diff options
| author | Joe Lawrence <joe.lawrence@stratus.com> | 2014-10-05 13:24:21 -0400 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-10-06 05:57:43 -0700 |
| commit | 789cbbeca4eb7141cbd748ee93772471101b507b (patch) | |
| tree | 357a38595c99840947212b6ec89a7a6d4ada2aee /kernel/workqueue.c | |
| parent | c98fed9fc6a7449affd941d8a8e9fcb0c72977d6 (diff) | |
workqueue: Add quiescent state between work items
Similar to the stop_machine deadlock scenario on !PREEMPT kernels
addressed in b22ce2785d97 "workqueue: cond_resched() after processing
each work item", kworker threads requeueing back-to-back with zero jiffy
delay can stall RCU. The cond_resched call introduced in that fix will
yield only iff there are other higher priority tasks to run, so force a
quiescent RCU state between work items.
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Link: https://lkml.kernel.org/r/20140926105227.01325697@jlaw-desktop.mno.stratus.com
Link: https://lkml.kernel.org/r/20140929115445.40221d8e@jlaw-desktop.mno.stratus.com
Fixes: b22ce2785d97 ("workqueue: cond_resched() after processing each work item")
Cc: <stable@vger.kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 5dbe22aa3efd..345bec95e708 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2043,8 +2043,10 @@ __acquires(&pool->lock) * kernels, where a requeueing work item waiting for something to * happen could deadlock with stop_machine as such work item could * indefinitely requeue itself while all other CPUs are trapped in - * stop_machine. + * stop_machine. At the same time, report a quiescent RCU state so + * the same condition doesn't freeze RCU. */ + rcu_note_voluntary_context_switch(current); cond_resched(); spin_lock_irq(&pool->lock); |