linux-kernel - [PATCH bpf-next 0/2] Allow mmap of /sys/kernel/btf/vmlinux

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Message-Id: <20250501-vmlinux-mmap-v1-0-aa2724572598@isovalent.com>
Date: Thu, 01 May 2025 15:28:20 +0100
From: Lorenz Bauer <lmb@...valent.com>
To: Arnd Bergmann <arnd@...db.de>, Alexei Starovoitov <ast@...nel.org>, 
 Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>, 
 Martin KaFai Lau <martin.lau@...ux.dev>, 
 Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>, 
 Yonghong Song <yonghong.song@...ux.dev>, 
 John Fastabend <john.fastabend@...il.com>, KP Singh <kpsingh@...nel.org>, 
 Stanislav Fomichev <sdf@...ichev.me>, Hao Luo <haoluo@...gle.com>, 
 Jiri Olsa <jolsa@...nel.org>, Mykola Lysenko <mykolal@...com>, 
 Shuah Khan <shuah@...nel.org>
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org, 
 bpf@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 Lorenz Bauer <lmb@...valent.com>
Subject: [PATCH bpf-next 0/2] Allow mmap of /sys/kernel/btf/vmlinux

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@...valent.com>
---
Lorenz Bauer (2):
      btf: allow mmap of vmlinux btf
      selftests: bpf: add a test for mmapable vmlinux BTF

 include/asm-generic/vmlinux.lds.h                  |  3 +-
 kernel/bpf/sysfs_btf.c                             | 25 ++++++-
 tools/testing/selftests/bpf/prog_tests/btf_sysfs.c | 79 ++++++++++++++++++++++
 3 files changed, 104 insertions(+), 3 deletions(-)
---
base-commit: 38d976c32d85ef12dcd2b8a231196f7049548477
change-id: 20250501-vmlinux-mmap-2ec5563c3ef1

Best regards,
-- 
Lorenz Bauer <lmb@...valent.com>