[CRIU] [PATCH CRIU 2/7] pre-dump: add dirty memory statistics logger thread

[Pavel Tikhomirov]

On memory predumping target process is unfreezed so it can change
its memory, criu uses kernel soft-dirty tracking mechanism to find
regions of unchanged memory and can skip dumping unchanged pages
in iterative migration. Introduce dirty_logger_pthread to get
number of dirty memory pages and all pages. Thus we will be
able to analize memory iterative migration flow.

move free_pstree to the end of cr_pre_dump_finish as will need it in
dirty_logger_pthread

Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
---
 criu/Makefile.crtools       |  1 +
 criu/cr-dump.c              | 36 +++++++++++++++++++++++++++++++++++-
 criu/dirty-logger.c         |  6 ++++++
 criu/include/dirty-logger.h |  6 ++++++
 4 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 criu/dirty-logger.c
 create mode 100644 criu/include/dirty-logger.h

diff --git a/criu/Makefile.crtools b/criu/Makefile.crtools
index ef152d2..666a906 100644
--- a/criu/Makefile.crtools
+++ b/criu/Makefile.crtools
@@ -13,6 +13,7 @@ obj-y			+= cr-exec.o
 obj-y			+= cr-restore.o
 obj-y			+= cr-service.o
 obj-y			+= crtools.o
+obj-y			+= dirty-logger.o
 obj-y			+= eventfd.o
 obj-y			+= eventpoll.o
 obj-y			+= fault-injection.o
diff --git a/criu/cr-dump.c b/criu/cr-dump.c
index ade2f31..f188c1e 100644
--- a/criu/cr-dump.c
+++ b/criu/cr-dump.c
@@ -22,6 +22,8 @@
 #include <sched.h>
 #include <sys/resource.h>
 
+#include <pthread.h>
+
 #include "protobuf.h"
 #include "images/fdinfo.pb-c.h"
 #include "images/fs.pb-c.h"
@@ -80,6 +82,7 @@
 #include "seccomp.h"
 #include "seize.h"
 #include "fault-injection.h"
+#include "dirty-logger.h"
 
 #include "asm/dump.h"
 
@@ -1426,15 +1429,25 @@ static int setup_alarm_handler()
 static int cr_pre_dump_finish(struct list_head *ctls, int ret)
 {
 	struct parasite_ctl *ctl, *n;
+	pthread_t dirty_logger;
+	int pthread_ret, arg = 0;
 
 	pstree_switch_state(root_item, TASK_ALIVE);
-	free_pstree(root_item);
 
 	timing_stop(TIME_FROZEN);
 
 	if (ret < 0)
 		goto err;
 
+	if (opts.log_dirty) {
+		pr_info("Start dirty memory logger on pre-dumping tasks' memory\n");
+		pthread_ret = pthread_create(&dirty_logger, NULL, dirty_logger_pthread, (void *)&arg);
+		if (pthread_ret) {
+			pr_err("Pthread creation of dirty_logger_pthread failed: %d\n", pthread_ret);
+			return -1;
+		}
+	}
+
 	pr_info("Pre-dumping tasks' memory\n");
 	list_for_each_entry_safe(ctl, n, ctls, pre_list) {
 		struct page_xfer xfer;
@@ -1477,6 +1490,27 @@ static int cr_pre_dump_finish(struct list_head *ctls, int ret)
 		write_stats(DUMP_STATS);
 		pr_info("Pre-dumping finished successfully\n");
 	}
+
+	if (opts.log_dirty) {
+		pr_info("Stop dirty memory logger\n");
+		pthread_ret = pthread_cancel(dirty_logger);
+		if (pthread_ret && pthread_ret != ESRCH) {
+			pr_err("Pthread cancel of dirty_logger_pthread failed: %d\n", pthread_ret);
+			ret = -1;
+			goto exit;
+		}
+		pthread_ret = pthread_join(dirty_logger, NULL);
+		if (pthread_ret) {
+			pr_perror("Pthread join of dirty_logger_pthread failed: %d\n", pthread_ret);
+			ret = -1;
+			goto exit;
+		}
+		if (arg == -1)
+			pr_perror("Pthread dirty_logger_pthread failed\n");
+	}
+
+exit:
+	free_pstree(root_item);
 	return ret;
 }
 
diff --git a/criu/dirty-logger.c b/criu/dirty-logger.c
new file mode 100644
index 0000000..6620626
--- /dev/null
+++ b/criu/dirty-logger.c
@@ -0,0 +1,6 @@
+#include <pthread.h>
+
+void *dirty_logger_pthread(void *arg)
+{
+	pthread_exit(NULL);
+}
diff --git a/criu/include/dirty-logger.h b/criu/include/dirty-logger.h
new file mode 100644
index 0000000..312c44b
--- /dev/null
+++ b/criu/include/dirty-logger.h
@@ -0,0 +1,6 @@
+#ifndef __CR_DIRTY_LOGGER_H__
+#define __CR_DIRTY_LOGGER_H__
+
+extern void *dirty_logger_pthread(void *arg);
+
+#endif
-- 
1.9.3