On Mon, Apr 14, 2025, James Houghton wrote:
> libcgroup.o is built separately from KVM selftests and cgroup selftests,
> so different compiler flags used by the different selftests will not
> conflict with each other.
This fails to build on some of my systems. And it generates a warning, which
thanks to me building KVM selftests with -Werror, is the only such warning in
all of KVM selftests.
tools/testing/selftests/cgroup/lib/cgroup_util.c:511:17: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
511 | read(fd, buf, sizeof(buf));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/fcntl.h:314,
from tools/testing/selftests/cgroup/lib/cgroup_util.c:6:
In function ‘open’,
inlined from ‘get_temp_fd’ at tools/testing/selftests/cgroup/lib/cgroup_util.c:493:9:
/usr/include/x86_64-linux-gnu/bits/fcntl2.h:50:11: error: call to ‘__open_missing_mode’ declared with attribute error: open with O_CREAT or O_TMPFILE in second argument needs 3 arguments
50 | __open_missing_mode ();
| ^~~~~~~~~~~~~~~~~~~~~~
Given that the code in question has nothing to do with cgroups and is used only
by test_memcontrol.c, my vote is to move it into test_memcontrol.c and let the
cgroups folks sort things out at their leisure (if it even ever becomes an issue
for them).
E.g. slot this is before making cgroup_util.c a library?
--
From: Sean Christopherson <seanjc@xxxxxxxxxx>
Date: Mon, 28 Apr 2025 17:38:14 -0700
Subject: [PATCH] selftests: cgroup: Move memcontrol specific helpers out of
common cgroup_util.c
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.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
tools/testing/selftests/cgroup/cgroup_util.c | 78 -------------------
tools/testing/selftests/cgroup/cgroup_util.h | 5 --
.../selftests/cgroup/test_memcontrol.c | 78 +++++++++++++++++++
3 files changed, 78 insertions(+), 83 deletions(-)
diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 1e2d46636a0c..023a87ff7ebc 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -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 19b131ee7707..bdc50a8e6b85 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.h
+++ b/tools/testing/selftests/cgroup/cgroup_util.h
@@ -49,11 +49,6 @@ 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 16f5d74ae762..5414ca4df24c 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;
+static int get_temp_fd(void)
+{
+ return open(".", O_TMPFILE | O_RDWR | O_EXCL);
+}
+
+static 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;
+}
+
+static 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;
+}
+
+static 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;
+}
+
+static 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.
base-commit: 4a243ec9b255aeb0f033c646148aaf662fd92c64
--
