linux-kernel - Re: [PATCH 2/2] fuse: Adjust readdir() buffer to requesting buffer size.

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Message-ID: <CAJfpegtutvpYYzkW91SscwULcLt_xHeqCGLPmUHKAjozPAQQ8A@mail.gmail.com>
Date: Wed, 2 Apr 2025 10:18:15 +0200
From: Miklos Szeredi <miklos@...redi.hu>
To: Jaco Kroon <jaco@....co.za>
Cc: bernd.schubert@...tmail.fm, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, christophe.jaillet@...adoo.fr, 
	joannelkoong@...il.com, rdunlap@...radead.org, trapexit@...wn.link, 
	david.laight.linux@...il.com
Subject: Re: [PATCH 2/2] fuse: Adjust readdir() buffer to requesting buffer size.

On Wed, 2 Apr 2025 at 09:55, Jaco Kroon <jaco@....co.za> wrote:
>
> Hi,
>
> I can definitely build on that, thank you.
>
> What's the advantage of kvmalloc over folio's here, why should it be
> preferred?

It offers the best of both worlds: first tries plain malloc (which
just does a folio alloc internally for size > PAGE_SIZE) and if that
fails, falls back to vmalloc, which should always succeed since it
uses order 0 pages.

This saves the trouble of iterating the folio alloc until it succeeds,
which is both undeterministic and complex, neither of which is
desirable.

Thanks,
Miklos