Am 20.03.25 um 11:46 schrieb Pavel Begunkov:
On 3/19/25 19:15, Stefan Metzmacher wrote:
Am 19.03.25 um 19:37 schrieb Jens Axboe:
On 3/19/25 11:45 AM, Joe Damato wrote:
On Wed, Mar 19, 2025 at 11:20:50AM -0600, Jens Axboe wrote:
...
My argument would be the same as for other features - if you can do it simpler this other way, why not consider that? The end result would be the same, you can do fast sendfile() with sane buffer reuse. But the kernel side would be simpler, which is always a kernel main goal for those of us that have to maintain it.
Just adding sendfile2() works in the sense that it's an easier drop in replacement for an app, though the error queue side does mean it needs to change anyway - it's not just replacing one syscall with another. And if we want to be lazy, sure that's fine. I just don't think it's the best way to do it when we literally have a mechanism that's designed for this and works with reuse already with normal send zc (and receive side too, in the next kernel).
A few month (or even years) back, Pavel came up with an idea to implement some kind of splice into a fixed buffer, if that would be implemented I guess it would help me in Samba too. My first usage was on the receive side (from the network).
I did it as a testing ground for infra needed for ublk zerocopy, but if that's of interest I can resurrect the patches and see where it goes, especially since the aforementioned infra just got queued.
Would be great!
Have you posted the work in progress somewhere?
Thanks! metze