[CRIU] [PATCH 13/12] page-xfer: Don't send zero pages if none found

[Mike Rapoprt]

On June 30, 2017 9:38:55 AM GMT+03:00, Pavel Emelyanov <xemul at virtuozzo.com> wrote:
>On 06/29/2017 09:02 PM, Mike Rapoport wrote:
>> On Thu, Jun 29, 2017 at 01:33:44PM +0300, Pavel Emelyanov wrote:
>>> When page-server gets a request from lazy-daemon for a pagemap,
>>> the former cannot read no pages from the image.
>> 
>> Hm? Can you please rephrase a bit? "cannot read no pages" really
>finished
>> me :-P
>
>How about:
>
>"When page-server gets a request from lazy-daemon for a pagemap,
>the former cannot read zero pages from the image."
>
>?

'When page-server gets a request for an absent pagemap from lazy-pages daemon, it should not reply with "zero pages"'.

>>> Mike says: "The pagemap should be completely in sync between src
>>> and dst and dst should never request pages that are not present.
>>> Maybe we should return -1 here? At least we'll have a chance that
>>> dump will unroll everything..."
>>>
>>> Why not?!
>>>
>>> Signed-off-by: Pavel Emelyanov <xemul at virtuozzo.com>
>>> ---
>>>  criu/page-xfer.c | 4 +---
>>>  1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> diff --git a/criu/page-xfer.c b/criu/page-xfer.c
>>> index 24fc565..d949c06 100644
>>> --- a/criu/page-xfer.c
>>> +++ b/criu/page-xfer.c
>>> @@ -678,10 +678,8 @@ static int page_server_get_pages(int sk, struct
>page_server_iov *pi)
>>>  	 */
>>>
>>>  	if (pi->nr_pages == 0) {
>>> -		/* no iovs found means we've hit a zero page */
>>>  		pr_debug("no iovs found, zero pages\n");

Can we make it
 pr_err("%lx: no pages at %lx\n", pi->dst_id, pi->vaddr);
?

>>> -		pi->cmd = encode_ps_cmd(PS_IOV_ADD_F, 0);
>>> -		return send_psi(sk, pi);
>>> +		return -1;
>>>  	}
>>>
>>>  	pi->cmd = encode_ps_cmd(PS_IOV_ADD_F, PE_PRESENT);
>>> -- 
>>> 2.1.4
>>>
>>> _______________________________________________
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>>> CRIU at openvz.org
>>> https://lists.openvz.org/mailman/listinfo/criu
>>>
>> 
>> .
>> 

-- 
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