Re: [PATCH 2/3] smp: Adding new function wake_up_all_idle_cpus()

2014-09-04 Thread Daniel Lezcano 

On 09/04/2014 09:17 AM, Chuansheng Liu wrote:

Currently kick_all_cpus_sync() can break non-polling idle cpus
thru IPI interrupts.

But sometimes we need to break the polling idle cpus immediately
to reselect the suitable c-state, also for non-idle cpus, we need
to do nothing if we try to wake up them.

Here adding one new function wake_up_all_idle_cpus() to let all cpus
out of idle based on function wake_up_if_idle().


Acked-by: Daniel Lezcano 


Signed-off-by: Chuansheng Liu 
---
  include/linux/smp.h |2 ++
  kernel/smp.c|   22 ++
  2 files changed, 24 insertions(+)

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 34347f2..93dff5f 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -100,6 +100,7 @@ int smp_call_function_any(const struct cpumask *mask,
  smp_call_func_t func, void *info, int wait);

  void kick_all_cpus_sync(void);
+void wake_up_all_idle_cpus(void);

  /*
   * Generic and arch helpers
@@ -148,6 +149,7 @@ smp_call_function_any(const struct cpumask *mask, 
smp_call_func_t func,
  }

  static inline void kick_all_cpus_sync(void) {  }
+static inline void wake_up_all_idle_cpus(void) {  }

  #endif /* !SMP */

diff --git a/kernel/smp.c b/kernel/smp.c
index aff8aa1..9e0d0b2 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -13,6 +13,7 @@
  #include 
  #include 
  #include 
+#include 

  #include "smpboot.h"

@@ -699,3 +700,24 @@ void kick_all_cpus_sync(void)
smp_call_function(do_nothing, NULL, 1);
  }
  EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
+
+/**
+ * wake_up_all_idle_cpus - break all cpus out of idle
+ * wake_up_all_idle_cpus try to break all cpus which is in idle state even
+ * including idle polling cpus, for non-idle cpus, we will do nothing
+ * for them.
+ */
+void wake_up_all_idle_cpus(void)
+{
+   int cpu;
+
+   preempt_disable();
+   for_each_online_cpu(cpu) {
+   if (cpu == smp_processor_id())
+   continue;
+
+   wake_up_if_idle(cpu);
+   }
+   preempt_enable();
+}
+EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);




--
  Linaro.org │ Open source software for ARM SoCs

Follow Linaro:   Facebook |
 Twitter |
 Blog

--
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/

[PATCH 2/3] smp: Adding new function wake_up_all_idle_cpus()

2014-09-04 Thread Chuansheng Liu 
Currently kick_all_cpus_sync() can break non-polling idle cpus
thru IPI interrupts.

But sometimes we need to break the polling idle cpus immediately
to reselect the suitable c-state, also for non-idle cpus, we need
to do nothing if we try to wake up them.

Here adding one new function wake_up_all_idle_cpus() to let all cpus
out of idle based on function wake_up_if_idle().

Signed-off-by: Chuansheng Liu 
---
 include/linux/smp.h |2 ++
 kernel/smp.c|   22 ++
 2 files changed, 24 insertions(+)

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 34347f2..93dff5f 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -100,6 +100,7 @@ int smp_call_function_any(const struct cpumask *mask,
  smp_call_func_t func, void *info, int wait);
 
 void kick_all_cpus_sync(void);
+void wake_up_all_idle_cpus(void);
 
 /*
  * Generic and arch helpers
@@ -148,6 +149,7 @@ smp_call_function_any(const struct cpumask *mask, 
smp_call_func_t func,
 }
 
 static inline void kick_all_cpus_sync(void) {  }
+static inline void wake_up_all_idle_cpus(void) {  }
 
 #endif /* !SMP */
 
diff --git a/kernel/smp.c b/kernel/smp.c
index aff8aa1..9e0d0b2 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -13,6 +13,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include "smpboot.h"
 
@@ -699,3 +700,24 @@ void kick_all_cpus_sync(void)
smp_call_function(do_nothing, NULL, 1);
 }
 EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
+
+/**
+ * wake_up_all_idle_cpus - break all cpus out of idle
+ * wake_up_all_idle_cpus try to break all cpus which is in idle state even
+ * including idle polling cpus, for non-idle cpus, we will do nothing
+ * for them.
+ */
+void wake_up_all_idle_cpus(void)
+{
+   int cpu;
+
+   preempt_disable();
+   for_each_online_cpu(cpu) {
+   if (cpu == smp_processor_id())
+   continue;
+
+   wake_up_if_idle(cpu);
+   }
+   preempt_enable();
+}
+EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);
-- 
1.7.9.5

--
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/