Hi all,
Today's linux-next merge of the tip tree got a conflict in kernel/sched.c
between commit 6631e635c65d ("block: don't flush plugged IO on forced
preemtion scheduling") from Linus' tree and commits 098247b90a9e ("sched:
Provide p->on_rq") and a3380736e4b3 ("sched: Also serialize ttwu_local()
with p->pi_lock") from the tip tree.
I fixed them up (hopefully - see below) and can carry the fix as
necessary.
--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
diff --cc kernel/sched.c
index a187c3f,3e99c42..0000000
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@@ -4103,30 -4184,31 +4184,31 @@@ need_resched
* task to maintain concurrency. If so, wake
* up the task.
*/
- if (prev->flags & PF_WQ_WORKER) {
- struct task_struct *to_wakeup;
-
+ if (prev->flags & PF_WQ_WORKER)
to_wakeup = wq_worker_sleeping(prev, cpu);
- if (to_wakeup)
- try_to_wake_up_local(to_wakeup);
- }
deactivate_task(rq, prev, DEQUEUE_SLEEP);
+ prev->on_rq = 0;
+
+ /*
+ * If we are going to sleep and we have plugged IO queued, make
+ * sure to submit it to avoid deadlocks.
+ */
+ if (blk_needs_flush_plug(prev)) {
+ raw_spin_unlock(&rq->lock);
+ blk_flush_plug(prev);
+ raw_spin_lock(&rq->lock);
+ }
}
switch_count = &prev->nvcsw;
}
+ /*
- * If we are going to sleep and we have plugged IO queued, make
- * sure to submit it to avoid deadlocks.
- */
- if (prev->state != TASK_RUNNING && blk_needs_flush_plug(prev)) {
- raw_spin_unlock(&rq->lock);
- blk_flush_plug(prev);
- raw_spin_lock(&rq->lock);
- }
-
- /*
+ * All three: try_to_wake_up_local(), pre_schedule() and idle_balance()
+ * can drop rq->lock.
+ */
+ if (to_wakeup)
+ try_to_wake_up_local(to_wakeup);
pre_schedule(rq, prev);
-
if (unlikely(!rq->nr_running))
idle_balance(cpu, rq);
--
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