On Fri, Nov 1, 2019 at 12:27 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > On Thu, Oct 31, 2019 at 01:39:12PM -0700, Alexei Starovoitov wrote: > > On Thu, Oct 31, 2019 at 12:18 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > > > > > > > yes. older vmlinux and newer installed libbpf.so > > > > or any version of libbpf.a that is statically linked into apps > > > > is something that libbpf code has to support. > > > > The server can be rebooted into older than libbpf kernel and > > > > into newer than libbpf kernel. libbpf has to recognize all these > > > > combinations and work appropriately. > > > > That's what backward and forward compatibility is. > > > > That's what makes libbpf so difficult to test, develop and code review. > > > > What that particular server has in /usr/include is irrelevant. > > > > > > sure, anyway we can't compile following: > > > > > > tredaell@aldebaran ~ $ echo "#include <bpf/xsk.h>" | gcc -x c - > > > In file included from <stdin>:1: > > > /usr/include/bpf/xsk.h: In function ‘xsk_ring_prod__needs_wakeup’: > > > /usr/include/bpf/xsk.h:82:21: error: ‘XDP_RING_NEED_WAKEUP’ undeclared (first use in this function) > > > 82 | return *r->flags & XDP_RING_NEED_WAKEUP; > > > ... > > > > > > XDP_RING_NEED_WAKEUP is defined in kernel v5.4-rc1 (77cd0d7b3f257fd0e3096b4fdcff1a7d38e99e10). > > > XSK_UNALIGNED_BUF_ADDR_MASK and XSK_UNALIGNED_BUF_OFFSET_SHIFT are defined in kernel v5.4-rc1 (c05cd3645814724bdeb32a2b4d953b12bdea5f8c). > > > > > > with: > > > kernel-headers-5.3.6-300.fc31.x86_64 > > > libbpf-0.0.5-1.fc31.x86_64 > > > > > > if you're saying this is not supported, I guess we could be postponing > > > libbpf rpm releases until we have the related fedora kernel released > > > > why? github/libbpf is the source of truth for building packages > > and afaik it builds fine. > > because we will get issues like above if there's no kernel > avilable that we could compile libbpf against what is the issue again? bpf-next builds fine. github/libbpf builds fine. If distro is doing something else it's distro's mistake.
