tools/testing/selftests/bpf/progs/stacktrace_map.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/stacktrace_map.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/stacktrace_map.c
Extension
.c
Size
1817 bytes
Lines
79
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct sched_switch_args {
	unsigned long long pad;
	char prev_comm[TASK_COMM_LEN];
	int prev_pid;
	int prev_prio;
	long long prev_state;
	char next_comm[TASK_COMM_LEN];
	int next_pid;
	int next_prio;
};

__u32 stack_id;
SEC("tracepoint/sched/sched_switch")
int oncpu(struct sched_switch_args *ctx)
{
	__u32 max_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);
	__u32 key = 0, val = 0, *value_p;
	void *stack_p;

	value_p = bpf_map_lookup_elem(&control_map, &key);
	if (value_p && *value_p)
		return 0; /* skip if non-zero *value_p */

	/* The size of stackmap and stackid_hmap should be the same */
	key = bpf_get_stackid(ctx, &stackmap, 0);
	if ((int)key >= 0) {
		stack_id = key;
		bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
		stack_p = bpf_map_lookup_elem(&stack_amap, &key);
		if (stack_p)
			bpf_get_stack(ctx, stack_p, max_len, 0);
	}

	return 0;
}

char _license[] SEC("license") = "GPL";

Annotation

Implementation Notes