From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 82859C2D0DB for ; Mon, 27 Jan 2020 17:44:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3C037214D8 for ; Mon, 27 Jan 2020 17:44:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="lP8MpqhL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C037214D8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=fb.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 245E06B0287; Mon, 27 Jan 2020 12:44:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1ACBD6B0289; Mon, 27 Jan 2020 12:44:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ECB106B028A; Mon, 27 Jan 2020 12:43:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0071.hostedemail.com [216.40.44.71]) by kanga.kvack.org (Postfix) with ESMTP id CEB5D6B0287 for ; Mon, 27 Jan 2020 12:43:59 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id A25AE4405 for ; Mon, 27 Jan 2020 17:43:59 +0000 (UTC) X-FDA: 76424137398.25.walk09_5ac89eb53c12 X-HE-Tag: walk09_5ac89eb53c12 X-Filterd-Recvd-Size: 9480 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Mon, 27 Jan 2020 17:43:58 +0000 (UTC) Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00RHhqt0019708 for ; Mon, 27 Jan 2020 09:43:57 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=fGc40ISmXEiDZ7NX05rsMXJRJTtdaUr44omiBuxk3zU=; b=lP8MpqhL6aX/rH/5WHJruxyqH08uAJuGmbNmfYfNSd6y1v+c4PUh4DrA8TY9vfXgw9Dk kvS/8O0EK9hPyxxRNWxjO6s2PAvvS7arPCRv+tSC6/KX4w7pgFTXCgF6isV18jx0Cy5D E7CXt3BOQXmA0xxXHbipGuhwH2Q0EQ13vLY= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 2xs6jd6843-16 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 27 Jan 2020 09:43:57 -0800 Received: from intmgw002.41.prn1.facebook.com (2620:10d:c085:108::8) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Mon, 27 Jan 2020 09:43:51 -0800 Received: by devvm2643.prn2.facebook.com (Postfix, from userid 111017) id D85381DFEFCAD; Mon, 27 Jan 2020 09:35:07 -0800 (PST) Smtp-Origin-Hostprefix: devvm From: Roman Gushchin Smtp-Origin-Hostname: devvm2643.prn2.facebook.com To: , Andrew Morton CC: Michal Hocko , Johannes Weiner , Shakeel Butt , Vladimir Davydov , , , Bharata B Rao , Yafang Shao , Roman Gushchin Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 22/28] mm: memcg/slab: simplify memcg cache creation Date: Mon, 27 Jan 2020 09:34:47 -0800 Message-ID: <20200127173453.2089565-23-guro@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200127173453.2089565-1-guro@fb.com> References: <20200127173453.2089565-1-guro@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-01-27_06:2020-01-24,2020-01-27 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=999 bulkscore=0 suspectscore=2 adultscore=0 spamscore=0 lowpriorityscore=0 mlxscore=0 priorityscore=1501 phishscore=0 clxscore=1015 impostorscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1911200001 definitions=main-2001270143 X-FB-Internal: deliver 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: Because the number of non-root kmem_caches doesn't depend on the number of memory cgroups anymore and is generally not very big, there is no more need for a dedicated workqueue. Also, as there is no more need to pass any arguments to the memcg_create_kmem_cache() except the root kmem_cache, it's possible to just embed the work structure into the kmem_cache and avoid the dynamic allocation of the work structure. This will also simplify the synchronization: for each root kmem_cache there is only one work. So there will be no more concurrent attempts to create a non-root kmem_cache for a root kmem_cache: the second and all following attempts to queue the work will fail. On the kmem_cache destruction path there is no more need to call the expensive flush_workqueue() and wait for all pending works to be finished. Instead, cancel_work_sync() can be used to cancel/wait for only one work. Signed-off-by: Roman Gushchin --- include/linux/memcontrol.h | 1 - mm/memcontrol.c | 48 +------------------------------------- mm/slab.h | 2 ++ mm/slab_common.c | 22 +++++++++-------- 4 files changed, 15 insertions(+), 58 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 95d66f46493c..cf2a1703164a 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1445,7 +1445,6 @@ int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size); void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size); extern struct static_key_false memcg_kmem_enabled_key; -extern struct workqueue_struct *memcg_kmem_cache_wq; extern int memcg_nr_cache_ids; void memcg_get_cache_ids(void); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3f92b1c71aed..a48d13718ec9 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -374,8 +374,6 @@ void memcg_put_cache_ids(void) */ DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key); EXPORT_SYMBOL(memcg_kmem_enabled_key); - -struct workqueue_struct *memcg_kmem_cache_wq; #endif static int memcg_shrinker_map_size; @@ -2855,39 +2853,6 @@ static void memcg_free_cache_id(int id) ida_simple_remove(&memcg_cache_ida, id); } -struct memcg_kmem_cache_create_work { - struct kmem_cache *cachep; - struct work_struct work; -}; - -static void memcg_kmem_cache_create_func(struct work_struct *w) -{ - struct memcg_kmem_cache_create_work *cw = - container_of(w, struct memcg_kmem_cache_create_work, work); - struct kmem_cache *cachep = cw->cachep; - - memcg_create_kmem_cache(cachep); - - kfree(cw); -} - -/* - * Enqueue the creation of a per-memcg kmem_cache. - */ -static void memcg_schedule_kmem_cache_create(struct kmem_cache *cachep) -{ - struct memcg_kmem_cache_create_work *cw; - - cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN); - if (!cw) - return; - - cw->cachep = cachep; - INIT_WORK(&cw->work, memcg_kmem_cache_create_func); - - queue_work(memcg_kmem_cache_wq, &cw->work); -} - /** * memcg_kmem_get_cache: select memcg or root cache for allocation * @cachep: the original global kmem cache @@ -2904,7 +2869,7 @@ struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep) memcg_cachep = READ_ONCE(cachep->memcg_params.memcg_cache); if (unlikely(!memcg_cachep)) { - memcg_schedule_kmem_cache_create(cachep); + queue_work(system_wq, &cachep->memcg_params.work); return cachep; } @@ -7000,17 +6965,6 @@ static int __init mem_cgroup_init(void) { int cpu, node; -#ifdef CONFIG_MEMCG_KMEM - /* - * Kmem cache creation is mostly done with the slab_mutex held, - * so use a workqueue with limited concurrency to avoid stalling - * all worker threads in case lots of cgroups are created and - * destroyed simultaneously. - */ - memcg_kmem_cache_wq = alloc_workqueue("memcg_kmem_cache", 0, 1); - BUG_ON(!memcg_kmem_cache_wq); -#endif - cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL, memcg_hotplug_cpu_dead); diff --git a/mm/slab.h b/mm/slab.h index 732051d6861d..847ceeffff65 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -45,12 +45,14 @@ struct kmem_cache { * @memcg_cache: pointer to memcg kmem cache, used by all non-root memory * cgroups. * @root_caches_node: list node for slab_root_caches list. + * @work: work struct used to create the non-root cache. */ struct memcg_cache_params { struct kmem_cache *root_cache; struct kmem_cache *memcg_cache; struct list_head __root_caches_node; + struct work_struct work; }; #endif /* CONFIG_SLOB */ diff --git a/mm/slab_common.c b/mm/slab_common.c index 9ad13c7e28fc..a4853b12db1c 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -132,10 +132,18 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr, LIST_HEAD(slab_root_caches); +static void memcg_kmem_cache_create_func(struct work_struct *work) +{ + struct kmem_cache *cachep = container_of(work, struct kmem_cache, + memcg_params.work); + memcg_create_kmem_cache(cachep); +} + void slab_init_memcg_params(struct kmem_cache *s) { s->memcg_params.root_cache = NULL; s->memcg_params.memcg_cache = NULL; + INIT_WORK(&s->memcg_params.work, memcg_kmem_cache_create_func); } static void init_memcg_params(struct kmem_cache *s, @@ -584,15 +592,9 @@ static int shutdown_memcg_caches(struct kmem_cache *s) return 0; } -static void flush_memcg_workqueue(struct kmem_cache *s) +static void cancel_memcg_cache_creation(struct kmem_cache *s) { - /* - * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB - * deactivates the memcg kmem_caches through workqueue. Make sure all - * previous workitems on workqueue are processed. - */ - if (likely(memcg_kmem_cache_wq)) - flush_workqueue(memcg_kmem_cache_wq); + cancel_work_sync(&s->memcg_params.work); } #else static inline int shutdown_memcg_caches(struct kmem_cache *s) @@ -600,7 +602,7 @@ static inline int shutdown_memcg_caches(struct kmem_cache *s) return 0; } -static inline void flush_memcg_workqueue(struct kmem_cache *s) +static inline void cancel_memcg_cache_creation(struct kmem_cache *s) { } #endif /* CONFIG_MEMCG_KMEM */ @@ -619,7 +621,7 @@ void kmem_cache_destroy(struct kmem_cache *s) if (unlikely(!s)) return; - flush_memcg_workqueue(s); + cancel_memcg_cache_creation(s); get_online_cpus(); get_online_mems(); -- 2.24.1