On 18 March 2013 21:27, Frederic Weisbecker [off-list ref] wrote:

2013/3/18 Viresh Kumar [off-list ref]:

quoted

quoted

It would be nice to have some more precise naming. sched_select_busy_cpu() ?

You are correct that name can be improved but busy may give it a different
meaning. Maybe sched_select_non_idle_cpu()?

That works too yeah.

Here is the fixup that i applied (it fixes another stupid mistake in sched.h).
I have pushed this series here again:

http://git.linaro.org/gitweb?p=people/vireshk/linux.git;a=shortlog;h=refs/heads/sched-wq-migration-v3

commit e769ff0d78fd2fb504ae056a44b70bba7c259126
Author: Viresh Kumar [off-list ref]
Date:   Fri Sep 14 15:13:05 2012 +0530

    fixup! sched: Create sched_select_cpu() to give preferred CPU for
power saving

    Signed-off-by: Viresh Kumar [off-list ref]
---
 include/linux/sched.h | 19 ++++++++++---------
 kernel/sched/core.c   |  2 +-
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 216fa0d..db6655a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h

@@ -231,11 +231,18 @@ extern void init_idle_bootup_task(struct

task_struct *idle);
 extern int runqueue_is_locked(int cpu);

 #ifdef CONFIG_SMP
-extern int sched_select_cpu(unsigned int sd_flags);
+extern int sched_select_non_idle_cpu(unsigned int sd_flags);
+#else
+static inline int sched_select_non_idle_cpu(unsigned int sd_flags)
+{
+       return smp_processor_id();
+}
+#endif

-#ifdef CONFIG_NO_HZ
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
 extern void nohz_balance_enter_idle(int cpu);
 extern void set_cpu_sd_state_idle(void);
+
 /*
  * In the semi idle case, use the nearest busy cpu for migrating timers
  * from an idle cpu.  This is good for power-savings.

@@ -244,17 +251,11 @@ extern void set_cpu_sd_state_idle(void);
  * selecting an idle cpu will add more delays to the timers than intended
  * (as that cpu's timer base may not be uptodate wrt jiffies etc).
  */
-#define get_nohz_timer_target() sched_select_cpu(0)
+#define get_nohz_timer_target() sched_select_non_idle_cpu(0)
 #else
 static inline void nohz_balance_enter_idle(int cpu) { }
 static inline void set_cpu_sd_state_idle(void) { }