summaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
authorPeter Zijlstra <peterz@infradead.org>2017-02-02 16:55:06 +0100
committerIngo Molnar <mingo@kernel.org>2017-02-24 08:58:33 +0100
commit8cb68b343a66cf19834472012590490d34d31703 (patch)
tree9fb6c71ddb2c046c0aaceb748248d94cc74a351d /kernel
parent2bfe01eff4307409b95859e860261d0907149b61 (diff)
downloadlinux-8cb68b343a66cf19834472012590490d34d31703.tar.gz
sched/core: Fix update_rq_clock() splat on hotplug (and suspend/resume)
The hotplug code still triggers the warning about using a stale rq->clock value. Fix things up to actually run update_rq_clock() in a place where we record the 'UPDATED' flag, and then modify the annotation to retain this flag over the rq->lock fiddling that happens as a result of actually migrating all the tasks elsewhere. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Tested-by: Mike Galbraith <efault@gmx.de> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Tested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ross Zwisler <zwisler@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 4d25b35ea372 ("sched/fair: Restore previous rq_flags when migrating tasks in hotplug") Link: http://lkml.kernel.org/r/20170202155506.GX6515@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c14
1 files changed, 4 insertions, 10 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 34e2291..2d6e828 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5557,7 +5557,7 @@ static void migrate_tasks(struct rq *dead_rq)
{
struct rq *rq = dead_rq;
struct task_struct *next, *stop = rq->stop;
- struct rq_flags rf, old_rf;
+ struct rq_flags rf;
int dest_cpu;
/*
@@ -5576,7 +5576,9 @@ static void migrate_tasks(struct rq *dead_rq)
* class method both need to have an up-to-date
* value of rq->clock[_task]
*/
+ rq_pin_lock(rq, &rf);
update_rq_clock(rq);
+ rq_unpin_lock(rq, &rf);
for (;;) {
/*
@@ -5589,7 +5591,7 @@ static void migrate_tasks(struct rq *dead_rq)
/*
* pick_next_task() assumes pinned rq->lock:
*/
- rq_pin_lock(rq, &rf);
+ rq_repin_lock(rq, &rf);
next = pick_next_task(rq, &fake_task, &rf);
BUG_ON(!next);
next->sched_class->put_prev_task(rq, next);
@@ -5618,13 +5620,6 @@ static void migrate_tasks(struct rq *dead_rq)
continue;
}
- /*
- * __migrate_task() may return with a different
- * rq->lock held and a new cookie in 'rf', but we need
- * to preserve rf::clock_update_flags for 'dead_rq'.
- */
- old_rf = rf;
-
/* Find suitable destination for @next, with force if needed. */
dest_cpu = select_fallback_rq(dead_rq->cpu, next);
@@ -5633,7 +5628,6 @@ static void migrate_tasks(struct rq *dead_rq)
raw_spin_unlock(&rq->lock);
rq = dead_rq;
raw_spin_lock(&rq->lock);
- rf = old_rf;
}
raw_spin_unlock(&next->pi_lock);
}