Add cgroup core selftests

This commit adds tests for some of the core functionalities
of cgroups v2.

The commit adds tests for some core principles of croup V2 API:

- test_cgcore_internal_process_constraint

  Tests internal process constraint.
  You can't add a pid to a domain parent if a controller is enabled.

- test_cgcore_top_down_constraint_enable

   Tests that you can't enable a controller on a child if it's not enabled
   on the parent.

- test_cgcore_top_down_constraint_disable

  Tests that you can't disable a controller on a parent if it's
  enabled in a child.

- test_cgcore_no_internal_process_constraint_on_threads

  Tests that there's no internal process constrain on threaded cgroups.
  You can add threads/processes on a parent with a controller enabled.

- test_cgcore_parent_becomes_threaded

  Tests that when a child becomes threaded the parent type becomes
  domain threaded.

- test_cgcore_invalid_domain

  In a situation like:

  A (domain threaded) - B (threaded) - C (domain)

  it tests that C can't be used until it is turned into a threaded cgroup.
  The "cgroup.type" file will report "domain (invalid)" in these cases.
  Operations which fail due to invalid topology use EOPNOTSUPP as the errno.

- test_cgcore_populated

  In a situation like:

  A(0) - B(0) - C(1)
         \ D(0)

  It tests that A, B and C's "populated" fields would be 1 while D's 0.
  It tests that after the one process in C is moved to root, A,B and C's
  "populated" fields would flip to "0" and file modified events will
  be generated on the "cgroup.events" files of both cgroups.

Signed-off-by: Claudio Zumbo <claudioz@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile
index f7a3139..23fbaa4 100644 (file)
--- a/tools/testing/selftests/cgroup/Makefile
+++ b/tools/testing/selftests/cgroup/Makefile
@@ -4,7 +4,9 @@ CFLAGS += -Wall
 all:
 
 TEST_GEN_PROGS = test_memcontrol
+TEST_GEN_PROGS += test_core
 
 include ../lib.mk
 
 $(OUTPUT)/test_memcontrol: cgroup_util.c
+$(OUTPUT)/test_core: cgroup_util.c

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 1e9e3c4..1c5d2b2 100644 (file)
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -229,6 +229,14 @@ retry:
        return ret;
 }
 
+int cg_enter_current(const char *cgroup)
+{
+       char pidbuf[64];
+
+       snprintf(pidbuf, sizeof(pidbuf), "%d", getpid());
+       return cg_write(cgroup, "cgroup.procs", pidbuf);
+}
+
 int cg_run(const char *cgroup,
           int (*fn)(const char *cgroup, void *arg),
           void *arg)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
index fe82a29..1ff6f9f 100644 (file)
--- a/tools/testing/selftests/cgroup/cgroup_util.h
+++ b/tools/testing/selftests/cgroup/cgroup_util.h
@@ -32,6 +32,7 @@ extern int cg_write(const char *cgroup, const char *control, char *buf);
 extern int cg_run(const char *cgroup,
                  int (*fn)(const char *cgroup, void *arg),
                  void *arg);
+extern int cg_enter_current(const char *cgroup);
 extern int cg_run_nowait(const char *cgroup,
                         int (*fn)(const char *cgroup, void *arg),
                         void *arg);

diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c
new file mode 100644 (file)
index 0000000..be59f9c
--- /dev/null
+++ b/tools/testing/selftests/cgroup/test_core.c
@@ -0,0 +1,395 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/limits.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "../kselftest.h"
+#include "cgroup_util.h"
+
+/*
+ * A(0) - B(0) - C(1)
+ *        \ D(0)
+ *
+ * A, B and C's "populated" fields would be 1 while D's 0.
+ * test that after the one process in C is moved to root,
+ * A,B and C's "populated" fields would flip to "0" and file
+ * modified events will be generated on the
+ * "cgroup.events" files of both cgroups.
+ */
+static int test_cgcore_populated(const char *root)
+{
+       int ret = KSFT_FAIL;
+       char *cg_test_a = NULL, *cg_test_b = NULL;
+       char *cg_test_c = NULL, *cg_test_d = NULL;
+
+       cg_test_a = cg_name(root, "cg_test_a");
+       cg_test_b = cg_name(root, "cg_test_a/cg_test_b");
+       cg_test_c = cg_name(root, "cg_test_a/cg_test_b/cg_test_c");
+       cg_test_d = cg_name(root, "cg_test_a/cg_test_b/cg_test_d");
+
+       if (!cg_test_a || !cg_test_b || !cg_test_c || !cg_test_d)
+               goto cleanup;
+
+       if (cg_create(cg_test_a))
+               goto cleanup;
+
+       if (cg_create(cg_test_b))
+               goto cleanup;
+
+       if (cg_create(cg_test_c))
+               goto cleanup;
+
+       if (cg_create(cg_test_d))
+               goto cleanup;
+
+       if (cg_enter_current(cg_test_c))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_a, "cgroup.events", "populated 1\n"))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_b, "cgroup.events", "populated 1\n"))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_c, "cgroup.events", "populated 1\n"))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_d, "cgroup.events", "populated 0\n"))
+               goto cleanup;
+
+       if (cg_enter_current(root))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_a, "cgroup.events", "populated 0\n"))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_b, "cgroup.events", "populated 0\n"))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_c, "cgroup.events", "populated 0\n"))
+               goto cleanup;
+
+       if (cg_read_strcmp(cg_test_d, "cgroup.events", "populated 0\n"))
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       if (cg_test_d)
+               cg_destroy(cg_test_d);
+       if (cg_test_c)
+               cg_destroy(cg_test_c);
+       if (cg_test_b)
+               cg_destroy(cg_test_b);
+       if (cg_test_a)
+               cg_destroy(cg_test_a);
+       free(cg_test_d);
+       free(cg_test_c);
+       free(cg_test_b);
+       free(cg_test_a);
+       return ret;
+}
+
+/*
+ * A (domain threaded) - B (threaded) - C (domain)
+ *
+ * test that C can't be used until it is turned into a
+ * threaded cgroup.  "cgroup.type" file will report "domain (invalid)" in
+ * these cases. Operations which fail due to invalid topology use
+ * EOPNOTSUPP as the errno.
+ */
+static int test_cgcore_invalid_domain(const char *root)
+{
+       int ret = KSFT_FAIL;
+       char *grandparent = NULL, *parent = NULL, *child = NULL;
+
+       grandparent = cg_name(root, "cg_test_grandparent");
+       parent = cg_name(root, "cg_test_grandparent/cg_test_parent");
+       child = cg_name(root, "cg_test_grandparent/cg_test_parent/cg_test_child");
+       if (!parent || !child || !grandparent)
+               goto cleanup;
+
+       if (cg_create(grandparent))
+               goto cleanup;
+
+       if (cg_create(parent))
+               goto cleanup;
+
+       if (cg_create(child))
+               goto cleanup;
+
+       if (cg_write(parent, "cgroup.type", "threaded"))
+               goto cleanup;
+
+       if (cg_read_strcmp(child, "cgroup.type", "domain invalid\n"))
+               goto cleanup;
+
+       if (!cg_enter_current(child))
+               goto cleanup;
+
+       if (errno != EOPNOTSUPP)
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       cg_enter_current(root);
+       if (child)
+               cg_destroy(child);
+       if (parent)
+               cg_destroy(parent);
+       if (grandparent)
+               cg_destroy(grandparent);
+       free(child);
+       free(parent);
+       free(grandparent);
+       return ret;
+}
+
+/*
+ * Test that when a child becomes threaded
+ * the parent type becomes domain threaded.
+ */
+static int test_cgcore_parent_becomes_threaded(const char *root)
+{
+       int ret = KSFT_FAIL;
+       char *parent = NULL, *child = NULL;
+
+       parent = cg_name(root, "cg_test_parent");
+       child = cg_name(root, "cg_test_parent/cg_test_child");
+       if (!parent || !child)
+               goto cleanup;
+
+       if (cg_create(parent))
+               goto cleanup;
+
+       if (cg_create(child))
+               goto cleanup;
+
+       if (cg_write(child, "cgroup.type", "threaded"))
+               goto cleanup;
+
+       if (cg_read_strcmp(parent, "cgroup.type", "domain threaded\n"))
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       if (child)
+               cg_destroy(child);
+       if (parent)
+               cg_destroy(parent);
+       free(child);
+       free(parent);
+       return ret;
+
+}
+
+/*
+ * Test that there's no internal process constrain on threaded cgroups.
+ * You can add threads/processes on a parent with a controller enabled.
+ */
+static int test_cgcore_no_internal_process_constraint_on_threads(const char *root)
+{
+       int ret = KSFT_FAIL;
+       char *parent = NULL, *child = NULL;
+
+       if (cg_read_strstr(root, "cgroup.controllers", "cpu") ||
+           cg_read_strstr(root, "cgroup.subtree_control", "cpu")) {
+               ret = KSFT_SKIP;
+               goto cleanup;
+       }
+
+       parent = cg_name(root, "cg_test_parent");
+       child = cg_name(root, "cg_test_parent/cg_test_child");
+       if (!parent || !child)
+               goto cleanup;
+
+       if (cg_create(parent))
+               goto cleanup;
+
+       if (cg_create(child))
+               goto cleanup;
+
+       if (cg_write(parent, "cgroup.type", "threaded"))
+               goto cleanup;
+
+       if (cg_write(child, "cgroup.type", "threaded"))
+               goto cleanup;
+
+       if (cg_write(parent, "cgroup.subtree_control", "+cpu"))
+               goto cleanup;
+
+       if (cg_enter_current(parent))
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       cg_enter_current(root);
+       cg_enter_current(root);
+       if (child)
+               cg_destroy(child);
+       if (parent)
+               cg_destroy(parent);
+       free(child);
+       free(parent);
+       return ret;
+}
+
+/*
+ * Test that you can't enable a controller on a child if it's not enabled
+ * on the parent.
+ */
+static int test_cgcore_top_down_constraint_enable(const char *root)
+{
+       int ret = KSFT_FAIL;
+       char *parent = NULL, *child = NULL;
+
+       parent = cg_name(root, "cg_test_parent");
+       child = cg_name(root, "cg_test_parent/cg_test_child");
+       if (!parent || !child)
+               goto cleanup;
+
+       if (cg_create(parent))
+               goto cleanup;
+
+       if (cg_create(child))
+               goto cleanup;
+
+       if (!cg_write(child, "cgroup.subtree_control", "+memory"))
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       if (child)
+               cg_destroy(child);
+       if (parent)
+               cg_destroy(parent);
+       free(child);
+       free(parent);
+       return ret;
+}
+
+/*
+ * Test that you can't disable a controller on a parent
+ * if it's enabled in a child.
+ */
+static int test_cgcore_top_down_constraint_disable(const char *root)
+{
+       int ret = KSFT_FAIL;
+       char *parent = NULL, *child = NULL;
+
+       parent = cg_name(root, "cg_test_parent");
+       child = cg_name(root, "cg_test_parent/cg_test_child");
+       if (!parent || !child)
+               goto cleanup;
+
+       if (cg_create(parent))
+               goto cleanup;
+
+       if (cg_create(child))
+               goto cleanup;
+
+       if (cg_write(parent, "cgroup.subtree_control", "+memory"))
+               goto cleanup;
+
+       if (cg_write(child, "cgroup.subtree_control", "+memory"))
+               goto cleanup;
+
+       if (!cg_write(parent, "cgroup.subtree_control", "-memory"))
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       if (child)
+               cg_destroy(child);
+       if (parent)
+               cg_destroy(parent);
+       free(child);
+       free(parent);
+       return ret;
+}
+
+/*
+ * Test internal process constraint.
+ * You can't add a pid to a domain parent if a controller is enabled.
+ */
+static int test_cgcore_internal_process_constraint(const char *root)
+{
+       int ret = KSFT_FAIL;
+       char *parent = NULL, *child = NULL;
+
+       parent = cg_name(root, "cg_test_parent");
+       child = cg_name(root, "cg_test_parent/cg_test_child");
+       if (!parent || !child)
+               goto cleanup;
+
+       if (cg_create(parent))
+               goto cleanup;
+
+       if (cg_create(child))
+               goto cleanup;
+
+       if (cg_write(parent, "cgroup.subtree_control", "+memory"))
+               goto cleanup;
+
+       if (!cg_enter_current(parent))
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       if (child)
+               cg_destroy(child);
+       if (parent)
+               cg_destroy(parent);
+       free(child);
+       free(parent);
+       return ret;
+}
+
+#define T(x) { x, #x }
+struct corecg_test {
+       int (*fn)(const char *root);
+       const char *name;
+} tests[] = {
+       T(test_cgcore_internal_process_constraint),
+       T(test_cgcore_top_down_constraint_enable),
+       T(test_cgcore_top_down_constraint_disable),
+       T(test_cgcore_no_internal_process_constraint_on_threads),
+       T(test_cgcore_parent_becomes_threaded),
+       T(test_cgcore_invalid_domain),
+       T(test_cgcore_populated),
+};
+#undef T
+
+int main(int argc, char *argv[])
+{
+       char root[PATH_MAX];
+       int i, ret = EXIT_SUCCESS;
+
+       if (cg_find_unified_root(root, sizeof(root)))
+               ksft_exit_skip("cgroup v2 isn't mounted\n");
+       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;
+               case KSFT_SKIP:
+                       ksft_test_result_skip("%s\n", tests[i].name);
+                       break;
+               default:
+                       ret = EXIT_FAILURE;
+                       ksft_test_result_fail("%s\n", tests[i].name);
+                       break;
+               }
+       }
+
+       return ret;
+}