The following commit has been merged into the sched/core branch of tip: Commit-ID: 2586af1ac187f6b3a50930a4e33497074e81762d Gitweb: https://git.kernel.org/tip/2586af1ac187f6b3a50930a4e33497074e81762d Author: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> AuthorDate: Mon, 21 Sep 2020 16:39:49 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Fri, 25 Sep 2020 14:23:24 +02:00 sched/rt: Disable RT_RUNTIME_SHARE by default 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 <bristot@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Tested-by: Wei Wang <wvw@xxxxxxxxxx> Link: https://lkml.kernel.org/r/b776ab46817e3db5d8ef79175fa0d71073c051c7.1600697903.git.bristot@xxxxxxxxxx --- 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 7481cd9..68d369c 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)
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