netdev - Re: [PATCH 04/18] bpf: Add name to struct bpf

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Date:   Thu, 27 Feb 2020 10:59:57 -0800
From:   Song Liu <song@...nel.org>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Jiri Olsa <jolsa@...nel.org>, Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        Andrii Nakryiko <andriin@...com>, Yonghong Song <yhs@...com>,
        Song Liu <songliubraving@...com>,
        Martin KaFai Lau <kafai@...com>,
        Jakub Kicinski <kuba@...nel.org>,
        David Miller <davem@...hat.com>,
        Björn Töpel <bjorn.topel@...el.com>,
        John Fastabend <john.fastabend@...il.com>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: Re: [PATCH 04/18] bpf: Add name to struct bpf_ksym

On Thu, Feb 27, 2020 at 12:50 AM Jiri Olsa <jolsa@...hat.com> wrote:
>
> On Wed, Feb 26, 2020 at 01:14:43PM -0800, Song Liu wrote:
> > On Wed, Feb 26, 2020 at 5:04 AM Jiri Olsa <jolsa@...nel.org> wrote:
> > >
> > > Adding name to 'struct bpf_ksym' object to carry the name
> > > of the symbol for bpf_prog, bpf_trampoline, bpf_dispatcher.
> > >
> > > The current benefit is that name is now generated only when
> > > the symbol is added to the list, so we don't need to generate
> > > it every time it's accessed.
> > >
> > > Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> >
> > The patch looks good. But I wonder whether we want pay the cost of
> > extra 128 bytes per bpf program. Maybe make it a pointer and only
> > generate the string when it is first used?
>
> I thought 128 would not be that bad, also the code is quite
> simple because of that.. if that's really a concern I could
> make the changes, but that would probably mean changing the
> design

I guess this is OK. We can further optimize it if needed.

Acked-by: Song Liu <songliubraving@...com>