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charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Aug 13, 2024 at 6:50=E2=80=AFPM Peter Zijlstra wrote: > > Hi, > > These patches apply on top of the EEVDF series (queue/sched/core), which > re-arranges the fair pick_task() functions to make them state invariant s= uch > that they can easily be restarted upon picking (and dequeueing) a delayed= task. > > This same is required to push (the final) put_prev_task() beyond pick_tas= k(), > like we do for sched_core already. > > This in turn is done to prepare for sched_ext, which wants a final callba= ck to > be in possesion of the next task, such that it can tell if the context sw= itch > will leave the sched_class. > > As such, this all re-arranges the current order of: > > put_prev_task(rq, prev); > next =3D pick_next_task(rq); /* implies set_next_task(.first=3Dtrue); *= / > > to sometihng like: > > next =3D pick_task(rq) > if (next !=3D prev) { > put_prev_task(rq, prev, next); > set_next_task(rq, next, true); > } > > The patches do a fair bit of cleaning up. Notably a bunch of sched_core s= tuff > -- Joel, could you please test this stuff, because the self-tests we have= are > hardly adequate. > > The EEVDF stuff was supposed to be merged already, but since Valentin see= ms to > be doing a read-through, I figured I'd give him a little extra time. A co= mplete > set can be found at: > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/pr= ep > So I booted queue.git sched/core branch on a newish Chromebook (after applying 700 patches for making it boot and spending 2 days on it since we boot old kernels -- I wasn't joking when I said I would carve some time up for you this week :P). With sched/core , it boots fine with core scheduling disabled, but when core scheduling is enabled I am getting hard hangs and occasionally get to the login screen if I'm lucky. So there's definitely something wonky in sched/core branch and core sched. I could not get a trace or logs yet, since once it hangs I have to hard power off. I could bissect it tomorrow though since it looks like a manageable set of patches on 6.11-rc1. Or did you already figure out the issue? I am based on: commit aef6987d89544d63a47753cf3741cabff0b5574c Author: Peter Zijlstra Date: Thu Jun 20 13:16:49 2024 +0200 sched/eevdf: Propagate min_slice up the cgroup hierarchy Thanks, - Joel (++ my open source email)