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sched/rt, Kconfig: Introduce CONFIG_PREEMPT_RT 

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 <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Clark Williams <williams@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Daniel Wagner <wagi@monom.org>
Acked-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Acked-by: Julia Cartwright <julia@ni.com>
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Acked-by: Gratian Crisan <gratian.crisan@ni.com>
Acked-by: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Andrew Morton <akpm@linuxfoundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1907172200190.1778@nanos.tec.linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner 2019-07-17 22:01:49 +02:00 committed by Ingo Molnar
parent e3d85487fb
commit a50a3f4b6a
2 changed files with 26 additions and 2 deletions
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3
arch/Kconfig
View File

@ -801,6 +801,9 @@ config ARCH_NO_COHERENT_DMA_MMAP
config ARCH_NO_PREEMPT
bool
config ARCH_SUPPORTS_RT
bool
config CPU_NO_EFFICIENT_FFS
def_bool n

25
kernel/Kconfig.preempt
View File

@ -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