Messages in this thread | | | Date | Fri, 30 Sep 2011 01:09:14 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH] workqueue: Restore cpus_allowed mask for sleeping workqueue rescue threads |
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Hello,
On Sun, Sep 25, 2011 at 09:02:25AM +0300, Gilad Ben-Yossef wrote: > Thank you for taking the time to answer my query :-) > > I agree there is no real problem with having an additional task > bound to an "isolated" CPU so long that it does not run and of > course that if a task on an isolated CPU initiated activity that > resulted in requiring the services of a rescuer workqueue thread it > most certainly needs to run there and that is fine. > > I guess my question is - apart form running on the isolated CPU, > does the fact that the rescuer thread is bound there can cause > activity on that CPU originating from a foreign CPU, such as for > example running an IPI handler in order to migrate it there?
Hmmm... indeed. This can cause an unnecessary wakeup / migration on an isolated CPU when another CPU asks for the rescuer, so yeah it makes sense to change the behavior. BTW, why didn't the original patch simply use set_cpus_allowed_ptr(cpu_all_mask)?
Thanks.
-- tejun
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