The DataLoaders will use the Dataset you are passing.
If you created these Datasets before your training loop, they won’t change.
I’m not sure it’s a good idea to shuffle the training and validation data inside the training loop, as this will yield a data leak.
If you really want to do that, you could create a new sampler or dataset after an epoch and wrap it in a DataLoader and start the next epoch.
The DataLoader will shuffle the data, if you pass shuffle=True as an argument and don’t use an own Sampler. If that’s the case, the Sampler determines, if the data is shuffled or not.