Re: [PATCH v2 0/6] sched: dynamic: Simplify PREEMPT_DYNAMIC

[Mete Durlu <meted@linux.ibm.com>]

On 03/08/2026 21:17, Mark Rutland wrote:
> All architectures which currently suppoort PREEMPT_DYNAMIC select
> ARCH_HAS_PREEMPT_LAZY.  On architectures which select
> ARCH_HAS_PREEMPT_LAZY, it has not been possible to select the NONE and
> VOLUNTARY preemption models since v7.0 due to commit:
> 
>    7dadeaa6e851 ("sched: Further restrict the preemption modes")
> 
> Hence in practice PREEMPT_DYNAMIC no longer supports the NONE or
> VOLUNTARY preemption models.
> 
> This series makes the de-facto situation official by making
> PREEMPT_DYNAMIC depend on ARCH_HAS_PREEMPT_LAZY, and removing redundant
> code.
> 
> Since v1, I've had to rebase atop v7.2-rc4 to avoid a conflict with
> commit:
> 
>    a2c02aa0c6ca ("powerpc: Remove dead non-preemption code")
> 
> Given this is now late in the cycle, and given the tip:sched/core branch
> is based on v7.2-rc1, I suspect tip folk might not want to queue this
> now. Please let me know what you'd prefer; I'm happy to rebase and
> resend after v7.3-rc1.
> 
> Since v1:
> * Rebase to v7.2-rc4
> * Apply Revied-by tags.
> * Fix typos in commit messages.
> * Add patch to cleanup accessors (per Shrikanth's comment)
> 
> Mark.
> 
Hi, I once again did a build test and the results
are looking the same;

$ ls -la baseline/vmlinux patched/vmlinux
-rwxrwxr-x 1 meted meted 409534568 Aug  5 11:38 baseline/vmlinux
-rwxrwxr-x 1 meted meted 408212872 Aug  5 10:50 patched/vmlinux

$ ls -la baseline/bzImage patched/bzImage
-rwxrwxr-x 1 meted meted 12922880 Aug  5 11:38 baseline/bzImage
-rwxrwxr-x 1 meted meted 12890112 Aug  5 10:51 patched/bzImage

Both bzImage and vmlinux are shrunk after the patch for s390.

bzImage ~32K  smaller
vmlinux ~1.2M smaller

FWIW, here is my tested-by;

Tested-by: Mete Durlu <meted@linux.ibm.com>