From: Alexander Potapenko <glider@google.com>
To: Harry Yoo <harry.yoo@oracle.com>
Cc: akpm@linux-foundation.org, vbabka@suse.cz, andreyknvl@gmail.com,
cl@gentwo.org, dvyukov@google.com, hannes@cmpxchg.org,
linux-mm@kvack.org, mhocko@kernel.org, muchun.song@linux.dev,
rientjes@google.com, roman.gushchin@linux.dev,
ryabinin.a.a@gmail.com, shakeel.butt@linux.dev,
surenb@google.com, vincenzo.frascino@arm.com,
yeoreum.yun@arm.com, tytso@mit.edu, adilger.kernel@dilger.ca,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
cgroups@vger.kernel.org, hao.li@linux.dev,
stable@vger.kernel.org
Subject: Re: [PATCH V5 1/8] mm/slab: use unsigned long for orig_size to ensure proper metadata align
Date: Fri, 9 Jan 2026 10:30:47 +0100 [thread overview]
Message-ID: <CAG_fn=Wyw-fGGQ802A1cUpkHHTnZi5gN7wZzRaF1s31SPOpC9g@mail.gmail.com> (raw)
In-Reply-To: <aWBfZ4ga9HQ8L8KM@hyeyoo>
> > Instead of calculating the offset of the original size in several
> > places, should we maybe introduce a function that returns a pointer to
> > it?
>
> Good point.
>
> The calculation of various metadata offset (including the original size)
> is repeated in several places, and perhaps it's worth cleaning up,
> something like this:
>
> enum {
> FREE_POINTER_OFFSET,
> ALLOC_TRACK_OFFSET,
> FREE_TRACK_OFFSET,
> ORIG_SIZE_OFFSET,
> KASAN_ALLOC_META_OFFSET,
> OBJ_EXT_OFFSET,
> FINAL_ALIGNMENT_PADDING_OFFSET,
> ...
> };
>
> orig_size = *(unsigned long *)get_metadata_ptr(p, ORIG_SIZE_OFFSET);
An alternative would be to declare a struct containing all the
metadata fields and use offsetof() (or simply do a cast and access the
fields via the struct pointer)
next prev parent reply other threads:[~2026-01-09 9:31 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-05 8:02 [PATCH V5 0/8] mm/slab: reduce slab accounting memory overhead by allocating slabobj_ext metadata within unsed slab space Harry Yoo
2026-01-05 8:02 ` [PATCH V5 1/8] mm/slab: use unsigned long for orig_size to ensure proper metadata align Harry Yoo
2026-01-07 11:43 ` Vlastimil Babka
2026-01-08 7:12 ` Harry Yoo
2026-01-08 11:39 ` Alexander Potapenko
2026-01-09 1:52 ` Harry Yoo
2026-01-09 9:30 ` Alexander Potapenko [this message]
2026-01-05 8:02 ` [PATCH V5 2/8] mm/slab: allow specifying free pointer offset when using constructor Harry Yoo
2026-01-05 8:02 ` [PATCH V5 3/8] ext4: specify the free pointer offset for ext4_inode_cache Harry Yoo
2026-01-07 13:54 ` Vlastimil Babka
2026-01-08 7:14 ` Harry Yoo
2026-01-05 8:02 ` [PATCH V5 4/8] mm/slab: abstract slabobj_ext access via new slab_obj_ext() helper Harry Yoo
2026-01-07 14:53 ` Hao Li
2026-01-08 7:21 ` Harry Yoo
2026-01-07 14:56 ` Vlastimil Babka
2026-01-08 8:03 ` Harry Yoo
2026-01-05 8:02 ` [PATCH V5 5/8] mm/slab: use stride to access slabobj_ext Harry Yoo
2026-01-05 8:02 ` [PATCH V5 6/8] mm/memcontrol,alloc_tag: handle slabobj_ext access under KASAN poison Harry Yoo
2026-01-05 8:02 ` [PATCH V5 7/8] mm/slab: save memory by allocating slabobj_ext array from leftover Harry Yoo
2026-01-07 17:08 ` Vlastimil Babka
2026-01-05 8:02 ` [PATCH V5 8/8] mm/slab: place slabobj_ext metadata in unused space within s->size Harry Yoo
2026-01-07 17:33 ` Vlastimil Babka
2026-01-08 9:02 ` Harry Yoo
2026-01-08 5:52 ` Hao Li
2026-01-08 8:41 ` Harry Yoo
2026-01-08 9:52 ` Hao Li
2026-01-08 10:28 ` Harry Yoo
2026-01-08 10:44 ` Harry Yoo
2026-01-08 10:52 ` Vlastimil Babka
2026-01-08 12:48 ` Hao Li
2026-01-09 2:32 ` Harry Yoo
2026-01-08 11:57 ` Hao Li
2026-01-05 8:05 ` [PATCH V5 0/8] mm/slab: reduce slab accounting memory overhead by allocating slabobj_ext metadata within unsed slab space Harry Yoo
2026-01-07 17:43 ` Vlastimil Babka
2026-01-08 7:05 ` Harry Yoo
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