NACK/Cmnt: [PULL][Noble] backport arm64 THP improvements from 6.9

Wed Apr 3 13:07:25 UTC 2024

On Wed, Apr 03, 2024 at 09:47:22AM +0200, Andrea Righi wrote:
> On Thu, Mar 28, 2024 at 06:25:45AM -0600, dann frazier wrote:
> > BugLink: https://bugs.launchpad.net/bugs/2059316
> > 
> > These are all clean cherry-picks from upstream, save one that required
> > minor backporting due to an API change. This does touch generic code.
> > I've regression tested as much as I've had time to given I just
> > learned about this patchset last week. But with the performance
> > improvements I've measured, and the GPU workload improvements reported
> > upstream, I think this is something we need to seriously consider
> > for our next LTS.
> > 
> > I plan to monitor upstream for Fixes commits during the 6.9
> > development cycle, in case regressions are found/fixed.
> 
> Hi Dann,
> 
> after thinking and discussing more about this with the team, we could
> try to mark all the patches as SAUCE and apply them to the noble/linux
> kernel (this would allow us to better identify them).
> 
> Then if we find critical issues in the future that may delay security
> updates we would be able to drop them quickly, if needed (it shouldn't
> happen, but just to be extra safe...).
> 
> So, I'm NACK-ing this for now, but if you can send another PR simply by
> updating the subject of the patches to add the keyword "SAUCE:" I'll be
> happy to apply it.

Andrea - that sounds like a reasonable plan. While we wait for an
official build, I'll try to get some stress-ng runs in on our ARM
server kit to see if we can turn up any issues ourselves.

  -dann

> 
> > 
> > The following changes since commit 4427c45609f6faf3b5b15e9e9246caa87894c36f:
> > 
> >   UBUNTU: Ubuntu-6.8.0-20.20 (2024-03-18 11:08:14 +0100)
> > 
> > are available in the Git repository at:
> > 
> >   git://git.launchpad.net/~dannf/ubuntu/+source/linux/+git/linux noble-mthp
> > 
> > for you to fetch changes up to 84cfdc5c9342767b6abc872a4baad5a50a58d4f0:
> > 
> >   arm64/mm: improve comment in contpte_ptep_get_lockless() (2024-03-27 15:59:18 -0600)
> > 
> > ----------------------------------------------------------------
> > David Hildenbrand (14):
> >       arm/pgtable: define PFN_PTE_SHIFT
> >       nios2/pgtable: define PFN_PTE_SHIFT
> >       powerpc/pgtable: define PFN_PTE_SHIFT
> >       riscv/pgtable: define PFN_PTE_SHIFT
> >       s390/pgtable: define PFN_PTE_SHIFT
> >       sparc/pgtable: define PFN_PTE_SHIFT
> >       mm/pgtable: make pte_next_pfn() independent of set_ptes()
> >       arm/mm: use pte_next_pfn() in set_ptes()
> >       powerpc/mm: use pte_next_pfn() in set_ptes()
> >       mm/memory: factor out copying the actual PTE in copy_present_pte()
> >       mm/memory: pass PTE to copy_present_pte()
> >       mm/memory: optimize fork() with PTE-mapped THP
> >       mm/memory: ignore dirty/accessed/soft-dirty bits in folio_pte_batch()
> >       mm/memory: ignore writable bit in folio_pte_batch()
> > 
> > Ryan Roberts (21):
> >       arm64/mm: make set_ptes() robust when OAs cross 48-bit boundary
> >       mm: clarify the spec for set_ptes()
> >       mm: thp: batch-collapse PMD with set_ptes()
> >       mm: introduce pte_advance_pfn() and use for pte_next_pfn()
> >       arm64/mm: convert pte_next_pfn() to pte_advance_pfn()
> >       x86/mm: convert pte_next_pfn() to pte_advance_pfn()
> >       mm: tidy up pte_next_pfn() definition
> >       arm64/mm: convert READ_ONCE(*ptep) to ptep_get(ptep)
> >       arm64/mm: convert set_pte_at() to set_ptes(..., 1)
> >       arm64/mm: convert ptep_clear() to ptep_get_and_clear()
> >       arm64/mm: new ptep layer to manage contig bit
> >       arm64/mm: dplit __flush_tlb_range() to elide trailing DSB
> >       arm64/mm: wire up PTE_CONT for user mappings
> >       arm64/mm: implement new wrprotect_ptes() batch API
> >       arm64/mm: implement new [get_and_]clear_full_ptes() batch APIs
> >       mm: add pte_batch_hint() to reduce scanning in folio_pte_batch()
> >       arm64/mm: implement pte_batch_hint()
> >       arm64/mm: __always_inline to improve fork() perf
> >       arm64/mm: automatically fold contpte mappings
> >       arm64/mm: export contpte symbols only to GPL users
> >       arm64/mm: improve comment in contpte_ptep_get_lockless()
> > 
> > dann frazier (1):
> >       UBUNTU: [Config] arm64: ARM64_CONTPTE=y
> > 
> >  arch/arm/include/asm/pgtable.h      |   2 +
> >  arch/arm/mm/mmu.c                   |   2 +-
> >  arch/arm64/Kconfig                  |   9 +
> >  arch/arm64/include/asm/pgtable.h    | 431 +++++++++++++++++++++++++++++++-----
> >  arch/arm64/include/asm/tlbflush.h   |  13 +-
> >  arch/arm64/kernel/efi.c             |   4 +-
> >  arch/arm64/kernel/mte.c             |   2 +-
> >  arch/arm64/kvm/guest.c              |   2 +-
> >  arch/arm64/mm/Makefile              |   1 +
> >  arch/arm64/mm/contpte.c             | 408 ++++++++++++++++++++++++++++++++++
> >  arch/arm64/mm/fault.c               |  12 +-
> >  arch/arm64/mm/fixmap.c              |   4 +-
> >  arch/arm64/mm/hugetlbpage.c         |  40 ++--
> >  arch/arm64/mm/kasan_init.c          |   6 +-
> >  arch/arm64/mm/mmu.c                 |  16 +-
> >  arch/arm64/mm/pageattr.c            |   6 +-
> >  arch/arm64/mm/trans_pgd.c           |   6 +-
> >  arch/nios2/include/asm/pgtable.h    |   2 +
> >  arch/powerpc/include/asm/pgtable.h  |   2 +
> >  arch/powerpc/mm/pgtable.c           |   5 +-
> >  arch/riscv/include/asm/pgtable.h    |   2 +
> >  arch/s390/include/asm/pgtable.h     |   2 +
> >  arch/sparc/include/asm/pgtable_64.h |   2 +
> >  arch/x86/include/asm/pgtable.h      |   8 +-
> >  debian.master/config/annotations    |   3 +
> >  include/linux/efi.h                 |   5 +
> >  include/linux/pgtable.h             |  65 +++++-
> >  mm/huge_memory.c                    |  58 ++---
> >  mm/memory.c                         | 219 ++++++++++++++----
> >  29 files changed, 1151 insertions(+), 186 deletions(-)
> >  create mode 100644 arch/arm64/mm/contpte.c
> > 