Re: [PATCH] selftests/bpf: Remove duplicate copies of the arena spinlock qnodes

[Emil Tsalapatis]

On Mon, Aug 17, 2026 at 9:02 AM Changwoo Min <changwoo@xxxxxxxxxx> wrote:
>
> >
> Hi Daniel,
>
> On 8/17/26 6:05 PM, Daniel Borkmann wrote:
> > On 8/3/26 2:18 AM, Changwoo Min wrote:
> >> bpf_arena_spin_lock.h defines its 64KB qnodes array in the header, so
> >> every translation unit including it emits a copy. __weak makes them all
> >> resolve to one instance, but bpftool gen object merges only the symbols
> >> and concatenates each input's .addr_space.1 bytes, leaving the surplus
> >> copies unreferenced in the linked object.
> >>
> >> libarena links ten such units, so nine copies were dead weight (bytes):
> >>
> >>    object                             before       after
> >>    -----------------------------------------------------
> >>    .addr_space.1 in libarena.bpf.o    676200       86376
> >>    libarena.skel.h                   2100123      892371
> >>    libarena_asan.skel.h              2641124     1466477
> >>
> >> Declare qnodes in the header and let each program define it once:
> >> libarena in src/common.bpf.c, and the arena_spin_lock test beside the
> >> lock it guards.
> >>
> >> Tested with test_progs -t arena_spin_lock and -t libarena.
> >>
> >> Signed-off-by: Changwoo Min <changwoo@xxxxxxxxxx>

Hi Changwoo,

Sorry for the late reply, for the next version feel free to add:

Reviewed-by: Emil Tsalapatis <emil@xxxxxxxxxxxxxxx>

> > This doesn't apply cleanly, could you respin against latest bpf-next?
>
> Sure. I will send the v2 rebased on the HEAD of the the bpf-next tree soon.
>
> Regards.
> Changwoo Min
>
> >
> > Thanks,
> > Daniel
> >
>
>