From: Hui Zhu zhuhui@kylinos.cn
Add comprehensive selftests for the memcg_bpf_ops struct_ops functionality.
The test creates a cgroup hierarchy with high and low priority cgroups, attaches a BPF program that monitors PGSCAN events on the high-priority cgroup, and verifies that low-priority tasks are throttled when the BPF program reports additional overage.
Test flow: 1. Create /memcg_ops_test/high and /memcg_ops_test/low cgroups 2. Attach BPF program to monitor high cgroup's PGSCAN events 3. When PGSCAN events exceed threshold (64 pages/sec), report 512 pages over high for low cgroup 4. Run memory-intensive workloads in both cgroups 5. Verify low-priority workload is significantly slower
The BPF program uses: - Tracepoint to monitor memcg:count_memcg_events - One-second sliding window for PGSCAN aggregation - Trigger mechanism with configurable threshold and overage
This validates that: - BPF programs can be attached to cgroup hierarchies - memcg_nr_pages_over_high hook is called correctly - Memory pressure calculation includes BPF-reported overage - Throttling behavior works as expected
This test does not use PSI for triggering due to the reasons discussed in: https://lore.kernel.org/lkml/1d9a162605a3f32ac215430131f7745488deaa34@linux....
Signed-off-by: Geliang Tang geliang@kernel.org Signed-off-by: Hui Zhu zhuhui@kylinos.cn --- MAINTAINERS | 2 + .../selftests/bpf/prog_tests/memcg_ops.c | 340 ++++++++++++++++++ .../selftests/bpf/progs/memcg_ops_over_high.c | 95 +++++ 3 files changed, 437 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/memcg_ops.c create mode 100644 tools/testing/selftests/bpf/progs/memcg_ops_over_high.c
diff --git a/MAINTAINERS b/MAINTAINERS index 158f3ba63ee7..10508c90136a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6356,6 +6356,8 @@ F: mm/memcontrol-v1.h F: mm/page_counter.c F: mm/swap_cgroup.c F: samples/cgroup/* +F: tools/testing/selftests/bpf/prog_tests/memcg_ops.c +F: tools/testing/selftests/bpf/progs/memcg_ops_over_high.c F: tools/testing/selftests/cgroup/memcg_protection.m F: tools/testing/selftests/cgroup/test_hugetlb_memcg.c F: tools/testing/selftests/cgroup/test_kmem.c diff --git a/tools/testing/selftests/bpf/prog_tests/memcg_ops.c b/tools/testing/selftests/bpf/prog_tests/memcg_ops.c new file mode 100644 index 000000000000..48f0ca4a032b --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/memcg_ops.c @@ -0,0 +1,340 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Memory controller eBPF struct ops test + */ + +#include <test_progs.h> +#include <bpf/btf.h> +#include "cgroup_helpers.h" + +struct local_config { + u64 threshold; + u64 high_cgroup_id; + unsigned int over_high; +} local_config; + +#include "memcg_ops_over_high.skel.h" + +#define OVER_HIGH_THRESHOLD 64 +#define OVER_HIGH_NUM 512 +#define FILE_SIZE (512 * 1024 * 1024ul) +#define BUFFER_SIZE (128 * 1024) +#define READ_ITERATIONS 5 +#define CG_LIMIT (512 * 1024 * 1024ul) + +#define CG_DIR "/memcg_ops_test" +#define CG_HIGH_DIR CG_DIR "/high" +#define CG_LOW_DIR CG_DIR "/low" + + +static int setup_cgroup(int *high_cgroup_id, int *low_cgroup_fd) +{ + int ret; + char limit_buf[20]; + + ret = setup_cgroup_environment(); + if (!ASSERT_OK(ret, "setup_cgroup_environment")) + goto cleanup; + + ret = create_and_get_cgroup(CG_DIR); + if (!ASSERT_GE(ret, 0, "create_and_get_cgroup "CG_DIR)) + goto cleanup; + close(ret); + ret = enable_controllers(CG_DIR, "memory"); + if (!ASSERT_OK(ret, "enable_controllers")) + goto cleanup; + snprintf(limit_buf, 20, "%ld", CG_LIMIT); + ret = write_cgroup_file(CG_DIR, "memory.max", limit_buf); + if (!ASSERT_OK(ret, "write_cgroup_file")) + goto cleanup; + + ret = create_and_get_cgroup(CG_HIGH_DIR); + if (!ASSERT_GE(ret, 0, "create_and_get_cgroup "CG_HIGH_DIR)) + goto cleanup; + close(ret); + ret = (int)get_cgroup_id(CG_HIGH_DIR); + if (!ASSERT_GE(ret, 0, "get_cgroup_id")) + goto cleanup; + *high_cgroup_id = ret; + + ret = create_and_get_cgroup(CG_LOW_DIR); + if (!ASSERT_GE(ret, 0, "create_and_get_cgroup "CG_LOW_DIR)) + goto cleanup; + *low_cgroup_fd = ret; + + return 0; + +cleanup: + cleanup_cgroup_environment(); + return -1; +} + +int write_file(const char *filename) +{ + int ret = -1; + size_t written = 0; + char *buffer; + FILE *fp; + + fp = fopen(filename, "wb"); + if (!fp) + goto out; + + buffer = malloc(BUFFER_SIZE); + if (!buffer) + goto cleanup_fp; + + memset(buffer, 'A', BUFFER_SIZE); + + while (written < FILE_SIZE) { + size_t to_write = (FILE_SIZE - written < BUFFER_SIZE) ? + (FILE_SIZE - written) : + BUFFER_SIZE; + + if (fwrite(buffer, 1, to_write, fp) != to_write) + goto cleanup; + written += to_write; + } + + ret = 0; +cleanup: + free(buffer); +cleanup_fp: + fclose(fp); +out: + return ret; +} + +int read_file(const char *filename, int iterations) +{ + int ret = -1; + char *buffer; + + buffer = malloc(BUFFER_SIZE); + if (!buffer) + goto out; + + for (int iter = 0; iter < iterations; iter++) { + FILE *fp = fopen(filename, "rb"); + + if (!fp) + goto cleanup; + + size_t total_read = 0; + size_t bytes_read; + + while ((bytes_read = fread(buffer, 1, BUFFER_SIZE, fp)) > 0) + total_read += bytes_read; + + fclose(fp); + + if (env.verbosity >= VERBOSE_NORMAL) + printf("%s %d %d done\n", + __func__, getpid(), iter); + } + + ret = 0; +cleanup: + free(buffer); +out: + return ret; +} + +static void real_test_memcg_ops_over_high_child_work(const char *cgroup_path, + char *data_filename, + char *time_filename) +{ + struct timeval start, end; + double elapsed; + FILE *fp; + + if (!ASSERT_OK(join_parent_cgroup(cgroup_path), "join_parent_cgroup")) + goto out; + + if (env.verbosity >= VERBOSE_NORMAL) + printf("%s %d begin\n", __func__, getpid()); + + gettimeofday(&start, NULL); + + if (!ASSERT_OK(write_file(data_filename), "write_file")) + goto out; + + if (env.verbosity >= VERBOSE_NORMAL) + printf("%s %d write_file done\n", __func__, getpid()); + + if (!ASSERT_OK(read_file(data_filename, READ_ITERATIONS), "read_file")) + goto out; + + gettimeofday(&end, NULL); + + elapsed = (end.tv_sec - start.tv_sec) + + (end.tv_usec - start.tv_usec) / 1000000.0; + + if (env.verbosity >= VERBOSE_NORMAL) + printf("%s %d end %.6f\n", __func__, getpid(), elapsed); + + fp = fopen(time_filename, "w"); + if (!ASSERT_OK_PTR(fp, "fopen")) + goto out; + fprintf(fp, "%.6f", elapsed); + fclose(fp); + +out: + exit(0); +} + +static int get_time(char *time_filename, double *time) +{ + int ret = -1; + FILE *fp; + + fp = fopen(time_filename, "r"); + if (!fp) + goto out; + + if (fscanf(fp, "%lf", time) < 0) + goto cleanup; + + ret = 0; +cleanup: + fclose(fp); +out: + return ret; +} + +static void real_test_memcg_ops_over_high(void) +{ + int ret; + char data_file1[] = "/tmp/test_data_XXXXXX"; + char data_file2[] = "/tmp/test_data_XXXXXX"; + char time_file1[] = "/tmp/test_time_XXXXXX"; + char time_file2[] = "/tmp/test_time_XXXXXX"; + pid_t pid1, pid2; + double time1, time2; + + ret = mkstemp(data_file1); + if (!ASSERT_GT(ret, 0, "mkstemp")) + return; + close(ret); + ret = mkstemp(data_file2); + if (!ASSERT_GT(ret, 0, "mkstemp")) + goto cleanup_data_file1; + close(ret); + ret = mkstemp(time_file1); + if (!ASSERT_GT(ret, 0, "mkstemp")) + goto cleanup_data_file2; + close(ret); + ret = mkstemp(time_file2); + if (!ASSERT_GT(ret, 0, "mkstemp")) + goto cleanup_time_file1; + close(ret); + + pid1 = fork(); + if (!ASSERT_GE(pid1, 0, "fork")) + goto cleanup; + if (pid1 == 0) + real_test_memcg_ops_over_high_child_work(CG_LOW_DIR, + data_file1, + time_file1); + + pid2 = fork(); + if (!ASSERT_GE(pid1, 0, "fork")) + goto cleanup; + if (pid2 == 0) + real_test_memcg_ops_over_high_child_work(CG_HIGH_DIR, + data_file2, + time_file2); + + ret = waitpid(pid1, NULL, 0); + if (!ASSERT_GT(ret, 0, "waitpid")) + goto cleanup; + + ret = waitpid(pid2, NULL, 0); + if (!ASSERT_GT(ret, 0, "waitpid")) + goto cleanup; + + if (CHECK_FAIL(get_time(time_file1, &time1))) + goto cleanup; + + if (CHECK_FAIL(get_time(time_file2, &time2))) + goto cleanup; + + ASSERT_TRUE(time1 > time2 && time1 - time2 > 1, + "low fast compare"); + +cleanup: + unlink(time_file2); +cleanup_time_file1: + unlink(time_file1); +cleanup_data_file2: + unlink(data_file2); +cleanup_data_file1: + unlink(data_file1); +} + +void test_memcg_ops_over_high(void) +{ + int err, map_fd; + struct memcg_ops_over_high *skel; + struct bpf_map *map; + size_t bss_sz; + struct memcg_ops_over_high__bss *bss_data; + __u32 key = 0; + struct bpf_program *prog = NULL; + struct bpf_link *link = NULL, *link2 = NULL; + DECLARE_LIBBPF_OPTS(bpf_struct_ops_opts, opts); + int high_cgroup_id, low_cgroup_fd; + + err = setup_cgroup(&high_cgroup_id, &low_cgroup_fd); + if (!ASSERT_OK(err, "setup_cgroup")) + goto out; + + skel = memcg_ops_over_high__open_and_load(); + if (!ASSERT_OK_PTR(skel, "memcg_ops_over_high__open_and_load")) + goto out; + + map = bpf_object__find_map_by_name(skel->obj, ".bss"); + if (!ASSERT_OK_PTR(map, "bpf_object__find_map_by_name .bss")) + goto out; + + map_fd = bpf_map__fd(map); + bss_sz = bpf_map__value_size(map); + bss_data = malloc(bpf_map__value_size(map)); + if (!ASSERT_OK_PTR(bss_data, "malloc(bpf_map__value_size(map))")) + goto out; + memset(bss_data, 0, sizeof(struct local_config)); + bss_data->local_config.high_cgroup_id = high_cgroup_id; + bss_data->local_config.threshold = OVER_HIGH_THRESHOLD; + bss_data->local_config.over_high = OVER_HIGH_NUM; + err = bpf_map_update_elem(map_fd, &key, bss_data, BPF_EXIST); + free(bss_data); + if (!ASSERT_OK(err, "bpf_map_update_elem")) + goto out; + + prog = bpf_object__find_program_by_name(skel->obj, + "handle_count_memcg_events"); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto out; + + link = bpf_program__attach(prog); + if (!ASSERT_OK_PTR(link, "bpf_program__attach")) + goto out; + + map = bpf_object__find_map_by_name(skel->obj, "mcg_ops"); + if (!ASSERT_OK_PTR(link, "bpf_object__find_map_by_name mcg_ops")) + goto out; + + opts.relative_fd = low_cgroup_fd; + link2 = bpf_map__attach_struct_ops_opts(map, &opts); + if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops_opts")) + goto out; + + real_test_memcg_ops_over_high(); + +out: + bpf_link__destroy(link); + bpf_link__destroy(link2); + memcg_ops_over_high__detach(skel); + close(low_cgroup_fd); + cleanup_cgroup_environment(); +} diff --git a/tools/testing/selftests/bpf/progs/memcg_ops_over_high.c b/tools/testing/selftests/bpf/progs/memcg_ops_over_high.c new file mode 100644 index 000000000000..5c9651ec96d4 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/memcg_ops_over_high.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +#define ONE_SECOND_NS 1000000000 + +struct local_config { + u64 threshold; + u64 high_cgroup_id; + unsigned int over_high; +} local_config; + +struct AggregationData { + u64 sum; + u64 window_start_ts; +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, u32); + __type(value, struct AggregationData); +} aggregation_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, u32); + __type(value, u64); +} trigger_ts_map SEC(".maps"); + +SEC("tp/memcg/count_memcg_events") +int +handle_count_memcg_events(struct trace_event_raw_memcg_rstat_events *ctx) +{ + u32 key = 0; + struct AggregationData *data; + u64 current_ts; + + if (ctx->id != local_config.high_cgroup_id || + (ctx->item != PGSCAN_KSWAPD && ctx->item != PGSCAN_DIRECT)) + goto out; + + data = bpf_map_lookup_elem(&aggregation_map, &key); + if (!data) + goto out; + + current_ts = bpf_ktime_get_ns(); + + if (current_ts - data->window_start_ts < ONE_SECOND_NS) { + data->sum += ctx->val; + } else { + data->window_start_ts = current_ts; + data->sum = ctx->val; + } + + if (data->sum > local_config.threshold) { + bpf_map_update_elem(&trigger_ts_map, &key, ¤t_ts, + BPF_ANY); + data->sum = 0; + data->window_start_ts = current_ts; + } + +out: + return 0; +} + +SEC("struct_ops/memcg_nr_pages_over_high") +unsigned int memcg_nr_pages_over_high_impl(struct mem_cgroup *memcg) +{ + u32 key = 0; + u64 *trigger_ts; + unsigned int ret = 0; + + trigger_ts = bpf_map_lookup_elem(&trigger_ts_map, &key); + if (!trigger_ts || *trigger_ts == 0) + goto out; + + u64 current_ts = bpf_ktime_get_ns(); + + if (current_ts - *trigger_ts < ONE_SECOND_NS) + ret = local_config.over_high; + +out: + return ret; +} + +SEC(".struct_ops.link") +struct memcg_bpf_ops mcg_ops = { + .memcg_nr_pages_over_high = (void *)memcg_nr_pages_over_high_impl, +}; + +char LICENSE[] SEC("license") = "GPL";