On Thu, Jul 09, 2015 at 03:12:59PM -0700, Andrew Morton wrote: > On Thu, 25 Jun 2015 16:44:13 -0500 Nathan Zimmer <[email protected]> wrote: > > > In kthread_create_on_node we set_cpus_allowed to cpu_all_mask > > regardless of what the node is requested. > > This seems incorrect. > > The `node' arg to kthread_create_on_node() refers to which node the > task_struct and thread_info are allocated from. It doesn't refer to > the CPUs upon which the thread is executed. See > kthread_create_info.node and that gruesome task_struct.pref_node_fork > thing. >
That's the initial mistake I made when reviewing Nathan's first path. > The kthread_create_on_node() kerneldoc explains this, in a confused > way. It needs a s/-1/NUMA_NO_NODE/. > > I'm a bit surprised that kthread_create_on_node() futzes with the new > thread's policy and cpumask after it has been created. Wouldn't it be > simpler/faster to have the thread itself set these things while it's > starting up? > Yeah, which is what Nathan's first patch did that I made a mistake with initially. It creates a thread, sets the mask then wakes it up which looks correct. Your documentation patch looks good to me, I would not have fallen into the trap if it had been applied. -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
