blk-cgroup: clear the throttle queue on fork
We were hitting a panic in production where we put too many times on the
request queue. This is because we'd get the throttle_queue of the
parent if we fork()'ed while we needed to be throttled, but we didn't
have a reference on it. Instead just clear these flags on fork so the
child doesn't pay for the sins of its father.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/kernel/fork.c b/kernel/fork.c
index 9440d61..694ae0e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -843,6 +843,11 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->fail_nth = 0;
#endif
+#ifdef CONFIG_BLK_CGROUP
+ tsk->throttle_queue = NULL;
+ tsk->use_memdelay = 0;
+#endif
+
return tsk;
free_stack:
