Re: [PATCH bpf-next v5 4/8] bpf: Introduce cgroup iter
From: Tejun Heo <tj@kernel.org>
Date: 2022-07-28 16:51:15
Also in:
bpf, cgroups, lkml
Hello, On Fri, Jul 22, 2022 at 05:48:25PM +0000, Yosry Ahmed wrote:
+
+ /* cgroup_iter walks either the live descendants of a cgroup subtree, or the
+ * ancestors of a given cgroup.
+ */
+ struct {
+ /* Cgroup file descriptor. This is root of the subtree if walking
+ * descendants; it's the starting cgroup if walking the ancestors.
+ * If it is left 0, the traversal starts from the default cgroup v2
+ * root. For walking v1 hierarchy, one should always explicitly
+ * specify the cgroup_fd.
+ */
+ __u32 cgroup_fd;So, we're identifying the starting point with an fd.
quoted hunk ↗ jump to hunk
+ __u32 traversal_order; + } cgroup; }; /* BPF syscall commands, see bpf(2) man-page for more details. */@@ -6136,6 +6156,16 @@ struct bpf_link_info { __u32 map_id; } map; }; + union { + struct { + __u64 cgroup_id; + __u32 traversal_order; + } cgroup;
but iterating the IDs. IDs are the better choice for cgroup2 as there's nothing specific to the calling program or the fds it has, but I guess this is because you want to use it for cgroup1, right? Oh well, that's okay I guess. Acked-by: Tejun Heo <tj@kernel.org> Thanks. -- tejun