On 9/22/20 7:14 PM, Wei Wang wrote: > On Mon, Sep 21, 2020 at 7:40 AM Daniel Bristot de Oliveira > <bris...@redhat.com> wrote: >> >> 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 >> > > Tested on an Android device and can no longer see long running RT > tasks (yes, Android have those for reasons). >
So: Tested-by: Wei Wang <w...@google.com> ? Thanks! -- Daniel
