linux-kernel - Re: fuse: increase readdir() buffer size

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Message-ID: <05b36be3-f43f-4a49-9724-1a0d8d3a8ce4@uls.co.za>
Date: Fri, 28 Mar 2025 12:15:47 +0200
From: Jaco Kroon <jaco@....co.za>
To: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: bernd.schubert@...tmail.fm, miklos@...redi.hu, rdunlap@...radead.org,
 trapexit@...wn.link
Subject: Re: fuse: increase readdir() buffer size

Hi All,

I've not seen feedback on this, please may I get some direction on this?

Kind regards,
Jaco

On 2025/03/15 00:16, Jaco Kroon wrote:
> This is a follow up to the attempt made a while ago.
>
> Whist the patch worked, newer kernels have moved from pages to folios,
> which gave me the motivation to implement the mechanism based on the
> userspace buffer size patch that Miklos supplied.
>
> That patch works as is, but I note there are changes to components
> (overlayfs and exportfs) that I've got very little experience with, and
> have not tested specifically here.  They do look logical.  I've marked
> Miklos as the Author: here, and added my own Signed-off-by - I hope this
> is correct.
>
> The second patch in the series implements the changes to fuse's readdir
> in order to utilize the first to enable reading more than one page of
> dent structures at a time from userspace, I've included a strace from
> before and after this patch in the commit to illustrate the difference.
>
> To get the relevant performance on glusterfs improved (which was
> mentioned elsewhere in the thread) changes to glusterfs to increase the
> number of cached dentries is also required (these are pushed to github
> but not yet merged, because similar to this patch, got stalled before
> getting to the "ready for merge" phase even though it's operational).
>
> Please advise if these two patches looks good (I've only done relatively
> basic testing now, and it's not running on production systems yet)
>
> Kind regards,
> Jaco
>