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Date: Thu, 10 May 2018 13:45:49 -0600
From: Shuah Khan <shuah@...nel.org>
To: Roman Gushchin <guro@...com>, Tejun Heo <tj@...nel.org>
Cc: Johannes Weiner <hannes@...xchg.org>,
Michal Hocko <mhocko@...e.com>,
Mike Rapoport <rppt@...ux.vnet.ibm.com>, kernel-team@...com,
linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
Shuah Khan <shuah@...nel.org>
Subject: Re: [PATCH v2] selftests/cgroup: memory controller self-tests
On 05/10/2018 10:37 AM, Roman Gushchin wrote:
> Cgroups are used for controlling the physical resource distribution
> (memory, CPU, io, etc) and often are used as basic building blocks
> for large distributed computing systems. Even small differences
> in the actual behavior may lead to significant incidents.
>
> The codebase is under the active development, which will unlikely
> stop at any time soon. Also it's scattered over different
> kernel subsystems, which makes regressions more probable.
>
> Given that, the lack of any tests is crying.
>
> This patch implements some basic tests for the memory controller,
> as well as a minimal required framework.
> It doesn't pretend for a very good coverage, but pretends
> to be a starting point.
>
> Hopefully, any following significant changes will
> include corresponding tests.
>
> Tests for CPU and io controllers, as well as cgroup core
> are next in the todo list.
>
> Signed-off-by: Roman Gushchin <guro@...com>
> Cc: Tejun Heo <tj@...nel.org>
> Cc: Shuah Khan <shuah@...nel.org>
> Cc: Johannes Weiner <hannes@...xchg.org>
> Cc: Michal Hocko <mhocko@...e.com>
> Cc: Mike Rapoport <rppt@...ux.vnet.ibm.com>
> Cc: kernel-team@...com
> Cc: linux-kselftest@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> ---
> tools/testing/selftests/Makefile | 1 +
> tools/testing/selftests/cgroup/Makefile | 10 +
> tools/testing/selftests/cgroup/cgroup_util.c | 317 ++++++++++
> tools/testing/selftests/cgroup/cgroup_util.h | 40 ++
> tools/testing/selftests/cgroup/test_memcontrol.c | 741 +++++++++++++++++++++++
> 5 files changed, 1109 insertions(+)
> create mode 100644 tools/testing/selftests/cgroup/Makefile
> create mode 100644 tools/testing/selftests/cgroup/cgroup_util.c
> create mode 100644 tools/testing/selftests/cgroup/cgroup_util.h
> create mode 100644 tools/testing/selftests/cgroup/test_memcontrol.c
>
> diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
> index 32aafa92074c..24d0331d6c11 100644
> --- a/tools/testing/selftests/Makefile
> +++ b/tools/testing/selftests/Makefile
> @@ -3,6 +3,7 @@ TARGETS = android
> TARGETS += bpf
> TARGETS += breakpoints
> TARGETS += capabilities
> +TARGETS += cgroup
> TARGETS += cpufreq
> TARGETS += cpu-hotplug
> TARGETS += efivarfs
> diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile
> new file mode 100644
> index 000000000000..f7a31392eb2f
> --- /dev/null
> +++ b/tools/testing/selftests/cgroup/Makefile
> @@ -0,0 +1,10 @@
> +# SPDX-License-Identifier: GPL-2.0
> +CFLAGS += -Wall
> +
> +all:
> +
> +TEST_GEN_PROGS = test_memcontrol
> +
> +include ../lib.mk
> +
> +$(OUTPUT)/test_memcontrol: cgroup_util.c
> diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
> new file mode 100644
> index 000000000000..a938b6c8b55a
> --- /dev/null
> +++ b/tools/testing/selftests/cgroup/cgroup_util.c
> @@ -0,0 +1,317 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#define _GNU_SOURCE
> +
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <linux/limits.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <sys/wait.h>
> +#include <unistd.h>
> +
> +#include "cgroup_util.h"
> +
> +static ssize_t read_text(const char *path, char *buf, size_t max_len)
> +{
> + ssize_t len;
> + int fd;
> +
> + fd = open(path, O_RDONLY);
> + if (fd < 0)
> + return fd;
> +
> + len = read(fd, buf, max_len - 1);
> + if (len < 0)
> + goto out;
> +
> + buf[len] = 0;
> +out:
> + close(fd);
> + return len;
> +}
> +
> +static ssize_t write_text(const char *path, char *buf, size_t len)
> +{
> + int fd;
> +
> + fd = open(path, O_WRONLY | O_APPEND);
> + if (fd < 0)
> + return fd;
> +
> + len = write(fd, buf, len);
> + if (len < 0) {
> + close(fd);
> + return len;
> + }
> +
> + close(fd);
> +
> + return len;
> +}
> +
> +char *cg_name(const char *root, const char *name)
> +{
> + size_t len = strlen(root) + strlen(name) + 2;
> + char *ret = malloc(len);
> +
> + if (name)
> + snprintf(ret, len, "%s/%s", root, name);
> +
> + return ret;
> +}
> +
> +char *cg_name_indexed(const char *root, const char *name, int index)
> +{
> + size_t len = strlen(root) + strlen(name) + 10;
> + char *ret = malloc(len);
> +
> + if (name)
> + snprintf(ret, len, "%s/%s_%d", root, name, index);
> +
> + return ret;
> +}
> +
> +int cg_read(const char *cgroup, const char *control, char *buf, size_t len)
> +{
> + char path[PATH_MAX];
> +
> + snprintf(path, sizeof(path), "%s/%s", cgroup, control);
> +
> + if (read_text(path, buf, len) >= 0)
> + return 0;
> +
> + return -1;
> +}
> +
> +int cg_read_strcmp(const char *cgroup, const char *control,
> + const char *expected)
> +{
> + size_t size = strlen(expected) + 1;
> + char *buf;
> +
> + buf = malloc(size);
> + if (!buf)
> + return -1;
> +
> + if (cg_read(cgroup, control, buf, size))
> + return -1;
> +
> + return strcmp(expected, buf);
> +}
> +
> +int cg_read_strstr(const char *cgroup, const char *control, const char *needle)
> +{
> + char buf[PAGE_SIZE];
> +
> + if (cg_read(cgroup, control, buf, sizeof(buf)))
> + return -1;
> +
> + return strstr(buf, needle) ? 0 : -1;
> +}
> +
> +long cg_read_long(const char *cgroup, const char *control)
> +{
> + char buf[128];
> +
> + if (cg_read(cgroup, control, buf, sizeof(buf)))
> + return -1;
> +
> + return atol(buf);
> +}
> +
> +long cg_read_key_long(const char *cgroup, const char *control, const char *key)
> +{
> + char buf[PAGE_SIZE];
> + char *ptr;
> +
> + if (cg_read(cgroup, control, buf, sizeof(buf)))
> + return -1;
> +
> + ptr = strstr(buf, key);
> + if (!ptr)
> + return -1;
> +
> + return atol(ptr + strlen(key));
> +}
> +
> +int cg_write(const char *cgroup, const char *control, char *buf)
> +{
> + char path[PATH_MAX];
> + size_t len = strlen(buf);
> +
> + snprintf(path, sizeof(path), "%s/%s", cgroup, control);
> +
> + if (write_text(path, buf, len) == len)
> + return 0;
> +
> + return -1;
> +}
> +
> +int cg_find_unified_root(char *root, size_t len)
> +{
> + char buf[10 * PAGE_SIZE];
> + char *fs, *mount, *type;
> + const char delim[] = "\n\t ";
> +
> + if (read_text("/proc/self/mounts", buf, sizeof(buf)) <= 0)
> + return -1;
> +
> + /*
> + * Example:
> + * cgroup /sys/fs/cgroup cgroup2 rw,seclabel,noexec,relatime 0 0
> + */
> + for (fs = strtok(buf, delim); fs; fs = strtok(NULL, delim)) {
> + mount = strtok(NULL, delim);
> + type = strtok(NULL, delim);
> + strtok(NULL, delim);
> + strtok(NULL, delim);
> + strtok(NULL, delim);
> +
> + if (strcmp(fs, "cgroup") == 0 &&
> + strcmp(type, "cgroup2") == 0) {
> + strncpy(root, mount, len);
> + return 0;
> + }
> + }
> +
> + return -1;
> +}
> +
> +int cg_create(const char *cgroup)
> +{
> + return mkdir(cgroup, 0644);
> +}
> +
> +static int cg_killall(const char *cgroup)
> +{
> + char buf[PAGE_SIZE];
> + char *ptr = buf;
> +
> + if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
> + return -1;
> +
> + while (ptr < buf + sizeof(buf)) {
> + int pid = strtol(ptr, &ptr, 10);
> +
> + if (pid == 0)
> + break;
> + if (*ptr)
> + ptr++;
> + else
> + break;
> + if (kill(pid, SIGKILL))
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +int cg_destroy(const char *cgroup)
> +{
> + int ret;
> +
> +retry:
> + ret = rmdir(cgroup);
> + if (ret && errno == EBUSY) {
> + ret = cg_killall(cgroup);
> + if (ret)
> + return ret;
> + usleep(100);
> + goto retry;
> + }
> +
> + if (ret && errno == ENOENT)
> + ret = 0;
> +
> + return ret;
> +}
> +
> +int cg_run(const char *cgroup,
> + int (*fn)(const char *cgroup, void *arg),
> + void *arg)
> +{
> + int pid, retcode;
> +
> + pid = fork();
> + if (pid < 0) {
> + return pid;
> + } else if (pid == 0) {
> + char buf[64];
> +
> + snprintf(buf, sizeof(buf), "%d", getpid());
> + if (cg_write(cgroup, "cgroup.procs", buf))
> + exit(EXIT_FAILURE);
> + exit(fn(cgroup, arg));
> + } else {
> + waitpid(pid, &retcode, 0);
> + if (WIFEXITED(retcode))
> + return WEXITSTATUS(retcode);
> + else
> + return -1;
> + }
> +}
> +
> +int cg_run_nowait(const char *cgroup,
> + int (*fn)(const char *cgroup, void *arg),
> + void *arg)
> +{
> + int pid;
> +
> + pid = fork();
> + if (pid == 0) {
> + char buf[64];
> +
> + snprintf(buf, sizeof(buf), "%d", getpid());
> + if (cg_write(cgroup, "cgroup.procs", buf))
> + exit(EXIT_FAILURE);
> + exit(fn(cgroup, arg));
> + }
> +
> + 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;
> +}
> diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
> new file mode 100644
> index 000000000000..000de075d3d8
> --- /dev/null
> +++ b/tools/testing/selftests/cgroup/cgroup_util.h
> @@ -0,0 +1,40 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#include <stdlib.h>
> +
> +#define PAGE_SIZE 4096
> +
> +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
> +
> +#define MB(x) (x << 20)
> +
> +/*
> + * Checks if two given values differ by less than err% of their sum.
> + */
> +static inline int values_close(long a, long b, int err)
> +{
> + return abs(a - b) <= (a + b) / 100 * err;
> +}
> +
> +extern int cg_find_unified_root(char *root, size_t len);
> +extern char *cg_name(const char *root, const char *name);
> +extern char *cg_name_indexed(const char *root, const char *name, int index);
> +extern int cg_create(const char *cgroup);
> +extern int cg_destroy(const char *cgroup);
> +extern int cg_read(const char *cgroup, const char *control,
> + char *buf, size_t len);
> +extern int cg_read_strcmp(const char *cgroup, const char *control,
> + const char *expected);
> +extern int cg_read_strstr(const char *cgroup, const char *control,
> + const char *needle);
> +extern long cg_read_long(const char *cgroup, const char *control);
> +long cg_read_key_long(const char *cgroup, const char *control, const char *key);
> +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_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);
> diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
> new file mode 100644
> index 000000000000..b6bbc4c1adc3
> --- /dev/null
> +++ b/tools/testing/selftests/cgroup/test_memcontrol.c
> @@ -0,0 +1,741 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#define _GNU_SOURCE
> +
> +#include <linux/limits.h>
> +#include <fcntl.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +
> +#include "../kselftest.h"
> +#include "cgroup_util.h"
> +
> +/*
> + * Can't use KSFT_ values,
> + * because there is no difference between SKIP and PASS values.
> + */
> +enum test_result {
> + TEST_SKIP,
> + TEST_FAIL,
> + TEST_PASS,
> +};
> +
Please check linux-kselftest next - You will see thet SKIP handling
patches in there.
Please clean this up before they get into 4.18-rc1
thanks,
-- Shuah
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