[v1,0/4] Fix lazy mmu mode

Message

Ryan Roberts March 2, 2025, 2:55 p.m. UTC

Hi All,

I'm planning to implement lazy mmu mode for arm64 to optimize vmalloc. As part
of that, I will extend lazy mmu mode to cover kernel mappings in vmalloc table
walkers. While lazy mmu mode is already used for kernel mappings in a few
places, this will extend it's use significantly.

Having reviewed the existing lazy mmu implementations in powerpc, sparc and x86,
it looks like there are a bunch of bugs, some of which may be more likely to
trigger once I extend the use of lazy mmu. So this series attempts to clarify
the requirements and fix all the bugs in advance of that series. See patch #1
commit log for all the details.

Note that I have only been able to compile test these changes so appreciate any
help in testing.

Applies on Friday's mm-unstable (5f089a9aa987), as I assume this would be
preferred via that tree.

Thanks,
Ryan

Ryan Roberts (4):
  mm: Fix lazy mmu docs and usage
  sparc/mm: Disable preemption in lazy mmu mode
  sparc/mm: Avoid calling arch_enter/leave_lazy_mmu() in set_ptes
  Revert "x86/xen: allow nesting of same lazy mode"

 arch/sparc/include/asm/pgtable_64.h   |  2 --
 arch/sparc/mm/tlb.c                   |  5 ++++-
 arch/x86/include/asm/xen/hypervisor.h | 15 ++-------------
 arch/x86/xen/enlighten_pv.c           |  1 -
 fs/proc/task_mmu.c                    | 11 ++++-------
 include/linux/pgtable.h               | 14 ++++++++------
 6 files changed, 18 insertions(+), 30 deletions(-)

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2.43.0