From: tip-bot for Peter Zijlstra <a.p.zijlstra@chello.nl>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com,
torvalds@linux-foundation.org, a.p.zijlstra@chello.nl,
efault@gmx.de, npiggin@kernel.dk, akpm@linux-foundation.org,
tglx@linutronix.de, frank.rowand@am.sony.com, mingo@elte.hu
Subject: [tip:sched/locking] sched: Serialize p->cpus_allowed and ttwu() using p->pi_lock
Date: Thu, 14 Apr 2011 08:34:11 GMT [thread overview]
Message-ID: <tip-013fdb8086acaae5f8eb96f9ad48fcd98882ac46@git.kernel.org> (raw)
In-Reply-To: <20110405152728.990364093@chello.nl>
Commit-ID: 013fdb8086acaae5f8eb96f9ad48fcd98882ac46
Gitweb: http://git.kernel.org/tip/013fdb8086acaae5f8eb96f9ad48fcd98882ac46
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 5 Apr 2011 17:23:45 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 14 Apr 2011 08:52:35 +0200
sched: Serialize p->cpus_allowed and ttwu() using p->pi_lock
Currently p->pi_lock already serializes p->sched_class, also put
p->cpus_allowed and try_to_wake_up() under it, this prepares the way
to do the first part of ttwu() without holding rq->lock.
By having p->sched_class and p->cpus_allowed serialized by p->pi_lock,
we prepare the way to call select_task_rq() without holding rq->lock.
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152728.990364093@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched.c | 37 ++++++++++++++++---------------------
1 files changed, 16 insertions(+), 21 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index dece28e..d398f2f 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2340,7 +2340,7 @@ EXPORT_SYMBOL_GPL(kick_process);
#ifdef CONFIG_SMP
/*
- * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held.
+ * ->cpus_allowed is protected by both rq->lock and p->pi_lock
*/
static int select_fallback_rq(int cpu, struct task_struct *p)
{
@@ -2373,7 +2373,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
}
/*
- * The caller (fork, wakeup) owns TASK_WAKING, ->cpus_allowed is stable.
+ * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
*/
static inline
int select_task_rq(struct rq *rq, struct task_struct *p, int sd_flags, int wake_flags)
@@ -2499,7 +2499,8 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
this_cpu = get_cpu();
smp_wmb();
- rq = task_rq_lock(p, &flags);
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
+ rq = __task_rq_lock(p);
if (!(p->state & state))
goto out;
@@ -2557,7 +2558,8 @@ out_running:
ttwu_stat(rq, p, cpu, wake_flags);
success = 1;
out:
- task_rq_unlock(rq, &flags);
+ __task_rq_unlock(rq);
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
put_cpu();
return success;
@@ -4694,6 +4696,8 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
BUG_ON(prio < 0 || prio > MAX_PRIO);
+ lockdep_assert_held(&p->pi_lock);
+
rq = task_rq_lock(p, &flags);
trace_sched_pi_setprio(p, prio);
@@ -5317,7 +5321,6 @@ long sched_getaffinity(pid_t pid, struct cpumask *mask)
{
struct task_struct *p;
unsigned long flags;
- struct rq *rq;
int retval;
get_online_cpus();
@@ -5332,9 +5335,9 @@ long sched_getaffinity(pid_t pid, struct cpumask *mask)
if (retval)
goto out_unlock;
- rq = task_rq_lock(p, &flags);
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
- task_rq_unlock(rq, &flags);
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
out_unlock:
rcu_read_unlock();
@@ -5882,18 +5885,8 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
unsigned int dest_cpu;
int ret = 0;
- /*
- * Serialize against TASK_WAKING so that ttwu() and wunt() can
- * drop the rq->lock and still rely on ->cpus_allowed.
- */
-again:
- while (task_is_waking(p))
- cpu_relax();
- rq = task_rq_lock(p, &flags);
- if (task_is_waking(p)) {
- task_rq_unlock(rq, &flags);
- goto again;
- }
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
+ rq = __task_rq_lock(p);
if (!cpumask_intersects(new_mask, cpu_active_mask)) {
ret = -EINVAL;
@@ -5921,13 +5914,15 @@ again:
if (migrate_task(p, rq)) {
struct migration_arg arg = { p, dest_cpu };
/* Need help from migration thread: drop lock and wait. */
- task_rq_unlock(rq, &flags);
+ __task_rq_unlock(rq);
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
tlb_migrate_finish(p->mm);
return 0;
}
out:
- task_rq_unlock(rq, &flags);
+ __task_rq_unlock(rq);
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
return ret;
}
next prev parent reply other threads:[~2011-04-14 8:35 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-bot for Peter Zijlstra [this message]
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 ` [PATCH 19/21] sched: Restructure ttwu some more Peter Zijlstra
2011-04-14 8:39 ` [tip:sched/locking] sched: Restructure ttwu() " 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
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=tip-013fdb8086acaae5f8eb96f9ad48fcd98882ac46@git.kernel.org \
--to=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=efault@gmx.de \
--cc=frank.rowand@am.sony.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=mingo@redhat.com \
--cc=npiggin@kernel.dk \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/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).