On 10/02/16 16:27, Juri Lelli wrote: > On 10/02/16 09:37, Steven Rostedt wrote: > > On Wed, 10 Feb 2016 11:32:58 +0000 > > Juri Lelli <[email protected]> wrote: > >
[...] > > > > I applied this patch and patch 2 and hit this: > > [...] > > > > It's the warning you added in __dl_sub_ac(). > > > > OK. There are still holes where we fail to properly update per-rq bw. It > seems (by running you test) that we fail to move the per-rq bw when we > move the root_domain bw due css_set_move_task(). So, the final > task_dead_dl() tries to remove bw from where there isn't. > > I'm trying to see how we can close this hole. > So, just to give an update from yesterday (kind of tricky this one :/). I think we still have (at least) two problems: - select_task_rq_dl, if we select a different target - select_task_rq might make use of select_fallback_rq, if cpus_allowed changed after the task went to sleep Second case is what creates the problem here, as we don't update task_rq(p) and fallback_cpu ac_bw. I was thinking we might do so, maybe adding fallback_cpu in task_struct, from migrate_task_rq_dl() (it has to be added yes), but I fear that we should hold both rq locks :/. Luca, did you already face this problem (if I got it right) and thought of a way to fix it? I'll go back and stare a bit more at those paths. Best, - Juri
