* Wei Yang (richardw.y...@linux.intel.com) wrote:
> When we are not in the last_stage, we need to update the cache if page
> is not the same.
>
> Currently this procedure is scattered in two places and mixed with
> encoding status check.
>
> This patch extract this general step out to make the code a little bit
> easy to read.
>
> Signed-off-by: Wei Yang <richardw.y...@linux.intel.com>
>
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> v2: give more comment on the behavior
> ---
> migration/ram.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index e9b40d636d..17cc9b2b44 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1594,25 +1594,30 @@ static int save_xbzrle_page(RAMState *rs, uint8_t
> **current_data,
> encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf,
> TARGET_PAGE_SIZE, XBZRLE.encoded_buf,
> TARGET_PAGE_SIZE);
> +
> + /*
> + * Update the cache contents, so that it corresponds to the data
> + * sent, in all cases except where we skip the page.
> + */
> + if (!last_stage && encoded_len != 0) {
> + memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
> + /*
> + * In the case where we couldn't compress, ensure that the caller
> + * sends the data from the cache, since the guest might have
> + * changed the RAM since we copied it.
> + */
> + *current_data = prev_cached_page;
> + }
> +
> if (encoded_len == 0) {
> trace_save_xbzrle_page_skipping();
> return 0;
> } else if (encoded_len == -1) {
> trace_save_xbzrle_page_overflow();
> xbzrle_counters.overflow++;
> - /* update data in the cache */
> - if (!last_stage) {
> - memcpy(prev_cached_page, *current_data, TARGET_PAGE_SIZE);
> - *current_data = prev_cached_page;
> - }
> return -1;
> }
>
> - /* we need to update the data in the cache, in order to get the same
> data */
> - if (!last_stage) {
> - memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
> - }
> -
> /* Send XBZRLE based compressed page */
> bytes_xbzrle = save_page_header(rs, rs->f, block,
> offset | RAM_SAVE_FLAG_XBZRLE);
> --
> 2.19.1
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
