bpf: Simplify bpf_prog_pack_[size|mask]

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Simplify the logic that selects bpf_prog_pack_size, and always use
(PMD_SIZE * num_possible_nodes()). This is a good tradeoff, as most of
the performance benefit observed is from less direct map fragmentation [0].

Also, module_alloc(4MB) may not allocate 4MB aligned memory. Therefore,
we cannot use (ptr & bpf_prog_pack_mask) to find the correct address of
bpf_prog_pack. Fix this by checking the header address falls in the range
of pack->ptr and (pack->ptr + bpf_prog_pack_size).

  [0] https://lore.kernel.org/bpf/20220707223546.4124919-1-song@kernel.org/

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20220713204950.3015201-1-song@kernel.org

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Song Liu 2022-07-13 13:49:50 -07:00 • committed by Daniel Borkmann

parent 00963a2e75

commit ea2babac63

1 changed files with 17 additions and 54 deletions

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kernel/bpf/core.c

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