Re: [PATCH v2] mm: fix swap offset when replacing shmem page

[Matthew Wilcox]

On Mon, Nov 19, 2018 at 09:07:27PM -0800, Hugh Dickins wrote:
> I don't much like my original use of the name "swap_index", when it was
> not the index in a swapfile (though it was the index in the radix tree);
> but it will become a correct name with your patch.
> 
> Though Matthew Wilcox seems to want us to avoid saying "radix tree"...

Naming is hard ... but the Linux radix tree looks almost nothing like
a classic computer science radix tree.  If you try to reconcile our
implementation with the wikipedia article on radix trees, you'll get
very confused.

A lot of places where we were saying 'radix tree' in comments should
really have said 'page cache'.  So is this a swap cache index?  I'm
not really familiar enough with the swapping code to say.