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-rw-r--r--kernel/sched/debug.c2
-rw-r--r--kernel/sched/fair.c29
-rw-r--r--kernel/sched/sched.h1
3 files changed, 27 insertions, 5 deletions
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 2e5fdd98dacc..34913a7f775a 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -311,6 +311,7 @@ static __init int sched_init_debug(void)
debugfs_create_u32("latency_ns", 0644, debugfs_sched, &sysctl_sched_latency);
debugfs_create_u32("min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_min_granularity);
+ debugfs_create_u32("idle_min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_idle_min_granularity);
debugfs_create_u32("wakeup_granularity_ns", 0644, debugfs_sched, &sysctl_sched_wakeup_granularity);
debugfs_create_u32("latency_warn_ms", 0644, debugfs_sched, &sysctl_resched_latency_warn_ms);
@@ -812,6 +813,7 @@ static void sched_debug_header(struct seq_file *m)
SEQ_printf(m, " .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
PN(sysctl_sched_latency);
PN(sysctl_sched_min_granularity);
+ PN(sysctl_sched_idle_min_granularity);
PN(sysctl_sched_wakeup_granularity);
P(sysctl_sched_child_runs_first);
P(sysctl_sched_features);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9c78c16ef462..d835061a9bd2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -60,6 +60,14 @@ unsigned int sysctl_sched_min_granularity = 750000ULL;
static unsigned int normalized_sysctl_sched_min_granularity = 750000ULL;
/*
+ * Minimal preemption granularity for CPU-bound SCHED_IDLE tasks.
+ * Applies only when SCHED_IDLE tasks compete with normal tasks.
+ *
+ * (default: 0.75 msec)
+ */
+unsigned int sysctl_sched_idle_min_granularity = 750000ULL;
+
+/*
* This value is kept at sysctl_sched_latency/sysctl_sched_min_granularity
*/
static unsigned int sched_nr_latency = 8;
@@ -665,6 +673,8 @@ static u64 __sched_period(unsigned long nr_running)
return sysctl_sched_latency;
}
+static bool sched_idle_cfs_rq(struct cfs_rq *cfs_rq);
+
/*
* We calculate the wall-time slice from the period by taking a part
* proportional to the weight.
@@ -674,6 +684,8 @@ static u64 __sched_period(unsigned long nr_running)
static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
unsigned int nr_running = cfs_rq->nr_running;
+ struct sched_entity *init_se = se;
+ unsigned int min_gran;
u64 slice;
if (sched_feat(ALT_PERIOD))
@@ -684,12 +696,13 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
for_each_sched_entity(se) {
struct load_weight *load;
struct load_weight lw;
+ struct cfs_rq *qcfs_rq;
- cfs_rq = cfs_rq_of(se);
- load = &cfs_rq->load;
+ qcfs_rq = cfs_rq_of(se);
+ load = &qcfs_rq->load;
if (unlikely(!se->on_rq)) {
- lw = cfs_rq->load;
+ lw = qcfs_rq->load;
update_load_add(&lw, se->load.weight);
load = &lw;
@@ -697,8 +710,14 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
slice = __calc_delta(slice, se->load.weight, load);
}
- if (sched_feat(BASE_SLICE))
- slice = max(slice, (u64)sysctl_sched_min_granularity);
+ if (sched_feat(BASE_SLICE)) {
+ if (se_is_idle(init_se) && !sched_idle_cfs_rq(cfs_rq))
+ min_gran = sysctl_sched_idle_min_granularity;
+ else
+ min_gran = sysctl_sched_min_granularity;
+
+ slice = max_t(u64, slice, min_gran);
+ }
return slice;
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index f2965b558683..15a8895698b9 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2403,6 +2403,7 @@ extern const_debug unsigned int sysctl_sched_migration_cost;
#ifdef CONFIG_SCHED_DEBUG
extern unsigned int sysctl_sched_latency;
extern unsigned int sysctl_sched_min_granularity;
+extern unsigned int sysctl_sched_idle_min_granularity;
extern unsigned int sysctl_sched_wakeup_granularity;
extern int sysctl_resched_latency_warn_ms;
extern int sysctl_resched_latency_warn_once;