On 10/07, David Howells wrote: > > Oleg Nesterov <[email protected]> wrote: > > > Change current_is_single_threaded() to use for_each_thread() rather > > than deprecated while_each_thread(). > > Wouldn't the old way be more efficient, given there's always going to be at > least one thread?
Yes, unfortunately. Before this change (in the likely case) we never do next_thread(), after this patch we always do list_first_entry(). > Granted, it's not much of an efficiency boost... Yes, and while_each_thread() is buggy. See the changelog in 0c740d0afc "introduce for_each_thread() to replace the buggy while_each_thread(). Yes, the race is almost purely theoretical, but still. To clarify, we had some "real" bugs fixed by s/while_each_thread/ for_each_thread/, but only because while_each_thread() was used wrongly. for_each_thread() is more safe, it only needs the stable task_struct. Oleg. -- 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/
