Re: [Qemu-devel] [PATCH v9 35/56] Postcopy: Calculate discard

[Juan Quintela]

"Dr. David Alan Gilbert (git)" <address@hidden> wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
>
> Where postcopy is preceeded by a period of precopy, the destination will
> have received pages that may have been dirtied on the source after the
> page was sent.  The destination must throw these pages away before
> starting it's CPUs.
>
> Calculate list of sent & dirty pages
> Provide helpers on the destination side to discard these.
>
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>

Reviewed-by: Juan Quintela <address@hidden>

But please, send a fix for:

>      return ret;
>  }
>  
> +/**
> + * postcopy_ram_discard_range: Discard a range of memory.
> + * We can assume that if we've been called postcopy_ram_hosttest returned 
> true.
> + *
> + * @mis: Current incoming migration state.
> + * @start, @length: range of memory to discard.
> + *
> + * returns: 0 on success.
> + */
> +int postcopy_ram_discard_range(MigrationIncomingState *mis, uint8_t *start,
> +                               size_t length)
> +{
> +    trace_postcopy_ram_discard_range(start, length);
> +    if (madvise(start, length, MADV_DONTNEED)) {

qemu_madvise(start, length, QEMU_MADV_DONTNEED)