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Subject: Re: [PATCH v2.6.36-rc7] infiniband: update workqueue usage
From: Ralph Campbell <ralph.campbell@qlogic.com>
To: Tejun Heo <tj@kernel.org>
CC: Roland Dreier <rolandd@cisco.com>, Sean Hefty <sean.hefty@intel.com>,
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Date: Tue, 19 Oct 2010 10:22:06 -0700
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On Tue, 2010-10-19 at 08:24 -0700, Tejun Heo wrote:

> * qib_cq_wq is a separate singlethread workqueue.  Does the queue
>   require strict single thread execution ordering?  IOW, does each
>   work have to be executed in the exact queued order and no two works
>   should execute in parallel?  Or was the singlethreadedness chosen
>   just to reduce the number of workers?

The work functions need to be called in-order and single threaded
or memory will be freed multiple times and other "bad things".