From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
paulmck@kernel.org, frederic@kernel.org, peterz@infradead.org
Subject: [PATCH 2/6] sched: Verify some SMP assumptions
Date: Mon, 15 Jun 2020 14:56:56 +0200 [thread overview]
Message-ID: <20200615131143.191539791@infradead.org> (raw)
In-Reply-To: 20200615125654.678940605@infradead.org
Validate that:
- __smp_call_single_queue() is only used on remote CPUs
- task and rq CPUs match on activate_task()
(and always use activate_task() where we should)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/core.c | 8 ++++----
kernel/smp.c | 2 ++
2 files changed, 6 insertions(+), 4 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1311,6 +1311,8 @@ static inline void dequeue_task(struct r
void activate_task(struct rq *rq, struct task_struct *p, int flags)
{
+ SCHED_WARN_ON(task_cpu(p) != cpu_of(rq));
+
if (task_contributes_to_load(p))
rq->nr_uninterruptible--;
@@ -1474,8 +1476,7 @@ static struct rq *move_queued_task(struc
{
lockdep_assert_held(&rq->lock);
- WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);
- dequeue_task(rq, p, DEQUEUE_NOCLOCK);
+ deactivate_task(rq, p, DEQUEUE_NOCLOCK);
set_task_cpu(p, new_cpu);
rq_unlock(rq, rf);
@@ -1483,8 +1484,7 @@ static struct rq *move_queued_task(struc
rq_lock(rq, rf);
BUG_ON(task_cpu(p) != new_cpu);
- enqueue_task(rq, p, 0);
- p->on_rq = TASK_ON_RQ_QUEUED;
+ activate_task(rq, p, 0);
check_preempt_curr(rq, p, 0);
return rq;
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -135,6 +135,8 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(cal
void __smp_call_single_queue(int cpu, struct llist_node *node)
{
+ WARN_ON_ONCE(cpu == smp_processor_id());
+
/*
* The list addition should be visible before sending the IPI
* handler locks the list to pull the entry off it because of
next prev parent reply other threads:[~2020-06-15 13:18 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 12:56 [PATCH 0/6] sched: TTWU, IPI, and assorted stuff Peter Zijlstra
2020-06-15 12:56 ` [PATCH 1/6] sched: Fix ttwu_queue_cond() Peter Zijlstra
2020-06-15 13:34 ` Peter Zijlstra
2020-06-15 16:45 ` Paul E. McKenney
2020-06-15 22:58 ` Paul E. McKenney
2020-06-22 9:11 ` Mel Gorman
2020-06-22 9:41 ` Peter Zijlstra
2020-06-15 12:56 ` Peter Zijlstra [this message]
2020-06-15 12:56 ` [PATCH 3/6] sched: s/WF_ON_RQ/WQ_ON_CPU/ Peter Zijlstra
2020-06-22 9:13 ` Mel Gorman
2020-06-15 12:56 ` [PATCH 4/6] smp, irq_work: Continue smp_call_function*() and irq_work*() integration Peter Zijlstra
2020-06-15 12:56 ` [PATCH 5/6] irq_work: Cleanup Peter Zijlstra
2020-06-16 15:16 ` Petr Mladek
2020-06-15 12:57 ` [PATCH 6/6] smp: Cleanup smp_call_function*() Peter Zijlstra
2020-06-15 14:34 ` Jens Axboe
2020-06-15 16:04 ` Daniel Thompson
2020-06-17 8:23 ` Christoph Hellwig
2020-06-17 9:00 ` Peter Zijlstra
2020-06-17 11:04 ` Peter Zijlstra
2020-06-18 6:51 ` Christoph Hellwig
2020-06-18 16:25 ` Peter Zijlstra
2020-06-15 16:23 ` [PATCH 0/6] sched: TTWU, IPI, and assorted stuff Paul E. McKenney
2020-06-15 16:40 ` Peter Zijlstra
2020-06-15 17:21 ` Paul E. McKenney
2020-06-15 19:11 ` Peter Zijlstra
2020-06-15 19:55 ` Paul E. McKenney
2020-06-16 16:31 ` Paul E. McKenney
2020-06-16 17:04 ` Peter Zijlstra
2020-06-16 17:17 ` Peter Zijlstra
2020-06-16 17:53 ` Paul E. McKenney
2020-06-19 13:44 ` Peter Zijlstra
2020-06-19 17:20 ` Paul E. McKenney
2020-06-19 17:48 ` Paul E. McKenney
2020-06-19 18:11 ` Peter Zijlstra
2020-06-19 18:46 ` Paul E. McKenney
2020-06-20 18:46 ` Paul E. McKenney
2020-06-16 17:51 ` Paul E. McKenney
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