Re: [Qemu-devel] [PATCH v3 05/10] migration: move handle of zero page to the thread

[Peter Xu]

On Tue, Aug 07, 2018 at 05:12:04PM +0800, address@hidden wrote:
> From: Xiao Guangrong <address@hidden>
> 
> Detecting zero page is not a light work, moving it to the thread to
> speed the main thread up, btw, handling ram_release_pages() for the
> zero page is moved to the thread as well
> 
> Signed-off-by: Xiao Guangrong <address@hidden>
> ---

[...]

> @@ -2239,17 +2290,10 @@ static int ram_save_target_page(RAMState *rs, 
> PageSearchStatus *pss,
>      }
>  
>      /*
> -     * Make sure the first page is sent out before other pages.
> -     *
> -     * we post it as normal page as compression will take much
> -     * CPU resource.
> +     * do not use multifd for compression as the first page in the new
> +     * block should be posted out before sending the compressed page
>       */
> -    if (block == rs->last_sent_block && save_page_use_compression(rs)) {
> -        res = compress_page_with_multi_thread(rs, block, offset);
> -        if (res > 0) {
> -            return res;
> -        }
> -    } else if (migrate_use_multifd()) {
> +    if (!save_page_use_compression(rs) && migrate_use_multifd()) {

Not related to this patch: I think we should just disallow user to
specify both compression and multifd together.  I vaguely remembered
that I left a comment somewhere in the multifd series but it must have
fallen throw the cracks...  Anyway it's not related to this patch:

Reviewed-by: Peter Xu <address@hidden>

Thanks,

>          return ram_save_multifd_page(rs, block, offset);
>      }
>  
> -- 
> 2.14.4
> 

-- 
Peter Xu