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=-16.7 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=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 AA67BC0018C for ; Thu, 10 Dec 2020 04:05:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 836DF23D51 for ; Thu, 10 Dec 2020 04:05:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732076AbgLJEF0 (ORCPT ); Wed, 9 Dec 2020 23:05:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731369AbgLJD7E (ORCPT ); Wed, 9 Dec 2020 22:59:04 -0500 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 660D1C0613D6 for ; Wed, 9 Dec 2020 19:58:16 -0800 (PST) Received: by mail-pg1-x542.google.com with SMTP id w5so2185468pgj.3 for ; Wed, 09 Dec 2020 19:58:16 -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=SoxvhqF5kzAZtJl03k3YBkt7stg9NndxerOH198myd8=; b=MXyupVF4C4cCkx/KyGFP1cJoP8wY7D8/9aEvqQOJCMtFgA+BkPF7/NYM/FgO2W7gQu JqQ3cLXLIYMl8h76esnC7KY0nF1ONxCW2Mrl2q9/VuQMmAeG0on/qltGuWyjqfDjpLsc 4PYMDWlTpZWe/VksXFYUV1XTSoSNx9FiGd2IRDCZX1zCXDd7evKpWDemGnmnh4j1RZNl 0/NYAYhCr1VFNcQjqyQmYKWkuy9GL+r6VmHwL0shSydfwrZUUBBewVMumSA+EWEFsq+y jTyS2CKSiN1xBZzKbbHpo4r7n23yKRDTzw5lgPjMga3AVpoxUbsp2htKTQVCtC8rXr4s ABzg== 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=SoxvhqF5kzAZtJl03k3YBkt7stg9NndxerOH198myd8=; b=tjUpEJmeSTdrKkixIpRFzPVTZYvpy/ADjammbWoMKFbKmYTtyhWSHf2AH7d3vHgJQC VUa9QcbhaOd0hBPYW24QuD6wngR4SDQaobvWAUxXDVNuCw6NCq3USg8AXjI33l/di3k3 LN5JRG+E/dbn6OvDb4yWcWD6dvRMfLUxbrkTo4D6WQtc+d1TlbQD6sZEBMnuyUyGq4Yf nE5+1jI0D+ZJkMnEQV4uuzneHPx+VC2UaZXibHMnQcbZW5YQQfJP1uh0QlhCV0X9g93s 0GDaA8Gc325ELSBtQ0dUXcg9C0W+MwV4ZzvudmTX0rBpjdXkOzKXHNMF2Tal/gq0fOWh WSJQ== X-Gm-Message-State: AOAM530VzF86t8670okZ8KaSi/Vi57s3XATD7UYGvitPrdRGrErVfc1B 80F4gMeIG2L7DcpP2zgxsFH5wQ== X-Google-Smtp-Source: ABdhPJx1r4miuySzTBfZhOWgs3vw8Jwv3oc0mgrVWiMUCGZDAFQVsMCILxuRQC2oGK19TnVhK6n0oQ== X-Received: by 2002:a17:90a:2ec1:: with SMTP id h1mr5530853pjs.18.1607572695986; Wed, 09 Dec 2020 19:58:15 -0800 (PST) Received: from localhost.localdomain ([103.136.220.85]) by smtp.gmail.com with ESMTPSA id f33sm4266535pgl.83.2020.12.09.19.58.05 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Dec 2020 19:58:15 -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 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 v8 05/12] mm/hugetlb: Defer freeing of HugeTLB pages Date: Thu, 10 Dec 2020 11:55:19 +0800 Message-Id: <20201210035526.38938-6-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20201210035526.38938-1-songmuchun@bytedance.com> References: <20201210035526.38938-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the subsequent patch, we will allocate the vmemmap pages when free HugeTLB pages. But update_and_free_page() is called from a non-task context(and hold hugetlb_lock), so we can defer the actual freeing in a workqueue to prevent use GFP_ATOMIC to allocate the vmemmap pages. Signed-off-by: Muchun Song --- mm/hugetlb.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++---- mm/hugetlb_vmemmap.c | 12 -------- mm/hugetlb_vmemmap.h | 17 ++++++++++++ 3 files changed, 88 insertions(+), 18 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 140135fc8113..0ff9b90e524f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1292,15 +1292,76 @@ 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 be called from a non-task context(and hold + * hugetlb_lock), we can defer the actual freeing in a workqueue to prevent + * use GFP_ATOMIC to allocate a lot of vmemmap pages. + * + * 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; + struct page *page; + + node = llist_del_all(&hpage_update_freelist); + while (node) { + page = container_of((struct address_space **)node, + struct page, mapping); + node = node->next; + page->mapping = NULL; + __free_hugepage(page_hstate(page), page); + + 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 | @@ -1313,13 +1374,17 @@ static void update_and_free_page(struct hstate *h, struct page *page) set_page_refcounted(page); if (hstate_is_gigantic(h)) { /* - * Temporarily drop the hugetlb_lock, because - * we might block in free_gigantic_page(). + * Temporarily drop the hugetlb_lock only when this type of + * HugeTLB page does not support vmemmap optimization (which + * contex do not hold the hugetlb_lock), because we might block + * in free_gigantic_page(). */ - spin_unlock(&hugetlb_lock); + if (!free_vmemmap_pages_per_hpage(h)) + spin_unlock(&hugetlb_lock); destroy_compound_gigantic_page(page, huge_page_order(h)); free_gigantic_page(page, huge_page_order(h)); - spin_lock(&hugetlb_lock); + if (!free_vmemmap_pages_per_hpage(h)) + spin_lock(&hugetlb_lock); } else { __free_pages(page, huge_page_order(h)); } diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index c464c5db8967..d080488cde16 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -197,18 +197,6 @@ (__boundary - 1 < (end) - 1) ? __boundary : (end); \ }) -/* - * How many vmemmap pages associated with a HugeTLB page that can be freed - * to the buddy allocator. - * - * Todo: Now it is zero, because all infrastructure is not ready. Once all the - * infrastructure is ready, we will rework this function to support the feature. - */ -static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) -{ - return 0; -} - static inline unsigned int vmemmap_pages_per_hpage(struct hstate *h) { return free_vmemmap_pages_per_hpage(h) + RESERVE_VMEMMAP_NR; diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h index 6923f03534d5..bf22cd003acb 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: Now it is zero, because all infrastructure is not ready. Once all the + * infrastructure is ready, we will rework this function to support the feature. + */ +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 */ -- 2.11.0