selftests: memcg: test high limit for single entry allocation

Test the enforcement of memory.high limit for large amount of memory
allocation within a single kernel entry.  There are valid use-cases
where the application can trigger large amount of memory allocation
within a single syscall e.g.  mlock() or mmap(MAP_POPULATE).

Make sure memory.high limit enforcement works for such use-cases.

Link: https://lkml.kernel.org/r/20220211064917.2028469-4-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Chris Down <chris@chrisdown.name>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 0cf7e90c0052..dbaa7aabbb4a 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -583,7 +583,7 @@ int clone_into_cgroup_run_wait(const char *cgroup)
 	return 0;
 }
 
-int cg_prepare_for_wait(const char *cgroup)
+static int __prepare_for_wait(const char *cgroup, const char *filename)
 {
 	int fd, ret = -1;
 
@@ -591,8 +591,7 @@ int cg_prepare_for_wait(const char *cgroup)
 	if (fd == -1)
 		return fd;
 
-	ret = inotify_add_watch(fd, cg_control(cgroup, "cgroup.events"),
-				IN_MODIFY);
+	ret = inotify_add_watch(fd, cg_control(cgroup, filename), IN_MODIFY);
 	if (ret == -1) {
 		close(fd);
 		fd = -1;
@@ -601,6 +600,16 @@ int cg_prepare_for_wait(const char *cgroup)
 	return fd;
 }
 
+int cg_prepare_for_wait(const char *cgroup)
+{
+	return __prepare_for_wait(cgroup, "cgroup.events");
+}
+
+int memcg_prepare_for_wait(const char *cgroup)
+{
+	return __prepare_for_wait(cgroup, "memory.events");
+}
+
 int cg_wait_for(int fd)
 {
 	int ret = -1;