From nobody Mon Apr 6 09:49:50 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 229E8ECAAD5 for ; Thu, 8 Sep 2022 07:59:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229601AbiIHH7B (ORCPT ); Thu, 8 Sep 2022 03:59:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231288AbiIHH6s (ORCPT ); Thu, 8 Sep 2022 03:58:48 -0400 Received: from mail-pf1-x434.google.com (mail-pf1-x434.google.com [IPv6:2607:f8b0:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2918CC2759 for ; Thu, 8 Sep 2022 00:58:47 -0700 (PDT) Received: by mail-pf1-x434.google.com with SMTP id z187so17099222pfb.12 for ; Thu, 08 Sep 2022 00:58:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date; bh=dN1vu9YkPP2qvJgARkUVS3Lj2dJbT8tyN8H4FWEm0MA=; b=euS70EXnFyEuCkfB97RoVTfQScHu6QidJEayfqWFXllx6tKNbBDs8Aqmkx9TtVL12O TTq6BHiy3Isdo97zquLkpB1THGASkfqZ3BWxO2AqRvTdP2cR6xiMaQejSbm/PoPX3m0G OBtLuoI8XsX/QCbYSuCERMB/p3HDnuO6xd7/z5l9DGjkPVJJ8FLdKvSzAm8l75rggPPQ Gt9I+4k7JbdvuQvFMcer0YtnXbUSAbUaQDiwQWnjsVUd1G4KFasZbLWn3PbuSF3wayCO p5i4SHWeezrRST417Vp3epc7DIaEdTiwpGjgQygjXj5EgLWCMVGVf7lWqebLHYrIOaWd kKAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date; bh=dN1vu9YkPP2qvJgARkUVS3Lj2dJbT8tyN8H4FWEm0MA=; b=yojHlJa7kt3vOhkzwgvOBWg3knWhQ1PzgpfLUkJYLNbmvCunIctBTnSmqNtrD0qFj+ TLg8sox7vAB/YOmypbAwrQX3O0dgxSJyY0BT5ceC42r9U6+tdmDO0BZbHR6dEEmcMCPh ntLTQ/Tb2g4RtAXdI5KJPEftCrOq8Pmbg2GTg4EQPuj1HsnKJ1yrNvGoBuIuzj9ceJhw T/mkeSxdRL0tQbnCe0mU8M2wTinVI1H54gPErtdyOTxi59ZFFJn/E6iE8ng3DKw+Isvv LgI353ZeeGADfEGeYhTx+/IetTThOOL6Lyt6/2WJ8xW3uMLgfpj6AkNYDO/CZA09JvO8 Mvew== X-Gm-Message-State: ACgBeo2j2Iacrx00P/krdsqhAPcTKOx82c9KBtcnal8QKT8ry4K/CBL8 +h58nomq7g8b5H6NLOuBg2Qnbg== X-Google-Smtp-Source: AA6agR49G6QcDPmAfuup5cvjmfzK6UHcAZrEeHq1TcrNSokGuLivx7bOYj8Y++Xb1F3n0B7DFKo9zA== X-Received: by 2002:a05:6a00:1650:b0:52f:20d6:e858 with SMTP id m16-20020a056a00165000b0052f20d6e858mr7863601pfc.36.1662623926544; Thu, 08 Sep 2022 00:58:46 -0700 (PDT) Received: from PXLDJ45XCM.bytedance.net ([139.177.225.231]) by smtp.gmail.com with ESMTPSA id p12-20020a170902bd0c00b001745919b197sm13629980pls.243.2022.09.08.00.58.40 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 08 Sep 2022 00:58:45 -0700 (PDT) From: Muchun Song To: gregkh@linuxfoundation.org, rafael@kernel.org, mike.kravetz@oracle.com, songmuchun@bytedance.com, akpm@linux-foundation.org, osalvador@suse.de, david@redhat.com, ying.huang@intel.com, aneesh.kumar@linux.ibm.com, rientjes@google.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, muchun.song@linux.dev Subject: [PATCH v3] mm: hugetlb: eliminate memory-less nodes handling Date: Thu, 8 Sep 2022 15:58:26 +0800 Message-Id: <20220908075826.37094-1-songmuchun@bytedance.com> X-Mailer: git-send-email 2.32.1 (Apple Git-133) MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The memory-notify-based approach aims to handle meory-less nodes, however, = it just adds the complexity of code as pointed by David in thread [1]. The handling of = memory-less nodes is introduced by commit 4faf8d950ec4 ("hugetlb: handle memory hot-plu= g events"). From its commit message, we cannot find any necessity of handling this case= . So, we can simply register/unregister sysfs entries in register_node/unregister_node t= o simlify the code. BTW, hotplug callback added because in hugetlb_register_all_nodes() we regi= ster sysfs nodes only for N_MEMORY nodes, seeing commit 9b5e5d0fdc91, which said it wa= s a preparation for handling memory-less nodes via memory hotplug. Since we want to remove = memory hotplug, so make sure we only register per-node sysfs for online (N_ONLINE) nodes in hugetlb_register_all_nodes(). https://lore.kernel.org/linux-mm/60933ffc-b850-976c-78a0-0ee6e0ea9ef0@redha= t.com/ [1] Suggested-by: David Hildenbrand Signed-off-by: Muchun Song Acked-by: David Hildenbrand --- v3: - Fix 'struct node' is not declared reported by LTP. v2: - Move declaration of function related to hugetlb to hugetlb.h (David). - Introduce hugetlb_sysfs_initialized() and call it from hugetlb_sysfs_ini= t() (David). - Move hugetlb_register_all_nodes() into hugetlb_sysfs_init() (David). - Fix implicit-function-declaration reported by LKP. - Register per-node sysfs for online (N_ONLINE) nodes instead of N_MEMORY = (Aneesh). drivers/base/node.c | 8 +++-- include/linux/hugetlb.h | 14 +++++++++ mm/hugetlb.c | 81 ++++++++++++++++++++++-----------------------= ---- 3 files changed, 57 insertions(+), 46 deletions(-) diff --git a/drivers/base/node.c b/drivers/base/node.c index ed391cb09999..80b1e91b9608 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -20,6 +20,7 @@ #include #include #include +#include =20 static struct bus_type node_subsys =3D { .name =3D "node", @@ -608,10 +609,12 @@ static int register_node(struct node *node, int num) node->dev.groups =3D node_dev_groups; error =3D device_register(&node->dev); =20 - if (error) + if (error) { put_device(&node->dev); - else + } else { + hugetlb_register_node(node); compaction_register_node(node); + } =20 return error; } @@ -625,6 +628,7 @@ static int register_node(struct node *node, int num) */ void unregister_node(struct node *node) { + hugetlb_unregister_node(node); compaction_unregister_node(node); node_remove_accesses(node); node_remove_caches(node); diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 852f911d676e..2d98d0ac4a48 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -16,6 +16,7 @@ struct ctl_table; struct user_struct; struct mmu_gather; +struct node; =20 #ifndef is_hugepd typedef struct { unsigned long pd; } hugepd_t; @@ -967,6 +968,11 @@ static inline void huge_ptep_modify_prot_commit(struct= vm_area_struct *vma, } #endif =20 +#ifdef CONFIG_NUMA +void hugetlb_register_node(struct node *node); +void hugetlb_unregister_node(struct node *node); +#endif + #else /* CONFIG_HUGETLB_PAGE */ struct hstate {}; =20 @@ -1141,6 +1147,14 @@ static inline void set_huge_pte_at(struct mm_struct = *mm, unsigned long addr, pte_t *ptep, pte_t pte) { } + +static inline void hugetlb_register_node(struct node *node) +{ +} + +static inline void hugetlb_unregister_node(struct node *node) +{ +} #endif /* CONFIG_HUGETLB_PAGE */ =20 static inline spinlock_t *huge_pte_lock(struct hstate *h, diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d0617d64d718..06ac469582da 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3880,24 +3880,14 @@ static int hugetlb_sysfs_add_hstate(struct hstate *= h, struct kobject *parent, return 0; } =20 -static void __init hugetlb_sysfs_init(void) -{ - struct hstate *h; - int err; - - hugepages_kobj =3D kobject_create_and_add("hugepages", mm_kobj); - if (!hugepages_kobj) - return; +#ifdef CONFIG_NUMA +static bool hugetlb_sysfs_initialized __ro_after_init; =20 - for_each_hstate(h) { - err =3D hugetlb_sysfs_add_hstate(h, hugepages_kobj, - hstate_kobjs, &hstate_attr_group); - if (err) - pr_err("HugeTLB: Unable to add hstate %s", h->name); - } +static inline void hugetlb_mark_sysfs_initialized(void) +{ + hugetlb_sysfs_initialized =3D true; } =20 -#ifdef CONFIG_NUMA =20 /* * node_hstate/s - associate per node hstate attributes, via their kobject= s, @@ -3953,7 +3943,7 @@ static struct hstate *kobj_to_node_hstate(struct kobj= ect *kobj, int *nidp) * Unregister hstate attributes from a single node device. * No-op if no hstate attributes attached. */ -static void hugetlb_unregister_node(struct node *node) +void hugetlb_unregister_node(struct node *node) { struct hstate *h; struct node_hstate *nhs =3D &node_hstates[node->dev.id]; @@ -3983,19 +3973,22 @@ static void hugetlb_unregister_node(struct node *no= de) * Register hstate attributes for a single node device. * No-op if attributes already registered. */ -static int hugetlb_register_node(struct node *node) +void hugetlb_register_node(struct node *node) { struct hstate *h; struct node_hstate *nhs =3D &node_hstates[node->dev.id]; int err; =20 + if (!hugetlb_sysfs_initialized) + return; + if (nhs->hugepages_kobj) - return 0; /* already allocated */ + return; /* already allocated */ =20 nhs->hugepages_kobj =3D kobject_create_and_add("hugepages", &node->dev.kobj); if (!nhs->hugepages_kobj) - return -ENOMEM; + return; =20 for_each_hstate(h) { err =3D hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, @@ -4005,28 +3998,9 @@ static int hugetlb_register_node(struct node *node) pr_err("HugeTLB: Unable to add hstate %s for node %d\n", h->name, node->dev.id); hugetlb_unregister_node(node); - return -ENOMEM; + break; } } - return 0; -} - -static int __meminit hugetlb_memory_callback(struct notifier_block *self, - unsigned long action, void *arg) -{ - int ret =3D 0; - struct memory_notify *mnb =3D arg; - int nid =3D mnb->status_change_nid; - - if (nid =3D=3D NUMA_NO_NODE) - return NOTIFY_DONE; - - if (action =3D=3D MEM_GOING_ONLINE) - ret =3D hugetlb_register_node(node_devices[nid]); - else if (action =3D=3D MEM_CANCEL_ONLINE || action =3D=3D MEM_OFFLINE) - hugetlb_unregister_node(node_devices[nid]); - - return notifier_from_errno(ret); } =20 /* @@ -4038,11 +4012,8 @@ static void __init hugetlb_register_all_nodes(void) { int nid; =20 - get_online_mems(); - hotplug_memory_notifier(hugetlb_memory_callback, 0); - for_each_node_state(nid, N_MEMORY) + for_each_online_node(nid) hugetlb_register_node(node_devices[nid]); - put_online_mems(); } #else /* !CONFIG_NUMA */ =20 @@ -4056,8 +4027,31 @@ static struct hstate *kobj_to_node_hstate(struct kob= ject *kobj, int *nidp) =20 static void hugetlb_register_all_nodes(void) { } =20 +static inline void hugetlb_mark_sysfs_initialized(void) +{ +} #endif =20 +static void __init hugetlb_sysfs_init(void) +{ + struct hstate *h; + int err; + + hugepages_kobj =3D kobject_create_and_add("hugepages", mm_kobj); + if (!hugepages_kobj) + return; + + for_each_hstate(h) { + err =3D hugetlb_sysfs_add_hstate(h, hugepages_kobj, + hstate_kobjs, &hstate_attr_group); + if (err) + pr_err("HugeTLB: Unable to add hstate %s", h->name); + } + + hugetlb_mark_sysfs_initialized(); + hugetlb_register_all_nodes(); +} + static int __init hugetlb_init(void) { int i; @@ -4112,7 +4106,6 @@ static int __init hugetlb_init(void) report_hugepages(); =20 hugetlb_sysfs_init(); - hugetlb_register_all_nodes(); hugetlb_cgroup_file_init(); =20 #ifdef CONFIG_SMP --=20 2.11.0