Hi Tejun, >> +/** >> + * tset_get_css - obtain and get css for (tset, subsys_id) >> + * @tset: target taskset >> + * @subsys_id: target subsystem id >> + * >> + * Since all of the tasks in a taskset are guaranteed to have the same css, it's >> + * safe to grab the ref of just the first task's css and treat it as though you >> + * have a ref on the taskset's "collective" css. >> + */ >> +#define tset_get_css(tset, subsys_id) \ >> + task_get_css(cgroup_taskset_first(tset), subsys_id) > > They aren't tho. It depends on the hierarchy configuration. csses > belonging to hierarchies which aren't the current migration target may > differ. Okay, I was confused by what you said earlier. In this case, we might as well just move all of the attach accounting to ->attach() and not deal with reverting it (unless we're guaranteed that the css of each task in the tset doesn't change between ->can_attach() and ->cancel_attach()). -- Aleksa Sarai (cyphar) www.cyphar.com -- 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
