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From: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
To: Harry Yoo <harry@kernel.org>, Suren Baghdasaryan <surenb@google.com>
Cc: 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,
	 "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Subject: [PATCH RFC 02/12] mm/slab: remove objs_per_slab()
Date: Wed, 15 Jul 2026 12:10:42 +0200	[thread overview]
Message-ID: <20260715-b4-objext_split-v1-2-9a49c4ccf4c3@kernel.org> (raw)
In-Reply-To: <20260715-b4-objext_split-v1-0-9a49c4ccf4c3@kernel.org>

The function has an unused kmem_cache argument and almost nothing uses
it anyway; doing slab->objects is simpler. Remove it with the last two
users. KUNIT_EXPECT_EQ() needs a cast to avoid "error: ‘typeof’ applied
to a bit-field" but we don't need to keep a wrapper just for that.

Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
---
 mm/kfence/kfence_test.c | 2 +-
 mm/slab.h               | 6 ------
 mm/slub.c               | 3 +--
 3 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
index de2d0f7d62b1..9867c03ef0ae 100644
--- a/mm/kfence/kfence_test.c
+++ b/mm/kfence/kfence_test.c
@@ -295,7 +295,7 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
 			 * memcg accounting works correctly.
 			 */
 			KUNIT_EXPECT_EQ(test, obj_to_index(s, slab, alloc), 0U);
-			KUNIT_EXPECT_EQ(test, objs_per_slab(s, slab), 1);
+			KUNIT_EXPECT_EQ(test, ((unsigned int)slab->objects), 1);
 
 			if (policy == ALLOCATE_ANY)
 				return alloc;
diff --git a/mm/slab.h b/mm/slab.h
index f5e336b6b6b0..01535e1e2d3c 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -330,12 +330,6 @@ static inline unsigned int obj_to_index(const struct kmem_cache *cache,
 	return __obj_to_index(cache, slab_address(slab), obj);
 }
 
-static inline int objs_per_slab(const struct kmem_cache *cache,
-				const struct slab *slab)
-{
-	return slab->objects;
-}
-
 /*
  * State of the slab allocator.
  *
diff --git a/mm/slub.c b/mm/slub.c
index a4be70d080fb..9e25f2dce7a6 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2127,7 +2127,6 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
 			gfp_t gfp, unsigned int alloc_flags)
 {
 	const bool allow_spin = alloc_flags_allow_spinning(alloc_flags);
-	unsigned int objects = objs_per_slab(s, slab);
 	bool new_slab = alloc_flags & SLAB_ALLOC_NEW_SLAB;
 	unsigned long new_exts;
 	unsigned long old_exts;
@@ -2183,7 +2182,7 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
 #endif
 retry:
 	old_exts = READ_ONCE(slab->obj_exts);
-	handle_failed_objexts_alloc(old_exts, vec, objects);
+	handle_failed_objexts_alloc(old_exts, vec, slab->objects);
 
 	if (new_slab) {
 		/*

-- 
2.55.0


  parent reply	other threads:[~2026-07-15 10:10 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-15 10:10 [PATCH RFC 00/12] mm/slab, alloc_tag: reduce obj_ext memory waste Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 01/12] mm/slab: skip kfence objects in allocation profiling Vlastimil Babka (SUSE)
2026-07-15 10:10 ` Vlastimil Babka (SUSE) [this message]
2026-07-15 10:10 ` [PATCH RFC 03/12] mm: move struct slabobj_ext to mm/slab.h Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 04/12] mm/slab: make slab_obj_ext() determine object index Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 05/12] mm/slab: abstract slabobj_ext.objcg access Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 06/12] mm/slab: abstract slabobj_ext.ref access Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 07/12] mm/slab: replace slab.stride with obj_exts_in_object Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 08/12] mm/slab: change struct slabobj_ext to a union Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 09/12] mm/slab: introduce slab_obj_ext_has_codetag() Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 10/12] mm/slab: reduce slabobj_ext memory with allocation profiling disabled Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 11/12] mm/slab: add slab_needs_objcg() helper Vlastimil Babka (SUSE)
2026-07-15 10:10 ` [PATCH RFC 12/12] mm/slab: stop allocating objcg pointers when unnecessary Vlastimil Babka (SUSE)

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