[Qemu-devel] Re: [PATCH 1/3] stop dirty tracking just at the end of migration

[Yaniv Kamay <ykamay@redhat.com>]

We need to update dirty map before ram_save_block() loop.

Glauber Costa wrote:
> If there is still work to do, it is not safe to assume we
> can end the dirty tracking. Specifically, kvm can update the dirty
> tracking log inside ram_save_block(), leaving pages still out of sync
> if we go with the current code.
>
> Based on a patch by Yaniv Kamay
>
> Signed-off-by: Glauber Costa <glommer@redhat.com>
> CC: Yaniv Kamay <ykamay@redhat.com>
> CC: Dor Laor <dlaor@redhat.com>
> ---
>  vl.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/vl.c b/vl.c
> index 5e6c621..1626f8a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3249,10 +3249,10 @@ static int ram_save_live(QEMUFile *f, int stage, void *opaque)
>      /* try transferring iterative blocks of memory */
>  
>      if (stage == 3) {
> -        cpu_physical_memory_set_dirty_tracking(0);
>  
>          /* flush all remaining blocks regardless of rate limiting */
>          while (ram_save_block(f) != 0);
> +        cpu_physical_memory_set_dirty_tracking(0);
>      }
>  
>      qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
>