[PATCH bpf-next v2 0/4] bpf: Add memory usage for arena and selftest

[Jiayuan Chen <jiayuan.chen@linux.dev>]

arena is the only map type whose map_mem_usage() still returns 0, so
bpftool and fdinfo always show 0 memlock for it no matter how many pages
it holds. This series adds the accounting, runs the arena selftests
serially so they don't OOM a small CI VM, and adds a test for it.

v1 -> v2:
- split the scratch_page -> arena refactor into a prep patch (no
  functional change)
- use WRITE_ONCE() for nr_pages to pair with the lockless reader
- reword the "run serially" commit message
- selftest: alloc prog returns 0 so the failure check is reached

v1: https://lore.kernel.org/bpf/20260716142746.8794-1-jiayuan.chen@linux.dev/

Jiayuan Chen (4):
  bpf: Pass arena instead of scratch_page to the pte callbacks
  bpf: Add memory usage for arena
  selftests/bpf: Run arena tests serially
  selftests/bpf: Add tests for memory usage for arena

 kernel/bpf/arena.c                            |  27 ++--
 .../selftests/bpf/prog_tests/arena_atomics.c  |   2 +-
 .../bpf/prog_tests/arena_direct_value.c       |   2 +-
 .../selftests/bpf/prog_tests/arena_htab.c     |   2 +-
 .../selftests/bpf/prog_tests/arena_list.c     |   2 +-
 .../bpf/prog_tests/arena_mem_usage.c          | 122 ++++++++++++++++++
 .../bpf/prog_tests/arena_spin_lock.c          |   2 +-
 .../bpf/prog_tests/arena_strsearch.c          |   2 +-
 .../selftests/bpf/prog_tests/libarena.c       |   2 +-
 .../selftests/bpf/prog_tests/libarena_asan.c  |   2 +-
 .../selftests/bpf/progs/arena_mem_usage.c     |  40 ++++++
 11 files changed, 186 insertions(+), 19 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/arena_mem_usage.c
 create mode 100644 tools/testing/selftests/bpf/progs/arena_mem_usage.c

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2.43.0