From nobody Mon Apr 27 16:11:49 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F010C43334 for ; Fri, 10 Jun 2022 18:03:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346605AbiFJSDt (ORCPT ); Fri, 10 Jun 2022 14:03:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346245AbiFJSDY (ORCPT ); Fri, 10 Jun 2022 14:03:24 -0400 Received: from out1.migadu.com (out1.migadu.com [IPv6:2001:41d0:2:863f::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 997956157 for ; Fri, 10 Jun 2022 11:03:22 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1654884200; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=n7eiALpPTcznIaF/fXFxgNtbZ4SHuwV6uZfI15xSoCI=; b=qcKvBzgxPkVHmma3sPc0dSPROIntT65cSF8/Y4tzMUDAecGTQAoT+9O2+GP21fIEJNkMF5 66GK6N8tnp/19FlzaLx21Ewi/0SOlakp+94UJJ9V8gegQ7i2Xd92K68bLozVoSCqdjRbrA cujBBXBgiXVX3OzcnID0cXvD8IyQyr4= From: Roman Gushchin To: Andrew Morton , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Naresh Kamboju , Vasily Averin , Qian Cai , Roman Gushchin , Kefeng Wang , Linux Kernel Functional Testing , Shakeel Butt Subject: [PATCH] mm: kmem: make mem_cgroup_from_obj() vmalloc()-safe Date: Fri, 10 Jun 2022 11:03:10 -0700 Message-Id: <20220610180310.1725111-1-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Currently mem_cgroup_from_obj() is not working properly with objects allocated using vmalloc(). It creates problems in some cases, when it's called for static objects belonging to modules or generally allocated using vmalloc(). This patch makes mem_cgroup_from_obj() safe to be called on objects allocated using vmalloc(). It also introduces mem_cgroup_from_slab_obj(), which is a faster version to use in places when we know the object is either a slab object or a generic slab page (e.g. when adding an object to a lru list). Suggested-by: Kefeng Wang Signed-off-by: Roman Gushchin Tested-by: Linux Kernel Functional Testing Acked-by: Shakeel Butt Acked-by: Michal Hocko Acked-by: Muchun Song Tested-by: Vasily Averin --- include/linux/memcontrol.h | 6 ++++ mm/list_lru.c | 2 +- mm/memcontrol.c | 71 +++++++++++++++++++++++++++----------- 3 files changed, 57 insertions(+), 22 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 0d7584e2f335..4d31ce55b1c0 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1761,6 +1761,7 @@ static inline int memcg_kmem_id(struct mem_cgroup *me= mcg) } =20 struct mem_cgroup *mem_cgroup_from_obj(void *p); +struct mem_cgroup *mem_cgroup_from_slab_obj(void *p); =20 static inline void count_objcg_event(struct obj_cgroup *objcg, enum vm_event_item idx) @@ -1858,6 +1859,11 @@ static inline struct mem_cgroup *mem_cgroup_from_obj= (void *p) return NULL; } =20 +static inline struct mem_cgroup *mem_cgroup_from_slab_obj(void *p) +{ + return NULL; +} + static inline void count_objcg_event(struct obj_cgroup *objcg, enum vm_event_item idx) { diff --git a/mm/list_lru.c b/mm/list_lru.c index ba76428ceece..a05e5bef3b40 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -71,7 +71,7 @@ list_lru_from_kmem(struct list_lru *lru, int nid, void *p= tr, if (!list_lru_memcg_aware(lru)) goto out; =20 - memcg =3D mem_cgroup_from_obj(ptr); + memcg =3D mem_cgroup_from_slab_obj(ptr); if (!memcg) goto out; =20 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4093062c5c9b..8c408d681377 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -783,7 +783,7 @@ void __mod_lruvec_kmem_state(void *p, enum node_stat_it= em idx, int val) struct lruvec *lruvec; =20 rcu_read_lock(); - memcg =3D mem_cgroup_from_obj(p); + memcg =3D mem_cgroup_from_slab_obj(p); =20 /* * Untracked pages have no memcg, no lruvec. Update only the @@ -2833,27 +2833,9 @@ int memcg_alloc_slab_cgroups(struct slab *slab, stru= ct kmem_cache *s, return 0; } =20 -/* - * Returns a pointer to the memory cgroup to which the kernel object is ch= arged. - * - * A passed kernel object can be a slab object or a generic kernel page, so - * different mechanisms for getting the memory cgroup pointer should be us= ed. - * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the c= aller - * can not know for sure how the kernel object is implemented. - * mem_cgroup_from_obj() can be safely used in such cases. - * - * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock= (), - * cgroup_mutex, etc. - */ -struct mem_cgroup *mem_cgroup_from_obj(void *p) +static __always_inline +struct mem_cgroup *mem_cgroup_from_obj_folio(struct folio *folio, void *p) { - struct folio *folio; - - if (mem_cgroup_disabled()) - return NULL; - - folio =3D virt_to_folio(p); - /* * Slab objects are accounted individually, not per-page. * Memcg membership data for each individual object is saved in @@ -2886,6 +2868,53 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p) return page_memcg_check(folio_page(folio, 0)); } =20 +/* + * Returns a pointer to the memory cgroup to which the kernel object is ch= arged. + * + * A passed kernel object can be a slab object, vmalloc object or a generic + * kernel page, so different mechanisms for getting the memory cgroup poin= ter + * should be used. + * + * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the c= aller + * can not know for sure how the kernel object is implemented. + * mem_cgroup_from_obj() can be safely used in such cases. + * + * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock= (), + * cgroup_mutex, etc. + */ +struct mem_cgroup *mem_cgroup_from_obj(void *p) +{ + struct folio *folio; + + if (mem_cgroup_disabled()) + return NULL; + + if (unlikely(is_vmalloc_addr(p))) + folio =3D page_folio(vmalloc_to_page(p)); + else + folio =3D virt_to_folio(p); + + return mem_cgroup_from_obj_folio(folio, p); +} + +/* + * Returns a pointer to the memory cgroup to which the kernel object is ch= arged. + * Similar to mem_cgroup_from_obj(), but faster and not suitable for objec= ts, + * allocated using vmalloc(). + * + * A passed kernel object must be a slab object or a generic kernel page. + * + * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock= (), + * cgroup_mutex, etc. + */ +struct mem_cgroup *mem_cgroup_from_slab_obj(void *p) +{ + if (mem_cgroup_disabled()) + return NULL; + + return mem_cgroup_from_obj_folio(virt_to_folio(p), p); +} + static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *m= emcg) { struct obj_cgroup *objcg =3D NULL; --=20 2.35.3