Re: [PATCH bpf-next v2] tools: bpftool: add support for reporting the effective cgroup progs

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

On Tue, Jul 30, 2019 at 3:01 PM Takshak Chahande <ctakshak@fb.com> wrote:
>
> Jakub Kicinski <jakub.kicinski@netronome.com> wrote on Tue [2019-Jul-30 14:03:00 -0700]:
> > Takshak said in the original submission:
> >
> > With different bpf attach_flags available to attach bpf programs specially
> > with BPF_F_ALLOW_OVERRIDE and BPF_F_ALLOW_MULTI, the list of effective
> > bpf-programs available to any sub-cgroups really needs to be available for
> > easy debugging.
> >
> > Using BPF_F_QUERY_EFFECTIVE flag, one can get the list of not only attached
> > bpf-programs to a cgroup but also the inherited ones from parent cgroup.
> >
> > So a new option is introduced to use BPF_F_QUERY_EFFECTIVE query flag here
> > to list all the effective bpf-programs available for execution at a specified
> > cgroup.
> >
> > Reused modified test program test_cgroup_attach from tools/testing/selftests/bpf:
> >   # ./test_cgroup_attach
> >
> > With old bpftool:
> >
> >  # bpftool cgroup show /sys/fs/cgroup/cgroup-test-work-dir/cg1/
> >   ID       AttachType      AttachFlags     Name
> >   271      egress          multi           pkt_cntr_1
> >   272      egress          multi           pkt_cntr_2
> >
> > Attached new program pkt_cntr_4 in cg2 gives following:
> >
> >  # bpftool cgroup show /sys/fs/cgroup/cgroup-test-work-dir/cg1/cg2
> >   ID       AttachType      AttachFlags     Name
> >   273      egress          override        pkt_cntr_4
> >
> > And with new "effective" option it shows all effective programs for cg2:
> >
> >  # bpftool cgroup show /sys/fs/cgroup/cgroup-test-work-dir/cg1/cg2 effective
> >   ID       AttachType      AttachFlags     Name
> >   273      egress          override        pkt_cntr_4
> >   271      egress          override        pkt_cntr_1
> >   272      egress          override        pkt_cntr_2
> >
> > Compared to original submission use a local flag instead of global
> > option.
> >
> > We need to clear query_flags on every command, in case batch mode
> > wants to use varying settings.
> >
> > v2: (Takshak)
> >  - forbid duplicated flags;
> >  - fix cgroup path freeing.
> >
> > Signed-off-by: Takshak Chahande <ctakshak@fb.com>
> > Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> > Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
...
>
> Reviewed-by: Takshak Chahande <ctakshak@fb.com>

Applied. Thanks