Re: [PATCH v2] sched/proxy: allow SCHED_PROXY_EXEC with PREEMPT_RT

[Quchaosheng]

Sebastian, Peter,

Both of you asked the same thing, so one answer for the thread: you are
right, there is no build failure today. The option cannot be turned on
next to PREEMPT_RT, and that dependency is exactly why nobody has hit the
errors I quoted. My patch is what would introduce the combination, not
what fixes it. Answering "the Kconfig says it is broken" was circular.

Peter put the objection better than I did: the feature is effectively
broken under PREEMPT_RT, and carrying a build option in that state buys
nothing. I withdraw the patch.

The boot and stress testing I described was real, but it was testing a
combination that should not exist, which makes it worthless as an
argument. If proxy execution becomes meaningful on PREEMPT_RT it will be
after the RT mutex maintains blocked_on, and that change will have to
justify itself from that work.

Quchaosheng