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 5AD2143B6CA; Wed, 15 Jul 2026 10:11:03 +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=1784110265; cv=none; b=hyemUFs4rTOd/S6hG5Ny85btyCsq427gb+N10hIlH11AklW+P2Ge3AvpJQWmDhUfLraqwEOIzRR2VmL7sqn1mtfewZBrKyXyJQN0TlKv+n06BI95U7oCdA8OX2zsmC5KpC3dJAhEgP07o/cXY3yJ//eGeY7EJkauz9xzzU9S/xY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784110265; c=relaxed/simple; bh=WUP+u5LtCO9Lnm0bpz/QH3WvOGZg0zXtJV5J+ezU95M=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=fSe3Xb8ybB82ImKMApaOCqmbKfQJu8KDgXEqdCG8oXYH51kh4hj3kfjS2D6pX6D5iCvAhb90OBeCr3X0uiDG0Qa/4/R0frOdhFdTTKEGYyHG5iqChCViInFCT2t9ot+EAT4smm4cJMM/pBjMhEwxssOqSQOtcCfDTwYIgaaRBJ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CIAt3+pe; 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="CIAt3+pe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8EF521F00A3D; Wed, 15 Jul 2026 10:11:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784110263; bh=GxN00IWro8eCPaP3MfYs22vlSvWNn2fiqNBuPgHAw1Y=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=CIAt3+peHEAjVLCFNdEtjzKI6Bn831EpZQol9Ve4nYeSqpWpoEXH+e1PZiE69sypP 1nJ13de+fohnPBl/BNpnTUPnAvLsaLRYx67o3i3crWhZ+5Yste9ZYlSMVqxJx3jp0t M5ulcTaGX3MFh4DZ4V9bU3v1znNXCpBkEmUcKozrFkKdKb7dSBF/pnOr2fqmADvnYS p1QlnbmjV61UxE8ygT37MjupfQDhVPwJQ1euv8w2itANBlrgDvzIyxNi/L66pVVI0A BoHx+F42FMcDhpYFTkq6U/aCa1NeoRS6Zh0wjgd8TE5xnatzwnEFUmG4r8e9jbvlFu 2ijvQhifFuvNw== From: "Vlastimil Babka (SUSE)" Date: Wed, 15 Jul 2026 12:10:45 +0200 Subject: [PATCH RFC 05/12] mm/slab: abstract slabobj_ext.objcg access 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: <20260715-b4-objext_split-v1-5-9a49c4ccf4c3@kernel.org> References: <20260715-b4-objext_split-v1-0-9a49c4ccf4c3@kernel.org> In-Reply-To: <20260715-b4-objext_split-v1-0-9a49c4ccf4c3@kernel.org> To: Harry Yoo , Suren Baghdasaryan Cc: Hao Li , Shakeel Butt , Alexander Potapenko , Marco Elver , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, "Vlastimil Babka (SUSE)" X-Mailer: b4 0.15.2 In preparation for changes to the structure, abstract access to the objcg field with a slab_obj_ext_objcgp() function. Rename the field to _objcg to make an unexpected direct access a compile error. No functional change intended. Signed-off-by: Vlastimil Babka (SUSE) --- mm/kfence/core.c | 2 +- mm/memcontrol.c | 23 +++++++++++++++-------- mm/slab.h | 9 ++++++++- mm/slub.c | 2 +- 4 files changed, 25 insertions(+), 11 deletions(-) diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 6577bd76954e..717e8baf7e5d 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -1249,7 +1249,7 @@ void __kfence_free(void *addr) struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr); #ifdef CONFIG_MEMCG - KFENCE_WARN_ON(meta->obj_exts.objcg); + KFENCE_WARN_ON(*slab_obj_ext_objcgp(&meta->obj_exts)); #endif /* * If the objects of the cache are SLAB_TYPESAFE_BY_RCU, defer freeing diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4e427286a88a..6303a2b1a9d0 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2865,6 +2865,7 @@ struct mem_cgroup *mem_cgroup_from_obj_slab(struct slab *slab, void *p) */ unsigned long obj_exts; struct slabobj_ext *obj_ext; + struct obj_cgroup *objcg; obj_exts = slab_obj_exts(slab); if (!obj_exts) @@ -2872,9 +2873,8 @@ struct mem_cgroup *mem_cgroup_from_obj_slab(struct slab *slab, void *p) get_slab_obj_exts(obj_exts); obj_ext = slab_obj_ext(slab->slab_cache, slab, obj_exts, p); - if (obj_ext->objcg) { - struct obj_cgroup *objcg = obj_ext->objcg; - + objcg = *slab_obj_ext_objcgp(obj_ext); + if (objcg) { put_slab_obj_exts(obj_exts); return obj_cgroup_memcg(objcg); } @@ -3577,6 +3577,7 @@ bool __memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, unsigned long obj_exts; struct slabobj_ext *obj_ext; struct obj_stock_pcp *stock; + struct obj_cgroup **objcgp; slab = virt_to_slab(p[i]); @@ -3612,10 +3613,15 @@ bool __memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, unlock_stock(stock); obj_exts = slab_obj_exts(slab); + get_slab_obj_exts(obj_exts); + obj_ext = slab_obj_ext(s, slab, obj_exts, p[i]); + objcgp = slab_obj_ext_objcgp(obj_ext); + obj_cgroup_get(objcg); - obj_ext->objcg = objcg; + *objcgp = objcg; + put_slab_obj_exts(obj_exts); } @@ -3628,16 +3634,17 @@ void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, size_t obj_size = obj_full_size(s); for (int i = 0; i < objects; i++) { - struct obj_cgroup *objcg; + struct obj_cgroup **objcgp, *objcg; struct slabobj_ext *obj_ext; struct obj_stock_pcp *stock; obj_ext = slab_obj_ext(s, slab, obj_exts, p[i]); - objcg = obj_ext->objcg; - if (!objcg) + objcgp = slab_obj_ext_objcgp(obj_ext); + if (!*objcgp) continue; - obj_ext->objcg = NULL; + objcg = *objcgp; + *objcgp = NULL; stock = trylock_stock(); __refill_obj_stock(objcg, stock, obj_size, true); diff --git a/mm/slab.h b/mm/slab.h index 36d067d6e7c0..789bd292075f 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -555,7 +555,7 @@ static inline bool need_kmalloc_no_objext(void) */ struct slabobj_ext { #ifdef CONFIG_MEMCG - struct obj_cgroup *objcg; + struct obj_cgroup *_objcg; #endif #ifdef CONFIG_MEM_ALLOC_PROFILING union codetag_ref ref; @@ -661,6 +661,13 @@ slab_obj_ext(struct kmem_cache *s, struct slab *slab, unsigned long obj_exts, return kasan_reset_tag(obj_ext); } +#ifdef CONFIG_MEMCG +static inline struct obj_cgroup **slab_obj_ext_objcgp(struct slabobj_ext *obj_ext) +{ + return &obj_ext->_objcg; +} +#endif + int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, gfp_t gfp, unsigned int alloc_flags); diff --git a/mm/slub.c b/mm/slub.c index 5e3f53bcd0d3..48e10198a3ce 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2523,7 +2523,7 @@ bool memcg_slab_post_charge(void *p, gfp_t flags) if (obj_exts) { get_slab_obj_exts(obj_exts); obj_ext = slab_obj_ext(s, slab, obj_exts, p); - if (unlikely(obj_ext->objcg)) { + if (unlikely(*slab_obj_ext_objcgp(obj_ext))) { put_slab_obj_exts(obj_exts); return true; } -- 2.55.0