ksize — get the actual amount of memory allocated for a given object
|const void * objp|
kmalloc may internally round up allocations and return more memory
ksize can be used to determine the actual amount of
memory allocated. The caller may use this additional memory, even though
a smaller amount of memory was initially specified with the kmalloc call.
The caller must guarantee that objp points to a valid object previously
allocated with either
kmem_cache_alloc. The object
must not be freed during the duration of the call.