From patchwork Wed Jan 6 14:19:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 12001761 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,URIBL_BLOCKED,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 87F47C433DB for ; Wed, 6 Jan 2021 14:22:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56E1423120 for ; Wed, 6 Jan 2021 14:22:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726827AbhAFOVj (ORCPT ); Wed, 6 Jan 2021 09:21:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726730AbhAFOVh (ORCPT ); Wed, 6 Jan 2021 09:21:37 -0500 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81DFCC061358 for ; Wed, 6 Jan 2021 06:20:57 -0800 (PST) Received: by mail-pl1-x629.google.com with SMTP id be12so1617922plb.4 for ; Wed, 06 Jan 2021 06:20:57 -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=o383ghz8HXXGrRY9KqtLQYFhlyvvQT/xvfQy7A2Mg1jVAo8f97qxZteIL9PDoL0Bvq cVmGpCz9aE4xOKwPvVOxBjPusSsT8Kbm8eube8E0rH/Rc4It+g13zWxEn9wMh7LyNJa+ LGFFYFRcixOYFkwMwmOyzHRp/5kAQsSUeDkJ98pEbz8HPdtoQsSstJX+ZjhuZRUEAGW2 c7aCilIgOh6Qg1o/pCnjl19db9xUn3shxOQCCsFlaU5REkTHIBAjTtMWjbxPcbaE/Ug1 C0ugndK5eB7z6f1srm0FDumoDEecZSgaGCmWptGHDlnOKpKrt0Jn603dtKSW+qfZbiOU F52w== 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=aqjUYDXl6Q5rgyQvI+McoUZ2FM2yzMwp1gu/CQIsG2qkVj5hnaBx2IdWYA5g8ao6Dn xQ8Tk94mwBLXHYGx+pXDXykIoM7h3Fo2NuZkFSpqzB6OSskvqgwDFX/pp6EWh7emhh4q XPe5AVO14VD311vIw+DYhq17Bnhr3S4Ud1pyKc3kE1bojXOcjdG7wjvfeiol9DKH9071 dTXcd/k6hsAIcgZlMXxZChhu8xz7FcelT3vzQZDhSdjrDBAhfNL59bIk1zJ1e8ma39Ke U6540EGAZRSmY5RhQ+OlEI5Rrgu+H4Cxut7FM2KlqnirCK2QOAyJlv+mym2vmy4pyMAD b/Yw== X-Gm-Message-State: AOAM5325RyepuF/eUPTnC21bvTjfFUNbi9PTusCVP9VWkxmc3wUK7sqs 8KNvZLaXiV9M9okMaIWjyr1w8Q== X-Google-Smtp-Source: ABdhPJy2D4DUnh0jFoHdDgH9rkdTzNtaF+xPdJt0bOSH/kuanYvrbndIV2FtJQdLvDbOj8v02hoFyw== X-Received: by 2002:a17:902:521:b029:dc:2836:ec17 with SMTP id 30-20020a1709020521b02900dc2836ec17mr4323835plf.47.1609942857016; Wed, 06 Jan 2021 06:20:57 -0800 (PST) Received: from localhost.bytedance.net ([139.177.225.232]) by smtp.gmail.com with ESMTPSA id a29sm2831730pfr.73.2021.01.06.06.20.45 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Jan 2021 06:20:56 -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 v12 05/13] mm/hugetlb: Defer freeing of HugeTLB pages Date: Wed, 6 Jan 2021 22:19:23 +0800 Message-Id: <20210106141931.73931-6-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210106141931.73931-1-songmuchun@bytedance.com> References: <20210106141931.73931-1-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 */