Re: [linus:master] [mm/secretmem] 97d34aa65c: stress-ng.secretmem.ops_per_sec 99.5% regression

[Lorenzo Stoakes (ARM)]

On Wed, Sep 23, 2026 at 08:35:47AM +0200, Vlastimil Babka (SUSE) wrote:
> On 9/23/26 03:00, kernel test robot wrote:
> >
> >
> > Hello,
> >
> > kernel test robot noticed a 99.5% regression of stress-ng.secretmem.ops_per_sec on:
> >
> > commit: 97d34aa65c29cca85e3e9050f4c936389b38a054 ("mm/secretmem: properly account locked pages") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
> Well maybe there is some inefficiency that can be fixed (haven't checked)
> but if it's the cost for proper accounting then so be it? I doubt creating
> secretmem pages is something userspace would have to do intensively enough
> to matter.

Yeah, exactly.

This isn't something that should be benchmarked, this is possibly the most
ludicrious benchmark I've ever seen :)

If establishing a secretmem region is on your hot path you have engineered your
software wrong.

This is effectively a security flaw so I'm afraid must remain.

--
Cheers, Lorenzo