[PATCH] preempt/dynamic: Make PREEMPT_DYNAMIC optional

[Frederic Weisbecker]

In order not to make the small trampoline overhead mandatory for archs
that support HAVE_STATIC_CALL but not HAVE_STATIC_CALL_INLINE, make
PREEMPT_DYNAMIC optional.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
---
 kernel/Kconfig.preempt | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 416017301660..1fe759677907 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -40,7 +40,6 @@ config PREEMPT
 	depends on !ARCH_NO_PREEMPT
 	select PREEMPTION
 	select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
-	select PREEMPT_DYNAMIC if HAVE_PREEMPT_DYNAMIC
 	help
 	  This option reduces the latency of the kernel by making
 	  all kernel code (that is not executing in a critical section)
@@ -83,11 +82,13 @@ config PREEMPTION
        select PREEMPT_COUNT
 
 config PREEMPT_DYNAMIC
-	bool
+	bool "Override preemption flavour at boot time"
+	depends on HAVE_PREEMPT_DYNAMIC && PREEMPT
+	default HAVE_STATIC_CALL_INLINE
 	help
 	  This option allows to define the preemption model on the kernel
-	  command line parameter and thus override the default preemption
-	  model defined during compile time.
+	  command line parameter "preempt=" and thus override the default
+	  preemption model defined during compile time.
 
 	  The feature is primarily interesting for Linux distributions which
 	  provide a pre-built kernel binary to reduce the number of kernel
@@ -99,3 +100,5 @@ config PREEMPT_DYNAMIC
 
 	  Interesting if you want the same pre-built kernel should be used for
 	  both Server and Desktop workloads.
+
+	  Say Y if you have CONFIG_HAVE_STATIC_CALL_INLINE.
-- 
2.25.1