[CRIU] [PATCH CRIU 04/14] dump/net/ipv4: add unused bitmask to allow negative sysctl values

[Pavel Emelyanov]

On 04/04/2016 01:21 PM, Pavel Tikhomirov wrote:
> 
> 
> On 04/04/2016 01:14 PM, Pavel Emelyanov wrote:
>> On 03/30/2016 01:42 PM, Pavel Tikhomirov wrote:
>>> Some sysctls can be set with value < 0: ipv4/conf//accept_source_route,
>>> ipv4/conf//medium_id, ipv4/conf//tag, ipv6/conf//accept_source_route,
>>> ipv6/conf//keep_addr_on_down. So we can not use -1 as unused value.
>>
>> I don't get the problem we fix with this patch. Why not just saving whatever
>> value we have instead of marking it with a special bit?
> 
> The problem is on old kernels we might not have all sysctls, so we need 
> somehow mark those to not to fail on them on restore. Before these 
> patch, we marked unused sysctls with -1, and did not restore it. But 
> what if some sysctl is really set to -1?

OK, so how old is the "old kernel"? And what sysctls are we talking about --
some that are already in CRIU, or the ones that you add with this set?