[Linux PPC] Disable PREEMPT

On 25/02/26 08:16, Christophe Leroy (CS GROUP) wrote:

+Peter

Hi Christian,

Le 25/02/2026 à 06:54, Christian Zigotzky a écrit :

quoted

Hello,

We were previously able to disable PREEMPT in the kernel 
configuration, but the latest kernels now enable it by default and it 
is no longer possible to disable it.

Is it possible to let us decide whether to activate PREEMPT or not?

Can you give more details on why you want to be able to deactivate 
PREEMPT ?

Read https://github.com/torvalds/linux/commit/7dadeaa6e851e

I use PREEMPT_NONE kernels on my Linux PPC servers. (Without desktop)

quoted

Currently we use the following revert patch for our non-preempt kernels.

--- a/kernel/Kconfig.preempt    2026-02-14 10:06:32.000000000 +0000
+++ b/kernel/Kconfig.preempt    2026-02-08 21:03:27.000000000 +0000

@@ -16,13 +16,11 @@ config ARCH_HAS_PREEMPT_LAZY

  choice
      prompt "Preemption Model"
-    default PREEMPT_LAZY if ARCH_HAS_PREEMPT_LAZY
      default PREEMPT_NONE

  config PREEMPT_NONE
      bool "No Forced Preemption (Server)"
      depends on !PREEMPT_RT
-    depends on ARCH_NO_PREEMPT
      select PREEMPT_NONE_BUILD if !PREEMPT_DYNAMIC
      help
        This is the traditional Linux preemption model, geared towards

@@ -37,7 +35,6 @@ config PREEMPT_NONE

  config PREEMPT_VOLUNTARY
      bool "Voluntary Kernel Preemption (Desktop)"
-    depends on !ARCH_HAS_PREEMPT_LAZY
      depends on !ARCH_NO_PREEMPT
      depends on !PREEMPT_RT
      select PREEMPT_VOLUNTARY_BUILD if !PREEMPT_DYNAMIC

---

Thanks in advance,

Christian

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