percpu_alloc_cgrp_local_storage.c

  1#include "bpf_experimental.h"
  2
  3struct val_t {
  4	long b, c, d;
  5};
  6
  7struct elem {
  8	long sum;
  9	struct val_t __percpu_kptr *pc;
 10};
 11
 12struct {
 13	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
 14	__uint(map_flags, BPF_F_NO_PREALLOC);
 15	__type(key, int);
 16	__type(value, struct elem);
 17} cgrp SEC(".maps");
 18
 19const volatile int nr_cpus;
 20
 21/* Initialize the percpu object */
 22SEC("fentry/bpf_fentry_test1")
 23int BPF_PROG(test_cgrp_local_storage_1)
 24{
 25	struct task_struct *task;
 26	struct val_t __percpu_kptr *p;
 27	struct elem *e;
 28
 29	task = bpf_get_current_task_btf();
 30	e = bpf_cgrp_storage_get(&cgrp, task->cgroups->dfl_cgrp, 0,
 31				 BPF_LOCAL_STORAGE_GET_F_CREATE);
 32	if (!e)
 33		return 0;
 34
 35	p = bpf_percpu_obj_new(struct val_t);
 36	if (!p)
 37		return 0;
 38
 39	p = bpf_kptr_xchg(&e->pc, p);
 40	if (p)
 41		bpf_percpu_obj_drop(p);
 42
 43	return 0;
 44}
 45
 46/* Percpu data collection */
 47SEC("fentry/bpf_fentry_test2")
 48int BPF_PROG(test_cgrp_local_storage_2)
 49{
 50	struct task_struct *task;
 51	struct val_t __percpu_kptr *p;
 52	struct val_t *v;
 53	struct elem *e;
 54
 55	task = bpf_get_current_task_btf();
 56	e = bpf_cgrp_storage_get(&cgrp, task->cgroups->dfl_cgrp, 0, 0);
 57	if (!e)
 58		return 0;
 59
 60	p = e->pc;
 61	if (!p)
 62		return 0;
 63
 64	v = bpf_per_cpu_ptr(p, 0);
 65	if (!v)
 66		return 0;
 67	v->c = 1;
 68	v->d = 2;
 69	return 0;
 70}
 71
 72int cpu0_field_d, sum_field_c;
 73int my_pid;
 74
 75/* Summarize percpu data collection */
 76SEC("fentry/bpf_fentry_test3")
 77int BPF_PROG(test_cgrp_local_storage_3)
 78{
 79	struct task_struct *task;
 80	struct val_t __percpu_kptr *p;
 81	struct val_t *v;
 82	struct elem *e;
 83	int i;
 84
 85	if ((bpf_get_current_pid_tgid() >> 32) != my_pid)
 86		return 0;
 87
 88	task = bpf_get_current_task_btf();
 89	e = bpf_cgrp_storage_get(&cgrp, task->cgroups->dfl_cgrp, 0, 0);
 90	if (!e)
 91		return 0;
 92
 93	p = e->pc;
 94	if (!p)
 95		return 0;
 96
 97	bpf_for(i, 0, nr_cpus) {
 98		v = bpf_per_cpu_ptr(p, i);
 99		if (v) {
100			if (i == 0)
101				cpu0_field_d = v->d;
102			sum_field_c += v->c;
103		}
104	}
105
106	return 0;
107}
108
109char _license[] SEC("license") = "GPL";