Hello, Lai. On Wed, May 13, 2015 at 09:43:19AM +0800, Lai Jiangshan wrote: > >> I think the workqueue.c has too much complicated and rarely used APIs > >> and exposes too much in this way. No one can set the nice value > >> and the cpuallowed of a task atomically. > > > > What do you mean no one can? > > normal/general task. not kworker. > > no one can set the nice value and the cpumallowed of a normal task atomically. > > The kernel doesn't have such APIs: > > lock_and_get_task_cpus_allowed(task); > /* modify cpumask */ > set_cpus_allowed_ptr_and_unlock();
I'm still not following. What are you trying to say? > > So, we're now requiring workqueue users to take care of > > synchronization, disabling and reinstating WQ_SYSFS (what if userland > > hits those knobs at the same time?) > > I think there is no userland knobs when !WQ_SYSFS. So, fail apply attrs calls if the workqueue is exposed to userland? Are you serious? > > and poking into workqueue struct to determine the current values of the > > I think the copy version of cpumask, nice, numa values are same as > the workqueue struct have. No poking is required. > (Its own lock-protect-region is the ONLY entry to call > apply_workqueue_attrs()). And how would the caller know the current values? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
