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From: Jens Axboe <axboe@kernel.dk>
To: Christian Brauner <brauner@kernel.org>, linux-fsdevel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jeff Layton <jlayton@kernel.org>, Jan Kara <jack@suse.cz>
Subject: Re: [PATCH] fs: switch f_iocb_flags and f_version
Date: Thu, 22 Aug 2024 08:55:55 -0600	[thread overview]
Message-ID: <19488597-8585-4875-8fa5-732f5cd9f2ee@kernel.dk> (raw)
In-Reply-To: <20240822-mutig-kurznachrichten-68d154f25f41@brauner>

On 8/22/24 8:14 AM, Christian Brauner wrote:
> Now that we shrank struct file by 24 bytes we still have a 4 byte hole.
> Move f_version into the union and f_iocb_flags out of the union to fill
> that hole and shrink struct file by another 4 bytes. This brings struct
> file to 200 bytes down from 232 bytes.

Nice! Now you just need to find 8 more bytes and we'll be down to 3
cachelines for struct file.

> I've tried to audit all codepaths that use f_version and none of them
> rely on it in file->f_op->release() and never have since commit
> 1da177e4c3f4 ("Linux-2.6.12-rc2").

Do we want to add a comment to this effect? I know it's obvious from
sharing with f_task_work, but...

-- 
Jens Axboe


  reply	other threads:[~2024-08-22 14:55 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-22 14:14 [PATCH] fs: switch f_iocb_flags and f_version Christian Brauner
2024-08-22 14:55 ` Jens Axboe [this message]
2024-08-22 15:10   ` Christian Brauner
2024-08-22 16:17     ` Jens Axboe
2024-08-23  8:16       ` Christian Brauner
2024-08-24  9:26         ` Christian Brauner
2024-08-22 15:54 ` Jeff Layton
2024-08-23  6:24 ` Christoph Hellwig
2024-08-23  6:34   ` Al Viro
2024-08-23  6:52     ` Christoph Hellwig
2024-08-23  6:59       ` Al Viro

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