPUs supports mwait
-                */
-               if (!pm_idle) {
-                       printk(KERN_INFO "using mwait in idle threads.\n");
-                       pm_idle = mwait_idle;
-               }
-       }
-       selected = 1;
-}
-
-static int __init idle_setup(char *str)
-{
-       if (!strcmp(str, "poll")) {
-               printk("using polling idle threads.\n");
-               pm_idle = poll_idle;
-       } else if (!strcmp(str, "mwait"))
-               force_mwait = 1;
-       else
-               return -1;
-
-       boot_option_idle_override = 1;
-       return 0;
-}
-early_param("idle", idle_setup);
-
 void __show_registers(struct pt_regs *regs, int all)
 {
        unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
index 131c2ee7ac5618e9fc92f576f4db19676bd235af..e2319f39988b042f364a73174a0d2ac254a5b60d 100644 (file)
@@ -106,26 +106,13 @@ void default_idle(void)
         * test NEED_RESCHED:
         */
        smp_mb();
-       local_irq_disable();
-       if (!need_resched()) {
+       if (!need_resched())
                safe_halt();    /* enables interrupts racelessly */
-               local_irq_disable();
-       }
-       local_irq_enable();
+       else
+               local_irq_enable();
        current_thread_info()->status |= TS_POLLING;
 }
 
-/*
- * On SMP it's slightly faster (but much more power-consuming!)
- * to poll the ->need_resched flag instead of waiting for the
- * cross-CPU IPI to arrive. Use this option with caution.
- */
-static void poll_idle(void)
-{
-       local_irq_enable();
-       cpu_relax();
-}
-
 #ifdef CONFIG_HOTPLUG_CPU
 DECLARE_PER_CPU(int, cpu_state);
 
@@ -192,110 +179,6 @@ void cpu_idle(void)
        }
 }
 
-static void do_nothing(void *unused)
-{
-}
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-       smp_mb();
-       /* kick all the CPUs so that they exit out of pm_idle */
-       smp_call_function(do_nothing, NULL, 0, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
-
-/*
- * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
- * which can obviate IPI to trigger checking of need_resched.
- * We execute MONITOR against need_resched and enter optimized wait state
- * through MWAIT. Whenever someone changes need_resched, we would be woken
- * up from MWAIT (without an IPI).
- *
- * New with Core Duo processors, MWAIT can take some hints based on CPU
- * capability.
- */
-void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
-{
-       if (!need_resched()) {
-               __monitor((void *)&current_thread_info()->flags, 0, 0);
-               smp_mb();
-               if (!need_resched())
-                       __mwait(ax, cx);
-       }
-}
-
-/* Default MONITOR/MWAIT with no hints, used for default C1 state */
-static void mwait_idle(void)
-{
-       if (!need_resched()) {
-               __monitor((void *)&current_thread_info()->flags, 0, 0);
-               smp_mb();
-               if (!need_resched())
-                       __sti_mwait(0, 0);
-               else
-                       local_irq_enable();
-       } else {
-               local_irq_enable();
-       }
-}
-
-
-static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
-{
-       if (force_mwait)
-               return 1;
-       /* Any C1 states supported? */
-       return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0;
-}
-
-void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
-{
-       static int selected;
-
-       if (selected)
-               return;
-#ifdef CONFIG_X86_SMP
-       if (pm_idle == poll_idle && smp_num_siblings > 1) {
-               printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
-                       " performance may degrade.\n");
-       }
-#endif
-       if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
-               /*
-                * Skip, if setup has overridden idle.
-                * One CPU supports mwait => All CPUs supports mwait
-                */
-               if (!pm_idle) {
-                       printk(KERN_INFO "using mwait in idle threads.\n");
-                       pm_idle = mwait_idle;
-               }
-       }
-       selected = 1;
-}
-
-static int __init idle_setup(char *str)
-{
-       if (!strcmp(str, "poll")) {
-               printk("using polling idle threads.\n");
-               pm_idle = poll_idle;
-       } else if (!strcmp(str, "mwait"))
-               force_mwait = 1;
-       else
-               return -1;
-
-       boot_option_idle_override = 1;
-       return 0;
-}
-early_param("idle", idle_setup);
-
 /* Prints also some state that isn't saved in the pt_regs */
 void __show_regs(struct pt_regs * regs)
 {
index 788da9781f80ffb5311b396cd3557b0786376dcd..0d90ff5fd1172440b724f161b1ad51657511eb3a 100644 (file)
@@ -418,13 +418,12 @@ static void acpi_processor_idle(void)
 
        cx = pr->power.state;
        if (!cx || acpi_idle_suspend) {
-               if (pm_idle_save)
-                       pm_idle_save();
-               else
+               if (pm_idle_save) {
+                       pm_idle_save(); /* enables IRQs */
+               } else {
                        acpi_safe_halt();
-
-               if (irqs_disabled())
                        local_irq_enable();
+               }
 
                return;
        }
@@ -520,10 +519,12 @@ static void acpi_processor_idle(void)
                 * Use the appropriate idle routine, the one that would
                 * be used without acpi C-states.
                 */
-               if (pm_idle_save)
-                       pm_idle_save();
-               else
+               if (pm_idle_save) {
+                       pm_idle_save(); /* enables IRQs */
+               } else {
                        acpi_safe_halt();
+                       local_irq_enable();
+               }
 
                /*
                 * TBD: Can't get time duration while in C1, as resumes
@@ -534,8 +535,6 @@ static void acpi_processor_idle(void)
                 *       skew otherwise.
                 */
                sleep_ticks = 0xFFFFFFFF;
-               if (irqs_disabled())
-                       local_irq_enable();
 
                break;
 
index 117343b0c271f7f3781d8d67e5e0370671b1e1a7..2e7974ec77eca6e94b2ee503d02580a87db717a2 100644 (file)
@@ -722,6 +722,7 @@ static inline void __mwait(unsigned long eax, unsigned long ecx)
 
 static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
 {
+       trace_hardirqs_on();
        /* "mwait %eax, %ecx;" */
        asm volatile("sti; .byte 0x0f, 0x01, 0xc9;"
                     :: "a" (eax), "c" (ecx));