Re: [PATCH bpf-next 1/1] bpf: btf: add btf=off boot parameter to disable and free vmlinux BTF

[Alexei Starovoitov]

On Thu, Sep 17, 2026 at 12:02 AM Jay Wang <wanjay@xxxxxxxxxx> wrote:
>
> Add a "btf=off" early boot parameter, similar to the existing "selinux=0"
> parameter, so users who do not want BTF can turn it off at boot; the
> section is then freed to save memory.

tbh I'm not excited about btf=off. BTF is not debug info anymore.
sched_ext, bpf-lsm (systemd uses it), hid-bpf, most of bcc/bpftrace
quietly stop working, and we'll be the ones triaging "libbpf: failed
to find valid kernel BTF" reports from people who copy-pasted a
"save 5MB" tuning guide.
This needs more thought.

>  .../admin-guide/kernel-parameters.txt         |  14 +++
>  arch/arm64/mm/mmu.c                           | 108 +++++++++++++++++-
>  arch/x86/mm/init_64.c                         |  30 +++++
>  arch/x86/mm/pat/set_memory.c                  |  28 ++++-
>  include/linux/btf.h                           |   9 ++
>  kernel/bpf/btf.c                              |  51 ++++++++-
>  kernel/bpf/sysfs_btf.c 
                       |   7 ++
>  kernel/bpf/verifier.c                         |   2 +-

This doesn't apply to bpf-next.
Consider using Alan's approach and support CONFIG_DEBUG_INFO_BTF=m

pw-bot: cr