A key difference between a tasklet and the kernel's softirq mechanism is that tasklets are simply easier to work with, making them a good choice for your typical driver. Of course, if you can use a threaded handler instead, just do that; later, we'll show a table that will help you decide what to use and when. One of the key things that makes tasklets easier to use is the fact that (on an SMP system) a particular tasklet will never run in parallel with itself; in other words, a given tasklet will run on exactly one CPU at a time (making it non-concurrent, or serialized, with respect to itself).
The header comment in linux/interrupt.h gives us some important properties of the tasklet as well:
[...] Properties:
* If tasklet_schedule() is called, then tasklet is guaranteed
to be executed on some cpu at least once after this.
* If the tasklet is already scheduled, but its execution is still not
started, it will be executed only once...