Re: [PATCH *] rmap VM, version 12

[Andrea Arcangeli]

On Wed, Jan 23, 2002 at 12:18:57PM -0800, David S. Miller wrote:
>    
>    OK, so only the _pgd_ quicklist is questionable and the
>    _pte_ quicklist is fine ?
> 
> That is my understanding.

pgd cache is fine too, the page fault will update the pgd using
swapper_pg_dir accordingly if needed. The swapper_pg_dir will only fault
in new pmd, it will never deallocate them (vfree only invalidates the
pte and free the pages), so it's safe. If vfree would deallocate them
just a simple context switch would break, no matter of the pgd cache.

Andrea