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-rw-r--r--kernel/sched/fair.c603
1 files changed, 380 insertions, 223 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2048138ce54b..533547e3c90a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -551,7 +551,11 @@ static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
static inline bool entity_before(const struct sched_entity *a,
const struct sched_entity *b)
{
- return (s64)(a->vruntime - b->vruntime) < 0;
+ /*
+ * Tiebreak on vruntime seems unnecessary since it can
+ * hardly happen.
+ */
+ return (s64)(a->deadline - b->deadline) < 0;
}
static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
@@ -720,7 +724,7 @@ static void update_entity_lag(struct cfs_rq *cfs_rq, struct sched_entity *se)
* Note: using 'avg_vruntime() > se->vruntime' is inacurate due
* to the loss in precision caused by the division.
*/
-int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static int vruntime_eligible(struct cfs_rq *cfs_rq, u64 vruntime)
{
struct sched_entity *curr = cfs_rq->curr;
s64 avg = cfs_rq->avg_vruntime;
@@ -733,7 +737,12 @@ int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se)
load += weight;
}
- return avg >= entity_key(cfs_rq, se) * load;
+ return avg >= (s64)(vruntime - cfs_rq->min_vruntime) * load;
+}
+
+int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ return vruntime_eligible(cfs_rq, se->vruntime);
}
static u64 __update_min_vruntime(struct cfs_rq *cfs_rq, u64 vruntime)
@@ -752,9 +761,8 @@ static u64 __update_min_vruntime(struct cfs_rq *cfs_rq, u64 vruntime)
static void update_min_vruntime(struct cfs_rq *cfs_rq)
{
- struct sched_entity *se = __pick_first_entity(cfs_rq);
+ struct sched_entity *se = __pick_root_entity(cfs_rq);
struct sched_entity *curr = cfs_rq->curr;
-
u64 vruntime = cfs_rq->min_vruntime;
if (curr) {
@@ -766,9 +774,9 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq)
if (se) {
if (!curr)
- vruntime = se->vruntime;
+ vruntime = se->min_vruntime;
else
- vruntime = min_vruntime(vruntime, se->vruntime);
+ vruntime = min_vruntime(vruntime, se->min_vruntime);
}
/* ensure we never gain time by being placed backwards. */
@@ -781,34 +789,34 @@ static inline bool __entity_less(struct rb_node *a, const struct rb_node *b)
return entity_before(__node_2_se(a), __node_2_se(b));
}
-#define deadline_gt(field, lse, rse) ({ (s64)((lse)->field - (rse)->field) > 0; })
+#define vruntime_gt(field, lse, rse) ({ (s64)((lse)->field - (rse)->field) > 0; })
-static inline void __update_min_deadline(struct sched_entity *se, struct rb_node *node)
+static inline void __min_vruntime_update(struct sched_entity *se, struct rb_node *node)
{
if (node) {
struct sched_entity *rse = __node_2_se(node);
- if (deadline_gt(min_deadline, se, rse))
- se->min_deadline = rse->min_deadline;
+ if (vruntime_gt(min_vruntime, se, rse))
+ se->min_vruntime = rse->min_vruntime;
}
}
/*
- * se->min_deadline = min(se->deadline, left->min_deadline, right->min_deadline)
+ * se->min_vruntime = min(se->vruntime, {left,right}->min_vruntime)
*/
-static inline bool min_deadline_update(struct sched_entity *se, bool exit)
+static inline bool min_vruntime_update(struct sched_entity *se, bool exit)
{
- u64 old_min_deadline = se->min_deadline;
+ u64 old_min_vruntime = se->min_vruntime;
struct rb_node *node = &se->run_node;
- se->min_deadline = se->deadline;
- __update_min_deadline(se, node->rb_right);
- __update_min_deadline(se, node->rb_left);
+ se->min_vruntime = se->vruntime;
+ __min_vruntime_update(se, node->rb_right);
+ __min_vruntime_update(se, node->rb_left);
- return se->min_deadline == old_min_deadline;
+ return se->min_vruntime == old_min_vruntime;
}
-RB_DECLARE_CALLBACKS(static, min_deadline_cb, struct sched_entity,
- run_node, min_deadline, min_deadline_update);
+RB_DECLARE_CALLBACKS(static, min_vruntime_cb, struct sched_entity,
+ run_node, min_vruntime, min_vruntime_update);
/*
* Enqueue an entity into the rb-tree:
@@ -816,18 +824,28 @@ RB_DECLARE_CALLBACKS(static, min_deadline_cb, struct sched_entity,
static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
avg_vruntime_add(cfs_rq, se);
- se->min_deadline = se->deadline;
+ se->min_vruntime = se->vruntime;
rb_add_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline,
- __entity_less, &min_deadline_cb);
+ __entity_less, &min_vruntime_cb);
}
static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
rb_erase_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline,
- &min_deadline_cb);
+ &min_vruntime_cb);
avg_vruntime_sub(cfs_rq, se);
}
+struct sched_entity *__pick_root_entity(struct cfs_rq *cfs_rq)
+{
+ struct rb_node *root = cfs_rq->tasks_timeline.rb_root.rb_node;
+
+ if (!root)
+ return NULL;
+
+ return __node_2_se(root);
+}
+
struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
{
struct rb_node *left = rb_first_cached(&cfs_rq->tasks_timeline);
@@ -850,23 +868,29 @@ struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
* with the earliest virtual deadline.
*
* We can do this in O(log n) time due to an augmented RB-tree. The
- * tree keeps the entries sorted on service, but also functions as a
- * heap based on the deadline by keeping:
+ * tree keeps the entries sorted on deadline, but also functions as a
+ * heap based on the vruntime by keeping:
*
- * se->min_deadline = min(se->deadline, se->{left,right}->min_deadline)
+ * se->min_vruntime = min(se->vruntime, se->{left,right}->min_vruntime)
*
- * Which allows an EDF like search on (sub)trees.
+ * Which allows tree pruning through eligibility.
*/
-static struct sched_entity *__pick_eevdf(struct cfs_rq *cfs_rq)
+static struct sched_entity *pick_eevdf(struct cfs_rq *cfs_rq)
{
struct rb_node *node = cfs_rq->tasks_timeline.rb_root.rb_node;
+ struct sched_entity *se = __pick_first_entity(cfs_rq);
struct sched_entity *curr = cfs_rq->curr;
struct sched_entity *best = NULL;
- struct sched_entity *best_left = NULL;
+
+ /*
+ * We can safely skip eligibility check if there is only one entity
+ * in this cfs_rq, saving some cycles.
+ */
+ if (cfs_rq->nr_running == 1)
+ return curr && curr->on_rq ? curr : se;
if (curr && (!curr->on_rq || !entity_eligible(cfs_rq, curr)))
curr = NULL;
- best = curr;
/*
* Once selected, run a task until it either becomes non-eligible or
@@ -875,95 +899,45 @@ static struct sched_entity *__pick_eevdf(struct cfs_rq *cfs_rq)
if (sched_feat(RUN_TO_PARITY) && curr && curr->vlag == curr->deadline)
return curr;
+ /* Pick the leftmost entity if it's eligible */
+ if (se && entity_eligible(cfs_rq, se)) {
+ best = se;
+ goto found;
+ }
+
+ /* Heap search for the EEVD entity */
while (node) {
- struct sched_entity *se = __node_2_se(node);
+ struct rb_node *left = node->rb_left;
/*
- * If this entity is not eligible, try the left subtree.
+ * Eligible entities in left subtree are always better
+ * choices, since they have earlier deadlines.
*/
- if (!entity_eligible(cfs_rq, se)) {
- node = node->rb_left;
+ if (left && vruntime_eligible(cfs_rq,
+ __node_2_se(left)->min_vruntime)) {
+ node = left;
continue;
}
- /*
- * Now we heap search eligible trees for the best (min_)deadline
- */
- if (!best || deadline_gt(deadline, best, se))
- best = se;
+ se = __node_2_se(node);
/*
- * Every se in a left branch is eligible, keep track of the
- * branch with the best min_deadline
+ * The left subtree either is empty or has no eligible
+ * entity, so check the current node since it is the one
+ * with earliest deadline that might be eligible.
*/
- if (node->rb_left) {
- struct sched_entity *left = __node_2_se(node->rb_left);
-
- if (!best_left || deadline_gt(min_deadline, best_left, left))
- best_left = left;
-
- /*
- * min_deadline is in the left branch. rb_left and all
- * descendants are eligible, so immediately switch to the second
- * loop.
- */
- if (left->min_deadline == se->min_deadline)
- break;
- }
-
- /* min_deadline is at this node, no need to look right */
- if (se->deadline == se->min_deadline)
+ if (entity_eligible(cfs_rq, se)) {
+ best = se;
break;
-
- /* else min_deadline is in the right branch. */
- node = node->rb_right;
- }
-
- /*
- * We ran into an eligible node which is itself the best.
- * (Or nr_running == 0 and both are NULL)
- */
- if (!best_left || (s64)(best_left->min_deadline - best->deadline) > 0)
- return best;
-
- /*
- * Now best_left and all of its children are eligible, and we are just
- * looking for deadline == min_deadline
- */
- node = &best_left->run_node;
- while (node) {
- struct sched_entity *se = __node_2_se(node);
-
- /* min_deadline is the current node */
- if (se->deadline == se->min_deadline)
- return se;
-
- /* min_deadline is in the left branch */
- if (node->rb_left &&
- __node_2_se(node->rb_left)->min_deadline == se->min_deadline) {
- node = node->rb_left;
- continue;
}
- /* else min_deadline is in the right branch */
node = node->rb_right;
}
- return NULL;
-}
-
-static struct sched_entity *pick_eevdf(struct cfs_rq *cfs_rq)
-{
- struct sched_entity *se = __pick_eevdf(cfs_rq);
-
- if (!se) {
- struct sched_entity *left = __pick_first_entity(cfs_rq);
- if (left) {
- pr_err("EEVDF scheduling fail, picking leftmost\n");
- return left;
- }
- }
+found:
+ if (!best || (curr && entity_before(curr, best)))
+ best = curr;
- return se;
+ return best;
}
#ifdef CONFIG_SCHED_DEBUG
@@ -1129,23 +1103,17 @@ static void update_tg_load_avg(struct cfs_rq *cfs_rq)
}
#endif /* CONFIG_SMP */
-/*
- * Update the current task's runtime statistics.
- */
-static void update_curr(struct cfs_rq *cfs_rq)
+static s64 update_curr_se(struct rq *rq, struct sched_entity *curr)
{
- struct sched_entity *curr = cfs_rq->curr;
- u64 now = rq_clock_task(rq_of(cfs_rq));
- u64 delta_exec;
-
- if (unlikely(!curr))
- return;
+ u64 now = rq_clock_task(rq);
+ s64 delta_exec;
delta_exec = now - curr->exec_start;
- if (unlikely((s64)delta_exec <= 0))
- return;
+ if (unlikely(delta_exec <= 0))
+ return delta_exec;
curr->exec_start = now;
+ curr->sum_exec_runtime += delta_exec;
if (schedstat_enabled()) {
struct sched_statistics *stats;
@@ -1155,20 +1123,54 @@ static void update_curr(struct cfs_rq *cfs_rq)
max(delta_exec, stats->exec_max));
}
- curr->sum_exec_runtime += delta_exec;
- schedstat_add(cfs_rq->exec_clock, delta_exec);
+ return delta_exec;
+}
+
+static inline void update_curr_task(struct task_struct *p, s64 delta_exec)
+{
+ trace_sched_stat_runtime(p, delta_exec);
+ account_group_exec_runtime(p, delta_exec);
+ cgroup_account_cputime(p, delta_exec);
+ if (p->dl_server)
+ dl_server_update(p->dl_server, delta_exec);
+}
+
+/*
+ * Used by other classes to account runtime.
+ */
+s64 update_curr_common(struct rq *rq)
+{
+ struct task_struct *curr = rq->curr;
+ s64 delta_exec;
+
+ delta_exec = update_curr_se(rq, &curr->se);
+ if (likely(delta_exec > 0))
+ update_curr_task(curr, delta_exec);
+
+ return delta_exec;
+}
+
+/*
+ * Update the current task's runtime statistics.
+ */
+static void update_curr(struct cfs_rq *cfs_rq)
+{
+ struct sched_entity *curr = cfs_rq->curr;
+ s64 delta_exec;
+
+ if (unlikely(!curr))
+ return;
+
+ delta_exec = update_curr_se(rq_of(cfs_rq), curr);
+ if (unlikely(delta_exec <= 0))
+ return;
curr->vruntime += calc_delta_fair(delta_exec, curr);
update_deadline(cfs_rq, curr);
update_min_vruntime(cfs_rq);
- if (entity_is_task(curr)) {
- struct task_struct *curtask = task_of(curr);
-
- trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
- cgroup_account_cputime(curtask, delta_exec);
- account_group_exec_runtime(curtask, delta_exec);
- }
+ if (entity_is_task(curr))
+ update_curr_task(task_of(curr), delta_exec);
account_cfs_rq_runtime(cfs_rq, delta_exec);
}
@@ -3164,7 +3166,7 @@ static bool vma_is_accessed(struct mm_struct *mm, struct vm_area_struct *vma)
* This is also done to avoid any side effect of task scanning
* amplifying the unfairness of disjoint set of VMAs' access.
*/
- if (READ_ONCE(current->mm->numa_scan_seq) < 2)
+ if ((READ_ONCE(current->mm->numa_scan_seq) - vma->numab_state->start_scan_seq) < 2)
return true;
pids = vma->numab_state->pids_active[0] | vma->numab_state->pids_active[1];
@@ -3307,6 +3309,8 @@ retry_pids:
if (!vma->numab_state)
continue;
+ vma->numab_state->start_scan_seq = mm->numa_scan_seq;
+
vma->numab_state->next_scan = now +
msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
@@ -3666,41 +3670,140 @@ static inline void
dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
#endif
+static void reweight_eevdf(struct cfs_rq *cfs_rq, struct sched_entity *se,
+ unsigned long weight)
+{
+ unsigned long old_weight = se->load.weight;
+ u64 avruntime = avg_vruntime(cfs_rq);
+ s64 vlag, vslice;
+
+ /*
+ * VRUNTIME
+ * ========
+ *
+ * COROLLARY #1: The virtual runtime of the entity needs to be
+ * adjusted if re-weight at !0-lag point.
+ *
+ * Proof: For contradiction assume this is not true, so we can
+ * re-weight without changing vruntime at !0-lag point.
+ *
+ * Weight VRuntime Avg-VRuntime
+ * before w v V
+ * after w' v' V'
+ *
+ * Since lag needs to be preserved through re-weight:
+ *
+ * lag = (V - v)*w = (V'- v')*w', where v = v'
+ * ==> V' = (V - v)*w/w' + v (1)
+ *
+ * Let W be the total weight of the entities before reweight,
+ * since V' is the new weighted average of entities:
+ *
+ * V' = (WV + w'v - wv) / (W + w' - w) (2)
+ *
+ * by using (1) & (2) we obtain:
+ *
+ * (WV + w'v - wv) / (W + w' - w) = (V - v)*w/w' + v
+ * ==> (WV-Wv+Wv+w'v-wv)/(W+w'-w) = (V - v)*w/w' + v
+ * ==> (WV - Wv)/(W + w' - w) + v = (V - v)*w/w' + v
+ * ==> (V - v)*W/(W + w' - w) = (V - v)*w/w' (3)
+ *
+ * Since we are doing at !0-lag point which means V != v, we
+ * can simplify (3):
+ *
+ * ==> W / (W + w' - w) = w / w'
+ * ==> Ww' = Ww + ww' - ww
+ * ==> W * (w' - w) = w * (w' - w)
+ * ==> W = w (re-weight indicates w' != w)
+ *
+ * So the cfs_rq contains only one entity, hence vruntime of
+ * the entity @v should always equal to the cfs_rq's weighted
+ * average vruntime @V, which means we will always re-weight
+ * at 0-lag point, thus breach assumption. Proof completed.
+ *
+ *
+ * COROLLARY #2: Re-weight does NOT affect weighted average
+ * vruntime of all the entities.
+ *
+ * Proof: According to corollary #1, Eq. (1) should be:
+ *
+ * (V - v)*w = (V' - v')*w'
+ * ==> v' = V' - (V - v)*w/w' (4)
+ *
+ * According to the weighted average formula, we have:
+ *
+ * V' = (WV - wv + w'v') / (W - w + w')
+ * = (WV - wv + w'(V' - (V - v)w/w')) / (W - w + w')
+ * = (WV - wv + w'V' - Vw + wv) / (W - w + w')
+ * = (WV + w'V' - Vw) / (W - w + w')
+ *
+ * ==> V'*(W - w + w') = WV + w'V' - Vw
+ * ==> V' * (W - w) = (W - w) * V (5)
+ *
+ * If the entity is the only one in the cfs_rq, then reweight
+ * always occurs at 0-lag point, so V won't change. Or else
+ * there are other entities, hence W != w, then Eq. (5) turns
+ * into V' = V. So V won't change in either case, proof done.
+ *
+ *
+ * So according to corollary #1 & #2, the effect of re-weight
+ * on vruntime should be:
+ *
+ * v' = V' - (V - v) * w / w' (4)
+ * = V - (V - v) * w / w'
+ * = V - vl * w / w'
+ * = V - vl'
+ */
+ if (avruntime != se->vruntime) {
+ vlag = (s64)(avruntime - se->vruntime);
+ vlag = div_s64(vlag * old_weight, weight);
+ se->vruntime = avruntime - vlag;
+ }
+
+ /*
+ * DEADLINE
+ * ========
+ *
+ * When the weight changes, the virtual time slope changes and
+ * we should adjust the relative virtual deadline accordingly.
+ *
+ * d' = v' + (d - v)*w/w'
+ * = V' - (V - v)*w/w' + (d - v)*w/w'
+ * = V - (V - v)*w/w' + (d - v)*w/w'
+ * = V + (d - V)*w/w'
+ */
+ vslice = (s64)(se->deadline - avruntime);
+ vslice = div_s64(vslice * old_weight, weight);
+ se->deadline = avruntime + vslice;
+}
+
static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
unsigned long weight)
{
- unsigned long old_weight = se->load.weight;
+ bool curr = cfs_rq->curr == se;
if (se->on_rq) {
/* commit outstanding execution time */
- if (cfs_rq->curr == se)
+ if (curr)
update_curr(cfs_rq);
else
- avg_vruntime_sub(cfs_rq, se);
+ __dequeue_entity(cfs_rq, se);
update_load_sub(&cfs_rq->load, se->load.weight);
}
dequeue_load_avg(cfs_rq, se);
- update_load_set(&se->load, weight);
-
if (!se->on_rq) {
/*
* Because we keep se->vlag = V - v_i, while: lag_i = w_i*(V - v_i),
* we need to scale se->vlag when w_i changes.
*/
- se->vlag = div_s64(se->vlag * old_weight, weight);
+ se->vlag = div_s64(se->vlag * se->load.weight, weight);
} else {
- s64 deadline = se->deadline - se->vruntime;
- /*
- * When the weight changes, the virtual time slope changes and
- * we should adjust the relative virtual deadline accordingly.
- */
- deadline = div_s64(deadline * old_weight, weight);
- se->deadline = se->vruntime + deadline;
- if (se != cfs_rq->curr)
- min_deadline_cb_propagate(&se->run_node, NULL);
+ reweight_eevdf(cfs_rq, se, weight);
}
+ update_load_set(&se->load, weight);
+
#ifdef CONFIG_SMP
do {
u32 divider = get_pelt_divider(&se->avg);
@@ -3712,8 +3815,17 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
enqueue_load_avg(cfs_rq, se);
if (se->on_rq) {
update_load_add(&cfs_rq->load, se->load.weight);
- if (cfs_rq->curr != se)
- avg_vruntime_add(cfs_rq, se);
+ if (!curr)
+ __enqueue_entity(cfs_rq, se);
+
+ /*
+ * The entity's vruntime has been adjusted, so let's check
+ * whether the rq-wide min_vruntime needs updated too. Since
+ * the calculations above require stable min_vruntime rather
+ * than up-to-date one, we do the update at the end of the
+ * reweight process.
+ */
+ update_min_vruntime(cfs_rq);
}
}
@@ -3857,14 +3969,11 @@ static void update_cfs_group(struct sched_entity *se)
#ifndef CONFIG_SMP
shares = READ_ONCE(gcfs_rq->tg->shares);
-
- if (likely(se->load.weight == shares))
- return;
#else
- shares = calc_group_shares(gcfs_rq);
+ shares = calc_group_shares(gcfs_rq);
#endif
-
- reweight_entity(cfs_rq_of(se), se, shares);
+ if (unlikely(se->load.weight != shares))
+ reweight_entity(cfs_rq_of(se), se, shares);
}
#else /* CONFIG_FAIR_GROUP_SCHED */
@@ -3991,6 +4100,10 @@ static inline void update_tg_load_avg(struct cfs_rq *cfs_rq)
if (cfs_rq->tg == &root_task_group)
return;
+ /* rq has been offline and doesn't contribute to the share anymore: */
+ if (!cpu_active(cpu_of(rq_of(cfs_rq))))
+ return;
+
/*
* For migration heavy workloads, access to tg->load_avg can be
* unbound. Limit the update rate to at most once per ms.
@@ -4007,6 +4120,49 @@ static inline void update_tg_load_avg(struct cfs_rq *cfs_rq)
}
}
+static inline void clear_tg_load_avg(struct cfs_rq *cfs_rq)
+{
+ long delta;
+ u64 now;
+
+ /*
+ * No need to update load_avg for root_task_group, as it is not used.
+ */
+ if (cfs_rq->tg == &root_task_group)
+ return;
+
+ now = sched_clock_cpu(cpu_of(rq_of(cfs_rq)));
+ delta = 0 - cfs_rq->tg_load_avg_contrib;
+ atomic_long_add(delta, &cfs_rq->tg->load_avg);
+ cfs_rq->tg_load_avg_contrib = 0;
+ cfs_rq->last_update_tg_load_avg = now;
+}
+
+/* CPU offline callback: */
+static void __maybe_unused clear_tg_offline_cfs_rqs(struct rq *rq)
+{
+ struct task_group *tg;
+
+ lockdep_assert_rq_held(rq);
+
+ /*
+ * The rq clock has already been updated in
+ * set_rq_offline(), so we should skip updating
+ * the rq clock again in unthrottle_cfs_rq().
+ */
+ rq_clock_start_loop_update(rq);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(tg, &task_groups, list) {
+ struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+ clear_tg_load_avg(cfs_rq);
+ }
+ rcu_read_unlock();
+
+ rq_clock_stop_loop_update(rq);
+}
+
/*
* Called within set_task_rq() right before setting a task's CPU. The
* caller only guarantees p->pi_lock is held; no other assumptions,
@@ -4303,6 +4459,8 @@ static inline bool skip_blocked_update(struct sched_entity *se)
static inline void update_tg_load_avg(struct cfs_rq *cfs_rq) {}
+static inline void clear_tg_offline_cfs_rqs(struct rq *rq) {}
+
static inline int propagate_entity_load_avg(struct sched_entity *se)
{
return 0;
@@ -4665,11 +4823,14 @@ static inline unsigned long task_util(struct task_struct *p)
return READ_ONCE(p->se.avg.util_avg);
}
-static inline unsigned long _task_util_est(struct task_struct *p)
+static inline unsigned long task_runnable(struct task_struct *p)
{
- struct util_est ue = READ_ONCE(p->se.avg.util_est);
+ return READ_ONCE(p->se.avg.runnable_avg);
+}
- return max(ue.ewma, (ue.enqueued & ~UTIL_AVG_UNCHANGED));
+static inline unsigned long _task_util_est(struct task_struct *p)
+{
+ return READ_ONCE(p->se.avg.util_est) & ~UTIL_AVG_UNCHANGED;
}
static inline unsigned long task_util_est(struct task_struct *p)
@@ -4686,9 +4847,9 @@ static inline void util_est_enqueue(struct cfs_rq *cfs_rq,
return;
/* Update root cfs_rq's estimated utilization */
- enqueued = cfs_rq->avg.util_est.enqueued;
+ enqueued = cfs_rq->avg.util_est;
enqueued += _task_util_est(p);
- WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued);
+ WRITE_ONCE(cfs_rq->avg.util_est, enqueued);
trace_sched_util_est_cfs_tp(cfs_rq);
}
@@ -4702,34 +4863,20 @@ static inline void util_est_dequeue(struct cfs_rq *cfs_rq,
return;
/* Update root cfs_rq's estimated utilization */
- enqueued = cfs_rq->avg.util_est.enqueued;
+ enqueued = cfs_rq->avg.util_est;
enqueued -= min_t(unsigned int, enqueued, _task_util_est(p));
- WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued);
+ WRITE_ONCE(cfs_rq->avg.util_est, enqueued);
trace_sched_util_est_cfs_tp(cfs_rq);
}
#define UTIL_EST_MARGIN (SCHED_CAPACITY_SCALE / 100)
-/*
- * Check if a (signed) value is within a specified (unsigned) margin,
- * based on the observation that:
- *
- * abs(x) < y := (unsigned)(x + y - 1) < (2 * y - 1)
- *
- * NOTE: this only works when value + margin < INT_MAX.
- */
-static inline bool within_margin(int value, int margin)
-{
- return ((unsigned int)(value + margin - 1) < (2 * margin - 1));
-}
-
static inline void util_est_update(struct cfs_rq *cfs_rq,
struct task_struct *p,
bool task_sleep)
{
- long last_ewma_diff, last_enqueued_diff;
- struct util_est ue;
+ unsigned int ewma, dequeued, last_ewma_diff;
if (!sched_feat(UTIL_EST))
return;
@@ -4741,71 +4888,73 @@ static inline void util_est_update(struct cfs_rq *cfs_rq,
if (!task_sleep)
return;
+ /* Get current estimate of utilization */
+ ewma = READ_ONCE(p->se.avg.util_est);
+
/*
* If the PELT values haven't changed since enqueue time,
* skip the util_est update.
*/
- ue = p->se.avg.util_est;
- if (ue.enqueued & UTIL_AVG_UNCHANGED)
+ if (ewma & UTIL_AVG_UNCHANGED)
return;
- last_enqueued_diff = ue.enqueued;
+ /* Get utilization at dequeue */
+ dequeued = task_util(p);
/*
* Reset EWMA on utilization increases, the moving average is used only
* to smooth utilization decreases.
*/
- ue.enqueued = task_util(p);
- if (sched_feat(UTIL_EST_FASTUP)) {
- if (ue.ewma < ue.enqueued) {
- ue.ewma = ue.enqueued;
- goto done;
- }
+ if (ewma <= dequeued) {
+ ewma = dequeued;
+ goto done;
}
/*
* Skip update of task's estimated utilization when its members are
* already ~1% close to its last activation value.
*/
- last_ewma_diff = ue.enqueued - ue.ewma;
- last_enqueued_diff -= ue.enqueued;
- if (within_margin(last_ewma_diff, UTIL_EST_MARGIN)) {
- if (!within_margin(last_enqueued_diff, UTIL_EST_MARGIN))
- goto done;
-
- return;
- }
+ last_ewma_diff = ewma - dequeued;
+ if (last_ewma_diff < UTIL_EST_MARGIN)
+ goto done;
/*
* To avoid overestimation of actual task utilization, skip updates if
* we cannot grant there is idle time in this CPU.
*/
- if (task_util(p) > arch_scale_cpu_capacity(cpu_of(rq_of(cfs_rq))))
+ if (dequeued > arch_scale_cpu_capacity(cpu_of(rq_of(cfs_rq))))
return;
/*
+ * To avoid underestimate of task utilization, skip updates of EWMA if
+ * we cannot grant that thread got all CPU time it wanted.
+ */
+ if ((dequeued + UTIL_EST_MARGIN) < task_runnable(p))
+ goto done;
+
+
+ /*
* Update Task's estimated utilization
*
* When *p completes an activation we can consolidate another sample
- * of the task size. This is done by storing the current PELT value
- * as ue.enqueued and by using this value to update the Exponential
- * Weighted Moving Average (EWMA):
+ * of the task size. This is done by using this value to update the
+ * Exponential Weighted Moving Average (EWMA):
*
* ewma(t) = w * task_util(p) + (1-w) * ewma(t-1)
* = w * task_util(p) + ewma(t-1) - w * ewma(t-1)
* = w * (task_util(p) - ewma(t-1)) + ewma(t-1)
- * = w * ( last_ewma_diff ) + ewma(t-1)
- * = w * (last_ewma_diff + ewma(t-1) / w)
+ * = w * ( -last_ewma_diff ) + ewma(t-1)
+ * = w * (-last_ewma_diff + ewma(t-1) / w)
*
* Where 'w' is the weight of new samples, which is configured to be
* 0.25, thus making w=1/4 ( >>= UTIL_EST_WEIGHT_SHIFT)
*/
- ue.ewma <<= UTIL_EST_WEIGHT_SHIFT;
- ue.ewma += last_ewma_diff;
- ue.ewma >>= UTIL_EST_WEIGHT_SHIFT;
+ ewma <<= UTIL_EST_WEIGHT_SHIFT;
+ ewma -= last_ewma_diff;
+ ewma >>= UTIL_EST_WEIGHT_SHIFT;
done:
- ue.enqueued |= UTIL_AVG_UNCHANGED;
- WRITE_ONCE(p->se.avg.util_est, ue);
+ ewma |= UTIL_AVG_UNCHANGED;
+ WRITE_ONCE(p->se.avg.util_est, ewma);
trace_sched_util_est_se_tp(&p->se);
}
@@ -7533,16 +7682,16 @@ cpu_util(int cpu, struct task_struct *p, int dst_cpu, int boost)
if (sched_feat(UTIL_EST)) {
unsigned long util_est;
- util_est = READ_ONCE(cfs_rq->avg.util_est.enqueued);
+ util_est = READ_ONCE(cfs_rq->avg.util_est);
/*
* During wake-up @p isn't enqueued yet and doesn't contribute
- * to any cpu_rq(cpu)->cfs.avg.util_est.enqueued.
+ * to any cpu_rq(cpu)->cfs.avg.util_est.
* If @dst_cpu == @cpu add it to "simulate" cpu_util after @p
* has been enqueued.
*
* During exec (@dst_cpu = -1) @p is enqueued and does
- * contribute to cpu_rq(cpu)->cfs.util_est.enqueued.
+ * contribute to cpu_rq(cpu)->cfs.util_est.
* Remove it to "simulate" cpu_util without @p's contribution.
*
* Despite the task_on_rq_queued(@p) check there is still a
@@ -7671,7 +7820,7 @@ static inline void eenv_pd_busy_time(struct energy_env *eenv,
for_each_cpu(cpu, pd_cpus) {
unsigned long util = cpu_util(cpu, p, -1, 0);
- busy_time += effective_cpu_util(cpu, util, ENERGY_UTIL, NULL);
+ busy_time += effective_cpu_util(cpu, util, NULL, NULL);
}
eenv->pd_busy_time = min(eenv->pd_cap, busy_time);
@@ -7694,7 +7843,7 @@ eenv_pd_max_util(struct energy_env *eenv, struct cpumask *pd_cpus,
for_each_cpu(cpu, pd_cpus) {
struct task_struct *tsk = (cpu == dst_cpu) ? p : NULL;
unsigned long util = cpu_util(cpu, p, dst_cpu, 1);
- unsigned long eff_util;
+ unsigned long eff_util, min, max;
/*
* Performance domain frequency: utilization clamping
@@ -7703,7 +7852,23 @@ eenv_pd_max_util(struct energy_env *eenv, struct cpumask *pd_cpus,
* NOTE: in case RT tasks are running, by default the
* FREQUENCY_UTIL's utilization can be max OPP.
*/
- eff_util = effective_cpu_util(cpu, util, FREQUENCY_UTIL, tsk);
+ eff_util = effective_cpu_util(cpu, util, &min, &max);
+
+ /* Task's uclamp can modify min and max value */
+ if (tsk && uclamp_is_used()) {
+ min = max(min, uclamp_eff_value(p, UCLAMP_MIN));
+
+ /*
+ * If there is no active max uclamp constraint,
+ * directly use task's one, otherwise keep max.
+ */
+ if (uclamp_rq_is_idle(cpu_rq(cpu)))
+ max = uclamp_eff_value(p, UCLAMP_MAX);
+ else
+ max = max(max, uclamp_eff_value(p, UCLAMP_MAX));
+ }
+
+ eff_util = sugov_effective_cpu_perf(cpu, eff_util, min, max);
max_util = max(max_util, eff_util);
}
@@ -8105,7 +8270,6 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int
struct task_struct *curr = rq->curr;
struct sched_entity *se = &curr->se, *pse = &p->se;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
- int next_buddy_marked = 0;
int cse_is_idle, pse_is_idle;
if (unlikely(se == pse))
@@ -8122,7 +8286,6 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int
if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK)) {
set_next_buddy(pse);
- next_buddy_marked = 1;
}
/*
@@ -8955,7 +9118,7 @@ static int detach_tasks(struct lb_env *env)
case migrate_util:
util = task_util_est(p);
- if (util > env->imbalance)
+ if (shr_bound(util, env->sd->nr_balance_failed) > env->imbalance)
goto next;
env->imbalance -= util;
@@ -11079,12 +11242,16 @@ static int should_we_balance(struct lb_env *env)
continue;
}
- /* Are we the first idle CPU? */
+ /*
+ * Are we the first idle core in a non-SMT domain or higher,
+ * or the first idle CPU in a SMT domain?
+ */
return cpu == env->dst_cpu;
}
- if (idle_smt == env->dst_cpu)
- return true;
+ /* Are we the first idle CPU with busy siblings? */
+ if (idle_smt != -1)
+ return idle_smt == env->dst_cpu;
/* Are we the first CPU of this group ? */
return group_balance_cpu(sg) == env->dst_cpu;
@@ -12304,6 +12471,9 @@ static void rq_offline_fair(struct rq *rq)
/* Ensure any throttled groups are reachable by pick_next_task */
unthrottle_offline_cfs_rqs(rq);
+
+ /* Ensure that we remove rq contribution to group share: */
+ clear_tg_offline_cfs_rqs(rq);
}
#endif /* CONFIG_SMP */
@@ -12927,19 +13097,6 @@ next_cpu:
return 0;
}
-#else /* CONFIG_FAIR_GROUP_SCHED */
-
-void free_fair_sched_group(struct task_group *tg) { }
-
-int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
-{
- return 1;
-}
-
-void online_fair_sched_group(struct task_group *tg) { }
-
-void unregister_fair_sched_group(struct task_group *tg) { }
-
#endif /* CONFIG_FAIR_GROUP_SCHED */