diff options
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c | 170 |
1 files changed, 76 insertions, 94 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c b/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c index bed1661596f7..3bd27d2ea668 100644 --- a/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c @@ -1,6 +1,22 @@ // SPDX-License-Identifier: GPL-2.0-only /* - * Functions to manage eBPF programs attached to cgroup subsystems + * This test makes sure BPF stats collection using rstat works correctly. + * The test uses 3 BPF progs: + * (a) counter: This BPF prog is invoked every time we attach a process to a + * cgroup and locklessly increments a percpu counter. + * The program then calls cgroup_rstat_updated() to inform rstat + * of an update on the (cpu, cgroup) pair. + * + * (b) flusher: This BPF prog is invoked when an rstat flush is ongoing, it + * aggregates all percpu counters to a total counter, and also + * propagates the changes to the ancestor cgroups. + * + * (c) dumper: This BPF prog is a cgroup_iter. It is used to output the total + * counter of a cgroup through reading a file in userspace. + * + * The test sets up a cgroup hierarchy, and the above programs. It spawns a few + * processes in the leaf cgroups and makes sure all the counters are aggregated + * correctly. * * Copyright 2022 Google LLC. */ @@ -21,8 +37,10 @@ #define PAGE_SIZE 4096 #define MB(x) (x << 20) +#define PROCESSES_PER_CGROUP 3 + #define BPFFS_ROOT "/sys/fs/bpf/" -#define BPFFS_VMSCAN BPFFS_ROOT"vmscan/" +#define BPFFS_ATTACH_COUNTERS BPFFS_ROOT "attach_counters/" #define CG_ROOT_NAME "root" #define CG_ROOT_ID 1 @@ -79,7 +97,7 @@ static int setup_bpffs(void) return err; /* Create a directory to contain stat files in bpffs */ - err = mkdir(BPFFS_VMSCAN, 0755); + err = mkdir(BPFFS_ATTACH_COUNTERS, 0755); if (!ASSERT_OK(err, "mkdir")) return err; @@ -89,7 +107,7 @@ static int setup_bpffs(void) static void cleanup_bpffs(void) { /* Remove created directory in bpffs */ - ASSERT_OK(rmdir(BPFFS_VMSCAN), "rmdir "BPFFS_VMSCAN); + ASSERT_OK(rmdir(BPFFS_ATTACH_COUNTERS), "rmdir "BPFFS_ATTACH_COUNTERS); /* Unmount bpffs, if it wasn't already mounted when we started */ if (mounted_bpffs) @@ -118,18 +136,6 @@ static int setup_cgroups(void) cgroups[i].fd = fd; cgroups[i].id = get_cgroup_id(cgroups[i].path); - - /* - * Enable memcg controller for the entire hierarchy. - * Note that stats are collected for all cgroups in a hierarchy - * with memcg enabled anyway, but are only exposed for cgroups - * that have memcg enabled. - */ - if (i < N_NON_LEAF_CGROUPS) { - err = enable_controllers(cgroups[i].path, "memory"); - if (!ASSERT_OK(err, "enable_controllers")) - return err; - } } return 0; } @@ -154,109 +160,85 @@ static void destroy_hierarchy(void) cleanup_bpffs(); } -static int reclaimer(const char *cgroup_path, size_t size) -{ - static char size_buf[128]; - char *buf, *ptr; - int err; - - /* Join cgroup in the parent process workdir */ - if (join_parent_cgroup(cgroup_path)) - return EACCES; - - /* Allocate memory */ - buf = malloc(size); - if (!buf) - return ENOMEM; - - /* Write to memory to make sure it's actually allocated */ - for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE) - *ptr = 1; - - /* Try to reclaim memory */ - snprintf(size_buf, 128, "%lu", size); - err = write_cgroup_file_parent(cgroup_path, "memory.reclaim", size_buf); - - free(buf); - /* memory.reclaim returns EAGAIN if the amount is not fully reclaimed */ - if (err && errno != EAGAIN) - return errno; - - return 0; -} - -static int induce_vmscan(void) +static int attach_processes(void) { - int i, status; + int i, j, status; - /* - * In every leaf cgroup, run a child process that allocates some memory - * and attempts to reclaim some of it. - */ + /* In every leaf cgroup, attach 3 processes */ for (i = N_NON_LEAF_CGROUPS; i < N_CGROUPS; i++) { - pid_t pid; - - /* Create reclaimer child */ - pid = fork(); - if (pid == 0) { - status = reclaimer(cgroups[i].path, MB(5)); - exit(status); + for (j = 0; j < PROCESSES_PER_CGROUP; j++) { + pid_t pid; + + /* Create child and attach to cgroup */ + pid = fork(); + if (pid == 0) { + if (join_parent_cgroup(cgroups[i].path)) + exit(EACCES); + exit(0); + } + + /* Cleanup child */ + waitpid(pid, &status, 0); + if (!ASSERT_TRUE(WIFEXITED(status), "child process exited")) + return 1; + if (!ASSERT_EQ(WEXITSTATUS(status), 0, + "child process exit code")) + return 1; } - - /* Cleanup reclaimer child */ - waitpid(pid, &status, 0); - ASSERT_TRUE(WIFEXITED(status), "reclaimer exited"); - ASSERT_EQ(WEXITSTATUS(status), 0, "reclaim exit code"); } return 0; } static unsigned long long -get_cgroup_vmscan_delay(unsigned long long cgroup_id, const char *file_name) +get_attach_counter(unsigned long long cgroup_id, const char *file_name) { - unsigned long long vmscan = 0, id = 0; + unsigned long long attach_counter = 0, id = 0; static char buf[128], path[128]; /* For every cgroup, read the file generated by cgroup_iter */ - snprintf(path, 128, "%s%s", BPFFS_VMSCAN, file_name); + snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS, file_name); if (!ASSERT_OK(read_from_file(path, buf, 128), "read cgroup_iter")) return 0; /* Check the output file formatting */ - ASSERT_EQ(sscanf(buf, "cg_id: %llu, total_vmscan_delay: %llu\n", - &id, &vmscan), 2, "output format"); + ASSERT_EQ(sscanf(buf, "cg_id: %llu, attach_counter: %llu\n", + &id, &attach_counter), 2, "output format"); /* Check that the cgroup_id is displayed correctly */ ASSERT_EQ(id, cgroup_id, "cgroup_id"); - /* Check that the vmscan reading is non-zero */ - ASSERT_GT(vmscan, 0, "vmscan_reading"); - return vmscan; + /* Check that the counter is non-zero */ + ASSERT_GT(attach_counter, 0, "attach counter non-zero"); + return attach_counter; } -static void check_vmscan_stats(void) +static void check_attach_counters(void) { - unsigned long long vmscan_readings[N_CGROUPS], vmscan_root; + unsigned long long attach_counters[N_CGROUPS], root_attach_counter; int i; - for (i = 0; i < N_CGROUPS; i++) { - vmscan_readings[i] = get_cgroup_vmscan_delay(cgroups[i].id, - cgroups[i].name); - } + for (i = 0; i < N_CGROUPS; i++) + attach_counters[i] = get_attach_counter(cgroups[i].id, + cgroups[i].name); /* Read stats for root too */ - vmscan_root = get_cgroup_vmscan_delay(CG_ROOT_ID, CG_ROOT_NAME); + root_attach_counter = get_attach_counter(CG_ROOT_ID, CG_ROOT_NAME); + + /* Check that all leafs cgroups have an attach counter of 3 */ + for (i = N_NON_LEAF_CGROUPS; i < N_CGROUPS; i++) + ASSERT_EQ(attach_counters[i], PROCESSES_PER_CGROUP, + "leaf cgroup attach counter"); /* Check that child1 == child1_1 + child1_2 */ - ASSERT_EQ(vmscan_readings[1], vmscan_readings[3] + vmscan_readings[4], - "child1_vmscan"); + ASSERT_EQ(attach_counters[1], attach_counters[3] + attach_counters[4], + "child1_counter"); /* Check that child2 == child2_1 + child2_2 */ - ASSERT_EQ(vmscan_readings[2], vmscan_readings[5] + vmscan_readings[6], - "child2_vmscan"); + ASSERT_EQ(attach_counters[2], attach_counters[5] + attach_counters[6], + "child2_counter"); /* Check that test == child1 + child2 */ - ASSERT_EQ(vmscan_readings[0], vmscan_readings[1] + vmscan_readings[2], - "test_vmscan"); + ASSERT_EQ(attach_counters[0], attach_counters[1] + attach_counters[2], + "test_counter"); /* Check that root >= test */ - ASSERT_GE(vmscan_root, vmscan_readings[1], "root_vmscan"); + ASSERT_GE(root_attach_counter, attach_counters[1], "root_counter"); } /* Creates iter link and pins in bpffs, returns 0 on success, -errno on failure. @@ -278,12 +260,12 @@ static int setup_cgroup_iter(struct cgroup_hierarchical_stats *obj, linfo.cgroup.order = BPF_CGROUP_ITER_SELF_ONLY; opts.link_info = &linfo; opts.link_info_len = sizeof(linfo); - link = bpf_program__attach_iter(obj->progs.dump_vmscan, &opts); + link = bpf_program__attach_iter(obj->progs.dumper, &opts); if (!ASSERT_OK_PTR(link, "attach_iter")) return -EFAULT; /* Pin the link to a bpffs file */ - snprintf(path, 128, "%s%s", BPFFS_VMSCAN, file_name); + snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS, file_name); err = bpf_link__pin(link, path); ASSERT_OK(err, "pin cgroup_iter"); @@ -313,7 +295,7 @@ static int setup_progs(struct cgroup_hierarchical_stats **skel) if (!ASSERT_OK(err, "setup_cgroup_iter")) return err; - bpf_program__set_autoattach((*skel)->progs.dump_vmscan, false); + bpf_program__set_autoattach((*skel)->progs.dumper, false); err = cgroup_hierarchical_stats__attach(*skel); if (!ASSERT_OK(err, "attach")) return err; @@ -328,13 +310,13 @@ static void destroy_progs(struct cgroup_hierarchical_stats *skel) for (i = 0; i < N_CGROUPS; i++) { /* Delete files in bpffs that cgroup_iters are pinned in */ - snprintf(path, 128, "%s%s", BPFFS_VMSCAN, + snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS, cgroups[i].name); ASSERT_OK(remove(path), "remove cgroup_iter pin"); } /* Delete root file in bpffs */ - snprintf(path, 128, "%s%s", BPFFS_VMSCAN, CG_ROOT_NAME); + snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS, CG_ROOT_NAME); ASSERT_OK(remove(path), "remove cgroup_iter root pin"); cgroup_hierarchical_stats__destroy(skel); } @@ -347,9 +329,9 @@ void test_cgroup_hierarchical_stats(void) goto hierarchy_cleanup; if (setup_progs(&skel)) goto cleanup; - if (induce_vmscan()) + if (attach_processes()) goto cleanup; - check_vmscan_stats(); + check_attach_counters(); cleanup: destroy_progs(skel); hierarchy_cleanup: |