Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> writes: > Em Fri, Jun 12, 2020 at 10:57:59PM -0700, Andrii Nakryiko escreveu: >> On Fri, Jun 12, 2020 at 8:45 PM Alexei Starovoitov >> <alexei.starovoitov@xxxxxxxxx> wrote: >> > >> > On Fri, Jun 12, 2020 at 03:31:50PM -0700, Andrii Nakryiko wrote: >> > > Add bpf_iter-based way to find all the processes that hold open FDs against >> > > BPF object (map, prog, link, btf). Add new flag (-o, for "ownership", given >> > > -p is already taken) to trigger collection and output of these PIDs. >> > > >> > > Sample output for each of 4 BPF objects: >> > > >> > > $ sudo ./bpftool -o prog show >> > > 1992: cgroup_skb name egress_alt tag 9ad187367cf2b9e8 gpl >> > > loaded_at 2020-06-12T14:18:10-0700 uid 0 >> > > xlated 48B jited 59B memlock 4096B map_ids 2074 >> > > btf_id 460 >> > > pids: 913709,913732,913733,913734 >> > > 2062: cgroup_device tag 8c42dee26e8cd4c2 gpl >> > > loaded_at 2020-06-12T14:37:52-0700 uid 0 >> > > xlated 648B jited 409B memlock 4096B >> > > pids: 1 >> > > >> > > $ sudo ./bpftool -o map show >> > > 2074: array name test_cgr.bss flags 0x400 >> > > key 4B value 8B max_entries 1 memlock 8192B >> > > btf_id 460 >> > > pids: 913709,913732,913733,913734 >> > > >> > > $ sudo ./bpftool -o link show >> > > 82: cgroup prog 1992 >> > > cgroup_id 0 attach_type egress >> > > pids: 913709,913732,913733,913734 >> > > 86: cgroup prog 1992 >> > > cgroup_id 0 attach_type egress >> > > pids: 913709,913732,913733,913734 >> > >> > This is awesome. > > Indeed. > >> Thanks. >> >> > >> > Why extra flag though? I think it's so useful that everyone would want to see > > Agreed. > >> No good reason apart from "being safe by default". If turned on by >> default, bpftool would need to probe for bpf_iter support first. I can >> add probing and do this by default. > > I think this is the way to go. +1 And also +1 on the awesomeness of this feature! :) -Toke
