Liang Li <liang.z...@intel.com> wrote:
> Add the code to create and destroy the multiple threads those will
> be used to do data compression. Left some functions empty to keep
> clearness, and the code will be added later.
>
> Signed-off-by: Liang Li <liang.z...@intel.com>
> Signed-off-by: Yang Zhang <yang.z.zh...@intel.com>
> Reviewed-by: Dr.David Alan Gilbert <dgilb...@redhat.com>
And here I am again.
Reviewing patch 8, I found that we need to fix some things here.
> +static int ram_save_compressed_page(QEMUFile *f, RAMBlock *block,
> + ram_addr_t offset, bool last_stage)
> +{
> + int bytes_sent = -1;
> +
> + /* To be done*/
> +
> + return bytes_sent;
> +}
We have three return values, here, that are not the same that for normal
pages
0: this is the 1st page for a particular thread, nothing to sent yet
n > 0: we are sending the previous compresed page for the choosen
thread
Notice that the only way that ram_save_page() can return 0 is for xbzrle
when a page has modified but it has exactly the same value that before.
(it can have been modified twice, +1, -1 or whatever)
Notice that ram_save_page() can only return 0 (duplicate page) or > 0
(real size written)
> +
> /*
> * ram_find_and_save_block: Finds a page to send and sends it to f
> *
> @@ -679,7 +751,12 @@ static int ram_find_and_save_block(QEMUFile *f, bool
> last_stage)
> ram_bulk_stage = false;
> }
> } else {
> - bytes_sent = ram_save_page(f, block, offset, last_stage);
> + if (migrate_use_compression()) {
> + bytes_sent = ram_save_compressed_page(f, block, offset,
> + last_stage);
> + } else {
> + bytes_sent = ram_save_page(f, block, offset, last_stage);
> + }
I need more context, this is the corrent code
} else {
bytes_sent = ram_save_page(f, block, offset, last_stage);
/* if page is unmodified, continue to the next */
if (bytes_sent > 0) {
last_sent_block = block;
break;
}
}
And we should change to:
} else if (migrate_use_compression()) {
bytes_sent = ram_save_compressed_page(f, block, offset,
last_stage);
last_sent_block = block;
break;
} else {
bytes_sent = ram_save_page(f, block, offset, last_stage);
/* if page is unmodified, continue to the next */
if (bytes_sent > 0) {
last_sent_block = block;
break;
}
}
This would mean that we don't need to arrange for the zero byte return
on qemu.
