Currently, tools/testing/selftests/cgroup/ has no dmem-specific test. This leaves dmem accounting and dmem.max enforcement largely unvalidated without a production driver.
Add test_dmem, driven by the dmem_selftest helper module parameters (alloc/free) on the dmem_selftest region. insmod the helper before running the tests. The tests cover: - test_dmem_max: nested hierarchy with per-leaf dmem.max values and verifies that over-limit charges fail while in-limit charges succeed in dmem.current. - test_dmem_alloc_byte_granularity: non-page-aligned alloc sizes, dmem.current equals the requested byte count, and free-to-zero behavior. Limits are read with cg_read_key_long(). The helper is stat'd in main() so a missing module skips the whole test instead of each subtest. Signed-off-by: Albert Esteve <[email protected]> --- tools/testing/selftests/cgroup/.gitignore | 1 + tools/testing/selftests/cgroup/Makefile | 2 + tools/testing/selftests/cgroup/test_dmem.c | 314 +++++++++++++++++++++++++++++ 3 files changed, 317 insertions(+) diff --git a/tools/testing/selftests/cgroup/.gitignore b/tools/testing/selftests/cgroup/.gitignore index 952e4448bf07..ea2322598217 100644 --- a/tools/testing/selftests/cgroup/.gitignore +++ b/tools/testing/selftests/cgroup/.gitignore @@ -2,6 +2,7 @@ test_core test_cpu test_cpuset +test_dmem test_freezer test_hugetlb_memcg test_kill diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index a08661320a07..d01e8eb1ead2 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -11,6 +11,7 @@ TEST_GEN_MODS_DIR := test_modules TEST_GEN_PROGS = test_core TEST_GEN_PROGS += test_cpu TEST_GEN_PROGS += test_cpuset +TEST_GEN_PROGS += test_dmem TEST_GEN_PROGS += test_freezer TEST_GEN_PROGS += test_hugetlb_memcg TEST_GEN_PROGS += test_kill @@ -27,6 +28,7 @@ include lib/libcgroup.mk $(OUTPUT)/test_core: $(LIBCGROUP_O) $(OUTPUT)/test_cpu: $(LIBCGROUP_O) $(OUTPUT)/test_cpuset: $(LIBCGROUP_O) +$(OUTPUT)/test_dmem: $(LIBCGROUP_O) $(OUTPUT)/test_freezer: $(LIBCGROUP_O) $(OUTPUT)/test_hugetlb_memcg: $(LIBCGROUP_O) $(OUTPUT)/test_kill: $(LIBCGROUP_O) diff --git a/tools/testing/selftests/cgroup/test_dmem.c b/tools/testing/selftests/cgroup/test_dmem.c new file mode 100644 index 000000000000..3793664678b9 --- /dev/null +++ b/tools/testing/selftests/cgroup/test_dmem.c @@ -0,0 +1,314 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test the dmem (device memory) cgroup controller. + * + * Depends on the dmem_selftest helper module + * (tools/testing/selftests/cgroup/test_modules/dmem_selftest.c). + */ + +#define _GNU_SOURCE + +#include <linux/limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +#include "kselftest.h" +#include "cgroup_util.h" + +#define DM_SELFTEST_REGION "dmem_selftest" +#define DM_SELFTEST_ALLOC "/sys/module/dmem_selftest/parameters/alloc" +#define DM_SELFTEST_FREE "/sys/module/dmem_selftest/parameters/free" + +static long dmem_read_limit(const char *cgroup, const char *ctrl) +{ + return cg_read_key_long(cgroup, ctrl, DM_SELFTEST_REGION " "); +} + +static int dmem_write_limit(const char *cgroup, const char *ctrl, long val) +{ + char wr[64]; + + snprintf(wr, sizeof(wr), "%s %ld", DM_SELFTEST_REGION, val); + return cg_write(cgroup, ctrl, wr); +} + +static int dmem_selftest_alloc(long bytes) +{ + char wr[32]; + + snprintf(wr, sizeof(wr), "%ld", bytes); + return write_text(DM_SELFTEST_ALLOC, wr, strlen(wr)); +} + +static int dmem_selftest_free(void) +{ + char wr[] = "1"; + + return write_text(DM_SELFTEST_FREE, wr, strlen(wr)); +} + +/* + * First, this test creates the following hierarchy: + * A + * A/B dmem.max=8M + * A/B/C dmem.max=2M + * A/B/D dmem.max=1M + * A/B/E dmem.max=75K + * A/B/F dmem.max=25K + * A/B/G dmem.max=8K + * A/B/H dmem.max=0 + * + * Then for each leaf cgroup it tries to alloc above dmem.max + * and expects the request to fail and dmem.current to remain + * unchanged. + * + * For leaves with non-zero dmem.max, it additionally allocs a + * smaller amount and verifies dmem.current matches the requested + * size exactly (the controller accounts in bytes, with no page + * rounding), then frees and verifies dmem.current returns + * to the previous value. + */ +static int test_dmem_max(const char *root) +{ + static const long leaf_max[] = { + MB(2), MB(1), KB(75), KB(25), KB(8), 0 + }; + static const long pass_sz[] = { + MB(1), MB(1), KB(4), KB(4), KB(4), 0 + }; + char *parent[2] = {NULL}; + char *children[ARRAY_SIZE(leaf_max)] = {NULL}; + + _Static_assert(ARRAY_SIZE(pass_sz) == ARRAY_SIZE(leaf_max), + "pass_sz doesn't match leaf_max length"); + long cur_before, cur_after; + int ret = KSFT_FAIL; + int charged = 0; + int in_child = 0; + long v; + int i; + + parent[0] = cg_name(root, "dmem_prot_0"); + if (!parent[0]) + goto cleanup; + + parent[1] = cg_name(parent[0], "dmem_prot_1"); + if (!parent[1]) + goto cleanup; + + if (cg_create(parent[0])) + goto cleanup; + + if (cg_write(parent[0], "cgroup.subtree_control", "+dmem")) + goto cleanup; + + if (cg_create(parent[1])) + goto cleanup; + + if (cg_write(parent[1], "cgroup.subtree_control", "+dmem")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(children); i++) { + children[i] = cg_name_indexed(parent[1], "dmem_child", i); + if (!children[i]) + goto cleanup; + if (cg_create(children[i])) + goto cleanup; + } + + if (dmem_write_limit(parent[1], "dmem.max", MB(8))) + goto cleanup; + for (i = 0; i < ARRAY_SIZE(children); i++) + if (dmem_write_limit(children[i], "dmem.max", leaf_max[i])) + goto cleanup; + + v = dmem_read_limit(parent[1], "dmem.max"); + if (v != MB(8)) + goto cleanup; + for (i = 0; i < ARRAY_SIZE(children); i++) { + v = dmem_read_limit(children[i], "dmem.max"); + if (v != leaf_max[i]) + goto cleanup; + } + + for (i = 0; i < ARRAY_SIZE(children); i++) { + if (cg_enter_current(children[i])) + goto cleanup; + in_child = 1; + + cur_before = dmem_read_limit(children[i], "dmem.current"); + if (cur_before < 0) + goto cleanup; + + if (dmem_selftest_alloc(leaf_max[i] + 1) >= 0) { + charged = 1; + goto cleanup; + } + + cur_after = dmem_read_limit(children[i], "dmem.current"); + if (cur_after != cur_before) + goto cleanup; + + if (pass_sz[i] > 0) { + if (dmem_selftest_alloc(pass_sz[i]) < 0) + goto cleanup; + charged = 1; + + cur_after = dmem_read_limit(children[i], "dmem.current"); + if (cur_after != cur_before + pass_sz[i]) + goto cleanup; + + if (dmem_selftest_free() < 0) + goto cleanup; + charged = 0; + + cur_after = dmem_read_limit(children[i], "dmem.current"); + if (cur_after != cur_before) + goto cleanup; + } + + if (cg_enter_current(root)) + goto cleanup; + in_child = 0; + } + + ret = KSFT_PASS; + +cleanup: + if (charged) + dmem_selftest_free(); + if (in_child) + cg_enter_current(root); + for (i = ARRAY_SIZE(children) - 1; i >= 0; i--) { + if (!children[i]) + continue; + cg_destroy(children[i]); + free(children[i]); + } + for (i = ARRAY_SIZE(parent) - 1; i >= 0; i--) { + if (!parent[i]) + continue; + cg_destroy(parent[i]); + free(parent[i]); + } + return ret; +} + +/* + * Alloc non-page-aligned byte sizes and verify dmem.current matches + * the requested size exactly. The controller charges the byte count + * passed to dmem_cgroup_try_charge() with no page rounding, for this + * helper and for production drivers. Then free must return usage to 0. + */ +static int test_dmem_alloc_byte_granularity(const char *root) +{ + static const long sizes[] = { + 1, 4095, 4097, KB(75) + 1, MB(1), MB(1) + 1 + }; + char *cg = NULL; + long cur; + int ret = KSFT_FAIL; + int charged = 0; + int in_child = 0; + size_t i; + + cg = cg_name(root, "dmem_dbg_byte_gran"); + if (!cg) + goto cleanup; + + if (cg_create(cg)) + goto cleanup; + + if (dmem_write_limit(cg, "dmem.max", MB(16))) + goto cleanup; + + if (cg_enter_current(cg)) + goto cleanup; + in_child = 1; + + for (i = 0; i < ARRAY_SIZE(sizes); i++) { + if (dmem_selftest_alloc(sizes[i]) < 0) + goto cleanup; + charged = 1; + + cur = dmem_read_limit(cg, "dmem.current"); + if (cur != sizes[i]) + goto cleanup; + + if (dmem_selftest_free() < 0) + goto cleanup; + charged = 0; + + cur = dmem_read_limit(cg, "dmem.current"); + if (cur != 0) + goto cleanup; + } + + ret = KSFT_PASS; + +cleanup: + if (charged) + dmem_selftest_free(); + if (in_child) + cg_enter_current(root); + if (cg) { + cg_destroy(cg); + free(cg); + } + return ret; +} + +#define T(x) { x, #x } +struct dmem_test { + int (*fn)(const char *root); + const char *name; +} tests[] = { + T(test_dmem_max), + T(test_dmem_alloc_byte_granularity), +}; +#undef T + +int main(int argc, char **argv) +{ + char root[PATH_MAX]; + struct stat st; + int i; + + ksft_print_header(); + + if (cg_find_unified_root(root, sizeof(root), NULL)) + ksft_exit_skip("cgroup v2 isn't mounted\n"); + + if (cg_read_strstr(root, "cgroup.controllers", "dmem")) + ksft_exit_skip("dmem controller isn't available (CONFIG_CGROUP_DMEM?)\n"); + + if (cg_read_strstr(root, "cgroup.subtree_control", "dmem")) + if (cg_write(root, "cgroup.subtree_control", "+dmem")) + ksft_exit_skip("Failed to enable dmem controller\n"); + + if (stat(DM_SELFTEST_ALLOC, &st) < 0) + ksft_exit_skip( + "dmem_selftest helper not loaded (insmod test_modules/dmem_selftest.ko)\n"); + + if (dmem_read_limit(root, "dmem.capacity") < 0) + ksft_exit_skip("dmem_selftest region not registered\n"); + + ksft_set_plan(ARRAY_SIZE(tests)); + + for (i = 0; i < ARRAY_SIZE(tests); i++) { + switch (tests[i].fn(root)) { + case KSFT_PASS: + ksft_test_result_pass("%s\n", tests[i].name); + break; + default: + ksft_test_result_fail("%s\n", tests[i].name); + break; + } + } + + ksft_finished(); +} -- 2.55.0
