[CRIU] [PATCH] Add test case for code page sharing

[Christopher Covington]

We've observed at least one scenario where processes originally
sharing physical memory no longer do so after dump and restore.
This increases memory usage and degrades performance. Here is a
test case (created outside of the ZDTM framework for expedience)
that demonstrates the issue. The test fails with CRIU 1.4. Run
`make && ./test_sharing.sh` to build and run the test.

Acked-by: Aaron Lindsay <alindsay at qti.qualcomm.com>
Signed-off-by: Christopher Covington <cov at codeaurora.org>

Change-Id: If0cacb7ed8c12c7dee2dff7d6016fbddf1d13157
---
 test/code-sharing/Makefile        | 11 +++++
 test/code-sharing/test_sharing.c  | 90 +++++++++++++++++++++++++++++++++++++++
 test/code-sharing/test_sharing.sh | 63 +++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 test/code-sharing/Makefile
 create mode 100644 test/code-sharing/test_sharing.c
 create mode 100755 test/code-sharing/test_sharing.sh

diff --git a/test/code-sharing/Makefile b/test/code-sharing/Makefile
new file mode 100644
index 0000000..e30d6f3
--- /dev/null
+++ b/test/code-sharing/Makefile
@@ -0,0 +1,11 @@
+OBJS=test_sharing
+
+all: $(OBJS)
+.PHONY: all
+
+run: all
+	./test_sharing.sh
+
+clean:
+	rm -f $(OBJS) test-*.out
+.PHONY: clean
diff --git a/test/code-sharing/test_sharing.c b/test/code-sharing/test_sharing.c
new file mode 100644
index 0000000..43553e3
--- /dev/null
+++ b/test/code-sharing/test_sharing.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <signal.h>
+
+/*
+ * This binary sleeps continuously, but prints the current physical address for
+ * main() to a file (in the current directory, named like test-$pid.out) every
+ * time it receives SIGTERM.
+ */
+
+FILE *out;
+
+int main(int argc, char *argv);
+
+void error(char *error) {
+	fprintf(out, "ERROR %d: %s\n", errno, error);
+	printf("ERROR %d: %s\n", errno, error);
+	fflush(out);
+	exit(1);
+}
+
+void print_pa(int signal) {
+	int fd;
+	uint64_t entry;
+
+	//ensure main()'s page is present
+	fd = open("/proc/self/mem", O_RDONLY);
+	if (!fd)
+		error("Failed to open /proc/self/mem");
+	if (lseek(fd, (unsigned long) &main, SEEK_SET) == -1)
+		error("Failed to seek in /proc/self/mem");
+	if (read(fd, &entry, sizeof(entry)) != sizeof(entry))
+		error("Failed to read in /proc/self/mem");
+	close(fd);
+
+	//read PA for main()
+	fd = open("/proc/self/pagemap", O_RDONLY);
+	if (!fd)
+		error("Failed to open /proc/self/pagemap");
+	if (lseek64(fd, ((long long) &main / getpagesize()) * sizeof(entry), SEEK_SET) == -1)
+		error("Failed to seek in /proc/self/pagemap");
+	if (read(fd, &entry, sizeof(entry)) != sizeof(entry))
+		error("Failed to read in /proc/self/pagemap");
+	close(fd);
+
+	fprintf(out, "PA for main() in pid %d: 0x%" PRIx64 "\n", getpid(), entry & 0x3fffffffffffff);
+	fflush(out);
+}
+
+int main(int argc, char *argv) {
+	char out_filename[50];
+	struct sigaction sig = {
+		.sa_handler = print_pa
+	};
+
+	if (sprintf(out_filename, "test-%d.out", getpid()) < 0) {
+		printf("ERROR: Unable to write log filename\n");
+		return 1;
+	}
+	out = fopen(out_filename, "a");
+	if (!out) {
+		printf("ERROR: Unable to open log file\n");
+		return 1;
+	}
+
+	sigaction(SIGTERM, &sig, NULL);
+
+	while (1) {
+		sleep(1);
+	}
+}
diff --git a/test/code-sharing/test_sharing.sh b/test/code-sharing/test_sharing.sh
new file mode 100755
index 0000000..1c4233b
--- /dev/null
+++ b/test/code-sharing/test_sharing.sh
@@ -0,0 +1,63 @@
+# Copyright (c) 2015, The Linux Foundation. All rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 and
+# only version 2 as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+set -ex
+
+if [[ -f ./test_sharing ]]; then
+  cp ./test_sharing /tmp/test_sharing
+elif [[ ! -f /tmp/test_sharing ]]; then
+  echo "ERROR: Please copy the test_sharing binary from test/code-sharing to" \
+    "/tmp/test_sharing if not running from the build directory"
+  exit 1
+fi
+chmod +x /tmp/test_sharing
+
+# Start pid0 (will never be criu dumped)
+cat /dev/null | setsid /tmp/test_sharing &> /dev/null &
+pid0=$!
+
+# Start pid1 (will be the first process criu dumped)
+cat /dev/null | setsid /tmp/test_sharing &> /dev/null &
+pid1=$!
+
+mkdir /tmp/criudump-$pid1
+criu dump -t $pid1 -v4 -o dump-$pid1.log -D /tmp/criudump-$pid1 || echo "Error: 'criu dump' exited with nonzero exit code!"
+
+# Start pid2 (will be the second process criu dumped)
+cat /dev/null | setsid /tmp/test_sharing &> /dev/null &
+pid2=$!
+
+mkdir /tmp/criudump-$pid2
+criu dump -t $pid2 -v4 -o dump-$pid2.log -D /tmp/criudump-$pid2 || echo "Error: 'criu dump' exited with nonzero exit code!"
+
+criu restore -v2 -d -R -D /tmp/criudump-$pid1
+criu restore -v2 -d -R -D /tmp/criudump-$pid2
+
+# Start pid3 (is not criu dumped)
+cat /dev/null | setsid /tmp/test_sharing &> /dev/null &
+pid3=$!
+
+sleep 1s #ensure pid3 is started before sending SIGTERM
+# Sent SIGTERM to cause all processes to write out the PA of main()
+kill -SIGTERM $pid0 $pid1 $pid2 $pid3
+sleep 1s
+
+set +x
+echo "pid0: $(cat test-$pid0.out)"
+echo "pid1: $(cat test-$pid1.out)"
+echo "pid2: $(cat test-$pid2.out)"
+echo "pid3: $(cat test-$pid3.out)"
+
+echo "We would expect that pid's 0, 1, 2, 3 would all have the same PA, as they" \
+  "would if they were not criu dumped (note that pids 0 and 3 share the same" \
+  "PA since they were not)."
+
+kill -SIGKILL $pid0 $pid1 $pid2 $pid3
-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project