On Wed, Aug 10, 2022 at 5:17 PM Kui-Feng Lee <kuifeng@xxxxxx> wrote:
>
> Allow creating an iterator that loops through resources of one task/thread.
>
> People could only create iterators to loop through all resources of
> files, vma, and tasks in the system, even though they were interested
> in only the resources of a specific task or process. Passing the
> additional parameters, people can now create an iterator to go
> through all resources or only the resources of a task.
>
> Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxx>
> ---
> include/linux/bpf.h | 29 ++++++++
> include/uapi/linux/bpf.h | 8 +++
> kernel/bpf/task_iter.c | 126 ++++++++++++++++++++++++++-------
> tools/include/uapi/linux/bpf.h | 8 +++
> 4 files changed, 147 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 11950029284f..6bbe53d06faa 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1716,8 +1716,37 @@ int bpf_obj_get_user(const char __user *pathname, int flags);
> extern int bpf_iter_ ## target(args); \
> int __init bpf_iter_ ## target(args) { return 0; }
>
> +/*
> + * The task type of iterators.
> + *
> + * For BPF task iterators, they can be parameterized with various
> + * parameters to visit only some of tasks.
> + *
> + * BPF_TASK_ITER_ALL (default)
> + * Iterate over resources of every task.
> + *
> + * BPF_TASK_ITER_TID
> + * Iterate over resources of a task/tid.
> + *
> + * BPF_TASK_ITER_TGID
> + * Iterate over reosurces of evevry task of a process / task group.
> + */
> +enum bpf_iter_task_type {
> + BPF_TASK_ITER_ALL = 0,
> + BPF_TASK_ITER_TID,
> + BPF_TASK_ITER_TGID,
> +};
> +
> struct bpf_iter_aux_info {
> struct bpf_map *map;
> + struct {
> + enum bpf_iter_task_type type;
> + union {
> + u32 tid;
> + u32 tgid;
> + u32 pid_fd;
> + };
> + } task;
You don't seem to use pid_fd in bpf_iter_aux_info at all, is that
right? Drop it? And for tid/tgid, I'd use kernel-side terminology for
this internal data structure and just have single u32 pid here. Then
type determines whether you are iterating tasks or task leaders
(processes), no ambiguity.
> };
>
> typedef int (*bpf_iter_attach_target_t)(struct bpf_prog *prog,
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index ffcbf79a556b..6328aca0cf5c 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -91,6 +91,14 @@ union bpf_iter_link_info {
> struct {
> __u32 map_fd;
> } map;
> + /*
> + * Parameters of task iterators.
> + */
> + struct {
> + __u32 tid;
> + __u32 tgid;
> + __u32 pid_fd;
> + } task;
> };
>
[...]
