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

[Pavel Emelyanov]

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."

?

>> 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");
>> -		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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>>
> 
> .
>