From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com, juri.lelli@redhat.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de
Cc: linux-kernel@vger.kernel.org, qperret@google.com,
valentin.schneider@arm.com, qais.yousef@arm.com,
ktkhai@virtuozzo.com, peterz@infradead.org
Subject: [PATCH 5/7] sched: Simplify sched_class::pick_next_task()
Date: Fri, 08 Nov 2019 14:15:58 +0100 [thread overview]
Message-ID: <20191108131909.660595546@infradead.org> (raw)
In-Reply-To: 20191108131553.027892369@infradead.org
Now that the indirect class call never uses the last two arguments of
pick_next_task(), remove them.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/core.c | 6 +++---
kernel/sched/deadline.c | 5 +----
kernel/sched/fair.c | 7 ++++++-
kernel/sched/idle.c | 5 +----
kernel/sched/rt.c | 5 +----
kernel/sched/sched.h | 18 +++---------------
kernel/sched/stop_task.c | 5 +----
7 files changed, 16 insertions(+), 35 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3924,7 +3924,7 @@ pick_next_task(struct rq *rq, struct tas
/* Assumes fair_sched_class->next == idle_sched_class */
if (!p) {
put_prev_task(rq, prev);
- p = pick_next_task_idle(rq, NULL, NULL);
+ p = pick_next_task_idle(rq);
}
return p;
@@ -3941,7 +3941,7 @@ pick_next_task(struct rq *rq, struct tas
put_prev_task(rq, prev);
for_each_class(class) {
- p = class->pick_next_task(rq, NULL, NULL);
+ p = class->pick_next_task(rq);
if (p)
return p;
}
@@ -6203,7 +6203,7 @@ static struct task_struct *__pick_migrat
struct task_struct *next;
for_each_class(class) {
- next = class->pick_next_task(rq, NULL, NULL);
+ next = class->pick_next_task(rq);
if (next) {
next->sched_class->put_prev_task(rq, next);
return next;
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1770,15 +1770,12 @@ static struct sched_dl_entity *pick_next
return rb_entry(left, struct sched_dl_entity, rb_node);
}
-static struct task_struct *
-pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+static struct task_struct *pick_next_task_dl(struct rq *rq)
{
struct sched_dl_entity *dl_se;
struct dl_rq *dl_rq = &rq->dl;
struct task_struct *p;
- WARN_ON_ONCE(prev || rf);
-
if (!sched_dl_runnable(rq))
return NULL;
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6743,6 +6743,11 @@ done: __maybe_unused;
return NULL;
}
+static struct task_struct *__pick_next_task_fair(struct rq *rq)
+{
+ return pick_next_task_fair(rq, NULL, NULL);
+}
+
/*
* Account for a descheduled task:
*/
@@ -10621,7 +10626,7 @@ const struct sched_class fair_sched_clas
.check_preempt_curr = check_preempt_wakeup,
- .pick_next_task = pick_next_task_fair,
+ .pick_next_task = __pick_next_task_fair,
.put_prev_task = put_prev_task_fair,
.set_next_task = set_next_task_fair,
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -391,13 +391,10 @@ static void set_next_task_idle(struct rq
schedstat_inc(rq->sched_goidle);
}
-struct task_struct *
-pick_next_task_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+struct task_struct *pick_next_task_idle(struct rq *rq)
{
struct task_struct *next = rq->idle;
- WARN_ON_ONCE(prev || rf);
-
set_next_task_idle(rq, next);
return next;
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1564,13 +1564,10 @@ static struct task_struct *_pick_next_ta
return rt_task_of(rt_se);
}
-static struct task_struct *
-pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+static struct task_struct *pick_next_task_rt(struct rq *rq)
{
struct task_struct *p;
- WARN_ON_ONCE(prev || rf);
-
if (!sched_rt_runnable(rq))
return NULL;
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1713,20 +1713,8 @@ struct sched_class {
void (*check_preempt_curr)(struct rq *rq, struct task_struct *p, int flags);
- /*
- * Both @prev and @rf are optional and may be NULL, in which case the
- * caller must already have invoked put_prev_task(rq, prev, rf).
- *
- * Otherwise it is the responsibility of the pick_next_task() to call
- * put_prev_task() on the @prev task or something equivalent, IFF it
- * returns a next task.
- *
- * In that case (@rf != NULL) it may return RETRY_TASK when it finds a
- * higher prio class has runnable tasks.
- */
- struct task_struct * (*pick_next_task)(struct rq *rq,
- struct task_struct *prev,
- struct rq_flags *rf);
+ struct task_struct *(*pick_next_task)(struct rq *rq);
+
void (*put_prev_task)(struct rq *rq, struct task_struct *p);
void (*set_next_task)(struct rq *rq, struct task_struct *p);
@@ -1822,7 +1810,7 @@ static inline bool sched_fair_runnable(s
}
extern struct task_struct *pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
-extern struct task_struct *pick_next_task_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
+extern struct task_struct *pick_next_task_idle(struct rq *rq);
#ifdef CONFIG_SMP
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -34,11 +34,8 @@ static void set_next_task_stop(struct rq
stop->se.exec_start = rq_clock_task(rq);
}
-static struct task_struct *
-pick_next_task_stop(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+static struct task_struct *pick_next_task_stop(struct rq *rq)
{
- WARN_ON_ONCE(prev || rf);
-
if (!sched_stop_runnable(rq))
return NULL;
next prev parent reply other threads:[~2019-11-08 13:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-08 13:15 [PATCH 0/7] scheduler patches Peter Zijlstra
2019-11-08 13:15 ` [PATCH 1/7] sched: Fix pick_next_task() vs change pattern race Peter Zijlstra
2019-11-08 14:28 ` Quentin Perret
2019-11-08 16:05 ` Valentin Schneider
2019-11-08 20:49 ` Peter Zijlstra
2019-11-08 17:03 ` Qais Yousef
2019-11-08 13:15 ` [PATCH 2/7] sched/fair: Better document newidle_balance() Peter Zijlstra
2019-11-11 9:32 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2019-11-08 13:15 ` [PATCH 3/7] sched: Make pick_next_task_idle() more consistent Peter Zijlstra
2019-11-11 9:32 ` [tip: sched/core] sched/core: " tip-bot2 for Peter Zijlstra
2019-11-08 13:15 ` [PATCH 4/7] sched: Optimize pick_next_task() Peter Zijlstra
2019-11-08 14:33 ` Quentin Perret
2019-11-08 16:46 ` Vincent Guittot
2019-11-08 20:46 ` Peter Zijlstra
2019-11-11 9:32 ` [tip: sched/core] sched/core: " tip-bot2 for Peter Zijlstra
2019-11-08 13:15 ` Peter Zijlstra [this message]
2019-11-11 9:32 ` [tip: sched/core] sched/core: Simplify sched_class::pick_next_task() tip-bot2 for Peter Zijlstra
2019-11-08 13:15 ` [PATCH 6/7] sched/fair: Use mul_u32_u32() Peter Zijlstra
2019-11-11 9:32 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2019-11-08 13:16 ` [PATCH 7/7] sched: Further clarify sched_class::set_next_task() Peter Zijlstra
2019-11-11 9:32 ` [tip: sched/core] sched/core: " tip-bot2 for Peter Zijlstra
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