On Thu, 29 Jun 2023 at 08:55, David Howells <dhowells@xxxxxxxxxx> wrote:
>
> Matt Whitlock, Matthew Wilcox and Dave Chinner are of the opinion that data
> in the pipe must not be seen to change and that if it does, this is a bug.
I'm not convinced.
The whole *point* of vmsplice (and splicing from a file) is the zero-copy.
If you don't want the zero-copy, then you should use just "write()".
So I disagree violently. This is not a bug unless you can point to
some other correctness issues.
The "stableness" of the data is literally the *only* difference
between vmsplice() and write().
> Whilst this does allow the code to be somewhat simplified, it also results
> in a loss of performance: stolen pages have to be reloaded in accessed
> again; more data has to be copied.
No. It literally results in a loss of THE WHOLE POINT of vmsplice().
Linus
