Re: [PATCH v3 09/13] migration/ram: Consolidate variable reset after placement in ram_load_postcopy()

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

* David Hildenbrand (david@redhat.com) wrote:
> Let's consolidate resetting the variables.
> 
> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> Cc: Juan Quintela <quintela@redhat.com>
> Cc: Peter Xu <peterx@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Thanks, I think that's actually fixing a case where huge zero pages
weren't placed as zero pages?

Dave

> ---
>  migration/ram.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index f815f4e532..1a5ff07997 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -3126,7 +3126,7 @@ static int ram_load_postcopy(QEMUFile *f)
>      /* Temporary page that is later 'placed' */
>      void *postcopy_host_page = mis->postcopy_tmp_page;
>      void *host_page = NULL;
> -    bool all_zero = false;
> +    bool all_zero = true;
>      int target_pages = 0;
>  
>      while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
> @@ -3152,7 +3152,6 @@ static int ram_load_postcopy(QEMUFile *f)
>          addr &= TARGET_PAGE_MASK;
>  
>          trace_ram_load_postcopy_loop((uint64_t)addr, flags);
> -        place_needed = false;
>          if (flags & (RAM_SAVE_FLAG_ZERO | RAM_SAVE_FLAG_PAGE |
>                       RAM_SAVE_FLAG_COMPRESS_PAGE)) {
>              block = ram_block_from_stream(f, flags);
> @@ -3180,9 +3179,7 @@ static int ram_load_postcopy(QEMUFile *f)
>               */
>              page_buffer = postcopy_host_page +
>                            host_page_offset_from_ram_block_offset(block, addr);
> -            /* If all TP are zero then we can optimise the place */
>              if (target_pages == 1) {
> -                all_zero = true;
>                  host_page = host_page_from_ram_block_offset(block, addr);
>              } else if (host_page != host_page_from_ram_block_offset(block,
>                                                                      addr)) {
> @@ -3199,7 +3196,6 @@ static int ram_load_postcopy(QEMUFile *f)
>               */
>              if (target_pages == (block->page_size / TARGET_PAGE_SIZE)) {
>                  place_needed = true;
> -                target_pages = 0;
>              }
>              place_source = postcopy_host_page;
>          }
> @@ -3276,6 +3272,10 @@ static int ram_load_postcopy(QEMUFile *f)
>                  ret = postcopy_place_page(mis, host_page, place_source,
>                                            block);
>              }
> +            place_needed = false;
> +            target_pages = 0;
> +            /* Assume we have a zero page until we detect something different */
> +            all_zero = true;
>          }
>      }
>  
> -- 
> 2.24.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK