Re: [Qemu-devel] [PATCH 01/15] migration: remove last_sent_block from save_page_header

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

* Liang Li (liang.z.li@intel.com) wrote:
> From: Juan Quintela <quintela@redhat.com>
> 
> Compression code (still not on tree) want to call this funtion from
> outside the migration thread, so we can't write to last_sent_block.
> 
> Instead of reverting full patch:
> 
> [PULL 07/11] save_block_hdr: we can recalculate
> 
> Just revert the parts that touch last_sent_block.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>

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

> ---
>  arch_init.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch_init.c b/arch_init.c
> index fcfa328..4c8fcee 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -332,19 +332,14 @@ static size_t save_page_header(QEMUFile *f, RAMBlock *block, ram_addr_t offset)
>  {
>      size_t size;
>  
> -    if (block == last_sent_block) {
> -        offset |= RAM_SAVE_FLAG_CONTINUE;
> -    }
> -
>      qemu_put_be64(f, offset);
>      size = 8;
>  
> -    if (block != last_sent_block) {
> +    if (!(offset & RAM_SAVE_FLAG_CONTINUE)) {
>          qemu_put_byte(f, strlen(block->idstr));
>          qemu_put_buffer(f, (uint8_t *)block->idstr,
>                          strlen(block->idstr));
>          size += 1 + strlen(block->idstr);
> -        last_sent_block = block;
>      }
>      return size;
>  }
> @@ -644,6 +639,10 @@ static int ram_save_page(QEMUFile *f, RAMBlock* block, ram_addr_t offset,
>      XBZRLE_cache_lock();
>  
>      current_addr = block->offset + offset;
> +
> +    if (block == last_sent_block) {
> +        offset |= RAM_SAVE_FLAG_CONTINUE;
> +    }
>      if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
>          if (ret != RAM_SAVE_CONTROL_DELAYED) {
>              if (bytes_xmit > 0) {
> @@ -739,6 +738,7 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
>  
>              /* if page is unmodified, continue to the next */
>              if (pages > 0) {
> +                last_sent_block = block;
>                  break;
>              }
>          }
> -- 
> 1.9.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK