From patchwork Fri Nov 13 10:59:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 11903077 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 15813139F for ; Fri, 13 Nov 2020 11:16:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCD7E22253 for ; Fri, 13 Nov 2020 11:16:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bytedance-com.20150623.gappssmtp.com header.i=@bytedance-com.20150623.gappssmtp.com header.b="GkG5ugGo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726768AbgKMLQz (ORCPT ); Fri, 13 Nov 2020 06:16:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726501AbgKMLDM (ORCPT ); Fri, 13 Nov 2020 06:03:12 -0500 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 783A7C061A4A for ; Fri, 13 Nov 2020 03:02:50 -0800 (PST) Received: by mail-pf1-x442.google.com with SMTP id q10so7362256pfn.0 for ; Fri, 13 Nov 2020 03:02:50 -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=vcV5fAWWMBHeyweXdcrSnAyduSHKw3FF3vonlmGtxeQ=; b=GkG5ugGo7afFvzcVWG0uVadPXARhWCh67dhbqbpTbmIVZKNqmVIpsFg7CVXFIV3NEo RDIzcxfDzAJhEDfgx3xDPKxYuSWL9OhYBLwUnaDCyhbY+QnQQXL0JpCvVCH1lfJ7ZQxA ONnJ8/wWPB5aDwAwuD+YcmurfSkwDg8rU9tonjCsdvycvK3/2fQg2DPyXUDNBqRZtr+o mhqvplLA7nGcNbAXzwUBDea9GI1QI1zWBEZ6fJ3Eh+RgeaxYcoJoM2IpIQ1hXvJZ1QAu 5Q9lHOWpXdTaVRef5blqHgWKOa3QhJN8tR870SSqsW1b4xQwm4FqBrubV6xH13Pd9XRN CuWw== 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=vcV5fAWWMBHeyweXdcrSnAyduSHKw3FF3vonlmGtxeQ=; b=JPNzfoIawDroqrm9OGs38qvouV/ZGYWyR6/uQCjYtO5mHqPlgmFdq12XwUwhZGdWn+ yWnOUw/rSrUQqlWOYDslFuADAgEt2tnr5oNdECi54XHBIjQ2X3K/icy8KTCy0J3AvSvw tyy4RSM9D7hPBnbc63Q2PmytfqfmnZhdu1rntU03+yTlEEBIgafg2mZAui5vTdEw4crq 7/YsU4NI1MQ9YtXY+cDM1aXP5tXO+rLdwpuJvfV/6bzqeZmAIKF7Y1BvAtzdWrTnK04Q 0tlJX8ocvAklm5VvoxnnnbzMCtK10sJRu/nTilVpgcTfZs1AR8cXbyzgUm3Z2n3U5dwO NoSw== X-Gm-Message-State: AOAM532AQiP0yARS235EcPNvvvOXyEPwLhsm+QWH1AFUHOom26fbozZN tHRfNkQzTKyJe+7hc2L1YrdPbg== X-Google-Smtp-Source: ABdhPJwjl1roJo8W6r9y3YrlPbLX28igbMI2+0vuCQlC05Klj/YC3PratEhWwTn260/jMo9Nr5AoZg== X-Received: by 2002:a17:90a:6392:: with SMTP id f18mr2295613pjj.143.1605265370011; Fri, 13 Nov 2020 03:02:50 -0800 (PST) Received: from localhost.localdomain ([61.120.150.78]) by smtp.gmail.com with ESMTPSA id f1sm8909959pfc.56.2020.11.13.03.02.39 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 Nov 2020 03:02:49 -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 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 v4 10/21] mm/hugetlb: Defer freeing of hugetlb pages Date: Fri, 13 Nov 2020 18:59:41 +0800 Message-Id: <20201113105952.11638-11-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20201113105952.11638-1-songmuchun@bytedance.com> References: <20201113105952.11638-1-songmuchun@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org In the subsequent patch, we will allocate the vmemmap pages when free huge pages. But 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 the vmemmap pages. Signed-off-by: Muchun Song --- mm/hugetlb.c | 98 +++++++++++++++++++++++++++++++++++++++++++++------- mm/hugetlb_vmemmap.c | 5 --- mm/hugetlb_vmemmap.h | 10 ++++++ 3 files changed, 96 insertions(+), 17 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index a0ce6f33a717..4aabf12aca9b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1221,7 +1221,7 @@ static void destroy_compound_gigantic_page(struct page *page, __ClearPageHead(page); } -static void free_gigantic_page(struct page *page, unsigned int order) +static void __free_gigantic_page(struct page *page, unsigned int order) { /* * If the page isn't allocated using the cma allocator, @@ -1288,20 +1288,100 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, { return NULL; } -static inline void free_gigantic_page(struct page *page, unsigned int order) { } +static inline void __free_gigantic_page(struct page *page, + unsigned int order) { } 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); +} + +#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP +static inline void free_gigantic_page(struct hstate *h, struct page *page) +{ + __free_gigantic_page(page, huge_page_order(h)); +} +#else +static inline void free_gigantic_page(struct hstate *h, struct page *page) +{ + /* + * Temporarily drop the hugetlb_lock, because + * we might block in __free_gigantic_page(). + */ + spin_unlock(&hugetlb_lock); + __free_gigantic_page(page, huge_page_order(h)); + spin_lock(&hugetlb_lock); +} +#endif + +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 | @@ -1313,14 +1393,8 @@ static void update_and_free_page(struct hstate *h, struct page *page) set_compound_page_dtor(page, NULL_COMPOUND_DTOR); set_page_refcounted(page); if (hstate_is_gigantic(h)) { - /* - * Temporarily drop the hugetlb_lock, because - * we might block in free_gigantic_page(). - */ - 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); + free_gigantic_page(h, page); } else { __free_pages(page, huge_page_order(h)); } @@ -1761,7 +1835,7 @@ static struct page *alloc_fresh_huge_page(struct hstate *h, if (vmemmap_pgtable_prealloc(h, page)) { if (hstate_is_gigantic(h)) - free_gigantic_page(page, huge_page_order(h)); + free_gigantic_page(h, page); else put_page(page); return NULL; diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 937562a15f1e..e6fca02b57b2 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -115,11 +115,6 @@ static inline bool vmemmap_pmd_huge(pmd_t *pmd) } #endif -static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) -{ - return h->nr_free_vmemmap_pages; -} - 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 fb8b77659ed5..a23fb1375859 100644 --- a/mm/hugetlb_vmemmap.h +++ b/mm/hugetlb_vmemmap.h @@ -16,6 +16,11 @@ void __init hugetlb_vmemmap_init(struct hstate *h); int vmemmap_pgtable_prealloc(struct hstate *h, struct page *page); void vmemmap_pgtable_free(struct page *page); void free_huge_page_vmemmap(struct hstate *h, struct page *head); + +static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) +{ + return h->nr_free_vmemmap_pages; +} #else static inline void hugetlb_vmemmap_init(struct hstate *h) { @@ -33,5 +38,10 @@ static inline void vmemmap_pgtable_free(struct page *page) 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 */