Messages in this thread | | | Subject | Re: 回复: [PATCH] debugobjects: install cpu hotplug callback | From | Waiman Long <> | Date | Tue, 25 Aug 2020 20:48:53 -0400 |
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On 8/25/20 7:53 PM, Thomas Gleixner wrote: > On Tue, Aug 25 2020 at 18:26, Waiman Long wrote: >> On 8/25/20 12:53 AM, Zhang, Qiang wrote: >>> When a cpu going offline, we should free objects in "percpu_obj_pool" >>> free_objs list which corresponding to this cpu. >> The percpu free object pool is supposed to be accessed only by that >> particular cpu without any lock. Trying to access it from another cpu >> can cause a race condition unless one can make sure that the offline cpu >> won't become online in the mean time. > It is actually safe because CPU hotplug is globally serialized and there > is no way that an offline CPU will come back from death valley > magically. If such a zombie ever surfaces then we have surely more > serious problems than accessing that pool :)
Thanks for the clarification. I haven't looked into where the callback functions are being called so I am not 100% sure.
Cheers, Longman
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