[PATCH bpf-next 0/5] bpf: Reduce memory usage for bpf_global_percpu_ma

[Yonghong Song <yonghong.song@linux.dev>]

Currently when a bpf program intends to allocate memory for percpu kptr,
the verifier will call bpf_mem_alloc_init() to prefill all supported
unit sizes and this caused memory consumption very big for large number
of cpus. For example, for 128-cpu system, the total memory consumption
with initial prefill is ~175MB. Things will become worse for systems
with even more cpus.

Patch 1 is a preparatory patch.
Patch 2 addresses memory consumption issue by avoiding to prefill
with all unit sizes, i.e. only prefilling with user specified size.
Patch 3 further reduces memory consumption by limiting the 
number of prefill entries for percpu memory allocation.
Patch 4 rejects percpu memory allocation with bpf_global_percpu_ma
when unit size is greater than 512 bytes.
Patch 5 fixed one test due to Patch 4 and added one test to
show the verification failure log message.

Yonghong Song (5):
  bpf: Refactor to have a memalloc cache destroying function
  bpf: Allow per unit prefill for non-fix-size percpu memory allocator
  bpf: Refill only one percpu element in memalloc
  bpf: Limit up to 512 bytes for bpf_global_percpu_ma allocation
  selftests/bpf: Cope with 512 bytes limit with bpf_global_percpu_ma

 include/linux/bpf_mem_alloc.h                 |  5 ++
 kernel/bpf/memalloc.c                         | 83 +++++++++++++++++--
 kernel/bpf/verifier.c                         | 30 +++----
 .../selftests/bpf/progs/percpu_alloc_fail.c   | 18 ++++
 .../testing/selftests/bpf/progs/test_bpf_ma.c |  9 --
 5 files changed, 114 insertions(+), 31 deletions(-)

-- 
2.34.1