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selftests/bpf: Add tests for BPF_F_PRESERVE_ELEMS

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Add tests for perf event array with and without BPF_F_PRESERVE_ELEMS.

Add a perf event to array via fd mfd. Without BPF_F_PRESERVE_ELEMS, the
perf event is removed when mfd is closed. With BPF_F_PRESERVE_ELEMS, the
perf event is removed when the map is freed.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200930224927.1936644-3-songliubraving@fb.com
This commit is contained in:
Song Liu
2020-09-30 15:49:27 -07:00
committed by Alexei Starovoitov
parent 792caccc45
commit d6b4206841
2 changed files with 104 additions and 0 deletions
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38
tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c Normal file
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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2020 Facebook
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(max_entries, 1);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
} array_1 SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(max_entries, 1);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__uint(map_flags, BPF_F_PRESERVE_ELEMS);
} array_2 SEC(".maps");
SEC("raw_tp/sched_switch")
int BPF_PROG(read_array_1)
{
struct bpf_perf_event_value val;
return bpf_perf_event_read_value(&array_1, 0, &val, sizeof(val));
}
SEC("raw_tp/task_rename")
int BPF_PROG(read_array_2)
{
struct bpf_perf_event_value val;
return bpf_perf_event_read_value(&array_2, 0, &val, sizeof(val));
}
char LICENSE[] SEC("license") = "GPL";