Re: [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP

From: Linus Torvalds
Date: Tue Apr 19 2022 - 22:19:15 EST


On Tue, Apr 19, 2022 at 7:03 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> Here is the quote from Song's cover letter for bpf_prog_pack series:

I care about performance as much as the next person, but I care about
correctness too.

That large-page code was a disaster, and was buggy and broken.

And even with those four patches, it's still broken.

End result: there's no way that thigh gets re-enabled without the
correctness being in place.

At a minimum, to re-enable it, it needs (a) that zeroing and (b)
actual numbers on real loads. (not some artificial benchmark).

Because without (a) there's no way in hell I'll enable it.

And without (b), "performance" isn't actually an argument.

Linus