[PATCH v2 00/13] mm: Some cleanups for page allocator APIs

[Brendan Jackman]

Some tweaks and cleanups for page allocator entrypoint and flags. This
is motivated by preparation for __GFP_UNMAPPED [1] (which will probably
become ALLOC_UNMAPPED in its next iteration), but all this is supposed
to be an improvement to the codebase in its own right: unifying code
paths, reducing API surface, and removing GFP flags.

[1] https://lore.kernel.org/all/20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@xxxxxxxxxx/

This started with unifying  __alloc_frozen_pages[_nolock]_noprof() and
expanded from there.

Unifying the nolock allocator entrypoint with the normal allocator
entrypoint means adding an alloc_flags argument to the later (only
exposed within mm/). This presents an opportunity to take advantage of
that arg to remove some GFP flags, if we add that alloc_flags arg a bit
more broadly to allocator entrypoints.

To distinguish between mm-internal and "public" allocator entrypoints,
it makes sense to use the __ prefix. There are already some public APIs
with that prefix. For *alloc_pages*, just removing those variants seems
like a nice cleanup anyway, so do that. For get_free_pages, the "__"
variant is the _only_ variant and it's very widely used, so it doesn't
seem worthwhile to modify that. Therefore, scope this "__" change
specifically to the *alloc_pages* API, which means we leave the
*folio_alloc* API untouched too, even though that could probably be
cleaned up if so desired.

Tested:

- KVM, mm, and BPF selftests in a QEMU VM

- kunit.py on x86_64

- For the ALLOC_NO_CODETAG bits I just booted a VM and read
  /proc/allocinfo. I confirmed that if I remove ALLOC_NO_CODETAG, the
  kernel crashes in early boot, so I was at least booting code that
  depends on this logic.

I used Google's internal version of Antigravity (AI coding harness) to
do the repetitive bits, those commits are marked with Assisted-by, the
rest is manual.

Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
---
Changes in v2:
- Fixed up whitespace in nolock unification patch
- Introduced ALLOC_DEFAULT to replace literal 0 for alloc_flags
- All other patches are new
- Link to v1: https://patch.msgid.link/20260617-alloc-trylock-v1-1-83fd7858832e@xxxxxxxxxx

---
Brendan Jackman (13):
      mm/page_alloc: rename ALLOC_TRYLOCK -> ALLOC_NOLOCK
      mm/page_alloc: some renames to clarify alloc_flags scopes
      mm/page_alloc: unify __alloc_frozen_pages[_nolock]_noprof()
      mm/page_alloc: relax GFP WARN in nolock allocs
      perf/x86/intel: Use higher-level allocator
      KVM: VMX: Use higher-level allocator
      x86/virt: Use higher-level allocator
      sgi-xp: Use higher-level allocator
      net/funeth: Switch to higher-level allocator
      mm: Remove __alloc_pages_node()
      alloc_tag: Move to mm/
      mm: Move __alloc_pages() to mm/internal.h
      mm: remove __GFP_NO_CODETAG

 Documentation/admin-guide/cgroup-v1/cpusets.rst  |   2 +-
 Documentation/admin-guide/mm/transhuge.rst       |   2 +-
 MAINTAINERS                                      |   2 +-
 arch/x86/events/intel/ds.c                       |   6 +-
 arch/x86/kvm/vmx/vmx.c                           |   2 +-
 arch/x86/virt/hw.c                               |   2 +-
 drivers/misc/sgi-xp/xpc_uv.c                     |   2 +-
 drivers/net/ethernet/fungible/funeth/funeth_rx.c |   2 +-
 include/linux/gfp.h                              |  28 +--
 lib/Makefile                                     |   1 -
 mm/Makefile                                      |   1 +
 {lib => mm}/alloc_tag.c                          |  18 +-
 mm/compaction.c                                  |   4 +-
 mm/hugetlb.c                                     |   3 +-
 mm/internal.h                                    |  20 +-
 mm/mempolicy.c                                   |  10 +-
 mm/page_alloc.c                                  | 254 +++++++++++++----------
 mm/page_frag_cache.c                             |   4 +-
 mm/slub.c                                        |   6 +-
 19 files changed, 193 insertions(+), 176 deletions(-)
---
base-commit: cbe5256a15fc26f592efb037e528da54b2139ee5
change-id: 20260617-alloc-trylock-14ad37dab337

Best regards,
--  
Brendan Jackman <jackmanb@xxxxxxxxxx>