From: Harry Yoo <harry@kernel.org>
To: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Chris Down <chris@chrisdown.name>,
Andrew Morton <akpm@linux-foundation.org>,
Hao Li <hao.li@linux.dev>, Christoph Lameter <cl@gentwo.org>,
David Rientjes <rientjes@google.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Kees Cook <kees@kernel.org>, Marco Elver <elver@google.com>,
GONG Ruiqi <gongruiqi@huaweicloud.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
Kieran Bingham <kbingham@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
linux-mm@kvack.org, linux-hardening@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com
Subject: Re: [PATCH 0/8] mm/slab: Support selecting slab hardening features at boot
Date: Tue, 27 Oct 2026 18:31:37 +0000 [thread overview]
Message-ID: <179312451613.474906.1475329637924619088@kernel.org> (raw)
In-Reply-To: <16121542-acd5-4727-b64c-f8d519145b63@kernel.org>
On Tue, Oct 27, 2026 at 08:10:40AM +0100, Vlastimil Babka (SUSE) wrote:
> These two should be only a small cpu overhead, which is why distros
> generally enable them [1].
Yeah I'd expect the impact on them to be small enough.
> > slab_buckets=
> > kmalloc_partition=
>
> These are more valid as there's a memory overhead tradeoff.
quickly measuring it on a VM with 64 CPUs and 64 GiB RAM:
w/ partitioned kmalloc: 94.0 MiB (235 kmalloc caches)
w/o partitioned kmalloc: 76.1 MiB (~17.9 MiB diff) (40 kmalloc caches)
Mostly due to a large number number of under-utilized slabs after boot.
(per memalloc profiling)
slab_buckets had relately smaller impact, about ~1MiB after boot.
(Of course this is just after boot, and actual bloat depends on memory
usage and fragmentation on production)
--
Cheers,
Harry / Hyeonggon
prev parent reply other threads:[~2026-10-27 18:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-27 7:35 Chris Down
2026-10-27 7:35 ` [PATCH 1/8] mm/slub: Support disabling freelist hardening " Chris Down
2026-10-27 7:35 ` [PATCH 2/8] slub_kunit: Add a test for slab_freelist_hardened= Chris Down
2026-10-27 7:35 ` [PATCH 3/8] mm/slub: Support disabling freelist randomisation at boot Chris Down
2026-10-27 7:35 ` [PATCH 4/8] slub_kunit: Add a test for slab_freelist_random= Chris Down
2026-10-27 7:35 ` [PATCH 5/8] mm/slab: Support disabling SLAB_BUCKETS at boot Chris Down
2026-10-27 7:36 ` [PATCH 6/8] slub_kunit: Add a test for the slab_buckets boot parameter Chris Down
2026-10-27 7:36 ` [PATCH 7/8] mm/slab: Support disabling KMALLOC_PARTITION_CACHES at boot Chris Down
2026-10-27 7:36 ` [PATCH 8/8] slub_kunit: Add a test for the kmalloc_partition boot parameter Chris Down
2026-10-27 8:10 ` [PATCH 0/8] mm/slab: Support selecting slab hardening features at boot Vlastimil Babka (SUSE)
2026-10-27 18:31 ` Harry Yoo [this message]
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