[CRIU] [PATCH v4 07/12] criu: page-xfer: add ability to skip writing lazy pages

[Mike Rapoport]

On Thu, Jun 9, 2016 at 6:05 PM, Pavel Emelyanov <xemul at virtuozzo.com> wrote:
> On 06/09/2016 05:18 PM, Mike Rapoport wrot
>>>
>>> OK, this creates ... broken pagemap/pages image set, as pagemap is present,
>>> but the respective page-set is not :( Can we add optional bool lazy bit
>>> for this?
>>
>> I'd add entire 'u32 flags' for upward compatibility :)
>
> In protobuf bools work just fine :)
>
>>> AFAIU the restore side reads the pagemap and understands that
>>> it's lazy by looking at VMA, does it?
>>
>> Yep, the restore side reads pagemap, checks if the vma can be lazy and
>> skips the pages. The page read has a hack to avoid lseek of pages.img.
>> The whole think is kinda hackish...
>
> Indeed :) Let's try to add bool lazy on pagemap entry, things should get simpler.

I'd add 'bool zero' as well, gut feeling we'll need it...

> -- Pavel
>



-- 
Sincerely yours,
Mike.