On Mon, Jun 15, 2020 at 12:33 AM Jann Horn <[email protected]> wrote:
>
> So in summary I guess the test was just really slow up until now
> because it was hitting a slowpath that you wouldn't hit during normal
> usage? At least for vmsplice(), writing uninitialized pages doesn't
> really make a whole lot of sense...
Heh. My main worry with that commit was that we'd see the reverse
effect: somebody implicitly depending on the continued sharing of
pages in some odd splice situation, and where breaking the COW would
result in a performance degradation.
The fact that it went the other way instead is somewhat ironic.
But good.
I guess I'll just ping the stable people to say "yeah, put that in
stable too". It's a fix, and apparently it _helps_ performance for the
degenerate cases rather than hurting anything.
Linus
