Commit 172895e6 authored by Yuyang Du's avatar Yuyang Du Committed by Ingo Molnar
Browse files

sched/fair: Rename SCHED_LOAD_SHIFT to NICE_0_LOAD_SHIFT and remove SCHED_LOAD_SCALE 



After cleaning up the sched metrics, there are two definitions that are
ambiguous and confusing: SCHED_LOAD_SHIFT and SCHED_LOAD_SHIFT.

Resolve this:

 - Rename SCHED_LOAD_SHIFT to NICE_0_LOAD_SHIFT, which better reflects what
   it is.

 - Replace SCHED_LOAD_SCALE use with SCHED_CAPACITY_SCALE and remove SCHED_LOAD_SCALE.

Suggested-by: default avatarBen Segall <bsegall@google.com>
Signed-off-by: default avatarYuyang Du <yuyang.du@intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: umgwanakikbuti@gmail.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1459829551-21625-3-git-send-email-yuyang.du@intel.com


[ Rewrote the changelog and fixed the build on 32-bit kernels. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 6ecdd749

kernel/sched/fair.c

+2 −2
Original line number Diff line number Diff line
@@ -719,7 +719,7 @@ void post_init_entity_util_avg(struct sched_entity *se) 
{

	struct cfs_rq *cfs_rq = cfs_rq_of(se);

	struct sched_avg *sa = &se->avg;

	long cap = (long)(scale_load_down(SCHED_LOAD_SCALE) - cfs_rq->avg.util_avg) / 2;

	long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2;



	if (cap > 0) {

		if (cfs_rq->avg.util_avg != 0) {
@@ -7010,7 +7010,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s 
	if (busiest->group_type == group_overloaded &&

	    local->group_type   == group_overloaded) {

		load_above_capacity = busiest->sum_nr_running *

					SCHED_LOAD_SCALE;

				      scale_load_down(NICE_0_LOAD);

		if (load_above_capacity > busiest->group_capacity)

			load_above_capacity -= busiest->group_capacity;

		else

kernel/sched/sched.h

+11 −11
Original line number Diff line number Diff line
@@ -56,25 +56,25 @@ static inline void cpu_load_update_active(struct rq *this_rq) { } 
 * increase coverage and consistency always enable it on 64bit platforms.

 */

#ifdef CONFIG_64BIT

# define SCHED_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)

# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)

# define scale_load(w)		((w) << SCHED_FIXEDPOINT_SHIFT)

# define scale_load_down(w)	((w) >> SCHED_FIXEDPOINT_SHIFT)

#else

# define SCHED_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT)

# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT)

# define scale_load(w)		(w)

# define scale_load_down(w)	(w)

#endif



#define SCHED_LOAD_SCALE	(1L << SCHED_LOAD_SHIFT)



/*

 * NICE_0's weight (visible to users) and its load (invisible to users) have

 * independent ranges, but they should be well calibrated. We use scale_load()

 * and scale_load_down(w) to convert between them, and the following must be true:

 * scale_load(sched_prio_to_weight[20]) == NICE_0_LOAD

 * Task weight (visible to users) and its load (invisible to users) have

 * independent resolution, but they should be well calibrated. We use

 * scale_load() and scale_load_down(w) to convert between them. The

 * following must be true:

 *

 *  scale_load(sched_prio_to_weight[USER_PRIO(NICE_TO_PRIO(0))]) == NICE_0_LOAD

 *

 */

#define NICE_0_LOAD		SCHED_LOAD_SCALE

#define NICE_0_SHIFT		SCHED_LOAD_SHIFT

#define NICE_0_LOAD		(1L << NICE_0_LOAD_SHIFT)



/*

 * Single value that decides SCHED_DEADLINE internal math precision.
@@ -863,7 +863,7 @@ DECLARE_PER_CPU(struct sched_domain *, sd_asym); 
struct sched_group_capacity {

	atomic_t ref;

	/*

	 * CPU capacity of this group, SCHED_LOAD_SCALE being max capacity

	 * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity

	 * for a single CPU.

	 */

	unsigned int capacity;

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