From: Al Viro <viro@zeniv.linux.org.uk>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: linux-fsdevel@vger.kernel.org, torvalds@linux-foundation.org,
brauner@kernel.org, jack@suse.cz, paul@paul-moore.com,
axboe@kernel.dk, audit@vger.kernel.org, io-uring@vger.kernel.org
Subject: Re: [RFC PATCH v2 15/18] struct filename: saner handling of long names
Date: Sun, 30 Nov 2025 04:06:22 +0000 [thread overview]
Message-ID: <20251130040622.GO3538@ZenIV> (raw)
In-Reply-To: <CAGudoHFjycOW1ROqsm1_8j47AGawjXC3kVctvWURFvSDvhq2jg@mail.gmail.com>
On Sat, Nov 29, 2025 at 06:33:22PM +0100, Mateusz Guzik wrote:
> This makes sizeof struct filename 152 bytes. At the same time because
> of the SLAB_HWCACHE_ALIGN flag, the obj is going to take 192 bytes.
>
> I don't know what would be the nice way to handle this in Linux, but
> as is this is just failing to take advantage of memory which is going
> to get allocated anyway.
>
> Perhaps the macro could be bumped to 168 and the size checked with a
> static assert on 64 bit platforms?
Could be done, even though I wonder how much would that really save.
> Or some magic based on reported
> cache line size.
No comments. At least, none suitable for polite company.
BTW, one thing that might make sense is storing the name length in there...
next prev parent reply other threads:[~2025-11-30 4:06 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-29 17:01 [RFC PATCH v2 00/18] io_uring, struct filename and audit Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 01/18] do_faccessat(): import pathname only once Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 02/18] do_fchmodat(): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 03/18] do_fchownat(): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 04/18] do_utimes_path(): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 05/18] chdir(2): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 06/18] chroot(2): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 07/18] user_statfs(): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 08/18] do_sys_truncate(): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 09/18] do_readlinkat(): " Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 10/18] get rid of audit_reusename() Al Viro
2025-12-16 2:14 ` Paul Moore
2025-11-29 17:01 ` [RFC PATCH v2 11/18] ntfs: ->d_compare() must not block Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 12/18] getname_flags() massage, part 1 Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 13/18] getname_flags() massage, part 2 Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 14/18] struct filename: use names_cachep only for getname() and friends Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 15/18] struct filename: saner handling of long names Al Viro
2025-11-29 17:33 ` Mateusz Guzik
2025-11-30 4:06 ` Al Viro [this message]
2025-11-30 4:38 ` Mateusz Guzik
2025-11-29 17:01 ` [RFC PATCH v2 16/18] allow incomplete imports of filenames Al Viro
2025-11-29 17:01 ` [RFC PATCH v2 17/18] fs: touch up predicts in putname() Al Viro
2025-11-29 17:34 ` Mateusz Guzik
2025-11-29 17:01 ` [RFC PATCH v2 18/18] struct filename ->refcnt doesn't need to be atomic Al Viro
2025-12-16 2:18 ` Paul Moore
2025-12-10 1:31 ` [RFC PATCH v2 00/18] io_uring, struct filename and audit Jens Axboe
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