From: Peter Zijlstra <peterz@infradead.org>
To: umgwanakikbuti@gmail.com, mingo@elte.hu
Cc: ktkhai@parallels.com, rostedt@goodmis.org, juri.lelli@gmail.com,
pang.xunlei@linaro.org, oleg@redhat.com,
linux-kernel@vger.kernel.org,
"Peter Zijlstra" <peterz@infradead.org>
Subject: [RFC][PATCH 1/7] sched: Replace post_schedule with a balance callback list
Date: Mon, 01 Jun 2015 15:58:19 +0200 [thread overview]
Message-ID: <20150601140839.630055365@infradead.org> (raw)
In-Reply-To: 20150601135818.506080835@infradead.org
[-- Attachment #1: peterz-sched-post_schedule-1.patch --]
[-- Type: text/plain, Size: 6815 bytes --]
Generalize the post_schedule() stuff into a balance callback list.
This allows us to more easily use it outside of schedule() and cross
sched_class.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/core.c | 36 ++++++++++++++++++++++++------------
kernel/sched/deadline.c | 19 ++++++++++---------
kernel/sched/rt.c | 25 +++++++++++--------------
kernel/sched/sched.h | 19 +++++++++++++++++--
4 files changed, 62 insertions(+), 37 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2277,23 +2277,35 @@ static struct rq *finish_task_switch(str
#ifdef CONFIG_SMP
/* rq->lock is NOT held, but preemption is disabled */
-static inline void post_schedule(struct rq *rq)
+static void __balance_callback(struct rq *rq)
{
- if (rq->post_schedule) {
- unsigned long flags;
+ struct callback_head *head, *next;
+ void (*func)(struct rq *rq);
+ unsigned long flags;
- raw_spin_lock_irqsave(&rq->lock, flags);
- if (rq->curr->sched_class->post_schedule)
- rq->curr->sched_class->post_schedule(rq);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ head = rq->balance_callback;
+ rq->balance_callback = NULL;
+ while (head) {
+ func = (void (*)(struct rq *))head->func;
+ next = head->next;
+ head->next = NULL;
+ head = next;
- rq->post_schedule = 0;
+ func(rq);
}
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static inline void balance_callback(struct rq *rq)
+{
+ if (unlikely(rq->balance_callback))
+ __balance_callback(rq);
}
#else
-static inline void post_schedule(struct rq *rq)
+static inline void balance_callback(struct rq *rq)
{
}
@@ -2311,7 +2323,7 @@ asmlinkage __visible void schedule_tail(
/* finish_task_switch() drops rq->lock and enables preemtion */
preempt_disable();
rq = finish_task_switch(prev);
- post_schedule(rq);
+ balance_callback(rq);
preempt_enable();
if (current->set_child_tid)
@@ -2822,7 +2834,7 @@ static void __sched __schedule(void)
} else
raw_spin_unlock_irq(&rq->lock);
- post_schedule(rq);
+ balance_callback(rq);
}
static inline void sched_submit_work(struct task_struct *tsk)
@@ -7216,7 +7228,7 @@ void __init sched_init(void)
rq->sd = NULL;
rq->rd = NULL;
rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
- rq->post_schedule = 0;
+ rq->balance_callback = NULL;
rq->active_balance = 0;
rq->next_balance = jiffies;
rq->push_cpu = 0;
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -213,9 +213,16 @@ static inline bool need_pull_dl_task(str
return dl_task(prev);
}
-static inline void set_post_schedule(struct rq *rq)
+static DEFINE_PER_CPU(struct callback_head, dl_balance_head);
+
+static void push_dl_tasks(struct rq *);
+
+static inline void queue_push_tasks(struct rq *rq)
{
- rq->post_schedule = has_pushable_dl_tasks(rq);
+ if (!has_pushable_dl_tasks(rq))
+ return;
+
+ queue_balance_callback(rq, &per_cpu(dl_balance_head, rq->cpu), push_dl_tasks);
}
static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
@@ -1126,7 +1133,7 @@ struct task_struct *pick_next_task_dl(st
if (hrtick_enabled(rq))
start_hrtick_dl(rq, p);
- set_post_schedule(rq);
+ queue_push_tasks(rq);
return p;
}
@@ -1544,11 +1551,6 @@ static int pull_dl_task(struct rq *this_
return ret;
}
-static void post_schedule_dl(struct rq *rq)
-{
- push_dl_tasks(rq);
-}
-
/*
* Since the task is not running and a reschedule is not going to happen
* anytime soon on its runqueue, we try pushing it away now.
@@ -1784,7 +1786,6 @@ const struct sched_class dl_sched_class
.set_cpus_allowed = set_cpus_allowed_dl,
.rq_online = rq_online_dl,
.rq_offline = rq_offline_dl,
- .post_schedule = post_schedule_dl,
.task_woken = task_woken_dl,
#endif
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -354,13 +354,16 @@ static inline int has_pushable_tasks(str
return !plist_head_empty(&rq->rt.pushable_tasks);
}
-static inline void set_post_schedule(struct rq *rq)
+static DEFINE_PER_CPU(struct callback_head, rt_balance_head);
+
+static void push_rt_tasks(struct rq *);
+
+static inline void queue_push_tasks(struct rq *rq)
{
- /*
- * We detect this state here so that we can avoid taking the RQ
- * lock again later if there is no need to push
- */
- rq->post_schedule = has_pushable_tasks(rq);
+ if (!has_pushable_tasks(rq))
+ return;
+
+ queue_balance_callback(rq, &per_cpu(rt_balance_head, rq->cpu), push_rt_tasks);
}
static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
@@ -417,7 +420,7 @@ static inline int pull_rt_task(struct rq
return 0;
}
-static inline void set_post_schedule(struct rq *rq)
+static inline void queue_push_tasks(struct rq *rq)
{
}
#endif /* CONFIG_SMP */
@@ -1497,7 +1500,7 @@ pick_next_task_rt(struct rq *rq, struct
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
- set_post_schedule(rq);
+ queue_push_tasks(rq);
return p;
}
@@ -2042,11 +2045,6 @@ static int pull_rt_task(struct rq *this_
return ret;
}
-static void post_schedule_rt(struct rq *rq)
-{
- push_rt_tasks(rq);
-}
-
/*
* If we are not running and we are not going to reschedule soon, we should
* try to push tasks away now
@@ -2318,7 +2316,6 @@ const struct sched_class rt_sched_class
.set_cpus_allowed = set_cpus_allowed_rt,
.rq_online = rq_online_rt,
.rq_offline = rq_offline_rt,
- .post_schedule = post_schedule_rt,
.task_woken = task_woken_rt,
.switched_from = switched_from_rt,
#endif
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -624,9 +624,10 @@ struct rq {
unsigned long cpu_capacity;
unsigned long cpu_capacity_orig;
+ struct callback_head *balance_callback;
+
unsigned char idle_balance;
/* For active balancing */
- int post_schedule;
int active_balance;
int push_cpu;
struct cpu_stop_work active_balance_work;
@@ -695,6 +696,21 @@ struct rq {
#endif
};
+static inline void
+queue_balance_callback(struct rq *rq,
+ struct callback_head *head,
+ void (*func)(struct rq *rq))
+{
+ lockdep_assert_held(&rq->lock);
+
+ if (unlikely(head->next))
+ return;
+
+ head->func = (void (*)(struct callback_head *))func;
+ head->next = rq->balance_callback;
+ rq->balance_callback = head;
+}
+
static inline int cpu_of(struct rq *rq)
{
#ifdef CONFIG_SMP
@@ -1192,7 +1208,6 @@ struct sched_class {
int (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags);
void (*migrate_task_rq)(struct task_struct *p, int next_cpu);
- void (*post_schedule) (struct rq *this_rq);
void (*task_waking) (struct task_struct *task);
void (*task_woken) (struct rq *this_rq, struct task_struct *task);
next prev parent reply other threads:[~2015-06-01 14:13 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-01 13:58 [RFC][PATCH 0/7] sched: balance callbacks Peter Zijlstra
2015-06-01 13:58 ` Peter Zijlstra [this message]
2015-06-03 4:41 ` [RFC][PATCH 1/7] sched: Replace post_schedule with a balance callback list Kamalesh Babulal
2015-06-03 7:21 ` Peter Zijlstra
2015-06-03 8:24 ` pang.xunlei
2015-06-03 8:55 ` Peter Zijlstra
2015-06-05 7:13 ` pang.xunlei
2015-06-05 7:19 ` Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 2/7] sched: Use replace normalize_task() with __sched_setscheduler() Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 3/7] sched: Allow balance callbacks for check_class_changed() Peter Zijlstra
2015-06-02 13:58 ` Kirill Tkhai
2015-06-02 14:27 ` Peter Zijlstra
2015-06-02 16:07 ` Peter Zijlstra
2015-06-02 16:27 ` Kirill Tkhai
2015-06-03 7:32 ` Peter Zijlstra
2015-06-03 10:40 ` Kirill Tkhai
2015-06-03 10:42 ` Kirill Tkhai
2015-06-03 10:45 ` Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 4/7] sched,rt: Remove return value from pull_rt_task() Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 5/7] sched,rt: Convert switched_{from,to}_rt() / prio_changed_rt() to balance callbacks Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 6/7] sched,dl: Remove return value from pull_dl_task() Peter Zijlstra
2015-06-01 13:58 ` [RFC][PATCH 7/7] sched,dl: Convert switched_{from,to}_dl() / prio_changed_dl() to balance callbacks Peter Zijlstra
2015-06-03 4:52 ` Kamalesh Babulal
2015-06-01 14:16 ` [RFC][PATCH 0/7] sched: " Peter Zijlstra
2015-06-01 14:42 ` Mike Galbraith
2015-06-02 6:48 ` Mike Galbraith
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150601140839.630055365@infradead.org \
--to=peterz@infradead.org \
--cc=juri.lelli@gmail.com \
--cc=ktkhai@parallels.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=oleg@redhat.com \
--cc=pang.xunlei@linaro.org \
--cc=rostedt@goodmis.org \
--cc=umgwanakikbuti@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).