[CRIU] [PATCH 3/7] Merging splice and read modes of pre-dump

[Andrei Vagin]

On Wed, Aug 21, 2019 at 04:36:58AM +0530, Abhishek Dubey wrote:
> Invoke appropriate pre-dump algorithm,
> as per --pre-dump-mode option supplied.
> 
> Default pre-dump mode is: splice
> 
> Signed-off-by: Abhishek Dubey <dubeyabhishek777 at gmail.com>
> ---
>  criu/cr-dump.c            | 13 +++++++++++--
>  criu/include/cr_options.h |  5 +++++
>  criu/include/mem.h        |  2 +-
>  3 files changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/criu/cr-dump.c b/criu/cr-dump.c
> index e070b8b..9baf7cf 100644
> --- a/criu/cr-dump.c
> +++ b/criu/cr-dump.c
> @@ -1189,7 +1189,9 @@ static int pre_dump_one_task(struct pstree_item *item, InventoryEntry *parent_ie
>  
>  	item->pid->ns[0].virt = misc.pid;
>  
> -	mdc.pre_dump = true;
> +	mdc.pre_dump = (opts.pre_dump_mode == PRE_DUMP_READ) ?
> +						  PRE_DUMP_READ
> +						: PRE_DUMP_SPLICE;

Could you explain what is going on here? Should we return an error if
opts.pre_dump_mode isn't equal to PRE_DUMP_READ or PRE_DUMP_SPLICE?

>  	mdc.lazy = false;
>  	mdc.stat = NULL;
>  	mdc.parent_ie = parent_ie;
> @@ -1513,7 +1515,14 @@ static int cr_pre_dump_finish(int status)
>  			goto err;
>  
>  		mem_pp = dmpi(item)->mem_pp;
> -		ret = page_xfer_dump_pages(&xfer, mem_pp);
> +
> +		if (opts.pre_dump_mode == PRE_DUMP_READ) {
> +			timing_stop(TIME_MEMWRITE);
> +			ret = page_xfer_predump_pages(item->pid->real,
> +							&xfer, mem_pp);
> +		}
> +		else
> +			ret = page_xfer_dump_pages(&xfer, mem_pp);
>  
>  		xfer.close(&xfer);
>  
> diff --git a/criu/include/cr_options.h b/criu/include/cr_options.h
> index c519c74..6b84e31 100644
> --- a/criu/include/cr_options.h
> +++ b/criu/include/cr_options.h
> @@ -39,6 +39,11 @@ struct cg_root_opt {
>  };
>  
>  /*
> + * Pre-dump variants
> + */
> +#define PRE_DUMP_SPLICE	1		/* Pre-dump using parasite */
> +#define PRE_DUMP_READ		2		/* Pre-dump using process_vm_readv syscall */
> +/*
>   * Cgroup management options.
>   */
>  #define CG_MODE_IGNORE		(0u << 0)	/* Zero is important here */
> diff --git a/criu/include/mem.h b/criu/include/mem.h
> index 251cb1a..74c2803 100644
> --- a/criu/include/mem.h
> +++ b/criu/include/mem.h
> @@ -15,7 +15,7 @@ struct pstree_item;
>  struct vma_area;
>  
>  struct mem_dump_ctl {
> -	bool			pre_dump;
> +	int			pre_dump;
>  	bool			lazy;
>  	struct proc_pid_stat	*stat;
>  	InventoryEntry		*parent_ie;
> -- 
> 2.7.4
>