From patchwork Sun Jan 17 15:10:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 12025521 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C76B3C433DB for ; Sun, 17 Jan 2021 15:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9306A22522 for ; Sun, 17 Jan 2021 15:21:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729349AbhAQPVX (ORCPT ); Sun, 17 Jan 2021 10:21:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729248AbhAQPOk (ORCPT ); Sun, 17 Jan 2021 10:14:40 -0500 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 E8150C061793 for ; Sun, 17 Jan 2021 07:14:10 -0800 (PST) Received: by mail-pf1-x434.google.com with SMTP id t29so3553416pfg.11 for ; Sun, 17 Jan 2021 07:14:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=9dJD9jIzWDoyhaAcVJQeaUo28aYYhfu54r+mE2CBxNg=; b=WZDoQulZaOHqUK7FYNLKOHufGI3gm9j2qkD0tsBiPKndmaWLewA1SGkCa+UjuLc7rW TLPzKj1a2Zrn7sD4jCbTlW0NiAmZwQB8S3KLRRGiWWAQQtawa31SstAs/YN7mI+l+tM2 +2ECS/Xej6ZG1fLc3Z7n7BEAyn7X6JN/z6MRe8R5BuKDrew2SI3j/dOPRU5zImglfkS+ USUuSkIIhiabsDk74CkWVM3UP6XZOWlfrPnzpbQPj41BoDwSnKGid1Zz8cvqm7mYSJlk o5Ywnn/8mdJ5vo8e3fkQNIuFBjwLVmQy1aqOIQlplkLi0qZh5uoYmpRP+hT0hl5TQvZQ nIXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=9dJD9jIzWDoyhaAcVJQeaUo28aYYhfu54r+mE2CBxNg=; b=tj8dzw7yMI3U6H4JzhcxpW/4a8SNROMuMFxa8BKkaVZVu5zx4AbIdg9Z+Ef0FH2TY/ Qgp4kyULcRV2TrhKfgwLlVWwPNIW21L+51UpkyKVL1x/A/eCbiTH+xMbKdYilKnGocbZ FLlX/Zzco7NfNzucVFaAhOGwFk40rfJ2o2BwxrO6denzBH9lceyYJ3/owp3mSufYL6bK teWPZQ4EuszEEouHFLSmvvSvRik34IGd3Z+7nwfQtmK8aMbeWW88+h76RzPTRCAjRCrC T/Vp0KPpGQUkMO/p78w8yNm2NSDgVeI80FzP2Au3EsYEObBarBeT2G4iHl5AhDZz6dd9 pB8Q== X-Gm-Message-State: AOAM533kUUwRMduC48d6NTIENoc3FaGCiKQ9ZqXQCwZiV4Ah3ku9J4dM Qn4HHK/LFz3MnTsN1U55m+Tn6A== X-Google-Smtp-Source: ABdhPJz+9H+G2DnPbSxxBH5sFXFhg3WUBNTmJ3IP8AMyUEP0AtODY7e2nHgbQHOSy42bOXlh6WCa1g== X-Received: by 2002:a63:78ca:: with SMTP id t193mr22215079pgc.391.1610896450449; Sun, 17 Jan 2021 07:14:10 -0800 (PST) Received: from localhost.bytedance.net ([139.177.225.247]) by smtp.gmail.com with ESMTPSA id i22sm9247915pjv.35.2021.01.17.07.13.49 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 17 Jan 2021 07:14:09 -0800 (PST) From: Muchun Song To: corbet@lwn.net, mike.kravetz@oracle.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, rdunlap@infradead.org, oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, almasrymina@google.com, rientjes@google.com, willy@infradead.org, osalvador@suse.de, mhocko@suse.com, song.bao.hua@hisilicon.com, david@redhat.com, naoya.horiguchi@nec.com Cc: duanxiongchun@bytedance.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Muchun Song Subject: [PATCH v13 04/12] mm: hugetlb: defer freeing of HugeTLB pages Date: Sun, 17 Jan 2021 23:10:45 +0800 Message-Id: <20210117151053.24600-5-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210117151053.24600-1-songmuchun@bytedance.com> References: <20210117151053.24600-1-songmuchun@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org In the subsequent patch, we should allocate the vmemmap pages when freeing HugeTLB pages. But update_and_free_page() is always called with holding hugetlb_lock, so we cannot use GFP_KERNEL to allocate vmemmap pages. However, we can defer the actual freeing in a kworker to prevent from using GFP_ATOMIC to allocate the vmemmap pages. The update_hpage_vmemmap_workfn() is where the call to allocate vmemmmap pages will be inserted. Signed-off-by: Muchun Song Reviewed-by: Mike Kravetz --- mm/hugetlb.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++-- mm/hugetlb_vmemmap.c | 12 --------- mm/hugetlb_vmemmap.h | 17 ++++++++++++ 3 files changed, 89 insertions(+), 14 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 140135fc8113..c165186ec2cf 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1292,15 +1292,85 @@ static inline void destroy_compound_gigantic_page(struct page *page, unsigned int order) { } #endif -static void update_and_free_page(struct hstate *h, struct page *page) +static void __free_hugepage(struct hstate *h, struct page *page); + +/* + * As update_and_free_page() is always called with holding hugetlb_lock, so we + * cannot use GFP_KERNEL to allocate vmemmap pages. However, we can defer the + * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate + * the vmemmap pages. + * + * The update_hpage_vmemmap_workfn() is where the call to allocate vmemmmap + * pages will be inserted. + * + * update_hpage_vmemmap_workfn() locklessly retrieves the linked list of pages + * to be freed and frees them one-by-one. As the page->mapping pointer is going + * to be cleared in update_hpage_vmemmap_workfn() anyway, it is reused as the + * llist_node structure of a lockless linked list of huge pages to be freed. + */ +static LLIST_HEAD(hpage_update_freelist); + +static void update_hpage_vmemmap_workfn(struct work_struct *work) { - int i; + struct llist_node *node; + + node = llist_del_all(&hpage_update_freelist); + + while (node) { + struct page *page; + struct hstate *h; + + page = container_of((struct address_space **)node, + struct page, mapping); + node = node->next; + page->mapping = NULL; + h = page_hstate(page); + + spin_lock(&hugetlb_lock); + __free_hugepage(h, page); + spin_unlock(&hugetlb_lock); + cond_resched(); + } +} +static DECLARE_WORK(hpage_update_work, update_hpage_vmemmap_workfn); + +static inline void __update_and_free_page(struct hstate *h, struct page *page) +{ + /* No need to allocate vmemmap pages */ + if (!free_vmemmap_pages_per_hpage(h)) { + __free_hugepage(h, page); + return; + } + + /* + * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap + * pages. + * + * Only call schedule_work() if hpage_update_freelist is previously + * empty. Otherwise, schedule_work() had been called but the workfn + * hasn't retrieved the list yet. + */ + if (llist_add((struct llist_node *)&page->mapping, + &hpage_update_freelist)) + schedule_work(&hpage_update_work); +} + +static void update_and_free_page(struct hstate *h, struct page *page) +{ if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) return; h->nr_huge_pages--; h->nr_huge_pages_node[page_to_nid(page)]--; + + __update_and_free_page(h, page); +} + +static void __free_hugepage(struct hstate *h, struct page *page) +{ + int i; + for (i = 0; i < pages_per_huge_page(h); i++) { page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 1 << PG_dirty | diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 4ffa2a4ae2a8..19f1898aaede 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -178,18 +178,6 @@ #define RESERVE_VMEMMAP_NR 2U #define RESERVE_VMEMMAP_SIZE (RESERVE_VMEMMAP_NR << PAGE_SHIFT) -/* - * How many vmemmap pages associated with a HugeTLB page that can be freed - * to the buddy allocator. - * - * Todo: Returns zero for now, which means the feature is disabled. We will - * enable it once all the infrastructure is there. - */ -static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) -{ - return 0; -} - static inline unsigned long free_vmemmap_pages_size_per_hpage(struct hstate *h) { return (unsigned long)free_vmemmap_pages_per_hpage(h) << PAGE_SHIFT; diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h index 6923f03534d5..01f8637adbe0 100644 --- a/mm/hugetlb_vmemmap.h +++ b/mm/hugetlb_vmemmap.h @@ -12,9 +12,26 @@ #ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP void free_huge_page_vmemmap(struct hstate *h, struct page *head); + +/* + * How many vmemmap pages associated with a HugeTLB page that can be freed + * to the buddy allocator. + * + * Todo: Returns zero for now, which means the feature is disabled. We will + * enable it once all the infrastructure is there. + */ +static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) +{ + return 0; +} #else static inline void free_huge_page_vmemmap(struct hstate *h, struct page *head) { } + +static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) +{ + return 0; +} #endif /* CONFIG_HUGETLB_PAGE_FREE_VMEMMAP */ #endif /* _LINUX_HUGETLB_VMEMMAP_H */