On Tue, 2012-09-25 at 12:40 -0700, Tejun Heo wrote:
> On Tue, Sep 25, 2012 at 09:34:39PM +0200, Maxim Levitsky wrote:
> > But this just adds the WQ_UNBOUND. Dunno, without lock I had several
> > crashes, that for high level of confidence caused by by parallel
> > execution of work items. Once I added this mutex, I couldnt reproduce
> > these.
>
> Yes the combination of WQ_UNBOUND and max_active==1 guarantees
> strictly ordered one-by-one execution.
>
> > I had the __blk_end_request fail with NULL msb->req. I can't see how
> > that can happen if work queue isn't executed in parallel.
> > (and then the I didn't even had by mistake the code that sets it to NULL
> > in msb_stop, so I really fail to see how that could happen due internal
> > bug in my code.
>
> If you're seeing parallel execution w/ ordered workqueue, it is a
> critical bug which would make the kernel crash left and right. Please
> try alloc_ordered_workqueue() and if you still see parallel execution,
> please report.
I will test this very soon. Good to know, I am pretty sure, it will
work.
>
> Thanks.
>
--
Best regards,
Maxim Levitsky
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