From 79cd0c3c01a0257258c1aea5bf9e518bb299fda6 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 20 Oct 2023 12:35:33 +0200
Subject: [PATCH] sched/fair: Remove SIS_PROP
References: bsc#1184587, bsc#1212887 (Scheduler functional and performance backports)
Git-commit: 984ffb6a4366752c949f7b39640aecdce222607f
Patch-mainline: v6.7-rc1
SIS_UTIL seems to work well, lets remove the old thing.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20231020134337.GD33965@noisy.programming.kicks-ass.net
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
include/linux/sched/topology.h | 2 --
kernel/sched/core.c | 5 -----
kernel/sched/fair.c | 48 ------------------------------------------
kernel/sched/features.h | 1 -
kernel/sched/sched.h | 3 ---
5 files changed, 59 deletions(-)
diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 4c14fe127223..de545ba85218 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -109,8 +109,6 @@ struct sched_domain {
u64 max_newidle_lb_cost;
unsigned long last_decay_max_lb_cost;
- u64 avg_scan_cost; /* select_idle_sibling */
-
#ifdef CONFIG_SCHEDSTATS
/* load_balance() stats */
unsigned int lb_count[CPU_MAX_IDLE_TYPES];
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a3cafb1f6c7f..9ecb2e3557f9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3817,9 +3817,6 @@ ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
if (rq->avg_idle > max)
rq->avg_idle = max;
- rq->wake_stamp = jiffies;
- rq->wake_avg_idle = rq->avg_idle / 2;
-
rq->idle_stamp = 0;
}
#endif
@@ -10099,8 +10096,6 @@ void __init sched_init(void)
rq->online = 0;
rq->idle_stamp = 0;
rq->avg_idle = 2*sysctl_sched_migration_cost;
- rq->wake_stamp = jiffies;
- rq->wake_avg_idle = rq->avg_idle;
rq->max_idle_balance_cost = sysctl_sched_migration_cost;
INIT_LIST_HEAD(&rq->cfs_tasks);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index cf99d912303b..86703cf25866 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7120,45 +7120,9 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
int i, cpu, idle_cpu = -1, nr = INT_MAX;
struct sched_domain_shared *sd_share;
- struct rq *this_rq = this_rq();
- int this = smp_processor_id();
- struct sched_domain *this_sd = NULL;
- u64 time = 0;
cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
- if (sched_feat(SIS_PROP) && !has_idle_core) {
- u64 avg_cost, avg_idle, span_avg;
- unsigned long now = jiffies;
-
- this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
- if (!this_sd)
- return -1;
-
- /*
- * If we're busy, the assumption that the last idle period
- * predicts the future is flawed; age away the remaining
- * predicted idle time.
- */
- if (unlikely(this_rq->wake_stamp < now)) {
- while (this_rq->wake_stamp < now && this_rq->wake_avg_idle) {
- this_rq->wake_stamp++;
- this_rq->wake_avg_idle >>= 1;
- }
- }
-
- avg_idle = this_rq->wake_avg_idle;
- avg_cost = this_sd->avg_scan_cost + 1;
-
- span_avg = sd->span_weight * avg_idle;
- if (span_avg > 4*avg_cost)
- nr = div_u64(span_avg, avg_cost);
- else
- nr = 4;
-
- time = cpu_clock(this);
- }
-
if (sched_feat(SIS_UTIL)) {
sd_share = rcu_dereference(per_cpu(sd_llc_shared, target));
if (sd_share) {
@@ -7212,18 +7176,6 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
if (has_idle_core)
set_idle_cores(target, false);
- if (sched_feat(SIS_PROP) && this_sd && !has_idle_core) {
- time = cpu_clock(this) - time;
-
- /*
- * Account for the scan cost of wakeups against the average
- * idle time.
- */
- this_rq->wake_avg_idle -= min(this_rq->wake_avg_idle, time);
-
- update_avg(&this_sd->avg_scan_cost, time);
- }
-
return idle_cpu;
}
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index e10074cb4be4..b21a948f53f1 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -60,7 +60,6 @@ SCHED_FEAT(TTWU_QUEUE, true)
/*
* When doing wakeups, attempt to limit superfluous scans of the LLC domain.
*/
-SCHED_FEAT(SIS_PROP, false)
SCHED_FEAT(SIS_UTIL, true)
/*
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 0c13cb71634e..411134e72b7a 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1060,9 +1060,6 @@ struct rq {
u64 idle_stamp;
u64 avg_idle;
- unsigned long wake_stamp;
- u64 wake_avg_idle;
-
/* This is used to determine avg_idle's max value */
u64 max_idle_balance_cost;