Re: [Qemu-devel] [PATCH] ram: Rename RAM_SAVE_FLAG_COMPRESS to RAM_SAVE_FLAG_ZERO

[Peter Xu <peterx@redhat.com>]

On Thu, May 11, 2017 at 05:50:28PM +0200, Juan Quintela wrote:
> Reflects better what it does now, and avoid confussions with
> RAM_SAVE_FLAG_COMPRESS_PAGE.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

> 
> ---
> 
> Hi
> 
> I always forgot the diffe9rent between COMPRESS and COMPRESS_PAGE.
> This patch makes it clean which is which.
> 
> Please, comment.
> 
> Later, Juan.
> 
> 
> ---
>  migration/ram.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 995d1fc..76c118c 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -48,8 +48,14 @@
>  /***********************************************************/
>  /* ram save/restore */
>  
> +/* RAM_SAVE_FLAG_ZERO used to be named RAM_SAVE_FLAG_COMPRESS, it
> + * worked for pages that where filled with the same char.  We switched
> + * it to only search for the zero value.  And to avoid confusion with
> + * RAM_SSAVE_FLAG_COMPRESS_PAGE just rename it.
> + */
> +
>  #define RAM_SAVE_FLAG_FULL     0x01 /* Obsolete, not used anymore */
> -#define RAM_SAVE_FLAG_COMPRESS 0x02
> +#define RAM_SAVE_FLAG_ZERO     0x02
>  #define RAM_SAVE_FLAG_MEM_SIZE 0x04
>  #define RAM_SAVE_FLAG_PAGE     0x08
>  #define RAM_SAVE_FLAG_EOS      0x10
> @@ -746,7 +752,7 @@ static int save_zero_page(RAMState *rs, RAMBlock *block, ram_addr_t offset,
>      if (is_zero_range(p, TARGET_PAGE_SIZE)) {
>          rs->zero_pages++;
>          rs->bytes_transferred +=
> -            save_page_header(rs, rs->f, block, offset | RAM_SAVE_FLAG_COMPRESS);
> +            save_page_header(rs, rs->f, block, offset | RAM_SAVE_FLAG_ZERO);
>          qemu_put_byte(rs->f, 0);
>          rs->bytes_transferred += 1;
>          pages = 1;
> @@ -2406,7 +2412,7 @@ static int ram_load_postcopy(QEMUFile *f)
>  
>          trace_ram_load_postcopy_loop((uint64_t)addr, flags);
>          place_needed = false;
> -        if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE)) {
> +        if (flags & (RAM_SAVE_FLAG_ZERO | RAM_SAVE_FLAG_PAGE)) {
>              block = ram_block_from_stream(f, flags);
>  
>              host = host_from_ram_block_offset(block, addr);
> @@ -2453,7 +2459,7 @@ static int ram_load_postcopy(QEMUFile *f)
>          last_host = host;
>  
>          switch (flags & ~RAM_SAVE_FLAG_CONTINUE) {
> -        case RAM_SAVE_FLAG_COMPRESS:
> +        case RAM_SAVE_FLAG_ZERO:
>              ch = qemu_get_byte(f);
>              memset(page_buffer, ch, TARGET_PAGE_SIZE);
>              if (ch) {
> @@ -2542,7 +2548,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
>          flags = addr & ~TARGET_PAGE_MASK;
>          addr &= TARGET_PAGE_MASK;
>  
> -        if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE |
> +        if (flags & (RAM_SAVE_FLAG_ZERO | RAM_SAVE_FLAG_PAGE |
>                       RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) {
>              RAMBlock *block = ram_block_from_stream(f, flags);
>  
> @@ -2604,7 +2610,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
>              }
>              break;
>  
> -        case RAM_SAVE_FLAG_COMPRESS:
> +        case RAM_SAVE_FLAG_ZERO:
>              ch = qemu_get_byte(f);
>              ram_handle_compressed(host, ch, TARGET_PAGE_SIZE);
>              break;
> -- 
> 2.9.3
> 

-- 
Peter Xu