Merge branch 'memcg-accounting-for-bpf-arena'

Puranjay Mohan says:

====================
memcg accounting for BPF arena

v4: https://lore.kernel.org/all/20260102181333.3033679-1-puranjay@kernel.org/
Changes in v4->v5:
- Remove unused variables from bpf_map_alloc_pages() (CI)

v3: https://lore.kernel.org/all/20260102151852.570285-1-puranjay@kernel.org/
Changes in v3->v4:
- Do memcg set/recover in arena_reserve_pages() rather than
  bpf_arena_reserve_pages() for symmetry with other kfuncs (Alexei)

v2: https://lore.kernel.org/all/20251231141434.3416822-1-puranjay@kernel.org/
Changes in v2->v3:
- Remove memcg accounting from bpf_map_alloc_pages() as the caller does
  it already. (Alexei)
- Do memcg set/recover in arena_alloc/free_pages() rather than
  bpf_arena_alloc/free_pages(), it reduces copy pasting in
  sleepable/non_sleepable functions.

v1: https://lore.kernel.org/all/20251230153006.1347742-1-puranjay@kernel.org/
Changes in v1->v2:
- Return both pointers through arguments from bpf_map_memcg_enter and
  make it return void. (Alexei)
- Add memcg accounting in arena_free_worker (AI)

This set adds memcg accounting logic into arena kfuncs and other places
that do allocations in arena.c.
====================

Link: https://patch.msgid.link/20260102200230.25168-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>