Mechanics of HugePages

I have a system with 8GB or RAM and accidentally set the nr_hugepages parameter to 5000 (~10GB). In practice the number allocated was limited by the available RAM at the time.

However, I am curious on a more fundamental level of how the Kernel deals with this.

-Is there some limit that the Kernel would impose on the percentage of RAM that can be allocated to Huge Pages?

-If the vast majority of RAM gets allocated to Huge Pages will that preclude many applications and/or libraries from getting loaded into memory or will they also get placed in Huge Pages?

-In general is there a reason to not allocate as much RAM as possible to Huge Pages?