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

[Pavel Emelyanov]

On 04/07/2016 04:28 PM, Pavel Tikhomirov wrote:
> 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");

You kill this thread right after pre-dump finish, so this thread only works when
the pre-dump is in action. This is quite short period of time, is it enough?

> +	}
> +
> +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
>