[PATCH v3] selftests: cgroup/memcontrol: add basic test for socket accounting

From: Mike Rapoport
Date: Tue May 22 2018 - 15:12:20 EST


The test verifies that when there is active TCP connection, the
memory.stat.sock and memory.current values are close.

Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
---
v3 changes:
* added changelog

v2 changes:
* bumped error percentage for comparing memory.current with memory.stat.sock
* added checks that memory.stat.sock == 0 and memory.current >= 0 after TCP
server exits
* simplified error handling

tools/testing/selftests/cgroup/test_memcontrol.c | 193 +++++++++++++++++++++++
1 file changed, 193 insertions(+)

diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
index beae06c9c899..cf0bddc9d271 100644
--- a/tools/testing/selftests/cgroup/test_memcontrol.c
+++ b/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -9,6 +9,12 @@
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <errno.h>

#include "../kselftest.h"
#include "cgroup_util.h"
@@ -772,6 +778,192 @@ static int test_memcg_oom_events(const char *root)
return ret;
}

+struct tcp_server_args {
+ unsigned short port;
+ int ctl[2];
+};
+
+static int tcp_server(const char *cgroup, void *arg)
+{
+ struct tcp_server_args *srv_args = arg;
+ struct sockaddr_in6 saddr = { 0 };
+ socklen_t slen = sizeof(saddr);
+ int sk, client_sk, ctl_fd, yes = 1, ret = -1;
+
+ close(srv_args->ctl[0]);
+ ctl_fd = srv_args->ctl[1];
+
+ saddr.sin6_family = AF_INET6;
+ saddr.sin6_addr = in6addr_any;
+ saddr.sin6_port = htons(srv_args->port);
+
+ sk = socket(AF_INET6, SOCK_STREAM, 0);
+ if (sk < 0)
+ return ret;
+
+ if (setsockopt(sk, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0)
+ goto cleanup;
+
+ if (bind(sk, (struct sockaddr *)&saddr, slen)) {
+ write(ctl_fd, &errno, sizeof(errno));
+ goto cleanup;
+ }
+
+ if (listen(sk, 1))
+ goto cleanup;
+
+ ret = 0;
+ if (write(ctl_fd, &ret, sizeof(ret)) != sizeof(ret)) {
+ ret = -1;
+ goto cleanup;
+ }
+
+ client_sk = accept(sk, NULL, NULL);
+ if (client_sk < 0)
+ goto cleanup;
+
+ ret = -1;
+ for (;;) {
+ uint8_t buf[0x100000];
+
+ if (write(client_sk, buf, sizeof(buf)) <= 0) {
+ if (errno == ECONNRESET)
+ ret = 0;
+ break;
+ }
+ }
+
+ close(client_sk);
+
+cleanup:
+ close(sk);
+ return ret;
+}
+
+static int tcp_client(const char *cgroup, unsigned short port)
+{
+ const char server[] = "localhost";
+ struct addrinfo *ai;
+ char servport[6];
+ int retries = 0x10; /* nice round number */
+ int sk, ret;
+
+ snprintf(servport, sizeof(servport), "%hd", port);
+ ret = getaddrinfo(server, servport, NULL, &ai);
+ if (ret)
+ return ret;
+
+ sk = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+ if (sk < 0)
+ goto free_ainfo;
+
+ ret = connect(sk, ai->ai_addr, ai->ai_addrlen);
+ if (ret < 0)
+ goto close_sk;
+
+ ret = KSFT_FAIL;
+ while (retries--) {
+ uint8_t buf[0x100000];
+ long current, sock;
+
+ if (read(sk, buf, sizeof(buf)) <= 0)
+ goto close_sk;
+
+ current = cg_read_long(cgroup, "memory.current");
+ sock = cg_read_key_long(cgroup, "memory.stat", "sock ");
+
+ if (current < 0 || sock < 0)
+ goto close_sk;
+
+ if (current < sock)
+ goto close_sk;
+
+ if (values_close(current, sock, 10)) {
+ ret = KSFT_PASS;
+ break;
+ }
+ }
+
+close_sk:
+ close(sk);
+free_ainfo:
+ freeaddrinfo(ai);
+ return ret;
+}
+
+/*
+ * This test checks socket memory accounting.
+ * The test forks a TCP server listens on a random port between 1000
+ * and 61000. Once it gets a client connection, it starts writing to
+ * its socket.
+ * The TCP client interleaves reads from the socket with check whether
+ * memory.current and memory.stat.sock are similar.
+ */
+static int test_memcg_sock(const char *root)
+{
+ int bind_retries = 5, ret = KSFT_FAIL, pid, err;
+ unsigned short port;
+ char *memcg;
+
+ memcg = cg_name(root, "memcg_test");
+ if (!memcg)
+ goto cleanup;
+
+ if (cg_create(memcg))
+ goto cleanup;
+
+ while (bind_retries--) {
+ struct tcp_server_args args;
+
+ if (pipe(args.ctl))
+ goto cleanup;
+
+ port = args.port = 1000 + rand() % 60000;
+
+ pid = cg_run_nowait(memcg, tcp_server, &args);
+ if (pid < 0)
+ goto cleanup;
+
+ close(args.ctl[1]);
+ if (read(args.ctl[0], &err, sizeof(err)) != sizeof(err))
+ goto cleanup;
+ close(args.ctl[0]);
+
+ if (!err)
+ break;
+ if (err != EADDRINUSE)
+ goto cleanup;
+
+ waitpid(pid, NULL, 0);
+ }
+
+ if (err == EADDRINUSE) {
+ ret = KSFT_SKIP;
+ goto cleanup;
+ }
+
+ if (tcp_client(memcg, port) != KSFT_PASS)
+ goto cleanup;
+
+ waitpid(pid, &err, 0);
+ if (WEXITSTATUS(err))
+ goto cleanup;
+
+ if (cg_read_long(memcg, "memory.current") < 0)
+ goto cleanup;
+
+ if (cg_read_key_long(memcg, "memory.stat", "sock "))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ cg_destroy(memcg);
+ free(memcg);
+
+ return ret;
+}
+
#define T(x) { x, #x }
struct memcg_test {
int (*fn)(const char *root);
@@ -785,6 +977,7 @@ struct memcg_test {
T(test_memcg_max),
T(test_memcg_oom_events),
T(test_memcg_swap_max),
+ T(test_memcg_sock),
};
#undef T

--
2.7.4