On Wed, Aug 25, 2021 at 12:02 PM Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> wrote: > > On 25/08/2021 08.32, Christoph Hellwig wrote: > > 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. > > > > A comment from the peanut gallery: I find the name folio completely > appropriate and easy to understand. Our vocabulary is already strongly > inspired by words used in the world of printed text: the smallest unit > of information is a char(acter) [ok, we usually call them bytes], a few > characters make up a word, there's a number of words to each (cache) > line, and a number of those is what makes up a page. So obviously a > folio is something consisting of a few pages. > > Are the analogies perfect? Of course not. But they are actually quite > apt; words, lines and pages don't universally have one size, but they do > form a natural hierarchy describing how we organize information. > > Splitting a word across lines can slow down the reader so should be > avoided... [sorry, couldn't resist]. > And if we ever want to manage page cache using an arbitrary number of contiguous filios, we can always saw them into a scroll ;-) Thanks, Amir.
