linux-kernel - Re: [RFC PATCH v3 3/3] btf: Reuse libbpf code for BTF type sorting verification and binary search

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Message-ID: <CAErzpmvahZJRFktDydp5tcpYnhCAw9P9UmPeC5XpRxPuo0mZ8w@mail.gmail.com>
Date: Wed, 29 Oct 2025 10:03:24 +0800
From: Donglin Peng <dolinux.peng@...il.com>
To: Andrii Nakryiko <andrii.nakryiko@...il.com>
Cc: ast@...nel.org, linux-kernel@...r.kernel.org, bpf@...r.kernel.org, 
	Eduard Zingerman <eddyz87@...il.com>, Alan Maguire <alan.maguire@...cle.com>, Song Liu <song@...nel.org>, 
	pengdonglin <pengdonglin@...omi.com>
Subject: Re: [RFC PATCH v3 3/3] btf: Reuse libbpf code for BTF type sorting
 verification and binary search

On Wed, Oct 29, 2025 at 2:40 AM Andrii Nakryiko
<andrii.nakryiko@...il.com> wrote:
>
> On Mon, Oct 27, 2025 at 6:54 AM Donglin Peng <dolinux.peng@...il.com> wrote:
> >
> > The previous commit implemented BTF sorting verification and binary
> > search algorithm in libbpf. This patch enables this functionality in
> > the kernel.
> >
> > Cc: Eduard Zingerman <eddyz87@...il.com>
> > Cc: Alexei Starovoitov <ast@...nel.org>
> > Cc: Andrii Nakryiko <andrii.nakryiko@...il.com>
> > Cc: Alan Maguire <alan.maguire@...cle.com>
> > Cc: Song Liu <song@...nel.org>
> > Signed-off-by: pengdonglin <pengdonglin@...omi.com>
> > Signed-off-by: Donglin Peng <dolinux.peng@...il.com>
> > ---
> > v2->v3:
> > - Include btf_sort.c directly in btf.c to reduce function call overhead
> > ---
> >  kernel/bpf/btf.c | 34 ++++++++++++++++++----------------
> >  1 file changed, 18 insertions(+), 16 deletions(-)
> >
> > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> > index 0de8fc8a0e0b..df258815a6ca 100644
> > --- a/kernel/bpf/btf.c
> > +++ b/kernel/bpf/btf.c
> > @@ -33,6 +33,7 @@
> >  #include <net/sock.h>
> >  #include <net/xdp.h>
> >  #include "../tools/lib/bpf/relo_core.h"
> > +#include "../tools/lib/bpf/btf_sort.h"
>
> I don't believe in code reuse for the sake of code reuse. This code
> sharing just makes everything more entangled and complicated.
> Reimplementing binary search is totally fine, IMO.

Thanks. Would you be open to the approach from v2, where we place
the common code in btf_sort.c and compile it separately rather than
including it directly?

>
> [...]