+Cc Michel (for the sched policy removal plan) On Mon, 2026-09-14 at 09:59 +0100, Tvrtko Ursulin wrote: > On 11/09/2026 10:36, Philipp Stanner wrote: > > Someone from RH might or might not work on that, and perhaps that would > > take until 2027. I'm keeping an eye open for people to pick it up, but > > everyone's always busy. > > Again, I am happy to work on that as long as it is clear there is no > duplication of effort.
I asked and made sure no one is working on it, so from our POV you have green light. > > > Regarding the bugfix, this was reported as a performance issue on high > > load, that only seems to be reachable for CFS users, a brand-new policy > > that is marked as experimental and is not used by anyone in production > > yet. So IMO we can move on on drm-misc-next with spsc-queue, which will > > also make CFS usable then. > > I think more logical order is to first fix it with a small backportable > fix even if experimental. That way people using 7.2 can actually test it > and contribute valuable feedback. I took another look and I think my only issue is basically just that the patch addresses something which we should have done regardless of the bug at hands. So I'd be already happy if the commit just had a different title and slightly extended commit message, like: "drm/sched: Fix vruntime race by extending locking" plus sth like "this simultaneously serves as a preparational step to replace the spsc_queue as a whole". > > > Is there a plan btw as to how you would like to proceed with CFS? > > So for me the most typical and useful plan, and in the context of the > desired spsc removal, is: > > - Merge this fix so it gets into 7.2 > - Spsc removal RFC for some upcoming release N. > - Remove experimental status from fair policy for kernel release >= N. > - Switch fair to default at >= N+1. Couldn't it be enabled first for dedicated users? AFAIK it was developed with Steam's gaming platforms in mind. Can their OS devs be asked to switch it on or test it downstream? > - Remove FIFO and RR and simplify to single embedded run queue at >= N+2.
