Free the page directory and the mm.

To free the page directory and the mm in the Linux kernel, you can use the following steps:

1. First, you need to obtain the page table directory pointer (pgd) from the mm.

   pgd_t *pgd = mm->pgd;

2. Next, you need to release the page table pages by calling the function `pgd_free()`. This function takes the pgd pointer and the address space identifier (asid) as arguments.

   pgd_free(mm, pgd, mm->asid);

Note that the asid is a unique identifier for the address space that is used to flush the TLB (Translation Lookaside Buffer) entries.

3. Finally, you can release the memory used by the mm by calling the function `kmem_cache_free()`. This function takes the pointer to the memory block and the cache descriptor as arguments.

   kmem_cache_free(mm_cachep, mm);

Here, `mm_cachep` is the cache descriptor for the mm_struct cache.

That's it! You have now freed the page directory and the mm in the Linux kernel.