On 2013/4/20 2:36, Tejun Heo wrote: > Hello, Li. > > On Fri, Apr 19, 2013 at 08:27:05PM +0800, Li Zefan wrote: >> I think this was introduced unintentionally when cpuset hotplug was >> made asynchronous. Fortunately it does no harm, as updating tasks' >> cpumask will just return failure and there's a guarantee_online_mems() >> when updating nodemask, and then the tasks will be moved to an ancestor >> cpuset. > > Yeah, which will update the masks to the proper values anyway, so it > was intentionally written that way as it didn't really matter either > way. I suppose this helps future changes? Maybe update the > description a bit? > I was trying to fix a bug: before moving tasks out of empty cpusets, update_tasks_nodemask() is called, which calls do_migrate_pages(xx, from, to) finally, from == node_to_be_offlined, to == empty_nodeamsk, so I guess no pages will be migrated. Then when those tasks are moving to an ancestor, do_migrate_pages(xx, from, to) is called again, from == empty_nodemask, to == ancestor's nodemask, so I guess again no pages will be migrated. This bug exists even before your changes. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
