Re: [PATCH v8 04/16] sched/core: uclamp: Add system default clamps

[Peter Zijlstra]

There was a bunch of repetition that seemed fragile; does something like
the below make sense?


Index: linux-2.6/kernel/sched/core.c
===================================================================
--- linux-2.6.orig/kernel/sched/core.c
+++ linux-2.6/kernel/sched/core.c
@@ -770,6 +770,9 @@ unsigned int sysctl_sched_uclamp_util_ma
 /* All clamps are required to be less or equal than these values */
 static struct uclamp_se uclamp_default[UCLAMP_CNT];
 
+#define for_each_clamp_id(clamp_id)    \
+       for ((clamp_id) = 0; (clamp_id) < UCLAMP_CNT; (clamp_id)++)
+
 /* Integer rounded range for each bucket */
 #define UCLAMP_BUCKET_DELTA DIV_ROUND_CLOSEST(SCHED_CAPACITY_SCALE, 
UCLAMP_BUCKETS)
 
@@ -790,6 +793,12 @@ static inline unsigned int uclamp_none(i
        return SCHED_CAPACITY_SCALE;
 }
 
+static inline void uclamp_se_set(struct uclamp_se *uc_se, unsigned int value)
+{
+       uc_se->value = value;
+       uc_se->bucket_id = uclamp_bucket_id(value);
+}
+
 static inline unsigned int
 uclamp_idle_value(struct rq *rq, unsigned int clamp_id, unsigned int 
clamp_value)
 {
@@ -977,7 +986,7 @@ static inline void uclamp_rq_inc(struct
        if (unlikely(!p->sched_class->uclamp_enabled))
                return;
 
-       for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id)
+       for_each_clamp_id(clamp_id)
                uclamp_rq_inc_id(p, rq, clamp_id);
 
        /* Reset clamp idle holding when there is one RUNNABLE task */
@@ -992,7 +1001,7 @@ static inline void uclamp_rq_dec(struct
        if (unlikely(!p->sched_class->uclamp_enabled))
                return;
 
-       for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id)
+       for_each_clamp_id(clamp_id)
                uclamp_rq_dec_id(p, rq, clamp_id);
 }
 
@@ -1021,16 +1030,13 @@ int sysctl_sched_uclamp_handler(struct c
        }
 
        if (old_min != sysctl_sched_uclamp_util_min) {
-               uclamp_default[UCLAMP_MIN].value =
-                       sysctl_sched_uclamp_util_min;
-               uclamp_default[UCLAMP_MIN].bucket_id =
-                       uclamp_bucket_id(sysctl_sched_uclamp_util_min);
+               uclamp_se_set(&uclamp_default[UCLAMP_MIN],
+                             sysctl_sched_uclamp_util_min);
        }
+
        if (old_max != sysctl_sched_uclamp_util_max) {
-               uclamp_default[UCLAMP_MAX].value =
-                       sysctl_sched_uclamp_util_max;
-               uclamp_default[UCLAMP_MAX].bucket_id =
-                       uclamp_bucket_id(sysctl_sched_uclamp_util_max);
+               uclamp_se_set(&uclamp_default[UCLAMP_MAX],
+                             sysctl_sched_uclamp_util_max);
        }
 
        /*
@@ -1052,7 +1058,7 @@ static void uclamp_fork(struct task_stru
 {
        unsigned int clamp_id;
 
-       for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id)
+       for_each_clamp_id(clamp_id)
                p->uclamp[clamp_id].active = false;
 }
 
@@ -1067,17 +1073,12 @@ static void __init init_uclamp(void)
                cpu_rq(cpu)->uclamp_flags = 0;
        }
 
-       for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) {
-               struct uclamp_se *uc_se = &init_task.uclamp_req[clamp_id];
-
-               uc_se->value = uclamp_none(clamp_id);
-               uc_se->bucket_id = uclamp_bucket_id(uc_se->value);
-       }
+       for_each_clamp_id(clamp_id)
+               uclamp_se_set(&init_task.uclamp_req[clamp_id], 
uclamp_none(clamp_id));
 
        /* System defaults allow max clamp values for both indexes */
-       uc_max.value = uclamp_none(UCLAMP_MAX);
-       uc_max.bucket_id = uclamp_bucket_id(uc_max.value);
-       for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id)
+       uclamp_se_set(&uc_max, uclamp_none(UCLAMP_MAX));
+       for_each_clamp_id(clamp_id)
                uclamp_default[clamp_id] = uc_max;
 }