tests: add /proc/pressure/* virtualization tests

Signed-off-by: Alexander Mikhalitsyn <[email protected]>

Author: mihalicyn

tests/meson.build

@@ -145,3 +145,10 @@ test_programs += executable(
     include_directories: config_include,
     install: false,
     build_by_default: want_tests != false)
+
+test_programs += executable(
+    'test-psi-triggers-poll',
+    'test-psi-triggers-poll.c',
+    include_directories: config_include,
+    install: false,
+    build_by_default: want_tests != false)

tests/test-psi-triggers-poll.c

@@ -0,0 +1,88 @@
+/* Borrowed from https://www.kernel.org/doc/Documentation/accounting/psi.rst */
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <poll.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#define WAIT_EVENTS_NUM 4
+
+/*
+* Monitor cpu partial stall with 2s tracking window size
+* and 20ms threshold.
+*/
+int main(int argc, char **argv) {
+	const char trig[] = "some 20000 2000000";
+	struct pollfd fds;
+	int n;
+	char *path;
+	size_t len;
+	int events_cnt = 0;
+
+	if (geteuid() != 0) {
+		fprintf(stderr, "Run me as root\n");
+		exit(1);
+	}
+
+	if (argc != 2)  {
+		fprintf(stderr, "Usage: %s [lxcfs_mount_path]\n", argv[0]);
+		exit(1);
+	}
+
+	len = strlen(argv[1]) + strlen("/proc/pressure/cpu") + 1;
+	path = alloca(len);
+	snprintf(path, len, "%s/proc/pressure/cpu", argv[1]);
+	fds.fd = open(path, O_RDWR | O_NONBLOCK);
+	if (fds.fd < 0) {
+		printf("%s open error: %s\n", path, strerror(errno));
+		return 1;
+	}
+	fds.events = POLLPRI;
+
+	if (write(fds.fd, trig, strlen(trig) + 1) < 0) {
+		printf("/proc/pressure/cpu write error: %s\n",
+			strerror(errno));
+		return 1;
+	}
+
+	printf("waiting for events...\n");
+	time_t t1 = time(NULL);
+	while (1) {
+		/* test code in proc_fuse.c poll_thread() generates 1 event per second */
+		n = poll(&fds, 1, 3 * 1000);
+		if (n < 0) {
+			printf("poll error: %s\n", strerror(errno));
+			return 1;
+		}
+		if (n == 0) {
+			printf("timeout\n");
+			return 1;
+		}
+		if (fds.revents & POLLERR) {
+			printf("got POLLERR, event source is gone\n");
+			return 1;
+		}
+		if (fds.revents & POLLPRI) {
+			printf("event triggered!\n");
+			events_cnt++;
+			if (events_cnt == WAIT_EVENTS_NUM)
+				break;
+		} else {
+			printf("unknown event received: 0x%x\n", fds.revents);
+			return 1;
+		}
+	}
+	time_t t2 = time(NULL);
+
+	printf("events_cnt = %d time diff = %ld\n", events_cnt, (long)(t2 - t1));
+	/* events frequency is 1 HZ, so we can expect that difference <= 1 */
+	if (labs((long)(t2 - t1) - events_cnt) > 1) {
+		printf("| (t2 - t1) - events_cnt | > 1 while should be <= 1\n");
+		return 1;
+	}
+
+	return 0;
+}

tests/test_proc.in

@@ -92,4 +92,7 @@ echo "==> Testing /proc/stat"
 echo "==> Testing /proc/meminfo"
 grep -q "^MemTotal.*65536 kB$" ${LXCFSDIR}/proc/meminfo
 
+echo "==> Testing /proc/pressure/{cpu, io, memory}"
+{{LXCFS_BUILD_ROOT}}/tests/test-psi-triggers-poll ${LXCFSDIR}
+
 PASS=1