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[bpf-next,v2,0/3] Allow mmap of /sys/kernel/btf/vmlinux

Message ID 20250502-vmlinux-mmap-v2-0-95c271434519@isovalent.com
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Series Allow mmap of /sys/kernel/btf/vmlinux | expand

Message

Lorenz Bauer May 2, 2025, 10:20 a.m. UTC 
I'd like to cut down the memory usage of parsing vmlinux BTF in ebpf-go.
With some upcoming changes the library is sitting at 5MiB for a parse.
Most of that memory is simply copying the BTF blob into user space.
By allowing vmlinux BTF to be mmapped read-only into user space I can
cut memory usage by about 75%.

Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
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Changes in v2:
- Use btf__new in selftest
- Avoid vm_iomap_memory in btf_vmlinux_mmap
- Add VM_DONTDUMP
- Add support to libbpf
- Link to v1: https://lore.kernel.org/r/20250501-vmlinux-mmap-v1-0-aa2724572598@isovalent.com

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Lorenz Bauer (3):
      btf: allow mmap of vmlinux btf
      selftests: bpf: add a test for mmapable vmlinux BTF
      libbpf: Use mmap to parse vmlinux BTF from sysfs

 include/asm-generic/vmlinux.lds.h                  |  3 +-
 kernel/bpf/sysfs_btf.c                             | 36 +++++++++-
 tools/lib/bpf/btf.c                                | 82 +++++++++++++++++++---
 tools/testing/selftests/bpf/prog_tests/btf_sysfs.c | 82 ++++++++++++++++++++++
 4 files changed, 189 insertions(+), 14 deletions(-)
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base-commit: 38d976c32d85ef12dcd2b8a231196f7049548477
change-id: 20250501-vmlinux-mmap-2ec5563c3ef1

Best regards,