bpf has been used extensively for tracing. For example, bcc contains an almost full set of bpf-based tools to trace kernel and user functions/events. Most tracing tools are currently either filtered based on pid or system-wide. Containers have been used quite extensively in industry and cgroup is often used together to provide resource isolation and protection. Several processes may run inside the same container. It is often desirable to get container-level tracing results as well, e.g. syscall count, function count, I/O activity, etc. This patch implements a new helper, bpf_get_current_cgroup_id(), which will return cgroup id based on the cgroup within which the current task is running. The later patch will provide an example to show that userspace can get the same cgroup id so it could configure a filter or policy in the bpf program based on task cgroup id. The helper is currently implemented for tracing. It can be added to other program types as well when needed.
Showing the changes to include/uapi/linux (1 of 5 files). Show all
Unified · Split
| @@ -2070,6 +2070,11 @@ union bpf_attr { · 2069 unmodified lines | ||
| 2070 | 2070 | * **CONFIG_SOCK_CGROUP_DATA** configuration option. |
| 2071 | 2071 | * Return |
| 2072 | 2072 | * The id is returned or 0 in case the id could not be retrieved. |
| 2073 | + * | |
| 2074 | + * u64 bpf_get_current_cgroup_id(void) | |
| 2075 | + * Return | |
| 2076 | + * A 64-bit integer containing the current cgroup id based | |
| 2077 | + * on the cgroup within which the current task is running. | |
| 2073 | 2078 | */ |
| 2074 | 2079 | #define __BPF_FUNC_MAPPER(FN) \ |
| 2075 | 2080 | FN(unspec), \ |
| @@ -2151,7 +2156,8 @@ union bpf_attr { · 75 unmodified lines | ||
| 2151 | 2156 | FN(lwt_seg6_action), \ |
| 2152 | 2157 | FN(rc_repeat), \ |
| 2153 | 2158 | FN(rc_keydown), \ |
| 2154 | − FN(skb_cgroup_id), | |
| 2159 | + FN(skb_cgroup_id), \ | |
| 2160 | + FN(get_current_cgroup_id), | |
| 2155 | 2161 | |
| 2156 | 2162 | /* integer value in 'imm' field of BPF_CALL instruction selects which helper |
| 2157 | 2163 | * function eBPF program intends to call |