[CRIU] [PATCH v4 07/12] criu: page-xfer: add ability to skip writing lazy pages

[Pavel Emelyanov]

On 06/06/2016 09:27 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
> ---
>  criu/cr-dump.c           | 2 +-
>  criu/include/page-xfer.h | 2 +-
>  criu/mem.c               | 2 +-
>  criu/page-xfer.c         | 4 +++-
>  criu/shmem.c             | 2 +-
>  5 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/criu/cr-dump.c b/criu/cr-dump.c
> index 6648dd4..2d529fd 100644
> --- a/criu/cr-dump.c
> +++ b/criu/cr-dump.c
> @@ -1430,7 +1430,7 @@ static int cr_pre_dump_finish(struct list_head *ctls, int ret)
>  		if (ret < 0)
>  			goto err;
>  
> -		ret = page_xfer_dump_pages(&xfer, ctl->mem_pp, 0);
> +		ret = page_xfer_dump_pages(&xfer, ctl->mem_pp, 0, true);
>  
>  		xfer.close(&xfer);
>  
> diff --git a/criu/include/page-xfer.h b/criu/include/page-xfer.h
> index 8492daa..fb222c3 100644
> --- a/criu/include/page-xfer.h
> +++ b/criu/include/page-xfer.h
> @@ -38,7 +38,7 @@ struct page_xfer {
>  extern int open_page_xfer(struct page_xfer *xfer, int fd_type, long id);
>  struct page_pipe;
>  extern int page_xfer_dump_pages(struct page_xfer *, struct page_pipe *,
> -				unsigned long off);
> +				unsigned long off, bool dump_lazy);
>  extern int connect_to_page_server(void);
>  extern int disconnect_from_page_server(void);
>  
> diff --git a/criu/mem.c b/criu/mem.c
> index a44ad69..66ca227 100644
> --- a/criu/mem.c
> +++ b/criu/mem.c
> @@ -254,7 +254,7 @@ static int dump_pages(struct page_pipe *pp, struct parasite_ctl *ctl,
>  	 */
>  	if (xfer) {
>  		timing_start(TIME_MEMWRITE);
> -		ret = page_xfer_dump_pages(xfer, pp, 0);
> +		ret = page_xfer_dump_pages(xfer, pp, 0, true);
>  		timing_stop(TIME_MEMWRITE);
>  	}
>  
> diff --git a/criu/page-xfer.c b/criu/page-xfer.c
> index 6561b0a..786516e 100644
> --- a/criu/page-xfer.c
> +++ b/criu/page-xfer.c
> @@ -321,7 +321,7 @@ int open_page_xfer(struct page_xfer *xfer, int fd_type, long id)
>  }
>  
>  int page_xfer_dump_pages(struct page_xfer *xfer, struct page_pipe *pp,
> -		unsigned long off)
> +			 unsigned long off, bool dump_lazy)
>  {
>  	struct page_pipe_buf *ppb;
>  	struct iovec *hole = NULL;
> @@ -359,6 +359,8 @@ int page_xfer_dump_pages(struct page_xfer *xfer, struct page_pipe *pp,
>  
>  			if (xfer->write_pagemap(xfer, iov))
>  				return -1;
> +			if (!dump_lazy && ppb->flags & PPB_LAZY)
> +				continue;

I have a question here -- if page_xfer_dump_pages sends a pagemap the receiver
would expect the subsequent pages on the socket, but instead, it _may_ receive
next pagemap if the previous one was lazy. How it this handled?

>  			if (xfer->write_pages(xfer, ppb->p[0], iov->iov_len))
>  				return -1;
>  		}
> diff --git a/criu/shmem.c b/criu/shmem.c
> index d9dd405..19d5339 100644
> --- a/criu/shmem.c
> +++ b/criu/shmem.c
> @@ -539,7 +539,7 @@ static int dump_pages(struct page_pipe *pp, struct page_xfer *xfer, void *addr)
>  			return -1;
>  		}
>  
> -	return page_xfer_dump_pages(xfer, pp, (unsigned long)addr);
> +	return page_xfer_dump_pages(xfer, pp, (unsigned long)addr, true);
>  }
>  
>  static int dump_one_shmem(struct shmem_info *si)
>