Subject: Re: [PATCH] copy.c: use `sendfile()` for in-kernel file copying on Linux

From: Collin Funk <[email-masked]>
Date: Fri, 20 Feb 2026 08:48:55 -0800

Ed Maste <[email-masked]> writes:

> On Sat, 14 Feb 2026 at 11:50, Chris Torek <[email-masked]> wrote:
>>
>> Ah, more importantly, FreeBSD's sendfile only operates on sockets.
>
> True. If benchmarking shows this is profitable then we'd want to use
> copy_file_range(2) on FreeBSD.

We use copy_file_range in GNU Coreutils. Note that it has quite a few
issues [1], including a recent one affecting files larger than INT_MAX
bytes [2][3].

Coreutils has Gnulib to work around this stuff, and the performance
improvement is meaningful for 'cp'. Based on earlier messages in this
thread, I am not sure if it is worth dealing with in this case.

Collin

[1] https://lwn.net/Articles/789527/
[2] https://sourceware.org/PR33245
[3] https://bugs.gnu.org/79139