[PATCH v3 4/4] mm, shmem, selftests: add tmpfs memcg= mount option tests

Mina Almasry
2021-11-11T23:42:03Z

Signed-off-by: Mina Almasry <almasrymina-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>

Cc: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
Cc: Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org>
Cc: Greg Thelen <gthelen-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Vladimir Davydov <vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Muchun Song <songmuchun-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>
Cc: riel-ebMLmSuQjDVBDgjK7y7TUQ@public.gmane.org
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org

---
tools/testing/selftests/vm/.gitignore | 1 +
tools/testing/selftests/vm/mmap_write.c | 103 ++++++++++++++++++++++
tools/testing/selftests/vm/tmpfs-memcg.sh | 91 +++++++++++++++++++
3 files changed, 195 insertions(+)
create mode 100644 tools/testing/selftests/vm/mmap_write.c
create mode 100755 tools/testing/selftests/vm/tmpfs-memcg.sh

diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore
index 2e7e86e852828..cb229974c5f15 100644
--- a/tools/testing/selftests/vm/.gitignore
+++ b/tools/testing/selftests/vm/.gitignore
@@ -19,6 +19,7 @@ madv_populate
userfaultfd
mlock-intersect-test
mlock-random-test
+mmap_write
virtual_address_range
gup_test
va_128TBswitch
diff --git a/tools/testing/selftests/vm/mmap_write.c b/tools/testing/selftests/vm/mmap_write.c
new file mode 100644
index 0000000000000..88a8468f2128c
--- /dev/null
+++ b/tools/testing/selftests/vm/mmap_write.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This program faults memory in tmpfs
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/shm.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+/* Global definitions. */
+
+/* Global variables. */
+static const char *self;
+static char *shmaddr;
+static int shmid;
+
+/*
+ * Show usage and exit.
+ */
+static void exit_usage(void)
+{
+ printf("Usage: %s -p <path to tmpfs file> -s <size to map>\n", self);
+ exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+ int fd = 0;
+ int key = 0;
+ int *ptr = NULL;
+ int c = 0;
+ int size = 0;
+ char path[256] = "";
+ int want_sleep = 0, private = 0;
+ int populate = 0;
+ int write = 0;
+ int reserve = 1;
+
+ /* Parse command-line arguments. */
+ setvbuf(stdout, NULL, _IONBF, 0);
+ self = argv[0];
+
+ while ((c = getopt(argc, argv, ":s:p:")) != -1) {
+ switch (c) {
+ case 's':
+ size = atoi(optarg);
+ break;
+ case 'p':
+ strncpy(path, optarg, sizeof(path));
+ break;
+ default:
+ errno = EINVAL;
+ perror("Invalid arg");
+ exit_usage();
+ }
+ }
+
+ printf("%s\n", path);
+ if (strncmp(path, "", sizeof(path)) != 0) {
+ printf("Writing to this path: %s\n", path);
+ } else {
+ errno = EINVAL;
+ perror("path not found");
+ exit_usage();
+ }
+
+ if (size != 0) {
+ printf("Writing this size: %d\n", size);
+ } else {
+ errno = EINVAL;
+ perror("size not found");
+ exit_usage();
+ }
+
+ fd = open(path, O_CREAT | O_RDWR, 0777);
+ if (fd == -1)
+ err(1, "Failed to open file.");
+
+ if (ftruncate(fd, size))
+ err(1, "failed to ftruncate %s", path);
+
+ ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ if (ptr == MAP_FAILED) {
+ close(fd);
+ err(1, "Error mapping the file");
+ }
+
+ printf("Writing to memory.\n");
+ memset(ptr, 1, size);
+ printf("Done writing to memory.\n");
+ close(fd);
+
+ return 0;
+}
diff --git a/tools/testing/selftests/vm/tmpfs-memcg.sh b/tools/testing/selftests/vm/tmpfs-memcg.sh
new file mode 100755
index 0000000000000..30da2fad06357
--- /dev/null
+++ b/tools/testing/selftests/vm/tmpfs-memcg.sh
@@ -0,0 +1,91 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+CGROUP_PATH=/dev/cgroup/memory/tmpfs-memcg-test
+
+function cleanup() {
+ rm -rf /mnt/tmpfs/*
+ umount /mnt/tmpfs
+ rm -rf /mnt/tmpfs
+
+ rmdir $CGROUP_PATH
+
+ echo CLEANUP DONE
+}
+
+function setup() {
+ mkdir -p $CGROUP_PATH
+ echo $((10 * 1024 * 1024)) > $CGROUP_PATH/memory.limit_in_bytes
+ echo 0 > $CGROUP_PATH/cpuset.cpus
+ echo 0 > $CGROUP_PATH/cpuset.mems
+
+ mkdir -p /mnt/tmpfs
+
+ echo SETUP DONE
+}
+
+function expect_equal() {
+ local expected="$1"
+ local actual="$2"
+ local error="$3"
+
+ if [[ "$actual" != "$expected" ]]; then
+ echo "expected ($expected) != actual ($actual): $3" >&2
+ cleanup
+ exit 1
+ fi
+}
+
+function expect_ge() {
+ local expected="$1"
+ local actual="$2"
+ local error="$3"
+
+ if [[ "$actual" -lt "$expected" ]]; then
+ echo "expected ($expected) < actual ($actual): $3" >&2
+ cleanup
+ exit 1
+ fi
+}
+
+cleanup
+setup
+
+mount -t tmpfs -o memcg=$CGROUP_PATH tmpfs /mnt/tmpfs
+
+TARGET_MEMCG_USAGE=$(cat $CGROUP_PATH/memory.usage_in_bytes)
+expect_equal 0 "$TARGET_MEMCG_USAGE" "Before echo, memcg usage should be 0"
+
+# Echo to allocate a page in the tmpfs
+echo
+echo
+echo hello > /mnt/tmpfs/test
+TARGET_MEMCG_USAGE=$(cat $CGROUP_PATH/memory.usage_in_bytes)
+expect_ge 4096 "$TARGET_MEMCG_USAGE" "After echo, memcg usage should be greater than 4096"
+echo "Echo test succeeded"
+
+echo
+echo
+tools/testing/selftests/vm/mmap_write -p /mnt/tmpfs/test -s $((1 * 1024 * 1024))
+TARGET_MEMCG_USAGE=$(cat $CGROUP_PATH/memory.usage_in_bytes)
+expect_ge $((1 * 1024 * 1024)) "$TARGET_MEMCG_USAGE" "After echo, memcg usage should greater than 1MB"
+echo "Write succeeded"
+
+# OOM the remote container on pagefault.
+echo
+echo
+echo "OOMing the remote container using pagefault."
+echo "This will take a long time because the kernel goes through reclaim retries,"
+echo "but should eventually be OOM-killed by 'Out of memory (Killing remote allocating task)'"
+tools/testing/selftests/vm/mmap_write -p /mnt/tmpfs/test -s $((11 * 1024 * 1024))
+
+# OOM the remote container on non pagefault.
+echo
+echo
+echo "OOMing the remote container using cat (non-pagefault)"
+echo "This will take a long time because the kernel goes through reclaim retries,"
+echo "but should eventually the cat command should receive an ENOMEM"
+cat /dev/random > /mnt/tmpfs/random
+
+cleanup
+echo SUCCESS