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

[Mark Rutland <mark.rutland@arm.com>]

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.

Mark Rutland (6):
  sched: dynamic: Make PREEMPT_DYNAMIC depend on ARCH_HAS_PREEMPT_LAZY
  sched: dynamic: Simplify {cond,might}_resched()
  sched: dynamic: Simplify preempt_schedule{,_notrace}()
  sched: dynamic: Simplify irqentry_exit_cond_resched()
  sched: dynamic: Remove HAVE_PREEMPT_DYNAMIC_{CALL,KEY}
  sched: dynamic: Simplify preempt model accessors

 arch/Kconfig                     |  38 -------
 arch/arm64/Kconfig               |   1 -
 arch/arm64/include/asm/preempt.h |  10 --
 arch/loongarch/Kconfig           |   1 -
 arch/powerpc/Kconfig             |   1 -
 arch/riscv/Kconfig               |   1 -
 arch/s390/Kconfig                |   1 -
 arch/s390/include/asm/preempt.h  |  11 --
 arch/x86/Kconfig                 |   1 -
 arch/x86/include/asm/preempt.h   |  28 -----
 include/asm-generic/preempt.h    |  10 --
 include/linux/irq-entry-common.h |  17 +--
 include/linux/kernel.h           |  20 ----
 include/linux/preempt.h          |  20 ++--
 include/linux/sched.h            |  31 +-----
 kernel/Kconfig.preempt           |   9 +-
 kernel/entry/common.c            |  17 +--
 kernel/sched/core.c              | 180 +------------------------------
 18 files changed, 23 insertions(+), 374 deletions(-)

-- 
2.30.2