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From: Kees Cook <keescook@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Michal Hocko <mhocko@suse.com>, Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Keith Busch <keith.busch@intel.com>
Subject: Re: [PATCH v10 1/3] mm: Shuffle initial free memory to improve memory-side-cache utilization
Date: Tue, 5 Feb 2019 23:11:06 +0000	[thread overview]
Message-ID: <CAGXu5jJJQq358_H=xAcf=17WixnFx-P6HqTuv8uQn2zGgNg3Fw@mail.gmail.com> (raw)
In-Reply-To: <20190205140415.544ae2876ee44e6edb8ca743@linux-foundation.org>

On Tue, Feb 5, 2019 at 10:04 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Thu, 31 Jan 2019 21:15:17 -0800 Dan Williams <dan.j.williams@intel.com> wrote:
>
> > +config SHUFFLE_PAGE_ALLOCATOR
> > +     bool "Page allocator randomization"
> > +     default SLAB_FREELIST_RANDOM && ACPI_NUMA
> > +     help
>
> SLAB_FREELIST_RANDOM is default n, so this patchset won't get much
> runtime testing.
>
> How about you cook up a (-mm only) patch which makes the kernel default
> to SLAB_FREELIST_RANDOM=y, SHUFFLE_PAGE_ALLOCATOR=y (or whatever) to
> ensure we get a decent amount of runtime testing?  Then I can hold that
> in -mm (and -next) until we get bored of it?

I love this plan. :)

FWIW, distros have enabled it by default for a while. Here's Ubuntu,
for example:

$ grep SLAB_FREELIST /boot/config-4.1*
/boot/config-4.15.0-45-generic:CONFIG_SLAB_FREELIST_RANDOM=y
/boot/config-4.15.0-45-generic:CONFIG_SLAB_FREELIST_HARDENED=y
/boot/config-4.18.0-13-generic:CONFIG_SLAB_FREELIST_RANDOM=y
/boot/config-4.18.0-13-generic:CONFIG_SLAB_FREELIST_HARDENED=y
/boot/config-4.18.0-14-generic:CONFIG_SLAB_FREELIST_RANDOM=y
/boot/config-4.18.0-14-generic:CONFIG_SLAB_FREELIST_HARDENED=y

and Fedora too:

$ curl -s 'https://git.kernel.org/pub/scm/linux/kernel/git/jwboyer/fedora.git/patch/fedora/configs/kernel-4.16.12-x86_64.config?h=f26'
| grep SLAB_FREELIST
+CONFIG_SLAB_FREELIST_RANDOM=y
+CONFIG_SLAB_FREELIST_HARDENED=y

-- 
Kees Cook

  reply	other threads:[~2019-02-05 23:11 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-01  5:15 [PATCH v10 0/3] mm: Randomize free memory Dan Williams
2019-02-01  5:15 ` [PATCH v10 1/3] mm: Shuffle initial free memory to improve memory-side-cache utilization Dan Williams
2019-02-05 22:04   ` Andrew Morton
2019-02-05 23:11     ` Kees Cook [this message]
2019-02-05 23:29       ` Matthew Wilcox
2019-05-31  7:33   ` Vlastimil Babka
2019-05-31 14:59     ` Dan Williams
2019-02-01  5:15 ` [PATCH v10 2/3] mm: Move buddy list manipulations into helpers Dan Williams
2019-02-19 15:24   ` Vlastimil Babka
2019-02-19 17:21     ` Dan Williams
2019-02-01  5:15 ` [PATCH v10 3/3] mm: Maintain randomization of page free lists Dan Williams
2019-02-01  9:58   ` Michal Hocko

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