[PATCH] sched/fair: Rename SCHED_LOAD_SHIFT to NICE_0_LOAD_SHIFT and remove SCHED_LOAD_SCALE

From: Yuyang Du
Date: Tue Apr 05 2016 - 00:12:27 EST


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: Ben Segall <bsegall@xxxxxxxxxx>
Signed-off-by: Yuyang Du <yuyang.du@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: dietmar.eggemann@xxxxxxx
Cc: lizefan@xxxxxxxxxx
Cc: morten.rasmussen@xxxxxxx
Cc: pjt@xxxxxxxxxx
Cc: umgwanakikbuti@xxxxxxxxx
Cc: vincent.guittot@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1459829551-21625-3-git-send-email-yuyang.du@xxxxxxxxx
[ Rewrote the changelog and fixed the build on 32-bit kernels. ]
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 4 ++--
kernel/sched/sched.h | 22 +++++++++++-----------
2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 76ca86e9fc20..e1485710d1ec 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -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
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index ad83361f9e67..d24e91b0a722 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -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;