Re: [PATCH bpf-next v2] bpf: Cache the last valid build_id.

[Namhyung Kim]

Hello,

On Wed, Feb 23, 2022 at 6:31 PM Song Liu <song@xxxxxxxxxx> wrote:
>
> On Wed, Feb 23, 2022 at 4:05 PM Hao Luo <haoluo@xxxxxxxxxx> wrote:
> >
> > For binaries that are statically linked, consecutive stack frames are
> > likely to be in the same VMA and therefore have the same build id.
> > As an optimization for this case, we can cache the previous frame's
> > VMA, if the new frame has the same VMA as the previous one, reuse the
> > previous one's build id. We are holding the MM locks as reader across
> > the entire loop, so we don't need to worry about VMA going away.
> >
> > Tested through "stacktrace_build_id" and "stacktrace_build_id_nmi" in
> > test_progs.
> >
> > Suggested-by: Greg Thelen <gthelen@xxxxxxxxxx>
> > Signed-off-by: Hao Luo <haoluo@xxxxxxxxxx>

Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>

Thanks,
Namhyung