From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Chris Mason <chris.mason@oracle.com>,
Frank Rowand <frank.rowand@am.sony.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Mike Galbraith <efault@gmx.de>, Oleg Nesterov <oleg@redhat.com>,
Paul Turner <pjt@google.com>, Jens Axboe <axboe@kernel.dk>,
Yong Zhang <yong.zhang0@gmail.com>
Cc: linux-kernel@vger.kernel.org, Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [PATCH 19/21] sched: Restructure ttwu some more
Date: Tue, 05 Apr 2011 17:23:57 +0200 [thread overview]
Message-ID: <20110405152729.475848012@chello.nl> (raw)
In-Reply-To: 20110405152338.692966333@chello.nl
[-- Attachment #1: sched-ttwu-foo.patch --]
[-- Type: text/plain, Size: 3612 bytes --]
The last few changes to ttwu that allow for adding remote queues.
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
kernel/sched.c | 93 ++++++++++++++++++++++++++++++++++++---------------------
1 file changed, 59 insertions(+), 34 deletions(-)
Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -2474,6 +2474,49 @@ ttwu_do_wakeup(struct rq *rq, struct tas
wq_worker_waking_up(p, cpu_of(rq));
}
+static void
+ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
+{
+#ifdef CONFIG_SMP
+ if (p->sched_contributes_to_load)
+ rq->nr_uninterruptible--;
+#endif
+
+ activate_task(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
+ p->on_rq = 1;
+ ttwu_do_wakeup(rq, p, wake_flags);
+}
+
+/*
+ * Called in case the task @p isn't fully descheduled from its runqueue,
+ * in this case we must do a remote wakeup. Its a 'light' wakeup though,
+ * since all we need to do is flip p->state to TASK_RUNNING, since
+ * the task is still ->on_rq.
+ */
+static int ttwu_remote(struct task_struct *p, int wake_flags)
+{
+ struct rq *rq;
+ int ret = 0;
+
+ rq = __task_rq_lock(p);
+ if (p->on_rq) {
+ ttwu_do_wakeup(rq, p, wake_flags);
+ ret = 1;
+ }
+ __task_rq_unlock(rq);
+
+ return ret;
+}
+
+static void ttwu_queue(struct task_struct *p, int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+
+ raw_spin_lock(&rq->lock);
+ ttwu_do_activate(rq, p, 0);
+ raw_spin_unlock(&rq->lock);
+}
+
/**
* try_to_wake_up - wake up a thread
* @p: the thread to be awakened
@@ -2492,27 +2535,25 @@ ttwu_do_wakeup(struct rq *rq, struct tas
static int
try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
{
- int cpu, this_cpu, success = 0;
unsigned long flags;
- struct rq *rq;
-
- this_cpu = get_cpu();
+ int cpu, success = 0;
smp_wmb();
raw_spin_lock_irqsave(&p->pi_lock, flags);
if (!(p->state & state))
goto out;
+ success = 1; /* we're going to change ->state */
cpu = task_cpu(p);
- if (p->on_rq) {
- rq = __task_rq_lock(p);
- if (p->on_rq)
- goto out_running;
- __task_rq_unlock(rq);
- }
+ if (p->on_rq && ttwu_remote(p, wake_flags))
+ goto stat;
#ifdef CONFIG_SMP
+ /*
+ * If the owning (remote) cpu is still in the middle of schedule() with
+ * this task as prev, wait until its done referencing the task.
+ */
while (p->on_cpu) {
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
/*
@@ -2521,8 +2562,10 @@ try_to_wake_up(struct task_struct *p, un
* to spin on ->on_cpu if p is current, since that would
* deadlock.
*/
- if (p == current)
- goto out_activate;
+ if (p == current) {
+ ttwu_queue(p, cpu);
+ goto stat;
+ }
#endif
cpu_relax();
}
@@ -2538,33 +2581,15 @@ try_to_wake_up(struct task_struct *p, un
p->sched_class->task_waking(p);
cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
-#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
-out_activate:
-#endif
-#endif /* CONFIG_SMP */
-
- rq = cpu_rq(cpu);
- raw_spin_lock(&rq->lock);
-
-#ifdef CONFIG_SMP
- if (cpu != task_cpu(p))
+ if (task_cpu(p) != cpu)
set_task_cpu(p, cpu);
+#endif /* CONFIG_SMP */
- if (p->sched_contributes_to_load)
- rq->nr_uninterruptible--;
-#endif
-
- activate_task(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
- p->on_rq = 1;
-out_running:
- ttwu_do_wakeup(rq, p, wake_flags);
- success = 1;
- __task_rq_unlock(rq);
-
+ ttwu_queue(p, cpu);
+stat:
ttwu_stat(p, cpu, wake_flags);
out:
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
- put_cpu();
return success;
}
next prev parent reply other threads:[~2011-04-05 15:31 UTC|newest]
Thread overview: 152+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-05 15:23 [PATCH 00/21] sched: Reduce runqueue lock contention -v6 Peter Zijlstra
2011-04-05 15:23 ` [PATCH 01/21] sched: Provide scheduler_ipi() callback in response to smp_send_reschedule() Peter Zijlstra
2011-04-13 21:15 ` Tony Luck
2011-04-13 21:38 ` Peter Zijlstra
2011-04-14 8:31 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 02/21] sched: Always provide p->on_cpu Peter Zijlstra
2011-04-14 8:31 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 03/21] mutex: Use p->on_cpu for the adaptive spin Peter Zijlstra
2011-04-14 8:32 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 04/21] sched: Change the ttwu success details Peter Zijlstra
2011-04-13 9:23 ` Peter Zijlstra
2011-04-13 10:48 ` Peter Zijlstra
2011-04-13 11:06 ` Peter Zijlstra
2011-04-13 18:39 ` Tejun Heo
2011-04-13 19:11 ` Peter Zijlstra
2011-04-14 8:32 ` [tip:sched/locking] sched: Change the ttwu() " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 05/21] sched: Clean up ttwu stats Peter Zijlstra
2011-04-14 8:33 ` [tip:sched/locking] sched: Clean up ttwu() stats tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 06/21] sched: Provide p->on_rq Peter Zijlstra
2011-04-14 8:33 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 07/21] sched: Serialize p->cpus_allowed and ttwu() using p->pi_lock Peter Zijlstra
2011-04-14 8:34 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 08/21] sched: Drop the rq argument to sched_class::select_task_rq() Peter Zijlstra
2011-04-14 8:34 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 09/21] sched: Remove rq argument to sched_class::task_waking() Peter Zijlstra
2011-04-14 8:35 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 10/21] sched: Deal with non-atomic min_vruntime reads on 32bits Peter Zijlstra
2011-04-14 8:35 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 11/21] sched: Delay task_contributes_to_load() Peter Zijlstra
2011-04-14 8:35 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 12/21] sched: Also serialize ttwu_local() with p->pi_lock Peter Zijlstra
2011-04-14 8:36 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 13/21] sched: Add p->pi_lock to task_rq_lock() Peter Zijlstra
2011-04-14 8:36 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-06-01 13:58 ` Arne Jansen
2011-06-01 16:35 ` Peter Zijlstra
2011-06-01 17:20 ` Arne Jansen
2011-06-01 18:09 ` Peter Zijlstra
2011-06-01 18:44 ` Peter Zijlstra
2011-06-01 19:30 ` Arne Jansen
2011-06-01 21:09 ` Linus Torvalds
2011-06-03 9:15 ` Peter Zijlstra
2011-06-03 10:02 ` Arne Jansen
2011-06-03 10:30 ` Peter Zijlstra
2011-06-03 11:52 ` Arne Jansen
2011-06-05 8:17 ` Ingo Molnar
2011-06-05 8:53 ` Arne Jansen
2011-06-05 9:41 ` Ingo Molnar
2011-06-05 9:45 ` Ingo Molnar
2011-06-05 9:43 ` Arne Jansen
2011-06-05 9:55 ` Ingo Molnar
2011-06-05 10:22 ` Arne Jansen
2011-06-05 11:01 ` Ingo Molnar
2011-06-05 11:19 ` [debug patch] printk: Add a printk killswitch to robustify NMI watchdog messages Ingo Molnar
2011-06-05 11:36 ` Ingo Molnar
2011-06-05 11:57 ` Arne Jansen
2011-06-05 13:39 ` Ingo Molnar
2011-06-05 13:54 ` Arne Jansen
2011-06-05 14:06 ` Ingo Molnar
2011-06-05 14:45 ` Arne Jansen
2011-06-05 14:10 ` Ingo Molnar
2011-06-05 14:31 ` Arne Jansen
2011-06-05 15:13 ` Ingo Molnar
2011-06-05 15:26 ` Ingo Molnar
2011-06-05 15:32 ` Ingo Molnar
2011-06-05 16:07 ` Arne Jansen
2011-06-05 16:35 ` Arne Jansen
2011-06-05 16:50 ` Arne Jansen
2011-06-05 17:20 ` Ingo Molnar
2011-06-05 17:42 ` Arne Jansen
2011-06-05 18:59 ` Ingo Molnar
2011-06-05 19:30 ` Arne Jansen
2011-06-05 19:44 ` Ingo Molnar
2011-06-05 20:15 ` Arne Jansen
2011-06-06 6:56 ` Arne Jansen
2011-06-06 9:01 ` Peter Zijlstra
2011-06-06 9:18 ` Arne Jansen
2011-06-06 9:24 ` Peter Zijlstra
2011-06-06 9:52 ` Peter Zijlstra
2011-06-06 10:00 ` Arne Jansen
2011-06-06 10:26 ` Peter Zijlstra
2011-06-06 13:25 ` Peter Zijlstra
2011-06-06 15:04 ` Ingo Molnar
2011-06-06 15:08 ` Ingo Molnar
2011-06-06 17:44 ` Mike Galbraith
2011-06-07 5:20 ` Mike Galbraith
2011-06-06 13:10 ` Ingo Molnar
2011-06-06 13:12 ` Peter Zijlstra
2011-06-06 13:21 ` Ingo Molnar
2011-06-06 13:31 ` Peter Zijlstra
2011-06-06 7:34 ` Arne Jansen
2011-06-05 15:34 ` Arne Jansen
2011-06-06 8:38 ` Peter Zijlstra
2011-06-06 14:58 ` Ingo Molnar
2011-06-06 15:09 ` Peter Zijlstra
2011-06-06 15:47 ` Peter Zijlstra
2011-06-06 15:52 ` Ingo Molnar
2011-06-06 16:00 ` Peter Zijlstra
2011-06-06 16:08 ` Ingo Molnar
2011-06-06 16:12 ` Peter Zijlstra
2011-06-06 16:17 ` Ingo Molnar
2011-06-06 16:38 ` Arne Jansen
2011-06-06 16:45 ` Arne Jansen
2011-06-06 16:53 ` Peter Zijlstra
2011-06-06 17:07 ` Ingo Molnar
2011-06-06 17:11 ` Peter Zijlstra
2011-06-08 15:50 ` Peter Zijlstra
2011-06-08 19:17 ` Ingo Molnar
2011-06-08 19:27 ` Linus Torvalds
2011-06-08 20:32 ` Peter Zijlstra
2011-06-08 20:53 ` Linus Torvalds
2011-06-08 20:54 ` Thomas Gleixner
2011-06-08 19:45 ` Peter Zijlstra
2011-06-08 20:52 ` Ingo Molnar
2011-06-08 21:49 ` Peter Zijlstra
2011-06-08 21:57 ` Thomas Gleixner
2011-06-06 16:44 ` Peter Zijlstra
2011-06-06 16:50 ` Peter Zijlstra
2011-06-06 17:13 ` Ingo Molnar
2011-06-06 17:04 ` Peter Zijlstra
2011-06-06 17:11 ` Ingo Molnar
2011-06-06 17:57 ` Arne Jansen
2011-06-06 18:07 ` Ingo Molnar
2011-06-06 18:14 ` Arne Jansen
2011-06-06 18:19 ` Peter Zijlstra
2011-06-06 22:08 ` Ingo Molnar
2011-06-03 12:44 ` [tip:sched/locking] sched: Add p->pi_lock to task_rq_lock() Linus Torvalds
2011-06-03 13:05 ` Arne Jansen
2011-06-04 21:29 ` Linus Torvalds
2011-06-04 22:08 ` Peter Zijlstra
2011-06-04 22:50 ` Linus Torvalds
2011-06-05 6:01 ` Arne Jansen
2011-06-05 7:57 ` Mike Galbraith
2011-04-05 15:23 ` [PATCH 14/21] sched: Drop rq->lock from first part of wake_up_new_task() Peter Zijlstra
2011-04-14 8:37 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 15/21] sched: Drop rq->lock from sched_exec() Peter Zijlstra
2011-04-14 8:37 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 16/21] sched: Remove rq->lock from the first half of ttwu() Peter Zijlstra
2011-04-14 8:38 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 17/21] sched: Remove rq argument from ttwu_stat() Peter Zijlstra
2011-04-14 8:38 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 18/21] sched: Rename ttwu_post_activation Peter Zijlstra
2011-04-14 8:39 ` [tip:sched/locking] sched: Rename ttwu_post_activation() to ttwu_do_wakeup() tip-bot for Peter Zijlstra
2011-04-05 15:23 ` Peter Zijlstra [this message]
2011-04-14 8:39 ` [tip:sched/locking] sched: Restructure ttwu() some more tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 20/21] sched: Move the second half of ttwu() to the remote cpu Peter Zijlstra
2011-04-14 8:39 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:23 ` [PATCH 21/21] sched: Remove need_migrate_task() Peter Zijlstra
2011-04-14 8:40 ` [tip:sched/locking] " tip-bot for Peter Zijlstra
2011-04-05 15:59 ` [PATCH 00/21] sched: Reduce runqueue lock contention -v6 Peter Zijlstra
2011-04-06 11:00 ` Peter Zijlstra
2011-04-27 16:54 ` Dave Kleikamp
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