From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B3803382E8 for ; Thu, 2 Jul 2026 04:09:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782965385; cv=none; b=WkTGs7ipA4o1ombTy4kGohkrA/pWr8BXDopbbHLQ8yaBKYjQ6H+LxfIbaXkq+4t+JdRoHDkV7Y9fP05Di6iPYijvWEGa+jVT6/DpzO00w7FCcIYFZkYLat5Cru7ju6jNd3y2axSWs2JkbImdwLh2vrn5KfljFVHx8jmsTW2vpWk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782965385; c=relaxed/simple; bh=4TVkPiN/AP61q1DXeS1SfdbeUv4cnmj4CY2shCJzaLQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pF+gYhD8NLJgrW044bjPXcqIy8UwzIiUlXNfPh5XyzCS0UWeDI6ZhwkTAOpdSQwC4cjbWAZ2fLUQyEsZsCdfVqTlq3pFNGksIzUysm3i5W4ER8Ae/ypkbGT7DZSfBigXC0HPgf/RUesX0MXnpGWEJBgnpQr01cV8INHuEhrnVxk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LE04eY4k; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LE04eY4k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D17411F00A3D; Thu, 2 Jul 2026 04:09:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782965384; bh=JnttxAJENdZnOWBFIzHxzAh7v9jg3+gRRpnQCe0gN5M=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=LE04eY4kFFpXXe8v/bJoBg/GokH8w+tsUEru9l7fUKX19WllIWl0rm8Xtsula20mQ ku7NZ+yyPhgkerGWpr+IpzNmKcGjKq1rzsMrnFsaTS8Ma3aXFFywvVEQZRPZNOeLBt vUfV71r9w4wFSt4DPjqQaURSx01Tsg5R+nou8j19XFT9c/eVouyE1FM2nluiGfwI8t a4MTK2indiJ31+mgM+iLGSKl5nVH6Fl94Zc9DOz4TBvbRD4+lPoScm73sz0lV0Rg1P f9faJ8+wvq7NNhY3stDgg7Jwkyj9J8k/OBZZEoKonTXWaxT5xwU7DQ2ssbJIMFFCoe V9A0K0GgqFvJA== From: "Harry Yoo (Oracle)" Date: Thu, 02 Jul 2026 13:09:24 +0900 Subject: [PATCH RFC hotfixes 1/2] mm/slab: decouple SLAB_NO_SHEAVES from SLAB_NO_OBJ_EXT Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260702-kmalloc-no-objext-v1-1-167175008538@kernel.org> References: <20260702-kmalloc-no-objext-v1-0-167175008538@kernel.org> In-Reply-To: <20260702-kmalloc-no-objext-v1-0-167175008538@kernel.org> To: Vlastimil Babka , Andrew Morton , Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Suren Baghdasaryan , Hao Ge , Kees Cook , Pedro Falcato , Shakeel Butt , Danielle Constantino Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Harry Yoo (Oracle)" X-Mailer: b4 0.14.3 Bootstrap caches are created with SLAB_NO_OBJ_EXT to disallow sheaves and obj_exts. To allow disabling obj_exts while allowing sheaves, decouple SLAB_NO_SHEAVES from SLAB_NO_OBJ_EXT. Bootstrap caches now have both SLAB_NO_SHEAVES and SLAB_NO_OBJ_EXT. No functional change intended. Cc: stable@vger.kernel.org Fixes: e47c897a2949 ("slab: add sheaves to most caches") Signed-off-by: Harry Yoo (Oracle) --- include/linux/slab.h | 13 +++++++++++-- mm/slub.c | 10 ++++++---- 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index 51f03f18c9a7..08d7b6c9c4d6 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -58,10 +58,13 @@ enum _slab_flag_bits { #endif _SLAB_OBJECT_POISON, _SLAB_CMPXCHG_DOUBLE, +#ifdef CONFIG_SLAB_OBJ_EXT _SLAB_NO_OBJ_EXT, -#if defined(CONFIG_SLAB_OBJ_EXT) && defined(CONFIG_64BIT) +#ifdef CONFIG_64BIT _SLAB_OBJ_EXT_IN_OBJ, #endif +#endif + _SLAB_NO_SHEAVES, _SLAB_FLAGS_LAST_BIT }; @@ -239,8 +242,14 @@ enum _slab_flag_bits { #endif #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */ -/* Slab created using create_boot_cache */ +/* Slab caches without obj_exts array */ +#ifdef CONFIG_SLAB_OBJ_EXT #define SLAB_NO_OBJ_EXT __SLAB_FLAG_BIT(_SLAB_NO_OBJ_EXT) +#else +#define SLAB_NO_OBJ_EXT __SLAB_FLAG_UNUSED +#endif + +#define SLAB_NO_SHEAVES __SLAB_FLAG_BIT(_SLAB_NO_SHEAVES) #if defined(CONFIG_SLAB_OBJ_EXT) && defined(CONFIG_64BIT) #define SLAB_OBJ_EXT_IN_OBJ __SLAB_FLAG_BIT(_SLAB_OBJ_EXT_IN_OBJ) diff --git a/mm/slub.c b/mm/slub.c index 9f754cf1c187..efc85053ae84 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -7777,12 +7777,12 @@ static unsigned int calculate_sheaf_capacity(struct kmem_cache *s, return 0; /* - * Bootstrap caches can't have sheaves for now (SLAB_NO_OBJ_EXT). + * Bootstrap caches can't have sheaves for now (SLAB_NO_SHEAVES). * SLAB_NOLEAKTRACE caches (e.g., kmemleak's object_cache) must not * have sheaves to avoid recursion when sheaf allocation triggers * kmemleak tracking. */ - if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE)) + if (s->flags & (SLAB_NO_SHEAVES | SLAB_NOLEAKTRACE)) return 0; /* @@ -8559,7 +8559,8 @@ void __init kmem_cache_init(void) create_boot_cache(kmem_cache_node, "kmem_cache_node", sizeof(struct kmem_cache_node), - SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0); + SLAB_HWCACHE_ALIGN | SLAB_NO_SHEAVES | SLAB_NO_OBJ_EXT, + 0, 0); hotplug_node_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); @@ -8569,7 +8570,8 @@ void __init kmem_cache_init(void) create_boot_cache(kmem_cache, "kmem_cache", offsetof(struct kmem_cache, per_node) + nr_node_ids * sizeof(struct kmem_cache_per_node_ptrs), - SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0); + SLAB_HWCACHE_ALIGN | SLAB_NO_SHEAVES | SLAB_NO_OBJ_EXT, + 0, 0); kmem_cache = bootstrap(&boot_kmem_cache); kmem_cache_node = bootstrap(&boot_kmem_cache_node); -- 2.53.0