sched_ext tasks currently are starved by RT hoggers especially since RT throttling was replaced by deadline servers to boost only CFS tasks. Several users in the community have reported issues with RT stalling sched_ext tasks. Add a sched_ext deadline server as well so that sched_ext tasks are also boosted and do not suffer starvation. 2 kselftest are provided to verify the starvation fixes and bandwidth allocation is looking correct. v5->v6: mostly no changes versus v5. - Added Acks to few patches. - Fixes to few nits suggested by Tejun. v4->v5: - Added a kselftest (total_bw) to sched_ext to verify bandwidth values from debugfs. - Address comment from Andrea about redundant rq clock invalidation. v3->v4: - Fixed issues with hotplugged CPUs having their DL server bandwidth altered due to loading SCX. - Fixed other issues. - Rebased on Linus master. - All sched_ext kselftests reliably pass now, also verified that the total_bw in debugfs (CONFIG_SCHED_DEBUG) is conserved with these patches. v2->v3: - Removed code duplication in debugfs. Made ext interface separate. - Fixed issue where rq_lock_irqsave was not used in the relinquish patch. - Fixed running bw accounting issue in dl_server_remove_params. Link to v1: https://lore.kernel.org/all/20250315022158.2354454-1-joelagnelf@xxxxxxxxxx/ Link to v2: https://lore.kernel.org/all/20250602180110.816225-1-joelagnelf@xxxxxxxxxx/ Link to v3: https://lore.kernel.org/all/20250613051734.4023260-1-joelagnelf@xxxxxxxxxx/ Link to v4: https://lore.kernel.org/all/20250617200523.1261231-1-joelagnelf@xxxxxxxxxx/ Link to v5: https://lore.kernel.org/all/20250620203234.3349930-1-joelagnelf@xxxxxxxxxx/ Andrea Righi (2): sched/deadline: Add support to remove DLserver's bandwidth contribution selftests/sched_ext: Add test for sched_ext dl_server Joel Fernandes (12): sched/debug: Fix updating of ppos on server write ops sched/debug: Stop and start server based on if it was active sched/deadline: Clear the defer params sched/deadline: Prevent setting server as started if params couldn't be applied sched/deadline: Return EBUSY if dl_bw_cpus is zero sched: Add support to pick functions to take rf sched: Add a server arg to dl_server_update_idle_time() sched/ext: Add a DL server for sched_ext tasks sched/debug: Add support to change sched_ext server params sched/ext: Relinquish DL server reservations when not needed sched/deadline: Fix DL server crash in inactive_timer callback selftests/sched_ext: Add test for DL server total_bw consistency include/linux/sched.h | 2 +- kernel/sched/core.c | 19 +- kernel/sched/deadline.c | 86 ++++-- kernel/sched/debug.c | 165 ++++++++-- kernel/sched/ext.c | 120 +++++++- kernel/sched/fair.c | 15 +- kernel/sched/idle.c | 4 +- kernel/sched/rt.c | 2 +- kernel/sched/sched.h | 13 +- kernel/sched/stop_task.c | 2 +- tools/testing/selftests/sched_ext/Makefile | 2 + .../selftests/sched_ext/rt_stall.bpf.c | 23 ++ tools/testing/selftests/sched_ext/rt_stall.c | 213 +++++++++++++ tools/testing/selftests/sched_ext/total_bw.c | 286 ++++++++++++++++++ 14 files changed, 869 insertions(+), 83 deletions(-) create mode 100644 tools/testing/selftests/sched_ext/rt_stall.bpf.c create mode 100644 tools/testing/selftests/sched_ext/rt_stall.c create mode 100644 tools/testing/selftests/sched_ext/total_bw.c -- 2.34.1
