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 <bris...@redhat.com> Cc: Ingo Molnar <mi...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Juri Lelli <juri.le...@redhat.com> Cc: Vincent Guittot <vincent.guit...@linaro.org> Cc: Dietmar Eggemann <dietmar.eggem...@arm.com> Cc: Steven Rostedt <rost...@goodmis.org> Cc: Ben Segall <bseg...@google.com> Cc: Mel Gorman <mgor...@suse.de> Cc: Daniel Bristot de Oliveira <bris...@redhat.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: linux-kernel@vger.kernel.org --- 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
