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Subject: Re: [GIT PULL] Memory folios for v5.15
From:   Jeff Layton <jlayton@kernel.org>
To:     Christoph Hellwig <hch@infradead.org>,
        Theodore Ts'o <tytso@mit.edu>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        David Howells <dhowells@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Linux-MM <linux-mm@kvack.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Date:   Wed, 25 Aug 2021 08:03:18 -0400
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On Wed, 2021-08-25 at 07:32 +0100, 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.
> 

Absolutely.  "folio" is no worse than "page", we've just had more time
to get used to "page".

> > 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.

Same here. Compound words are especially bad, as newbies will
continually have to look at whether it's "page_set" or "pageset".

-- 
Jeff Layton <jlayton@kernel.org>