sched: remove wait_runtime limit

remove the wait_runtime-limit fields and the code depending on it, now
that the math has been changed over to rely on the vruntime metric.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 5 insertions, 123 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 3a4ac0b75f2d..21cc3b2be023 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -180,7 +180,6 @@ struct cfs_rq {
         u64 exec_clock;
         u64 min_vruntime;
         s64 wait_runtime;
-        u64 sleeper_bonus;
         unsigned long wait_runtime_overruns, wait_runtime_underruns;
 
         struct rb_root tasks_timeline;
@@ -673,19 +672,6 @@ static inline void resched_task(struct task_struct *p)
 }
 #endif
 
-static u64 div64_likely32(u64 divident, unsigned long divisor)
-{
-#if BITS_PER_LONG == 32
-        if (likely(divident <= 0xffffffffULL))
-                return (u32)divident / divisor;
-        do_div(divident, divisor);
-
-        return divident;
-#else
-        return divident / divisor;
-#endif
-}
-
 #if BITS_PER_LONG == 32
 # define WMULT_CONST    (~0UL)
 #else
@@ -1016,8 +1002,6 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 
         if (p->se.wait_start_fair)
                 p->se.wait_start_fair -= fair_clock_offset;
-        if (p->se.sleep_start_fair)
-                p->se.sleep_start_fair -= fair_clock_offset;
 
 #ifdef CONFIG_SCHEDSTATS
         if (p->se.wait_start)
@@ -1592,7 +1576,6 @@ static void __sched_fork(struct task_struct *p)
         p->se.sum_exec_runtime          = 0;
         p->se.prev_sum_exec_runtime     = 0;
         p->se.wait_runtime              = 0;
-        p->se.sleep_start_fair          = 0;
 
 #ifdef CONFIG_SCHEDSTATS
         p->se.wait_start                = 0;
@@ -6582,7 +6565,6 @@ void normalize_rt_tasks(void)
                 p->se.wait_runtime              = 0;
                 p->se.exec_start                = 0;
                 p->se.wait_start_fair           = 0;
-                p->se.sleep_start_fair          = 0;
 #ifdef CONFIG_SCHEDSTATS
                 p->se.wait_start                = 0;
                 p->se.sleep_start               = 0;
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 62965f0ae37c..3350169a7d2a 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -148,7 +148,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
         P(wait_runtime);
         P(wait_runtime_overruns);
         P(wait_runtime_underruns);
-        P(sleeper_bonus);
 #undef P
 
         print_cfs_rq_runtime_sum(m, cpu, cfs_rq);
@@ -272,7 +271,6 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
         P(se.wait_runtime);
         P(se.wait_start_fair);
         P(se.exec_start);
-        P(se.sleep_start_fair);
         P(se.vruntime);
         P(se.sum_exec_runtime);
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 72f202a8be96..a94189c42d1a 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -249,41 +249,11 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
         return period;
 }
 
-static inline void
-limit_wait_runtime(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-        long limit = sysctl_sched_runtime_limit;
-
-        /*
-         * Niced tasks have the same history dynamic range as
-         * non-niced tasks:
-         */
-        if (unlikely(se->wait_runtime > limit)) {
-                se->wait_runtime = limit;
-                schedstat_inc(se, wait_runtime_overruns);
-                schedstat_inc(cfs_rq, wait_runtime_overruns);
-        }
-        if (unlikely(se->wait_runtime < -limit)) {
-                se->wait_runtime = -limit;
-                schedstat_inc(se, wait_runtime_underruns);
-                schedstat_inc(cfs_rq, wait_runtime_underruns);
-        }
-}
-
-static inline void
-__add_wait_runtime(struct cfs_rq *cfs_rq, struct sched_entity *se, long delta)
-{
-        se->wait_runtime += delta;
-        schedstat_add(se, sum_wait_runtime, delta);
-        limit_wait_runtime(cfs_rq, se);
-}
-
 static void
 add_wait_runtime(struct cfs_rq *cfs_rq, struct sched_entity *se, long delta)
 {
-        schedstat_add(cfs_rq, wait_runtime, -se->wait_runtime);
-        __add_wait_runtime(cfs_rq, se, delta);
-        schedstat_add(cfs_rq, wait_runtime, se->wait_runtime);
+        se->wait_runtime += delta;
+        schedstat_add(cfs_rq, wait_runtime, delta);
 }
 
 /*
@@ -294,7 +264,7 @@ static inline void
 __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
               unsigned long delta_exec)
 {
-        unsigned long delta, delta_fair, delta_mine, delta_exec_weighted;
+        unsigned long delta_fair, delta_mine, delta_exec_weighted;
         struct load_weight *lw = &cfs_rq->load;
         unsigned long load = lw->weight;
 
@@ -318,14 +288,6 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
         delta_fair = calc_delta_fair(delta_exec, lw);
         delta_mine = calc_delta_mine(delta_exec, curr->load.weight, lw);
 
-        if (cfs_rq->sleeper_bonus > sysctl_sched_min_granularity) {
-                delta = min((u64)delta_mine, cfs_rq->sleeper_bonus);
-                delta = min(delta, (unsigned long)(
-                        (long)sysctl_sched_runtime_limit - curr->wait_runtime));
-                cfs_rq->sleeper_bonus -= delta;
-                delta_mine -= delta;
-        }
-
         cfs_rq->fair_clock += delta_fair;
         /*
          * We executed delta_exec amount of time on the CPU,
@@ -461,58 +423,8 @@ update_stats_curr_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
  * Scheduling class queueing methods:
  */
 
-static void __enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se,
-                              unsigned long delta_fair)
-{
-        unsigned long load = cfs_rq->load.weight;
-        long prev_runtime;
-
-        /*
-         * Do not boost sleepers if there's too much bonus 'in flight'
-         * already:
-         */
-        if (unlikely(cfs_rq->sleeper_bonus > sysctl_sched_runtime_limit))
-                return;
-
-        if (sched_feat(SLEEPER_LOAD_AVG))
-                load = rq_of(cfs_rq)->cpu_load[2];
-
-        /*
-         * Fix up delta_fair with the effect of us running
-         * during the whole sleep period:
-         */
-        if (sched_feat(SLEEPER_AVG))
-                delta_fair = div64_likely32((u64)delta_fair * load,
-                                                load + se->load.weight);
-
-        delta_fair = calc_weighted(delta_fair, se);
-
-        prev_runtime = se->wait_runtime;
-        __add_wait_runtime(cfs_rq, se, delta_fair);
-        delta_fair = se->wait_runtime - prev_runtime;
-
-        /*
-         * Track the amount of bonus we've given to sleepers:
-         */
-        cfs_rq->sleeper_bonus += delta_fair;
-}
-
 static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-        struct task_struct *tsk = task_of(se);
-        unsigned long delta_fair;
-
-        if ((entity_is_task(se) && tsk->policy == SCHED_BATCH) ||
-                         !sched_feat(FAIR_SLEEPERS))
-                return;
-
-        delta_fair = (unsigned long)min((u64)(2*sysctl_sched_runtime_limit),
-                (u64)(cfs_rq->fair_clock - se->sleep_start_fair));
-
-        __enqueue_sleeper(cfs_rq, se, delta_fair);
-
-        se->sleep_start_fair = 0;
-
 #ifdef CONFIG_SCHEDSTATS
         if (se->sleep_start) {
                 u64 delta = rq_of(cfs_rq)->clock - se->sleep_start;
@@ -544,6 +456,8 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
                  * time that the task spent sleeping:
                  */
                 if (unlikely(prof_on == SLEEP_PROFILING)) {
+                        struct task_struct *tsk = task_of(se);
+
                         profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk),
                                      delta >> 20);
                 }
@@ -604,7 +518,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 {
         update_stats_dequeue(cfs_rq, se);
         if (sleep) {
-                se->sleep_start_fair = cfs_rq->fair_clock;
 #ifdef CONFIG_SCHEDSTATS
                 if (entity_is_task(se)) {
                         struct task_struct *tsk = task_of(se);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9b1b0d4ff966..97b15c27407f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -266,17 +266,6 @@ static ctl_table kern_table[] = {
         },
         {
                 .ctl_name       = CTL_UNNUMBERED,
-                .procname       = "sched_runtime_limit_ns",
-                .data           = &sysctl_sched_runtime_limit,
-                .maxlen         = sizeof(unsigned int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec_minmax,
-                .strategy       = &sysctl_intvec,
-                .extra1         = &min_sched_granularity_ns,
-                .extra2         = &max_sched_granularity_ns,
-        },
-        {
-                .ctl_name       = CTL_UNNUMBERED,
                 .procname       = "sched_child_runs_first",
                 .data           = &sysctl_sched_child_runs_first,
                 .maxlen         = sizeof(unsigned int),