Re: [Qemu-devel] [PATCH 1/2] migration/postcopy: reduce one operation to calculate fixup_start_addr

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Wei Yang (richardw.yang@linux.intel.com) wrote:
> Use the same way for run_end to calculate run_start, which saves one
> operation.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/ram.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 410e0f89fe..c4dc36e525 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2884,10 +2884,12 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
>          host_offset = run_start % host_ratio;
>          if (host_offset) {
>              do_fixup = true;
> -            run_start -= host_offset;
> -            fixup_start_addr = run_start;
> -            /* For the next pass */
> -            run_start = run_start + host_ratio;
> +            fixup_start_addr = run_start - host_offset;
> +            /*
> +             * This host page has gone, the next loop iteration starts
> +             * from after the fixup
> +             */
> +            run_start = fixup_start_addr + host_ratio;
>          } else {
>              /* Find the end of this run */
>              unsigned long run_end;
> -- 
> 2.17.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK