"Dr. David Alan Gilbert" <dgilb...@redhat.com> wrote:
> * Juan Quintela (quint...@redhat.com) wrote:
>> This implements the zero page dection and handling.
>>
>> Signed-off-by: Juan Quintela <quint...@redhat.com>
>>
>> ---
>>
>> Add comment for offset (dave)
>> }
>> }
>>
>> + for (int i = 0; i < p->zero_num; i++) {
>> + memset(p->host + p->zero[i], 0, qemu_target_page_size());
>> + }
>> +
>
> On the existing code, it tries to avoid doing the memset if the target
> page size matches; that avoids allocating the zero pages on the
> destination host; should we try and do the same here?
>
> Dave
Hi Dave
That only happens on postcopy.
With precopy we have to do the memset, because we can have:
write non zero to page 50
migrate page 50
write zeros to page 50
Another migration pass
If we don't write here, we have garbage on the page.
Or I am missing something?
Later, Juan.
