[Linux PPC] Disable PREEMPT

Christian Zigotzky
2026-02-26T05:37:59Z

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 :
>> 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)
>
>
>>
>> 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
>>
>

--
Sent with BrassMonkey 33.9.1 (https://github.com/chzigotzky/Web-Browsers-and-Suites-for-Linux-PPC/releases/tag/BrassMonkey_33.9.1)