Add Task 13 description

Task13/task13.txt

@@ -0,0 +1,28 @@
+This is Task 13 of the Eudyptula Challenge
+------------------------------------------
+
+Weren't those lists fun to play with?  You should get used to them, they
+are used all over the kernel in lots of different places.
+
+Now that we are allocating a structure that we want to use a lot of, we
+might want to start caring about the speed of the allocation, and not
+have to worry about the creation of those objects from the "general"
+memory pools of the kernel.
+
+This task is to take the code written in task 12, and cause all memory
+allocated from the 'struct identity' to come from a private slab cache
+just for the fun of it.
+
+Instead of using kmalloc() and kfree() in the module, use
+kmem_cache_alloc() and kmem_cache_free() instead.  Of course this means
+you will have to initialize your memory cache properly when the module
+starts up.  Don't forget to do that.  You are free to name your memory
+cache whatever you wish, but it should show up in the /proc/slabinfo
+file.
+
+Don't send the full module for this task, only a patch with the diff
+from task 12 showing the lines changed.  This means you will have to
+keep a copy of your 12 task results somewhere to make sure you don't
+overwrite them.
+
+Also show the output of /proc/slabinfo with your module loaded.