Only ever had the DPF light come on once and that was in my Qashqai. 20 minutes at around 3000 rpm (so fifth gear rather than 6th) along a nearby motorway did the trick. Don't worry if there is a hot burning smell - it's quite normal during a DPF regeneration
As this I likely to be an on recurring question I'll publish here the extract from the owners manual.
Diesel particle filter
The diesel particle filter system filters harmful soot particles out of the exhaust gases. The system includes a self-cleaning function that runs automatically during driving without any notification. The filter is cleaned by periodically burning off the soot particles at high temperature. This process takes place automatically under set driving conditions and may take up to 25 minutes. Typically it needs between 7 and 12 minutes. Autostop is not available and fuel consumption may be higher during this period. The emission of smells and smoke during this process is normal.
Under certain driving conditions, e.g. short distances, the system cannot clean itself automatically.
If the cleaning of the filter is required and if previous driving conditions did not enable automatic cleaning, it will be indicated by control indicator.
Simultaneously Diesel partic. filter is full continue driving or warning code 55 appears in the Driver
Warning light illuminates when diesel particle filter is full. Start cleaning process as soon as possible.
Warning light flashes when diesel particle filter has reached the maximum filling level.
Start cleaning process immediately to avoid damage to the engine.
To activate cleaning process, continue driving, keep engine speed above 2000 revolutions per minute.
Shift down if necessary. Diesel particle filter cleaning is then started.
service indicator illuminates additionally, cleaning is not possible, seek the assistance of a workshop.
Cleaning takes place quickest at high engine speeds and loads. The control indicator light extinguishes as soon as the self-cleaning operation is complete.
If the cleaning process is interrupted, there is a risk of provoking severe engine damage.