[PATCH 3/3] selftests: memcg: Add tests IN_DELETE_SELF and IN_IGNORED on memory.events

T.J. Mercier
2026-02-10T00:38:37Z

Add two new tests that verify inotify events are sent when memcg files
are removed.

Signed-off-by: T.J. Mercier <tjmercier@google.com>
---
.../selftests/cgroup/test_memcontrol.c | 126 ++++++++++++++++++
1 file changed, 126 insertions(+)

diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
index 4e1647568c5b..25a495347f7c 100644
--- a/tools/testing/selftests/cgroup/test_memcontrol.c
+++ b/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -10,6 +10,7 @@
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
+#include <sys/inotify.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <arpa/inet.h>
@@ -1625,6 +1626,129 @@ static int test_memcg_oom_group_score_events(const char *root)
return ret;
}

+static int read_event(int inotify_fd, int expected_event, int expected_wd)
+{
+ struct inotify_event event;
+ ssize_t len = 0;
+
+ len = read(inotify_fd, &event, sizeof(event));
+ if (len < (ssize_t)sizeof(event))
+ return -1;
+
+ if (event.mask != expected_event || event.wd != expected_wd) {
+ fprintf(stderr,
+ "event does not match expected values: mask %d (expected %d) wd %d (expected %d)\n",
+ event.mask, expected_event, event.wd, expected_wd);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int test_memcg_inotify_delete_file(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *memcg, *child_memcg;
+ int fd, wd;
+ struct inotify_event event;
+ ssize_t len = 0;
+
+ memcg = cg_name(root, "memcg_test_0");
+
+ if (!memcg)
+ goto cleanup;
+
+ if (cg_create(memcg))
+ goto cleanup;
+
+ if (cg_write(memcg, "cgroup.subtree_control", "+memory"))
+ goto cleanup;
+
+ child_memcg = cg_name(memcg, "child");
+ if (!child_memcg)
+ goto cleanup;
+
+ if (cg_create(child_memcg))
+ goto cleanup;
+
+ fd = inotify_init1(0);
+ if (fd == -1)
+ goto cleanup;
+
+ wd = inotify_add_watch(fd, cg_control(child_memcg, "memory.events"), IN_DELETE_SELF);
+ if (wd == -1)
+ goto cleanup;
+
+ cg_write(memcg, "cgroup.subtree_control", "-memory");
+
+ if (read_event(fd, IN_DELETE_SELF, wd))
+ goto cleanup;
+
+ if (read_event(fd, IN_IGNORED, wd))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (fd >= 0)
+ close(fd);
+ if (child_memcg)
+ cg_destroy(child_memcg);
+ free(child_memcg);
+ if (memcg)
+ cg_destroy(memcg);
+ free(memcg);
+
+ return ret;
+}
+
+static int test_memcg_inotify_delete_rmdir(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *memcg;
+ int fd, wd;
+ struct inotify_event event;
+ ssize_t len = 0;
+
+ memcg = cg_name(root, "memcg_test_0");
+
+ if (!memcg)
+ goto cleanup;
+
+ if (cg_create(memcg))
+ goto cleanup;
+
+ fd = inotify_init1(0);
+ if (fd == -1)
+ goto cleanup;
+
+ wd = inotify_add_watch(fd, cg_control(memcg, "memory.events"), IN_DELETE_SELF);
+ if (wd == -1)
+ goto cleanup;
+
+ if (cg_destroy(memcg))
+ goto cleanup;
+ free(memcg);
+ memcg = NULL;
+
+ if (read_event(fd, IN_DELETE_SELF, wd))
+ goto cleanup;
+
+ if (read_event(fd, IN_IGNORED, wd))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (fd >= 0)
+ close(fd);
+ if (memcg)
+ cg_destroy(memcg);
+ free(memcg);
+
+ return ret;
+}
+
#define T(x) { x, #x }
struct memcg_test {
int (*fn)(const char *root);
@@ -1644,6 +1768,8 @@ struct memcg_test {
T(test_memcg_oom_group_leaf_events),
T(test_memcg_oom_group_parent_events),
T(test_memcg_oom_group_score_events),
+ T(test_memcg_inotify_delete_file),
+ T(test_memcg_inotify_delete_rmdir),
};
#undef T

--
2.53.0.rc2.204.g2597b5adb4-goog