From patchwork Tue Jun 29 02:37:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12349033 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B27EC11F65 for ; Tue, 29 Jun 2021 02:37:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C914061D06 for ; Tue, 29 Jun 2021 02:37:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C914061D06 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1E1FA8D00C7; Mon, 28 Jun 2021 22:37:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1BB008D008F; Mon, 28 Jun 2021 22:37:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F274F8D00C7; Mon, 28 Jun 2021 22:37:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0098.hostedemail.com [216.40.44.98]) by kanga.kvack.org (Postfix) with ESMTP id CDAB18D008F for ; Mon, 28 Jun 2021 22:37:39 -0400 (EDT) Received: from smtpin34.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id D24D9204BB for ; Tue, 29 Jun 2021 02:37:39 +0000 (UTC) X-FDA: 78305200638.34.307D7B1 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf21.hostedemail.com (Postfix) with ESMTP id 798ECE000253 for ; Tue, 29 Jun 2021 02:37:39 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 5810C61D04; Tue, 29 Jun 2021 02:37:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1624934258; bh=CaNm4vNDR3KTJsf3X0s8Brc7Ur/yvhfd38eVU5bAIYg=; h=Date:From:To:Subject:In-Reply-To:From; b=t9rkEgUOnd6le4e8FAcfFdqv6VyH367DQ3TP0W2yDGcv5z7AEexWXRu6DBcD2AiBA kTvT72Rz/edrJuwfSkZzrQpAa6b9YG5TVeQrTd3v2NhZ3OVztUERJFLv4KL2f0fCAf SBhkfMJEQC4Lb+k2biXdQORgjeQx2jP562XrYYtE= Date: Mon, 28 Jun 2021 19:37:38 -0700 From: Andrew Morton To: akpm@linux-foundation.org, cl@linux.com, guro@fb.com, hannes@cmpxchg.org, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, longman@redhat.com, mhocko@kernel.org, mm-commits@vger.kernel.org, penberg@kernel.org, rientjes@google.com, shakeelb@google.com, torvalds@linux-foundation.org, vbabka@suse.cz, vdavydov.dev@gmail.com Subject: [patch 082/192] mm: memcg/slab: create a new set of kmalloc-cg- caches Message-ID: <20210629023738.MBexNoCOI%akpm@linux-foundation.org> In-Reply-To: <20210628193256.008961950a714730751c1423@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=t9rkEgUO; spf=pass (imf21.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 798ECE000253 X-Stat-Signature: e5nansc1piynan5zosxyqz7bjk8d5c4p X-HE-Tag: 1624934259-448527 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Waiman Long Subject: mm: memcg/slab: create a new set of kmalloc-cg- caches There are currently two problems in the way the objcg pointer array (memcg_data) in the page structure is being allocated and freed. On its allocation, it is possible that the allocated objcg pointer array comes from the same slab that requires memory accounting. If this happens, the slab will never become empty again as there is at least one object left (the obj_cgroup array) in the slab. When it is freed, the objcg pointer array object may be the last one in its slab and hence causes kfree() to be called again. With the right workload, the slab cache may be set up in a way that allows the recursive kfree() calling loop to nest deep enough to cause a kernel stack overflow and panic the system. One way to solve this problem is to split the kmalloc- caches (KMALLOC_NORMAL) into two separate sets - a new set of kmalloc- (KMALLOC_NORMAL) caches for unaccounted objects only and a new set of kmalloc-cg- (KMALLOC_CGROUP) caches for accounted objects only. All the other caches can still allow a mix of accounted and unaccounted objects. With this change, all the objcg pointer array objects will come from KMALLOC_NORMAL caches which won't have their objcg pointer arrays. So both the recursive kfree() problem and non-freeable slab problem are gone. Since both the KMALLOC_NORMAL and KMALLOC_CGROUP caches no longer have mixed accounted and unaccounted objects, this will slightly reduce the number of objcg pointer arrays that need to be allocated and save a bit of memory. On the other hand, creating a new set of kmalloc caches does have the effect of reducing cache utilization. So it is properly a wash. The new KMALLOC_CGROUP is added between KMALLOC_NORMAL and KMALLOC_RECLAIM so that the first for loop in create_kmalloc_caches() will include the newly added caches without change. [vbabka@suse.cz: don't create kmalloc-cg caches with cgroup.memory=nokmem] Link: https://lkml.kernel.org/r/20210512145107.6208-1-longman@redhat.com Link: https://lkml.kernel.org/r/20210505200610.13943-3-longman@redhat.com Signed-off-by: Waiman Long Signed-off-by: Vlastimil Babka Suggested-by: Vlastimil Babka Reviewed-by: Shakeel Butt Acked-by: Roman Gushchin Cc: Christoph Lameter Cc: David Rientjes Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Pekka Enberg Cc: Vladimir Davydov [longman@redhat.com: fix for CONFIG_ZONE_DMA=n] Link: https://lkml.kernel.org/r/20210512145107.6208-1-longman@redhat.com [akpm@linux-foundation.org: un-fat-finger v5 delta creation] [longman@redhat.com: disable cache merging for KMALLOC_NORMAL caches] Link: https://lkml.kernel.org/r/20210505200610.13943-4-longman@redhat.com Signed-off-by: Waiman Long Suggested-by: Roman Gushchin Acked-by: Roman Gushchin Reviewed-by: Shakeel Butt Reviewed-by: Vlastimil Babka Cc: Christoph Lameter Cc: David Rientjes Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Pekka Enberg Cc: Vladimir Davydov Signed-off-by: Andrew Morton --- include/linux/slab.h | 42 ++++++++++++++++++++++++++++++++--------- mm/internal.h | 5 ++++ mm/memcontrol.c | 2 - mm/slab_common.c | 32 ++++++++++++++++++++++--------- 4 files changed, 62 insertions(+), 19 deletions(-) --- a/include/linux/slab.h~mm-memcg-slab-create-a-new-set-of-kmalloc-cg-n-caches +++ a/include/linux/slab.h @@ -305,9 +305,21 @@ static inline void __check_heap_object(c /* * Whenever changing this, take care of that kmalloc_type() and * create_kmalloc_caches() still work as intended. + * + * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP + * is for accounted but unreclaimable and non-dma objects. All the other + * kmem caches can have both accounted and unaccounted objects. */ enum kmalloc_cache_type { KMALLOC_NORMAL = 0, +#ifndef CONFIG_ZONE_DMA + KMALLOC_DMA = KMALLOC_NORMAL, +#endif +#ifndef CONFIG_MEMCG_KMEM + KMALLOC_CGROUP = KMALLOC_NORMAL, +#else + KMALLOC_CGROUP, +#endif KMALLOC_RECLAIM, #ifdef CONFIG_ZONE_DMA KMALLOC_DMA, @@ -319,24 +331,36 @@ enum kmalloc_cache_type { extern struct kmem_cache * kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1]; +/* + * Define gfp bits that should not be set for KMALLOC_NORMAL. + */ +#define KMALLOC_NOT_NORMAL_BITS \ + (__GFP_RECLAIMABLE | \ + (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \ + (IS_ENABLED(CONFIG_MEMCG_KMEM) ? __GFP_ACCOUNT : 0)) + static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags) { -#ifdef CONFIG_ZONE_DMA /* * The most common case is KMALLOC_NORMAL, so test for it - * with a single branch for both flags. + * with a single branch for all the relevant flags. */ - if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0)) + if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0)) return KMALLOC_NORMAL; /* - * At least one of the flags has to be set. If both are, __GFP_DMA - * is more important. + * At least one of the flags has to be set. Their priorities in + * decreasing order are: + * 1) __GFP_DMA + * 2) __GFP_RECLAIMABLE + * 3) __GFP_ACCOUNT */ - return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM; -#else - return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL; -#endif + if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA)) + return KMALLOC_DMA; + if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || (flags & __GFP_RECLAIMABLE)) + return KMALLOC_RECLAIM; + else + return KMALLOC_CGROUP; } /* --- a/mm/internal.h~mm-memcg-slab-create-a-new-set-of-kmalloc-cg-n-caches +++ a/mm/internal.h @@ -116,6 +116,11 @@ extern void putback_lru_page(struct page extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address); /* + * in mm/memcontrol.c: + */ +extern bool cgroup_memory_nokmem; + +/* * in mm/page_alloc.c */ --- a/mm/memcontrol.c~mm-memcg-slab-create-a-new-set-of-kmalloc-cg-n-caches +++ a/mm/memcontrol.c @@ -83,7 +83,7 @@ DEFINE_PER_CPU(struct mem_cgroup *, int_ static bool cgroup_memory_nosocket; /* Kernel memory accounting disabled? */ -static bool cgroup_memory_nokmem; +bool cgroup_memory_nokmem; /* Whether the swap controller is active */ #ifdef CONFIG_MEMCG_SWAP --- a/mm/slab_common.c~mm-memcg-slab-create-a-new-set-of-kmalloc-cg-n-caches +++ a/mm/slab_common.c @@ -738,21 +738,25 @@ struct kmem_cache *kmalloc_slab(size_t s } #ifdef CONFIG_ZONE_DMA -#define INIT_KMALLOC_INFO(__size, __short_size) \ -{ \ - .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \ - .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \ - .name[KMALLOC_DMA] = "dma-kmalloc-" #__short_size, \ - .size = __size, \ -} +#define KMALLOC_DMA_NAME(sz) .name[KMALLOC_DMA] = "dma-kmalloc-" #sz, #else +#define KMALLOC_DMA_NAME(sz) +#endif + +#ifdef CONFIG_MEMCG_KMEM +#define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz, +#else +#define KMALLOC_CGROUP_NAME(sz) +#endif + #define INIT_KMALLOC_INFO(__size, __short_size) \ { \ .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \ .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \ + KMALLOC_CGROUP_NAME(__short_size) \ + KMALLOC_DMA_NAME(__short_size) \ .size = __size, \ } -#endif /* * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. @@ -838,8 +842,15 @@ void __init setup_kmalloc_cache_index_ta static void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) { - if (type == KMALLOC_RECLAIM) + if (type == KMALLOC_RECLAIM) { flags |= SLAB_RECLAIM_ACCOUNT; + } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) { + if (cgroup_memory_nokmem) { + kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx]; + return; + } + flags |= SLAB_ACCOUNT; + } kmalloc_caches[type][idx] = create_kmalloc_cache( kmalloc_info[idx].name[type], @@ -857,6 +868,9 @@ void __init create_kmalloc_caches(slab_f int i; enum kmalloc_cache_type type; + /* + * Including KMALLOC_CGROUP if CONFIG_MEMCG_KMEM defined + */ for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) { for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { if (!kmalloc_caches[type][i])