On 2/6/2019 3:52 PM, Steve Wise wrote:
> On 2/5/2019 4:39 PM, Jason Gunthorpe wrote:
>> On Thu, Jan 31, 2019 at 11:30:42AM -0800, Steve Wise wrote:
>>> While running NVMe/oF wire unplug tests, we hit this warning in
>>> kernel/workqueue.c:check_flush_dependency():
>>>
>>> WARN_ONCE(worker && ((worker->current_pwq->wq->flags &
>>> (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM),
>>> "workqueue: WQ_MEM_RECLAIM %s:%pf is flushing !WQ_MEM_RECLAIM %s:%pf",
>>> worker->current_pwq->wq->name, worker->current_func,
>>> target_wq->name, target_func);
>>>
>>> Which I think means we're flushing a workq that doesn't have
>>> WQ_MEM_RECLAIM set, from workqueue context that does have it set.
>>>
>>> Looking at rdma_addr_cancel() which is doing the flushing, it flushes
>>> the addr_wq which doesn't have MEM_RECLAIM set. Yet rdma_addr_cancel()
>>> is being called by the nvme host connection timeout/reconnect workqueue
>>> thread that does have WQ_MEM_RECLAIM set.
>> Since we haven't learned anything more, I think you should look to
>> remove either the WQ_MEM_RECLAIM or the rdma_addr_cancel() from the
>> nvme side.
> The nvme code is just calling rdma_destroy_id(), which in turn calls
> rdma_addr_cancel(), so I'll have to remove WQ_MEM_RECLAIM from the
> workqueue.
>
> I'll post this patch then.
What a mess. If I remove RECLAIM for nvme_wq, then I'll regress this
change, I think:
c669ccdc50c2 ("nvme: queue ns scanning and async request from nvme_wq")
