Re: [PATCH v9 09/25] tools/libx{l, c}: introduce should_checkpoint callback

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Dec 30, 2015 at 10:37:39AM +0800, Wen Congyang wrote:
> Under COLO, we are doing checkpoint on demand, if this
> callback returns 1, we will take another checkpoint.

So 1 means OK.

> 0 indicates unexpected error.

Why not return an error?
> 
> Signed-off-by: Yang Hongyang <hongyang.yang@easystack.cn>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>  tools/libxc/include/xenguest.h     | 18 ++++++++++++++++++
>  tools/libxl/libxl_save_msgs_gen.pl |  7 ++++---
>  2 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/libxc/include/xenguest.h b/tools/libxc/include/xenguest.h
> index bd133af..88d6e13 100644
> --- a/tools/libxc/include/xenguest.h
> +++ b/tools/libxc/include/xenguest.h
> @@ -62,6 +62,15 @@ struct save_callbacks {
>       * 1: take another checkpoint */
>      int (*checkpoint)(void* data);
>  
> +    /*
> +     * Called after the checkpoint callback.
> +     *
> +     * returns:
> +     * 0: terminate checkpointing gracefully

checkpointing terminated gracefully

Why not return -EXX instead ?

> +     * 1: take another checkpoint