lkml.org 
[lkml]   [2019]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[RFC][PATCH 11/13] sched/deadline: Move bandwidth accounting into {en,de}queue_dl_entity
In preparation of introducing !task sched_dl_entity; move the
bandwidth accounting into {en.de}queue_dl_entity().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/deadline.c | 125 ++++++++++++++++++++++++++----------------------
kernel/sched/sched.h | 6 ++
2 files changed, 75 insertions(+), 56 deletions(-)

--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -236,9 +236,8 @@ static void __dl_clear_params(struct sch
* up, and checks if the task is still in the "ACTIVE non contending"
* state or not (in the second case, it updates running_bw).
*/
-static void task_non_contending(struct task_struct *p)
+static void task_non_contending(struct sched_dl_entity *dl_se)
{
- struct sched_dl_entity *dl_se = &p->dl;
struct hrtimer *timer = &dl_se->inactive_timer;
struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
struct rq *rq = rq_of_dl_rq(dl_rq);
@@ -271,15 +270,18 @@ static void task_non_contending(struct t
* utilization now, instead of starting a timer
*/
if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) {
+ struct task_struct *p = dl_task_of(dl_se);
+
if (dl_task(p))
sub_running_bw(dl_se, dl_rq);
+
if (!dl_task(p) || p->state == TASK_DEAD) {
struct dl_bw *dl_b = dl_bw_of(task_cpu(p));

if (p->state == TASK_DEAD)
- sub_rq_bw(&p->dl, &rq->dl);
+ sub_rq_bw(dl_se, &rq->dl);
raw_spin_lock(&dl_b->lock);
- __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
+ __dl_sub(dl_b, dl_se->dl_bw, dl_bw_cpus(task_cpu(p)));
__dl_clear_params(dl_se);
raw_spin_unlock(&dl_b->lock);
}
@@ -288,7 +290,7 @@ static void task_non_contending(struct t
}

dl_se->dl_non_contending = 1;
- get_task_struct(p);
+ get_task_struct(dl_task_of(dl_se));
hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL);
}

@@ -1404,6 +1406,41 @@ enqueue_dl_entity(struct sched_dl_entity
BUG_ON(on_dl_rq(dl_se));

/*
+ * Check if a constrained deadline task was activated
+ * after the deadline but before the next period.
+ * If that is the case, the task will be throttled and
+ * the replenishment timer will be set to the next period.
+ */
+ if (!dl_se->dl_throttled && !dl_is_implicit(dl_se))
+ dl_check_constrained_dl(dl_se);
+
+ if (flags & (ENQUEUE_RESTORE|ENQUEUE_MIGRATING)) {
+ struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+ add_rq_bw(dl_se, dl_rq);
+ add_running_bw(dl_se, dl_rq);
+ }
+
+ /*
+ * If p is throttled, we do not enqueue it. In fact, if it exhausted
+ * its budget it needs a replenishment and, since it now is on
+ * its rq, the bandwidth timer callback (which clearly has not
+ * run yet) will take care of this.
+ * However, the active utilization does not depend on the fact
+ * that the task is on the runqueue or not (but depends on the
+ * task's state - in GRUB parlance, "inactive" vs "active contending").
+ * In other words, even if a task is throttled its utilization must
+ * be counted in the active utilization; hence, we need to call
+ * add_running_bw().
+ */
+ if (dl_se->dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
+ if (flags & ENQUEUE_WAKEUP)
+ task_contending(dl_se, flags);
+
+ return;
+ }
+
+ /*
* If this is a wakeup or a new instance, the scheduling
* parameters of the task might need updating. Otherwise,
* we want a replenishment of its runtime.
@@ -1422,9 +1459,28 @@ enqueue_dl_entity(struct sched_dl_entity
__enqueue_dl_entity(dl_se);
}

-static void dequeue_dl_entity(struct sched_dl_entity *dl_se)
+static void dequeue_dl_entity(struct sched_dl_entity *dl_se, int flags)
{
__dequeue_dl_entity(dl_se);
+
+ if (flags & (DEQUEUE_SAVE|DEQUEUE_MIGRATING)) {
+ struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+ sub_running_bw(dl_se, dl_rq);
+ sub_rq_bw(dl_se, dl_rq);
+ }
+
+ /*
+ * This check allows to start the inactive timer (or to immediately
+ * decrease the active utilization, if needed) in two cases:
+ * when the task blocks and when it is terminating
+ * (p->state == TASK_DEAD). We can handle the two cases in the same
+ * way, because from GRUB's point of view the same thing is happening
+ * (the task moves from "active contending" to "active non contending"
+ * or "inactive")
+ */
+ if (flags & DEQUEUE_SLEEP)
+ task_non_contending(dl_se);
}

static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
@@ -1454,38 +1510,8 @@ static void enqueue_task_dl(struct rq *r
return;
}

- /*
- * Check if a constrained deadline task was activated
- * after the deadline but before the next period.
- * If that is the case, the task will be throttled and
- * the replenishment timer will be set to the next period.
- */
- if (!p->dl.dl_throttled && !dl_is_implicit(&p->dl))
- dl_check_constrained_dl(&p->dl);
-
- if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & ENQUEUE_RESTORE) {
- add_rq_bw(&p->dl, &rq->dl);
- add_running_bw(&p->dl, &rq->dl);
- }
-
- /*
- * If p is throttled, we do not enqueue it. In fact, if it exhausted
- * its budget it needs a replenishment and, since it now is on
- * its rq, the bandwidth timer callback (which clearly has not
- * run yet) will take care of this.
- * However, the active utilization does not depend on the fact
- * that the task is on the runqueue or not (but depends on the
- * task's state - in GRUB parlance, "inactive" vs "active contending").
- * In other words, even if a task is throttled its utilization must
- * be counted in the active utilization; hence, we need to call
- * add_running_bw().
- */
- if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
- if (flags & ENQUEUE_WAKEUP)
- task_contending(&p->dl, flags);
-
- return;
- }
+ if (p->on_rq == TASK_ON_RQ_MIGRATING)
+ flags |= ENQUEUE_MIGRATING;

enqueue_dl_entity(&p->dl, pi_se, flags);

@@ -1495,31 +1521,18 @@ static void enqueue_task_dl(struct rq *r

static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
{
- dequeue_dl_entity(&p->dl);
+ dequeue_dl_entity(&p->dl, flags);
dequeue_pushable_dl_task(rq, p);
}

static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
{
update_curr_dl(rq);
- __dequeue_task_dl(rq, p, flags);

- if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & DEQUEUE_SAVE) {
- sub_running_bw(&p->dl, &rq->dl);
- sub_rq_bw(&p->dl, &rq->dl);
- }
+ if (p->on_rq == TASK_ON_RQ_MIGRATING)
+ flags |= DEQUEUE_MIGRATING;

- /*
- * This check allows to start the inactive timer (or to immediately
- * decrease the active utilization, if needed) in two cases:
- * when the task blocks and when it is terminating
- * (p->state == TASK_DEAD). We can handle the two cases in the same
- * way, because from GRUB's point of view the same thing is happening
- * (the task moves from "active contending" to "active non contending"
- * or "inactive")
- */
- if (flags & DEQUEUE_SLEEP)
- task_non_contending(p);
+ __dequeue_task_dl(rq, p, flags);
}

/*
@@ -2269,7 +2282,7 @@ static void switched_from_dl(struct rq *
* will reset the task parameters.
*/
if (task_on_rq_queued(p) && p->dl.dl_runtime)
- task_non_contending(p);
+ task_non_contending(&p->dl);

if (!task_on_rq_queued(p)) {
/*
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1661,6 +1661,10 @@ extern const u32 sched_prio_to_wmult[40
* MOVE - paired with SAVE/RESTORE, explicitly does not preserve the location
* in the runqueue.
*
+ * NOCLOCK - skip the update_rq_clock() (avoids double updates)
+ *
+ * MIGRATION - p->on_rq == TASK_ON_RQ_MIGRATING (used for DEADLINE)
+ *
* ENQUEUE_HEAD - place at front of runqueue (tail if not specified)
* ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline)
* ENQUEUE_MIGRATED - the task was migrated during wakeup
@@ -1671,6 +1675,7 @@ extern const u32 sched_prio_to_wmult[40
#define DEQUEUE_SAVE 0x02 /* Matches ENQUEUE_RESTORE */
#define DEQUEUE_MOVE 0x04 /* Matches ENQUEUE_MOVE */
#define DEQUEUE_NOCLOCK 0x08 /* Matches ENQUEUE_NOCLOCK */
+#define DEQUEUE_MIGRATING 0x80 /* Matches ENQUEUE_MIGRATING */

#define ENQUEUE_WAKEUP 0x01
#define ENQUEUE_RESTORE 0x02
@@ -1684,6 +1689,7 @@ extern const u32 sched_prio_to_wmult[40
#else
#define ENQUEUE_MIGRATED 0x00
#endif
+#define ENQUEUE_MIGRATING 0x80

#define RETRY_TASK ((void *)-1UL)


\
 
 \ /
  Last update: 2019-07-26 18:21    [W:0.257 / U:2.228 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site