On 18 March 2013 21:27, Frederic Weisbecker fweisbec@gmail.com wrote:
2013/3/18 Viresh Kumar viresh.kumar@linaro.org:
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%3Ba=shortlog%3Bh=ref...
commit e769ff0d78fd2fb504ae056a44b70bba7c259126 Author: Viresh Kumar viresh.kumar@linaro.org 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 viresh.kumar@linaro.org --- 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) { } - -static inline int sched_select_cpu(unsigned int sd_flags) -{ - return raw_smp_processor_id(); -} #endif -#endif /* CONFIG_SMP */
/* * Only dump TASK_* tasks. (0 for all tasks) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ccd76d7..0265a5e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -627,7 +627,7 @@ void sched_avg_update(struct rq *rq) * returned back. If it is idle, then we must look for another CPU which have * all the flags passed as argument as set. */ -int sched_select_cpu(unsigned int sd_flags) +int sched_select_non_idle_cpu(unsigned int sd_flags) { struct sched_domain *sd; int cpu = smp_processor_id();