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| author | Vlastimil Babka (SUSE) <vbabka@kernel.org> | 2026-07-27 14:54:05 +0200 |
|---|---|---|
| committer | Vlastimil Babka (SUSE) <vbabka@kernel.org> | 2026-08-04 12:23:22 +0200 |
| commit | 7def2e8549e5186cd4de97ab5ce56f7944d3da59 (patch) | |
| tree | 4f0f72704e7af2856102aa8032683b077cf523ba /include | |
| parent | c4ec6cb55750c80fc3d43b310eb7ccab33df3dcd (diff) | |
| download | linux-7def2e8549e5186cd4de97ab5ce56f7944d3da59.tar.gz linux-7def2e8549e5186cd4de97ab5ce56f7944d3da59.zip | |
mm/slab: add cache_ and slab_needs_objcg() helpers
Slabs of some caches never need the objcg part of struct slabobj_ext.
Introduce helpers to query this for a cache or a slab.
Introduce SLAB_MAY_ACCOUNT flag that is currently only internal and all
caches have it set except:
- KMALLOC_NORMAL caches, as long as KMALLOC_RECLAIM caches are separate
- KMALLOC_NO_OBJ_EXT caches, if they exist
For named caches we currently can't derive SLAB_MAY_ACCOUNT from
SLAB_ACCOUNT because some caches might be created without SLAB_ACCOUNT
and then used both with and without __GFP_ACCOUNT concurrently,
allocating obj_ext arrays on demand. So just add the SLAB_MAY_ACCOUNT
to all kmem caches, unless kmem accounting is disabled.
This can be improved later by finding out all caches used with
__GFP_ACCOUNT, creating them with the SLAB_MAY_ACCOUNT flag explicitly,
and then ignoring __GFP_ACCOUNT for all other caches (possibly with a
warning).
To make the evaluation of slab_needs_objcg() faster in the allocation
and free fast paths, add a obj_exts_needs_objcg flag into slab itself.
This optimization is only available on 64bit architectures where free
bits are available for the flag.
Reviewed-by: Hao Li <hao.li@linux.dev>
Link: https://patch.msgid.link/20260727-b4-objext_split-v3-11-c29ef0f1f257@kernel.org
Reviewed-by: Harry Yoo <harry@kernel.org>
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/slab.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h index 32c9f8ed7ae2..e1915026e030 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -45,6 +45,7 @@ enum _slab_flag_bits { #endif #ifdef CONFIG_MEMCG _SLAB_ACCOUNT, + _SLAB_MAY_ACCOUNT, #endif #ifdef CONFIG_KASAN_GENERIC _SLAB_KASAN, @@ -204,8 +205,10 @@ enum _slab_flag_bits { */ #ifdef CONFIG_MEMCG # define SLAB_ACCOUNT __SLAB_FLAG_BIT(_SLAB_ACCOUNT) +# define SLAB_MAY_ACCOUNT __SLAB_FLAG_BIT(_SLAB_MAY_ACCOUNT) #else # define SLAB_ACCOUNT __SLAB_FLAG_UNUSED +# define SLAB_MAY_ACCOUNT __SLAB_FLAG_UNUSED #endif #ifdef CONFIG_KASAN_GENERIC |