The RT_RUNTIME_SHARE sched feature enables the sharing of rt_runtime between CPUs, allowing a CPU to run a real-time task up to 100% of the time while leaving more space for non-real-time tasks to run on the CPU that lend rt_runtime.
The problem is that a CPU can easily borrow enough rt_runtime to allow a spinning rt-task to run forever, starving per-cpu tasks like kworkers, which are non-real-time by design. This patch disables RT_RUNTIME_SHARE by default, avoiding this problem. The feature will still be present for users that want to enable it, though. Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Vincent Guittot <[email protected]> Cc: Dietmar Eggemann <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Ben Segall <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] --- kernel/sched/features.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 7481cd96f391..68d369cba9e4 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -77,7 +77,7 @@ SCHED_FEAT(WARN_DOUBLE_CLOCK, false) SCHED_FEAT(RT_PUSH_IPI, true) #endif -SCHED_FEAT(RT_RUNTIME_SHARE, true) +SCHED_FEAT(RT_RUNTIME_SHARE, false) SCHED_FEAT(LB_MIN, false) SCHED_FEAT(ATTACH_AGE_LOAD, true) -- 2.26.2
