Re: [PATCH] [v2] filemap: Move prefaulting out of hot write path

[Andrew Morton]

On Fri, 28 Feb 2025 12:37:22 -0800 Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> wrote:

> There is a generic anti-pattern that shows up in the VFS and several
> filesystems where the hot write paths touch userspace twice when they
> could get away with doing it once.
> 
> Dave Chinner suggested that they should all be fixed up[1]. I agree[2].
> But, the series to do that fixup spans a bunch of filesystems and a lot
> of people. This patch fixes common code that absolutely everyone uses.
> It has measurable performance benefits[3].
> 
> I think this patch can go in and not be held up by the others.

I'll queue this in mm-hotfixes with a view to sneaking it into 6.14-rcX
as a basis for others to work against.