Messages in this thread Patch in this message | | | Date | Wed, 28 Feb 2007 18:47:21 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: Problem with freezable workqueues |
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On Wed, Feb 28, 2007 at 12:11:03PM +0100, Rafael J. Wysocki wrote: > > In addition to thawing worker thread before kthread_stopping it, there > > are minor changes required in worker threads, to check for > > is_cpu_offline(bind_cpu) when they come out of refrigerator and jump to > > wait_to_die if so (ex: softirq.c). > > > > I guess you would need these changes before freezer-based hotplug is > > merged, in which case Gautham can send those patches out first. > > Yes, please, if that's possible.
After looking at the current workqueue code, the above minor change I suggested is not required.
So you should be able to fix your "kthread_stop on a frozen worker thread hangs" problem by just a simple patch like this (against 2.6.20-mm2):
--- workqueue.c.org 2007-02-28 18:32:48.000000000 +0530 +++ workqueue.c 2007-02-28 18:44:23.000000000 +0530 @@ -718,6 +718,8 @@ static void cleanup_workqueue_thread(str insert_wq_barrier(cwq, &barr, 1); cwq->should_stop = 1; alive = 1; + if (frozen(cwq->thread)) + thaw(cwq->thread); } spin_unlock_irq(&cwq->lock); Can you test with this?
Note that as Oleg commented, freezable workqueues are broken w/o his patch here:
http://marc.theaimsgroup.com/?l=linux-kernel&m=116855740612755
So you need to have Andrew/Linux pick up the above patch first to have correctly functioning freezable workqueues.
-- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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