sched/rt: Disable RT_RUNTIME_SHARE by default

commit 2586af1ac187f6b3a50930a4e33497074e81762d upstream.

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,

Signed-off-by: Daniel Bristot de Oliveira <>
Signed-off-by: Peter Zijlstra (Intel) <>
Tested-by: Wei Wang <>
Signed-off-by: Mark-PK Tsai <>
Signed-off-by: Greg Kroah-Hartman <>
1 file changed