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In case it's useful, I gave patches 1-3 a try on one of our KVM hosts, backported to 6.18.54 and running our in-house sched_ext scheduler. It's not exactly the series as posted: to avoid changing the scheduler, the backport drops SCX_OPS_NUMA_BALANCING and drives the scan for all sched_ext tasks under the sched_numa_balancing static key alone, and it passes curr, as there is no donor there on 6.18. The fair.c parts are the same. As a controlled check, I used a stress-ng --vm worker touching 4G, pinned to a CPU on node 0 and then moved to a CPU on node 1 with taskset. Without the patches, under the same scheduler, mm->numa_scan_seq stays at 0, numa_preferred_nid stays at -1, numa_pte_updates in /proc/vmstat doesn't move, and all 4G stay on node 0. With the backport: - mm->numa_scan_seq advances (7 to 12 over two minutes); - numa_preferred_nid is 0 before the move and 1 about 20s after it; - the whole 4G (~1M pages) is migrated to node 1 within ~20s; - the task stays on the CPU it was pinned to. On an otherwise idle host, the vCPU threads of a running guest now get task_numa_work() calls as well. On a host running the same scheduler without the patches, a kprobe on task_numa_work() sees no calls at all in 30s, as task_tick_numa() is only reached from task_tick_fair(). Thanks for working on this, Vladimir