Re: [PATCH] fs: place f_ref to 3rd cache line in struct file to resolve false sharing

[Christian Brauner <brauner@kernel.org>]

On Fri, 28 Feb 2025 10:00:59 +0800, Pan Deng wrote:
> When running syscall pread in a high core count system, f_ref contends
> with the reading of f_mode, f_op, f_mapping, f_inode, f_flags in the
> same cache line.
> 
> This change places f_ref to the 3rd cache line where fields are not
> updated as frequently as the 1st cache line, and the contention is
> grealy reduced according to tests. In addition, the size of file
> object is kept in 3 cache lines.
> 
> [...]

Applied to the vfs-6.15.misc branch of the vfs/vfs.git tree.
Patches in the vfs-6.15.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.15.misc

[1/1] fs: place f_ref to 3rd cache line in struct file to resolve false sharing
      https://git.kernel.org/vfs/vfs/c/6a9ebf00c3be