[CRIU] [PATCH] mem: Don't track memory changes if --track-mem is not specified

[Pavel Emelyanov]

>> @@ -81,6 +77,17 @@ static struct mem_snap_ctx *mem_snap_init(struct parasite_ctl *ctl)
>>  	int p_fd, pm_fd;
>>  	PagemapHead *h;
>>  
>> +	/*
>> +	 * If we're not tracking memory changes, then it doesn't
>> +	 * matter whether we have parent images or not. Just
>> +	 * proceed with full memory dump.
>> +	 */
>> +
>> +	if (!opts.track_mem)
>> +		return NULL;
>> +
>> +	BUG_ON(!kerndat_has_dirty_track);
> 
> Are these BUG_ON really needed? I mean what happen if we drop them?

We will proceed reading pmes with soft-dirty bits containing zeroes,
i.e. -- spoiling the memory dump. Not to do this we ban track_mem
for kernels w/o soft-dirty in kerndat_init() so these bug-ons are
just to reflect that fact.