On Fri, May 20, 2022 at 7:35 PM Hao Luo <haoluo@xxxxxxxxxx> wrote: > > On Fri, May 20, 2022 at 5:59 PM Yonghong Song <yhs@xxxxxx> wrote: > > On 5/20/22 3:57 PM, Tejun Heo wrote: > > > Hello, > > > > > > On Fri, May 20, 2022 at 03:19:19PM -0700, Alexei Starovoitov wrote: > > >> We have bpf_map iterator that walks all bpf maps. > > >> When map iterator is parametrized with map_fd the iterator walks > > >> all elements of that map. > > >> cgroup iterator should have similar semantics. > > >> When non-parameterized it will walk all cgroups and their descendent > > >> depth first way. I believe that's what Yonghong is proposing. > > >> When parametrized it will start from that particular cgroup and > > >> walk all descendant of that cgroup only. > > >> The bpf prog can stop the iteration right away with ret 1. > > >> Maybe we can add two parameters. One -> cgroup_fd to use and another -> > > >> the order of iteration css_for_each_descendant_pre vs _post. > > >> wdyt? > > > > > > Sounds perfectly reasonable to me. > > > > This works for me too. Thanks! > > > > This sounds good to me. Thanks. Let's try to do it in the next iteration. Can we, in addition to descendant_pre and descendant_post walk algorithms also add the one that does ascendants walk (i.e., start from specified cgroup and walk up to the root cgroup)? I don't have specific example, but it seems natural to include it for "cgroup iterator" in general. Hopefully it won't add much code to the implementation.
