Hi, On Wed, 2019-07-17 at 22:01 +0200, Thomas Gleixner wrote: > Add a new entry to the preemption menu which enables the real-time > support > for the kernel. The choice is only enabled when an architecture > supports > it. > > It selects PREEMPT as the RT features depend on it. To achieve that > the > existing PREEMPT choice is renamed to PREEMPT_LL which select PREEMPT > as > well. > > No functional change. > > Signed-off-by: Thomas Gleixner <t...@linutronix.de> > Acked-by: Paul E. McKenney <paul...@linux.ibm.com> > Acked-by: Steven Rostedt (VMware) <rost...@goodmis.org> > Acked-by: Clark Williams <willi...@redhat.com> > Acked-by: Daniel Bristot de Oliveira <bris...@redhat.com> > Acked-by: Frederic Weisbecker <frede...@kernel.org> > Acked-by: Ingo Molnar <mi...@kernel.org> > Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org> > Acked-by: Marc Zyngier <marc.zyng...@arm.com> > Acked-by: Daniel Wagner <w...@monom.org> > ---
As one of the stable-rt maintainers, I'd obviously be very happy to see this finally go in. :-) And will be happy to do what I can to help with the remaining 311... Acked-by: Tom Zanussi <tom.zanu...@linux.intel.com> > V2: Fix typos in help text, collect acks > --- > arch/Kconfig | 3 +++ > kernel/Kconfig.preempt | 25 +++++++++++++++++++++++-- > 2 files changed, 26 insertions(+), 2 deletions(-) > > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -809,6 +809,9 @@ config ARCH_NO_COHERENT_DMA_MMAP > config ARCH_NO_PREEMPT > bool > > +config ARCH_SUPPORTS_RT > + bool > + > config CPU_NO_EFFICIENT_FFS > def_bool n > > --- a/kernel/Kconfig.preempt > +++ b/kernel/Kconfig.preempt > @@ -35,10 +35,10 @@ config PREEMPT_VOLUNTARY > > Select this if you are building a kernel for a desktop > system. > > -config PREEMPT > +config PREEMPT_LL > bool "Preemptible Kernel (Low-Latency Desktop)" > depends on !ARCH_NO_PREEMPT > - select PREEMPT_COUNT > + select PREEMPT > select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK > help > This option reduces the latency of the kernel by making > @@ -55,7 +55,28 @@ config PREEMPT > embedded system with latency requirements in the > milliseconds > range. > > +config PREEMPT_RT > + bool "Fully Preemptible Kernel (Real-Time)" > + depends on EXPERT && ARCH_SUPPORTS_RT > + select PREEMPT > + help > + This option turns the kernel into a real-time kernel by > replacing > + various locking primitives (spinlocks, rwlocks, etc.) with > + preemptible priority-inheritance aware variants, enforcing > + interrupt threading and introducing mechanisms to break up > long > + non-preemptible sections. This makes the kernel, except > for very > + low level and critical code pathes (entry code, scheduler, > low > + level interrupt handling) fully preemptible and brings > most > + execution contexts under scheduler control. > + > + Select this if you are building a kernel for systems which > + require real-time guarantees. > + > endchoice > > config PREEMPT_COUNT > bool > + > +config PREEMPT > + bool > + select PREEMPT_COUNT
