Thread (37 messages) 37 messages, 6 authors, 13h ago

Re: [PATCH bpf-next v4 00/12] bpf: make the vmlinux BTF an on-demand loadable module (CONFIG_DEBUG_INFO_BTF=m) to save ~5.4 MB memory

From: Alan Maguire <hidden>
Date: 2026-10-03 11:46:33
Also in: bpf, linux-doc, linux-input, linux-kbuild, linux-kselftest, linux-modules, linux-perf-users, lkml, rust-for-linux, sched-ext

On Fri, Oct 02, 2026 at 01:58 PM Ihor Solodrai [off-list ref] wrote:
quoted
     Keep zstd-compressed blob in the kernel image and decompress and
     parse it synchronously on first use.
imo this is the only one of the three worth considering.
This approach is clever; my prior thinking on this was since vmlinux is often
compressed anyway we don't win anything from having a compressed .BTF section.
But as you say if we compress the .BTF section within the kernel vmlinux,
when the kernel image is then uncompressed into memory we will save most of the
space taken up by vmlinux BTF due to its still-compressed size.

The only overall cost is if when we wind up using vmlinux BTF with the compressed
.BTF section, since we have to do a full vmlinux BTF allocation (on top of the
spac taken up by the compressed .BTF section) right? So slight penalty if vmlinux
is used, but big gain if not.

If I'm understanding it correctly, seems like this is a nice win!
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