[openib-general] Re: ipoib and core patches for 2.6.17

[Roland Dreier]

    Michael> I wander why. However, since ipoib workqueue is
    Michael> single-threaded, this gives us a drastically simple
    Michael> solution to all synchronisation problems, good for
    Michael> everything that isn't data-path.

I guess the main thing that I don't like is this:

 > -int ipoib_ib_dev_down(struct net_device *dev);
 > +int ipoib_ib_dev_down(struct net_device *dev, int flush);

Now we have to worry about getting another flush flag correct, and I'd
like to avoid that.

Also, the more different things there are in the same workqueue, the
more we have to worry about deadlocks when flushing the workqueue.

    Michael> Roland, how adding a global, system-wide, single-threaded
    Michael> wq to linux?  We might not be the only ones that have a
    Michael> problem with the default per-CPU workqueue.

Not a bad idea to propose.  There are about 20 other single-threaded
workqueues in the current tree, and some of them can probably be consolidated.

 - R.