From: Harry Yoo <harry@kernel.org>
To: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>, Hao Li <hao.li@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@gentwo.org>,
David Rientjes <rientjes@google.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
cgroups@vger.kernel.org
Subject: Re: [PATCH v3 07/13] mm/slab: replace slab.stride with obj_exts_in_object
Date: Wed, 29 Jul 2026 06:40:57 +0000 [thread overview]
Message-ID: <ammbWxBtX7KxgJ5R@dev> (raw)
In-Reply-To: <20260727-b4-objext_split-v3-7-c29ef0f1f257@kernel.org>
On Mon, Jul 27, 2026 at 02:54:01PM +0200, Vlastimil Babka (SUSE) wrote:
> The stride field is used to convert object index to an slabobj_ext so
> both compact arrays (kmalloc() or in-slab-leftover) and spread
> in-object-padding obj_ext layouts are supported.
>
> In practice thus the stride is always sizeof(slabobj_ext) or s->size.
>
> This simplifies the calculations, but with the upcoming slabobj_ext
> handling changes, it will be easier to stop storing the stride and
> instead just have a flag whether obj_ext is in the object padding.
> obj_exts_in_object() can then rely on this flag and slab_obj_ext()
> can use that to determine the stride.
>
> No functional change intended. Performance impact TBD, hopefully
> in the noise.
Performance impact is not TBD anymore?
> Reviewed-by: Suren Baghdasaryan <surenb@google.com>
> Reviewed-by: Hao Li <hao.li@linux.dev>
> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
> ---
Looks good to me,
Reviewed-by: Harry Yoo (Oracle) <harry@kernel.org>
next prev parent reply other threads:[~2026-07-29 6:41 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-27 12:53 [PATCH v3 00/13] mm/slab, alloc_tag: reduce obj_ext memory waste Vlastimil Babka (SUSE)
2026-07-27 12:53 ` [PATCH v3 01/13] mm/slab: skip kfence objects in allocation profiling Vlastimil Babka (SUSE)
2026-07-27 12:53 ` [PATCH v3 02/13] mm/slab: remove objs_per_slab() Vlastimil Babka (SUSE)
2026-07-27 12:53 ` [PATCH v3 03/13] mm: move struct slabobj_ext to mm/slab.h Vlastimil Babka (SUSE)
2026-07-27 12:53 ` [PATCH v3 04/13] mm/slab: make slab_obj_ext() determine object index Vlastimil Babka (SUSE)
2026-07-27 12:53 ` [PATCH v3 05/13] mm/slab: abstract slabobj_ext.objcg access Vlastimil Babka (SUSE)
2026-07-28 13:24 ` Harry Yoo
2026-07-28 13:25 ` Harry Yoo
2026-07-27 12:54 ` [PATCH v3 06/13] mm/slab: abstract slabobj_ext.ref access Vlastimil Babka (SUSE)
2026-07-28 13:41 ` Harry Yoo
2026-07-28 17:41 ` Vlastimil Babka (SUSE)
2026-07-29 6:18 ` Harry Yoo
2026-07-27 12:54 ` [PATCH v3 07/13] mm/slab: replace slab.stride with obj_exts_in_object Vlastimil Babka (SUSE)
2026-07-29 6:40 ` Harry Yoo [this message]
2026-07-29 9:27 ` Vlastimil Babka (SUSE)
2026-07-27 12:54 ` [PATCH v3 08/13] mm/slab: change struct slabobj_ext to a union Vlastimil Babka (SUSE)
2026-07-29 9:03 ` Harry Yoo
2026-07-27 12:54 ` [PATCH v3 09/13] mm/slab: introduce slab_obj_ext_has_codetag() Vlastimil Babka (SUSE)
2026-07-27 12:54 ` [PATCH v3 10/13] mm/slab: reduce slabobj_ext memory with allocation profiling disabled Vlastimil Babka (SUSE)
2026-07-27 14:07 ` Vlastimil Babka (SUSE)
2026-07-27 12:54 ` [PATCH v3 11/13] mm/slab: add cache_ and slab_needs_objcg() helpers Vlastimil Babka (SUSE)
2026-07-27 12:54 ` [PATCH v3 12/13] mm/slab: stop allocating objcg pointers when unnecessary Vlastimil Babka (SUSE)
2026-07-27 12:54 ` [PATCH v3 13/13] mm/slab, kfence, memcg: completely remove obj_ext for kfence objects Vlastimil Babka (SUSE)
2026-07-28 17:46 ` [PATCH v3 00/13] mm/slab, alloc_tag: reduce obj_ext memory waste Vlastimil Babka (SUSE)
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