[PATCH v4 3/7] cgroup: selftests: Move memcontrol specific helpers out of common cgroup_util.c

James Houghton
2025-05-08T18:46:54Z

From: Sean Christopherson <seanjc@google.com>

Move a handful of helpers out of cgroup_util.c and into test_memcontrol.c
that have nothing to with cgroups in general, in anticipation of making
cgroup_util.c a generic library that can be used by other selftests.

Make read_text() and write_text() non-static so test_memcontrol.c can
use them.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: James Houghton <jthoughton@google.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
---
Sean's original patch[1] didn't build for me, hence the read_text() and
write_text() change.

[1]: https://lore.kernel.org/kvm/aBAlcrTtBDeQCL0X@google.com/
---

tools/testing/selftests/cgroup/cgroup_util.c | 82 +------------------
tools/testing/selftests/cgroup/cgroup_util.h | 8 +-
.../selftests/cgroup/test_memcontrol.c | 78 ++++++++++++++++++
3 files changed, 83 insertions(+), 85 deletions(-)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 1e2d46636a0ca..0ef3b8b8d7f74 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -20,7 +20,7 @@
#include "../clone3/clone3_selftests.h"

/* Returns read len on success, or -errno on failure. */
-static ssize_t read_text(const char *path, char *buf, size_t max_len)
+ssize_t read_text(const char *path, char *buf, size_t max_len)
{
ssize_t len;
int fd;
@@ -39,7 +39,7 @@ static ssize_t read_text(const char *path, char *buf, size_t max_len)
}

/* Returns written len on success, or -errno on failure. */
-static ssize_t write_text(const char *path, char *buf, ssize_t len)
+ssize_t write_text(const char *path, char *buf, ssize_t len)
{
int fd;

@@ -488,84 +488,6 @@ int cg_run_nowait(const char *cgroup,
return pid;
}

-int get_temp_fd(void)
-{
- return open(".", O_TMPFILE | O_RDWR | O_EXCL);
-}
-
-int alloc_pagecache(int fd, size_t size)
-{
- char buf[PAGE_SIZE];
- struct stat st;
- int i;
-
- if (fstat(fd, &st))
- goto cleanup;
-
- size += st.st_size;
-
- if (ftruncate(fd, size))
- goto cleanup;
-
- for (i = 0; i < size; i += sizeof(buf))
- read(fd, buf, sizeof(buf));
-
- return 0;
-
-cleanup:
- return -1;
-}
-
-int alloc_anon(const char *cgroup, void *arg)
-{
- size_t size = (unsigned long)arg;
- char *buf, *ptr;
-
- buf = malloc(size);
- for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
- *ptr = 0;
-
- free(buf);
- return 0;
-}
-
-int is_swap_enabled(void)
-{
- char buf[PAGE_SIZE];
- const char delim[] = "\n";
- int cnt = 0;
- char *line;
-
- if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0)
- return -1;
-
- for (line = strtok(buf, delim); line; line = strtok(NULL, delim))
- cnt++;
-
- return cnt > 1;
-}
-
-int set_oom_adj_score(int pid, int score)
-{
- char path[PATH_MAX];
- int fd, len;
-
- sprintf(path, "/proc/%d/oom_score_adj", pid);
-
- fd = open(path, O_WRONLY | O_APPEND);
- if (fd < 0)
- return fd;
-
- len = dprintf(fd, "%d", score);
- if (len < 0) {
- close(fd);
- return len;
- }
-
- close(fd);
- return 0;
-}
-
int proc_mount_contains(const char *option)
{
char buf[4 * PAGE_SIZE];
diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
index 19b131ee77072..139c870ecc285 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.h
+++ b/tools/testing/selftests/cgroup/cgroup_util.h
@@ -21,6 +21,9 @@ static inline int values_close(long a, long b, int err)
return labs(a - b) <= (a + b) / 100 * err;
}

+extern ssize_t read_text(const char *path, char *buf, size_t max_len);
+extern ssize_t write_text(const char *path, char *buf, ssize_t len);
+
extern int cg_find_unified_root(char *root, size_t len, bool *nsdelegate);
extern char *cg_name(const char *root, const char *name);
extern char *cg_name_indexed(const char *root, const char *name, int index);
@@ -49,11 +52,6 @@ extern int cg_enter_current_thread(const char *cgroup);
extern int cg_run_nowait(const char *cgroup,
int (*fn)(const char *cgroup, void *arg),
void *arg);
-extern int get_temp_fd(void);
-extern int alloc_pagecache(int fd, size_t size);
-extern int alloc_anon(const char *cgroup, void *arg);
-extern int is_swap_enabled(void);
-extern int set_oom_adj_score(int pid, int score);
extern int cg_wait_for_proc_count(const char *cgroup, int count);
extern int cg_killall(const char *cgroup);
int proc_mount_contains(const char *option);
diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
index 16f5d74ae762e..2908f4e0629db 100644
--- a/tools/testing/selftests/cgroup/test_memcontrol.c
+++ b/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -24,6 +24,84 @@
static bool has_localevents;
static bool has_recursiveprot;

+int get_temp_fd(void)
+{
+ return open(".", O_TMPFILE | O_RDWR | O_EXCL);
+}
+
+int alloc_pagecache(int fd, size_t size)
+{
+ char buf[PAGE_SIZE];
+ struct stat st;
+ int i;
+
+ if (fstat(fd, &st))
+ goto cleanup;
+
+ size += st.st_size;
+
+ if (ftruncate(fd, size))
+ goto cleanup;
+
+ for (i = 0; i < size; i += sizeof(buf))
+ read(fd, buf, sizeof(buf));
+
+ return 0;
+
+cleanup:
+ return -1;
+}
+
+int alloc_anon(const char *cgroup, void *arg)
+{
+ size_t size = (unsigned long)arg;
+ char *buf, *ptr;
+
+ buf = malloc(size);
+ for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
+ *ptr = 0;
+
+ free(buf);
+ return 0;
+}
+
+int is_swap_enabled(void)
+{
+ char buf[PAGE_SIZE];
+ const char delim[] = "\n";
+ int cnt = 0;
+ char *line;
+
+ if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0)
+ return -1;
+
+ for (line = strtok(buf, delim); line; line = strtok(NULL, delim))
+ cnt++;
+
+ return cnt > 1;
+}
+
+int set_oom_adj_score(int pid, int score)
+{
+ char path[PATH_MAX];
+ int fd, len;
+
+ sprintf(path, "/proc/%d/oom_score_adj", pid);
+
+ fd = open(path, O_WRONLY | O_APPEND);
+ if (fd < 0)
+ return fd;
+
+ len = dprintf(fd, "%d", score);
+ if (len < 0) {
+ close(fd);
+ return len;
+ }
+
+ close(fd);
+ return 0;
+}
+
/*
* This test creates two nested cgroups with and without enabling
* the memory controller.
--
2.49.0.1015.ga840276032-goog