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Date:   Wed, 28 Jun 2023 17:05:08 +0200
Message-Id: <CTODJTSTD9WR.82GVFKOIDIUK@imme>
Cc:     "Christoph Lameter" <cl@linux.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>,
        "Kees Cook" <keescook@chromium.org>,
        "Rafael Aquini" <aquini@redhat.com>
Subject: Re: [PATCH] mm/slub: disable slab merging in the default
 configuration
From:   "Julian Pidancet" <julian.pidancet@oracle.com>
To:     "David Rientjes" <rientjes@google.com>
References: <20230627132131.214475-1-julian.pidancet@oracle.com>
 <48bd9819-3571-6b53-f1ad-ec013be742c0@google.com>
In-Reply-To: <48bd9819-3571-6b53-f1ad-ec013be742c0@google.com>
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--8090e66db7e30980d4e7ec6477b8ce05ba2136fb45d0958c46bd4cd69e74
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On Tue Jun 27, 2023 at 21:32, David Rientjes wrote:
> On Tue, 27 Jun 2023, Julian Pidancet wrote:
>
> > Make CONFIG_SLAB_MERGE_DEFAULT default to n unless CONFIG_SLUB_TINY is
> > enabled. Benefits of slab merging is limited on systems that are not
> > memory constrained: the overhead is negligible and evidence of its
> > effect on cache hotness is hard to come by.
> >=20
>
> I don't have an objection to this, I think it makes sense.
>
> When you say overhead here, I assume you're referring to memory footprint=
? =20
> Did you happen to have some system-wide numbers for what that looks like=
=20
> when running some benchmarks, or even what the slab usage looks like afte=
r=20
> a fresh boot?
>

Thank you David for the quick review. I'll re-run the benchmark and
measure slab usage when the system is under pressure.

Regards,

--=20
Julian

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