From: Kees Cook <keescook@chromium.org>
To: Julian Pidancet <julian.pidancet@oracle.com>
Cc: David Rientjes <rientjes@google.com>,
Christoph Lameter <cl@linux.com>,
"Lameter, Christopher" <cl@os.amperecomputing.com>,
Pekka Enberg <penberg@kernel.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
linux-mm@kvack.org, Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
Rafael Aquini <aquini@redhat.com>
Subject: Re: [PATCH v2] mm/slub: disable slab merging in the default configuration
Date: Mon, 3 Jul 2023 11:38:59 -0700 [thread overview]
Message-ID: <202307031137.87508EB@keescook> (raw)
In-Reply-To: <CTSGWINSM18Q.3HQ1DN27GNA1R@imme>
On Mon, Jul 03, 2023 at 12:33:25PM +0200, Julian Pidancet wrote:
> On Mon Jul 3, 2023 at 02:09, David Rientjes wrote:
> > I think we need more data beyond just kernbench. Christoph's point about
> > different page sizes is interesting. In the above results, I don't know
> > the page orders for the various slab caches that this workload will
> > stress. I think the memory overhead data may be different depending on
> > how slab_max_order is being used, if at all.
> >
> > We should be able to run this through a variety of different benchmarks
> > and measure peak slab usage at the same time for due diligence. I support
> > the change in the default, I would just prefer to know what the
> > implications of it is.
> >
> > Is it possible to collect data for other microbenchmarks and real-world
> > workloads? And perhaps also with different page sizes where this will
> > impact memory overhead more? I can help running more workloads once we
> > have the next set of data.
> >
>
> David,
>
> I agree about the need to perform those tests on hardware using larger
> pages. I will collect data if I have the chance to get my hands on one
> of these systems.
>
> Do you have specific tests or workload in mind ? Compiling the kernel
> with files sitting on an XFS partition is not exhaustive but it is the
> only test I could think of that is both easy to set up and can be
> reproduced while keeping external interferences as little as possible.
I think it is a sufficiently complicated heap allocation workload (and
real-world). I'd prefer we get this change landed in -next after -rc1 so
we can see if there are any regressions reported by the 0day and other
CI performance tests.
-Kees
--
Kees Cook
next prev parent reply other threads:[~2023-07-03 18:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-29 22:19 [PATCH v2] mm/slub: disable slab merging in the default configuration Julian Pidancet
2023-07-03 0:09 ` David Rientjes
2023-07-03 10:33 ` Julian Pidancet
2023-07-03 18:38 ` Kees Cook [this message]
2023-07-03 20:17 ` David Rientjes
2023-07-06 7:38 ` David Rientjes
2023-07-09 8:55 ` David Rientjes
2023-07-10 2:40 ` David Rientjes
2023-07-18 12:08 ` Julian Pidancet
2023-07-25 23:25 ` David Rientjes
2023-07-26 8:34 ` Vlastimil Babka
2023-07-10 14:56 ` Vlastimil Babka
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