From: Andrew Morton <akpm@linux-foundation.org>
To: Kees Cook <keescook@chromium.org>
Cc: Michal Hocko <mhocko@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Laura Abbott <labbott@redhat.com>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
LKML <linux-kernel@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>
Subject: Re: [PATCH v2] fork: Unconditionally clear stack on fork
Date: Wed, 18 Apr 2018 12:50:08 -0700 [thread overview]
Message-ID: <20180418125008.203632feeaf0cac4e51c5b79@linux-foundation.org> (raw)
In-Reply-To: <CAGXu5j+PmPUg9-gx3769X+kjXJo+markuPA3FwredM7jU8CdXg@mail.gmail.com>
On Wed, 18 Apr 2018 09:38:07 -0700 Kees Cook <keescook@chromium.org> wrote:
> >> So some quite careful quantitative testing is needed here, methinks.
> >
> > Well, I did some more with perf and cycle counts on running 100,000
> > execs of /bin/true.
> >
> > before:
> > Cycles: 218858861551 218853036130 214727610969 227656844122 224980542841
> > Mean: 221015379122.60
> > Std Dev: 4662486552.47
> >
> > after:
> > Cycles: 213868945060 213119275204 211820169456 224426673259 225489986348
> > Mean: 217745009865.40
> > Std Dev: 5935559279.99
> >
> > It continues to look like it's faster, though the deviation is rather
> > wide, but I'm not sure what I could do that would be less noisy. I'm
> > open to ideas!
>
> Friendly ping. Andrew, can you add this to -mm?
I did so on Feb 21 but didn't merge it up because I'd told myself that
careful perf testing is needed. I guess we've sufficiently ticked that
box. Kind of. Maybe.
Oh well, it's easy enough to revert. I'll add it to the next
batch-for-Linus.
next prev parent reply other threads:[~2018-04-18 19:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-21 2:16 Kees Cook
2018-02-21 10:29 ` Michal Hocko
2018-02-21 20:59 ` Andrew Morton
2018-02-22 2:15 ` Kees Cook
2018-04-18 16:38 ` Kees Cook
2018-04-18 19:50 ` Andrew Morton [this message]
2018-02-22 9:53 ` Mel Gorman
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