Re: [RFC PATCH v12 00/26] LUF(Lazy Unmap Flush) reducing tlb numbers over 90%

Byungchul Park
2025-02-20T23:23:35Z

On Thu, Feb 20, 2025 at 07:15:44AM -0800, Dave Hansen wrote:
> On 2/19/25 21:20, Byungchul Park wrote:
> > I'm posting the latest version so that anyone can try luf mechanism if
> > wanted by any chance. However, I tagged RFC again because there are
> > still issues that should be resolved to merge to mainline:
>
> I don't see anything fundamentally different here from the last 11
> versions. I think the entire approach is dangerous and basically makes
> things impossible to debug. It's not clear that some of the failure
> scenarios that I've brought up in the past have actually been fixed.

Respect your opinion.

> What I've said here still stands:
>
> > https://lore.kernel.org/all/fab1dd64-c652-4160-93b4-7b483a8874da@intel.com/
>
> > I think tglx would call all of this "tinkering". The approach to this
> > series is to "fix" narrow, specific cases that reviewers point out, make
> > it compile, then send it out again, hoping someone will apply it.
> >
> > So, for me, until the approach to this series changes: NAK, for x86.
> > Andrew, please don't take this series. Or, if you do, please drop the
> > patch enabling it on x86.
>
> I think I'd also like to stop being cc'd on this. If LUF is merged into

I will un-cc you from the next spin.

Byungchul

> mainline and proven to work on arm64 or riscv for a year, I'd be happy
> to take another look at enabling it on x86. I think that's just about
> the only thing that would make me reconsider.