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| author | Alex Tran <alex.t.tran@gmail.com> | 2025-11-14 22:35:31 -0800 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2025-11-25 14:32:00 -0800 |
| commit | 44bf4611827b7477db188ec932b827e1fabd3ee1 (patch) | |
| tree | 43e6839a1e5d303c51f7568a6548cc5616cb4c2f | |
| parent | 590699d85823f38b74d52a0811ef22ebb61afddc (diff) | |
docs: bpf: map_array: Specify BPF_MAP_TYPE_PERCPU_ARRAY value size limit
Specify value size limit for BPF_MAP_TYPE_PERCPU_ARRAY which
is PCPU_MIN_UNIT_SIZE (32 kb). In percpu allocator (mm: percpu),
any request with a size greater than PCPU_MIN_UNIT_SIZE is rejected.
Signed-off-by: Alex Tran <alex.t.tran@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251115063531.2302903-1-alex.t.tran@gmail.com
| -rw-r--r-- | Documentation/bpf/map_array.rst | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/Documentation/bpf/map_array.rst b/Documentation/bpf/map_array.rst index f2f51a53e8ae..fa56ff75190c 100644 --- a/Documentation/bpf/map_array.rst +++ b/Documentation/bpf/map_array.rst @@ -15,8 +15,9 @@ of constant size. The size of the array is defined in ``max_entries`` at creation time. All array elements are pre-allocated and zero initialized when created. ``BPF_MAP_TYPE_PERCPU_ARRAY`` uses a different memory region for each CPU whereas ``BPF_MAP_TYPE_ARRAY`` uses the same memory region. The value -stored can be of any size, however, all array elements are aligned to 8 -bytes. +stored can be of any size for ``BPF_MAP_TYPE_ARRAY`` and not more than +``PCPU_MIN_UNIT_SIZE`` (32 kB) for ``BPF_MAP_TYPE_PERCPU_ARRAY``. All +array elements are aligned to 8 bytes. Since kernel 5.5, memory mapping may be enabled for ``BPF_MAP_TYPE_ARRAY`` by setting the flag ``BPF_F_MMAPABLE``. The map definition is page-aligned and |