Re: [GIT PULL] Memory folios for v5.15

From: Christoph Hellwig
Date: Wed Aug 25 2021 - 02:35:41 EST


On Tue, Aug 24, 2021 at 03:44:48PM -0400, Theodore Ts'o wrote:
> The problem is whether we use struct head_page, or folio, or mempages,
> we're going to be subsystem users' faces. And people who are using it
> every day will eventually get used to anything, whether it's "folio"
> or "xmoqax", we sould give a thought to newcomers to Linux file system
> code. If they see things like "read_folio()", they are going to be
> far more confused than "read_pages()" or "read_mempages()".

Are they? It's not like page isn't some randomly made up term
as well, just one that had a lot more time to spread.

> So if someone sees "kmem_cache_alloc()", they can probably make a
> guess what it means, and it's memorable once they learn it.
> Similarly, something like "head_page", or "mempages" is going to a bit
> more obvious to a kernel newbie. So if we can make a tiny gesture
> towards comprehensibility, it would be good to do so while it's still
> easier to change the name.

All this sounds really weird to me. I doubt there is any name that
nicely explains "structure used to manage arbitrary power of two
units of memory in the kernel" very well. So I agree with willy here,
let's pick something short and not clumsy. I initially found the folio
name a little strange, but working with it I got used to it quickly.
And all the other uggestions I've seen s far are significantly worse,
especially all the odd compounds with page in it.