From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
To: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: kernel test robot <yi1.lai@intel.com>,
oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Daehyeon Ko <4ncienth@gmail.com>,
Mike Rapoport <rppt@kernel.org>,
David Hildenbrand <david@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Hagen Paul Pfeifer <hagen@jauu.net>,
Jakub Kacinski <kuba@kernel.org>,
James Bottomley <james.bottomley@hansenpartnership.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
"Liam R. Howlett" <liam@infradead.org>,
Michal Hocko <mhocko@suse.com>,
Stanislav Fomichev <sdf@fomichev.me>,
Suren Baghdasaryan <surenb@google.com>,
linux-mm@kvack.org
Subject: Re: [linus:master] [mm/secretmem] 97d34aa65c: stress-ng.secretmem.ops_per_sec 99.5% regression
Date: Wed, 23 Sep 2026 08:19:51 +0100 [thread overview]
Message-ID: <arN9UtxVQpWqTZ8C@gremlin> (raw)
In-Reply-To: <7ea6e90a-e2fb-4793-b6ea-e292388bdfdf@kernel.org>
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
prev parent reply other threads:[~2026-09-23 7:20 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-23 1:00 [linus:master] [mm/secretmem] 97d34aa65c: stress-ng.secretmem.ops_per_sec 99.5% regression kernel test robot
2026-09-23 6:35 ` Vlastimil Babka (SUSE)
2026-09-23 7:19 ` Lorenzo Stoakes (ARM) [this message]
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