Re: [RFC PATCH] cifs: Fix possible deadlock with cifs and work queues

[Peter Zijlstra]

On Wed, Mar 19, 2014 at 03:12:52PM -0400, Steven Rostedt wrote:
> My question to Tejun is, if we create another workqueue, to add the
> rdata->work to, would that prevent the above problem? Or what other
> fixes can we do?

The way I understand workqueues is that we cannot guarantee concurrency
like this. It tries, but there's no guarantee.

WQ_MAX_ACTIVE seems to be a hard upper limit of concurrent workers. So
given 511 other blocked works, the described problem will always happen.

Creating another workqueue doesn't actually create more threads.

There is the kthread_work stuff for if you want a guaranteed worker
thread.
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