Re: [Qemu-devel] [PATCHv4] block-migration: efficiently encode zero blocks

[Stefan Hajnoczi <stefanha@gmail.com>]

On Thu, Jul 18, 2013 at 09:48:50AM +0200, Peter Lieven wrote:
> this patch adds a efficient encoding for zero blocks by
> adding a new flag indicating a block is completely zero.
> 
> additionally bdrv_write_zeros() is used at the destination
> to efficiently write these zeroes. depending on the implementation
> this avoids that the destination target gets fully provisioned.
> 
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
> 
> v3->v4:
>  - rebased to current master
>  - stashed migrate_zero_blocks in BlkMigState.
>  - added additional comment in qapi-schema.json where to
>    enable the capability.
>  - added comment in the commit message about the benefit
>    of using bdrv_write_zeroes().
> 
> v2->v3:
>  - changed type of flags in blk_send() from int to uint64_t
>  - added migration capability setting to enable sending
>    of zero blocks.
> 
>  block-migration.c             |   32 ++++++++++++++++++++++++++------
>  include/migration/migration.h |    1 +
>  migration.c                   |    9 +++++++++
>  qapi-schema.json              |    8 +++++++-
>  4 files changed, 43 insertions(+), 7 deletions(-)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan