From patchwork Tue May 14 21:39:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Gushchin X-Patchwork-Id: 10943811 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 565C4924 for ; Tue, 14 May 2019 21:55:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 41F2C2883A for ; Tue, 14 May 2019 21:55:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 312D128885; Tue, 14 May 2019 21:55:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 679562883A for ; Tue, 14 May 2019 21:54:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 38EB36B0005; Tue, 14 May 2019 17:54:58 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 318AF6B0006; Tue, 14 May 2019 17:54:58 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1B8FC6B0007; Tue, 14 May 2019 17:54:58 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-yw1-f71.google.com (mail-yw1-f71.google.com [209.85.161.71]) by kanga.kvack.org (Postfix) with ESMTP id E84CC6B0005 for ; Tue, 14 May 2019 17:54:57 -0400 (EDT) Received: by mail-yw1-f71.google.com with SMTP id i125so640100ywf.5 for ; Tue, 14 May 2019 14:54:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:smtp-origin-hostprefix:from :smtp-origin-hostname:to:cc:smtp-origin-cluster:subject:date :message-id:in-reply-to:references:mime-version; bh=FtShZ2vB5fpsbZrZXegXCPM4YGPbu5mSBxgUC0FaF14=; b=SiwY5yBk8mSePd7PXtCqcvf6UHY063rzVlPNFHZ6aWcDMntg5yi1W7lFlwc+zyqgA8 Ulwc6AWnTZ+ULD9iY+9taY2rlKVMvBj68i2OzK3rxbrGbEIm+sdF3hZGWVs2z6m9JKBX 96KSbnoDaVfSLIGHwhL0UG+4X+A+moK/ChWryrcjppXzVImH0B61O8HCWvfoiikGBpc1 35ryqHZbToK6U6XsVzxEQZQyaK1sykeXgRam43/vT6oGfTjLfLc0BiIngsqmZeKtcanS VZ7hCVeIlq/HOGV7kIzhiAFFtSj1rXKq+sDQOO4ZxSszb5x/EKVfRqQeuViI8omwimQa 3/PQ== X-Gm-Message-State: APjAAAXkdvw3V78viE6tKpQJ6gT4kuDENrhHPC9YBHt/APEFKGrlCefa BRRzA3XJ2XGHQSguWyE3Hj/sJ1xxDpGp7phmpFBGafmA5bM2lb2cL4svofj94lGkGCdQhsunVwm opLpK7yEgNdufxTttRHX4KVk2/do8UOqBDuC68dJVRGW89YLRZTPfjSxGLRj7JX7J3w== X-Received: by 2002:a81:6cd2:: with SMTP id h201mr17958452ywc.484.1557870897692; Tue, 14 May 2019 14:54:57 -0700 (PDT) X-Google-Smtp-Source: APXvYqxF1n37Auw6LMvewHx+O1vktLxDhTghdFRjyUv6ZGc29P0JHAYQoCyQN3pKf6B90kc3anc2 X-Received: by 2002:a81:6cd2:: with SMTP id h201mr17958434ywc.484.1557870896869; Tue, 14 May 2019 14:54:56 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1557870896; cv=none; d=google.com; s=arc-20160816; b=oibxGsfQ82UmV/p5R7WJJNuEvmfvOX75aDpEXHdw7LGEVWHx1QGMwJJQAc0POFwrWU W7ar6ZN4JprgvSLn8kz9Nz9kxrJ2542C/ubhua3GvuhS4Zr57Ntjcua5xrToV8hWHxap AmoatpgaS+YNWABGOIwJyvgsYOxgm2u/iigFTXMPUYpT6RJUhh0crpZor/yEXkJVd52+ eyd8SJqWZ8maDnsnr4Xd7ZPsToU7mXlZ3Mxhh6IlkJ26K7s+4ZvFH40WoE0MkCamjZP7 XQoRvblyKpEikh2aRpMC17+Lt6j/XIZ6GyZwftiUiDnOACINHaf9LZm9dPLhcZ/SZwTs jk5Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:references:in-reply-to:message-id:date:subject :smtp-origin-cluster:cc:to:smtp-origin-hostname:from :smtp-origin-hostprefix:dkim-signature; bh=FtShZ2vB5fpsbZrZXegXCPM4YGPbu5mSBxgUC0FaF14=; b=eGNoZoHQy4anZyyN5HuY16TWebz6wd6prnjk5iFnKM1QSkMF/hFsNueLs/hJNfRF8Z /dcx5aUX6HAYQq368j8MEv39n0BvDTxUNDjomJzIHCB5HQ4sGcT8EUPos8ZoB83vb4k8 Z1g+lkP6MZELoVZlAg6+UIZLOReIzuRmgpu0un+nCbnfisOICy+F0dS+GGBQ7DHoaCz7 7bnkELq3nodbAP6HaDXfkTCtzaaqjLLe8fHC2rjCPHKvtihmU1sEyNlxpJN9svzU3pbA v/kPPAmq9Da5c1KTJvDKpvCvoqeJIT8nNMGiVeAqlfMhb1HMkQcJ7ozx8fI0vHNuBREV ZCKw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@fb.com header.s=facebook header.b=CtR8Hj6b; spf=pass (google.com: domain of prvs=0037dedd0e=guro@fb.com designates 67.231.153.30 as permitted sender) smtp.mailfrom="prvs=0037dedd0e=guro@fb.com"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fb.com Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com. [67.231.153.30]) by mx.google.com with ESMTPS id p70si5361590yba.232.2019.05.14.14.54.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 14 May 2019 14:54:56 -0700 (PDT) Received-SPF: pass (google.com: domain of prvs=0037dedd0e=guro@fb.com designates 67.231.153.30 as permitted sender) client-ip=67.231.153.30; Authentication-Results: mx.google.com; dkim=pass header.i=@fb.com header.s=facebook header.b=CtR8Hj6b; spf=pass (google.com: domain of prvs=0037dedd0e=guro@fb.com designates 67.231.153.30 as permitted sender) smtp.mailfrom="prvs=0037dedd0e=guro@fb.com"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=fb.com Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4ELsD5r030310 for ; Tue, 14 May 2019 14:54:56 -0700 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=FtShZ2vB5fpsbZrZXegXCPM4YGPbu5mSBxgUC0FaF14=; b=CtR8Hj6bWSgHnbETcMmphwyKWmZcyyxBu3VK/goj8IyuCRIk/0F3KCTuRPvjSTvlSFYe BLkttXobyzZ30JrGl8rXOvLsHngjFLqBFk9qIY/SDLiH9uIG53aVaGDtk8MUi2n+CsJi kAxoX8ydsvNyQgtxW/etx+lZZIyNeUq80/w= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2sg0pkhat8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Tue, 14 May 2019 14:54:56 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::125) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Tue, 14 May 2019 14:54:55 -0700 Received: by devvm2643.prn2.facebook.com (Postfix, from userid 111017) id 8BE24120772AE; Tue, 14 May 2019 14:39:41 -0700 (PDT) Smtp-Origin-Hostprefix: devvm From: Roman Gushchin Smtp-Origin-Hostname: devvm2643.prn2.facebook.com To: Andrew Morton , Shakeel Butt CC: , , , Johannes Weiner , Michal Hocko , Rik van Riel , Christoph Lameter , Vladimir Davydov , , Roman Gushchin Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v4 6/7] mm: reparent slab memory on cgroup removal Date: Tue, 14 May 2019 14:39:39 -0700 Message-ID: <20190514213940.2405198-7-guro@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190514213940.2405198-1-guro@fb.com> References: <20190514213940.2405198-1-guro@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-14_13:,, signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe 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: X-Virus-Scanned: ClamAV using ClamSMTP Let's reparent memcg slab memory on memcg offlining. This allows us to release the memory cgroup without waiting for the last outstanding kernel object (e.g. dentry used by another application). So instead of reparenting all accounted slab pages, let's do reparent a relatively small amount of kmem_caches. Reparenting is performed as a part of the deactivation process. Since the parent cgroup is already charged, everything we need to do is to splice the list of kmem_caches to the parent's kmem_caches list, swap the memcg pointer and drop the css refcounter for each kmem_cache and adjust the parent's css refcounter. Quite simple. Please, note that kmem_cache->memcg_params.memcg isn't a stable pointer anymore. It's safe to read it under rcu_read_lock() or with slab_mutex held. We can race with the slab allocation and deallocation paths. It's not a big problem: parent's charge and slab global stats are always correct, and we don't care anymore about the child usage and global stats. The child cgroup is already offline, so we don't use or show it anywhere. Local slab stats (NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE) aren't used anywhere except count_shadow_nodes(). But even there it won't break anything: after reparenting "nodes" will be 0 on child level (because we're already reparenting shrinker lists), and on parent level page stats always were 0, and this patch won't change anything. Signed-off-by: Roman Gushchin Reviewed-by: Shakeel Butt --- include/linux/slab.h | 4 ++-- mm/memcontrol.c | 14 ++++++++------ mm/slab.h | 21 ++++++++++++++++----- mm/slab_common.c | 21 ++++++++++++++++++--- 4 files changed, 44 insertions(+), 16 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index 1b54e5f83342..109cab2ad9b4 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -152,7 +152,7 @@ void kmem_cache_destroy(struct kmem_cache *); int kmem_cache_shrink(struct kmem_cache *); void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *); -void memcg_deactivate_kmem_caches(struct mem_cgroup *); +void memcg_deactivate_kmem_caches(struct mem_cgroup *, struct mem_cgroup *); /* * Please use this macro to create slab caches. Simply specify the @@ -638,7 +638,7 @@ struct memcg_cache_params { bool dying; }; struct { - struct mem_cgroup *memcg; + struct mem_cgroup __rcu *memcg; struct list_head children_node; struct list_head kmem_caches_node; struct percpu_ref refcnt; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 413cef3d8369..0655639433ed 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3224,15 +3224,15 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) */ memcg->kmem_state = KMEM_ALLOCATED; - memcg_deactivate_kmem_caches(memcg); - - kmemcg_id = memcg->kmemcg_id; - BUG_ON(kmemcg_id < 0); - parent = parent_mem_cgroup(memcg); if (!parent) parent = root_mem_cgroup; + memcg_deactivate_kmem_caches(memcg, parent); + + kmemcg_id = memcg->kmemcg_id; + BUG_ON(kmemcg_id < 0); + /* * Change kmemcg_id of this cgroup and all its descendants to the * parent's id, and then move all entries from this cgroup's list_lrus @@ -3265,7 +3265,6 @@ static void memcg_free_kmem(struct mem_cgroup *memcg) if (memcg->kmem_state == KMEM_ALLOCATED) { WARN_ON(!list_empty(&memcg->kmem_caches)); static_branch_dec(&memcg_kmem_enabled_key); - WARN_ON(page_counter_read(&memcg->kmem)); } } #else @@ -4677,6 +4676,9 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) /* The following stuff does not apply to the root */ if (!parent) { +#ifdef CONFIG_MEMCG_KMEM + INIT_LIST_HEAD(&memcg->kmem_caches); +#endif root_mem_cgroup = memcg; return &memcg->css; } diff --git a/mm/slab.h b/mm/slab.h index b86744c58702..7ba50e526d82 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -268,10 +268,18 @@ static __always_inline int memcg_charge_slab(struct page *page, struct lruvec *lruvec; int ret; - memcg = s->memcg_params.memcg; + rcu_read_lock(); + memcg = rcu_dereference(s->memcg_params.memcg); + while (memcg && !css_tryget_online(&memcg->css)) + memcg = parent_mem_cgroup(memcg); + rcu_read_unlock(); + + if (unlikely(!memcg)) + return true; + ret = memcg_kmem_charge_memcg(page, gfp, order, memcg); if (ret) - return ret; + goto out; lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg); mod_lruvec_state(lruvec, cache_vmstat_idx(s), 1 << order); @@ -279,8 +287,9 @@ static __always_inline int memcg_charge_slab(struct page *page, /* transer try_charge() page references to kmem_cache */ percpu_ref_get_many(&s->memcg_params.refcnt, 1 << order); css_put_many(&memcg->css, 1 << order); - - return 0; +out: + css_put(&memcg->css); + return ret; } /* @@ -293,10 +302,12 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order, struct mem_cgroup *memcg; struct lruvec *lruvec; - memcg = s->memcg_params.memcg; + rcu_read_lock(); + memcg = rcu_dereference(s->memcg_params.memcg); lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg); mod_lruvec_state(lruvec, cache_vmstat_idx(s), -(1 << order)); memcg_kmem_uncharge_memcg(page, order, memcg); + rcu_read_unlock(); percpu_ref_put_many(&s->memcg_params.refcnt, 1 << order); } diff --git a/mm/slab_common.c b/mm/slab_common.c index 1ee967b4805e..354762394162 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -237,7 +237,7 @@ void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg) list_add(&s->root_caches_node, &slab_root_caches); } else { css_get(&memcg->css); - s->memcg_params.memcg = memcg; + rcu_assign_pointer(s->memcg_params.memcg, memcg); list_add(&s->memcg_params.children_node, &s->memcg_params.root_cache->memcg_params.children); list_add(&s->memcg_params.kmem_caches_node, @@ -252,7 +252,8 @@ static void memcg_unlink_cache(struct kmem_cache *s) } else { list_del(&s->memcg_params.children_node); list_del(&s->memcg_params.kmem_caches_node); - css_put(&s->memcg_params.memcg->css); + mem_cgroup_put(rcu_dereference_protected(s->memcg_params.memcg, + lockdep_is_held(&slab_mutex))); } } #else @@ -776,11 +777,13 @@ static void kmemcg_cache_deactivate(struct kmem_cache *s) call_rcu(&s->memcg_params.rcu_head, kmemcg_schedule_work_after_rcu); } -void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) +void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg, + struct mem_cgroup *parent) { int idx; struct memcg_cache_array *arr; struct kmem_cache *s, *c; + unsigned int nr_reparented; idx = memcg_cache_id(memcg); @@ -798,6 +801,18 @@ void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) kmemcg_cache_deactivate(c); arr->entries[idx] = NULL; } + nr_reparented = 0; + list_for_each_entry(s, &memcg->kmem_caches, + memcg_params.kmem_caches_node) { + rcu_assign_pointer(s->memcg_params.memcg, parent); + css_put(&memcg->css); + nr_reparented++; + } + if (nr_reparented) { + list_splice_init(&memcg->kmem_caches, + &parent->kmem_caches); + css_get_many(&parent->css, nr_reparented); + } mutex_unlock(&slab_mutex); put_online_mems();