From patchwork Fri Jan 3 21:16:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 11317405 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 3836E14B4 for ; Fri, 3 Jan 2020 21:16:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1774A22314 for ; Fri, 3 Jan 2020 21:16:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KYliLu7W" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728678AbgACVQX (ORCPT ); Fri, 3 Jan 2020 16:16:23 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:46435 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728462AbgACVQW (ORCPT ); Fri, 3 Jan 2020 16:16:22 -0500 Received: by mail-pf1-f196.google.com with SMTP id n9so16165911pff.13; Fri, 03 Jan 2020 13:16:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:date:message-id:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=nGjz5CxUAKYp6WMiD/ZoHk/Q6LgCdxFGQ5sPCnHiLQ4=; b=KYliLu7WptqgB+gxQH7IRYKQr1Sg6h+Ays7yLsBtqSlDuEDgA8rV9LNP5ubiF/NWzj RA1/yZKaAP638EQVd+AQ2V+Kk+Gv78x69VHJYJmGFkz51WxU8Ct7tkLE65WCG6IMSaa0 xMzuczTIv8+nW7DH0db+9QlLgm1KmpCHbbXe2gz+A8j2kEi8h9N1ZHy+ByGjD0BysLlN +MS72w/ClxgCXNxbZ+qn1B8PEnVoGWBCspJhiqcNZEDmmR9ybZtJgtcr5jifneM8qdGI Rrhub3x11D/bWQW1JG2nJEND1VMJ4cIpc9vE0UNO9u7XTvUOkzHgvWUnlM64iwlQDnN6 Ib6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=nGjz5CxUAKYp6WMiD/ZoHk/Q6LgCdxFGQ5sPCnHiLQ4=; b=Nnidz6lLgjTAoh9VNtmNnTsFZzQWPYBVfNb5yExDmt9BMobu9JFAWXZ5XJiJEIZ/Es i7GcmzOZIPEVf3L820ceZa8JmKznAq+sOcCzG6cJjJvK2FrTcKq9wgHyYbcMVYn1WMbi 4YnRTVqIZo9QgLRmTbwTic5PEoegIb8UIflIi4m7vQCCl9NCixYVx9P8cLlusTMKA3qq J5cbLhbawVWZj4WY/uoZlYf3gB94Uk3MDyxouS52U4Vcdn0++kwx5ABWh4eJ9Rf1GtDS oBOt2Yq1AYXT/Mj+SeRkHp/s6ebxbvHS0fgvLT+p0A2JGV30NbokCTyvKWLuNJwCyOG8 OZHg== X-Gm-Message-State: APjAAAUSVc242aapPshJ+Zsqupa/zWovsY57SNSjXroNNhh9DKxGVwEG VDHzDx5YExaHxMhOJx/kufk= X-Google-Smtp-Source: APXvYqyCcTdW0ISpVJFhPsSKEkqmov38rMJhCcsvHK0W6V6zVVV/6g6gstqBAIAaFkEqU6ByA+85Xw== X-Received: by 2002:a62:ac08:: with SMTP id v8mr98702364pfe.83.1578086181985; Fri, 03 Jan 2020 13:16:21 -0800 (PST) Received: from localhost.localdomain ([2001:470:b:9c3:9e5c:8eff:fe4f:f2d0]) by smtp.gmail.com with ESMTPSA id a28sm68176390pfh.119.2020.01.03.13.16.21 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Jan 2020 13:16:21 -0800 (PST) Subject: [PATCH v16 1/9] mm: Adjust shuffle code to allow for future coalescing From: Alexander Duyck To: kvm@vger.kernel.org, mst@redhat.com, linux-kernel@vger.kernel.org, willy@infradead.org, mhocko@kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, mgorman@techsingularity.net, vbabka@suse.cz Cc: yang.zhang.wz@gmail.com, nitesh@redhat.com, konrad.wilk@oracle.com, david@redhat.com, pagupta@redhat.com, riel@surriel.com, lcapitulino@redhat.com, dave.hansen@intel.com, wei.w.wang@intel.com, aarcange@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com, alexander.h.duyck@linux.intel.com, osalvador@suse.de Date: Fri, 03 Jan 2020 13:16:20 -0800 Message-ID: <20200103211620.29237.31778.stgit@localhost.localdomain> In-Reply-To: <20200103210509.29237.18426.stgit@localhost.localdomain> References: <20200103210509.29237.18426.stgit@localhost.localdomain> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Alexander Duyck Move the head/tail adding logic out of the shuffle code and into the __free_one_page function since ultimately that is where it is really needed anyway. By doing this we should be able to reduce the overhead and can consolidate all of the list addition bits in one spot. Acked-by: Mel Gorman Acked-by: David Hildenbrand Reviewed-by: Dan Williams Signed-off-by: Alexander Duyck --- include/linux/mmzone.h | 12 -------- mm/page_alloc.c | 71 ++++++++++++++++++++++++++++-------------------- mm/shuffle.c | 12 ++++---- mm/shuffle.h | 6 ++++ 4 files changed, 54 insertions(+), 47 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 89d8ff06c9ce..245010b24747 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -116,18 +116,6 @@ static inline void add_to_free_area_tail(struct page *page, struct free_area *ar area->nr_free++; } -#ifdef CONFIG_SHUFFLE_PAGE_ALLOCATOR -/* Used to preserve page allocation order entropy */ -void add_to_free_area_random(struct page *page, struct free_area *area, - int migratetype); -#else -static inline void add_to_free_area_random(struct page *page, - struct free_area *area, int migratetype) -{ - add_to_free_area(page, area, migratetype); -} -#endif - /* Used for pages which are on another list */ static inline void move_to_free_area(struct page *page, struct free_area *area, int migratetype) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 85064abafcc3..2a5c83c0b8ea 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -878,6 +878,36 @@ static inline struct capture_control *task_capc(struct zone *zone) #endif /* CONFIG_COMPACTION */ /* + * If this is not the largest possible page, check if the buddy + * of the next-highest order is free. If it is, it's possible + * that pages are being freed that will coalesce soon. In case, + * that is happening, add the free page to the tail of the list + * so it's less likely to be used soon and more likely to be merged + * as a higher order page + */ +static inline bool +buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, + struct page *page, unsigned int order) +{ + struct page *higher_page, *higher_buddy; + unsigned long combined_pfn; + + if (order >= MAX_ORDER - 2) + return false; + + if (!pfn_valid_within(buddy_pfn)) + return false; + + combined_pfn = buddy_pfn & pfn; + higher_page = page + (combined_pfn - pfn); + buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1); + higher_buddy = higher_page + (buddy_pfn - combined_pfn); + + return pfn_valid_within(buddy_pfn) && + page_is_buddy(higher_page, higher_buddy, order + 1); +} + +/* * Freeing function for a buddy system allocator. * * The concept of a buddy system is to maintain direct-mapped table @@ -906,11 +936,13 @@ static inline void __free_one_page(struct page *page, struct zone *zone, unsigned int order, int migratetype) { - unsigned long combined_pfn; + struct capture_control *capc = task_capc(zone); unsigned long uninitialized_var(buddy_pfn); - struct page *buddy; + unsigned long combined_pfn; + struct free_area *area; unsigned int max_order; - struct capture_control *capc = task_capc(zone); + struct page *buddy; + bool to_tail; max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1); @@ -979,35 +1011,16 @@ static inline void __free_one_page(struct page *page, done_merging: set_page_order(page, order); - /* - * If this is not the largest possible page, check if the buddy - * of the next-highest order is free. If it is, it's possible - * that pages are being freed that will coalesce soon. In case, - * that is happening, add the free page to the tail of the list - * so it's less likely to be used soon and more likely to be merged - * as a higher order page - */ - if ((order < MAX_ORDER-2) && pfn_valid_within(buddy_pfn) - && !is_shuffle_order(order)) { - struct page *higher_page, *higher_buddy; - combined_pfn = buddy_pfn & pfn; - higher_page = page + (combined_pfn - pfn); - buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1); - higher_buddy = higher_page + (buddy_pfn - combined_pfn); - if (pfn_valid_within(buddy_pfn) && - page_is_buddy(higher_page, higher_buddy, order + 1)) { - add_to_free_area_tail(page, &zone->free_area[order], - migratetype); - return; - } - } - + area = &zone->free_area[order]; if (is_shuffle_order(order)) - add_to_free_area_random(page, &zone->free_area[order], - migratetype); + to_tail = shuffle_pick_tail(); else - add_to_free_area(page, &zone->free_area[order], migratetype); + to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order); + if (to_tail) + add_to_free_area_tail(page, area, migratetype); + else + add_to_free_area(page, area, migratetype); } /* diff --git a/mm/shuffle.c b/mm/shuffle.c index b3fe97fd6654..e65d57f39486 100644 --- a/mm/shuffle.c +++ b/mm/shuffle.c @@ -183,11 +183,11 @@ void __meminit __shuffle_free_memory(pg_data_t *pgdat) shuffle_zone(z); } -void add_to_free_area_random(struct page *page, struct free_area *area, - int migratetype) +bool shuffle_pick_tail(void) { static u64 rand; static u8 rand_bits; + bool ret; /* * The lack of locking is deliberate. If 2 threads race to @@ -198,10 +198,10 @@ void add_to_free_area_random(struct page *page, struct free_area *area, rand = get_random_u64(); } - if (rand & 1) - add_to_free_area(page, area, migratetype); - else - add_to_free_area_tail(page, area, migratetype); + ret = rand & 1; + rand_bits--; rand >>= 1; + + return ret; } diff --git a/mm/shuffle.h b/mm/shuffle.h index 777a257a0d2f..4d79f03b6658 100644 --- a/mm/shuffle.h +++ b/mm/shuffle.h @@ -22,6 +22,7 @@ enum mm_shuffle_ctl { DECLARE_STATIC_KEY_FALSE(page_alloc_shuffle_key); extern void page_alloc_shuffle(enum mm_shuffle_ctl ctl); extern void __shuffle_free_memory(pg_data_t *pgdat); +extern bool shuffle_pick_tail(void); static inline void shuffle_free_memory(pg_data_t *pgdat) { if (!static_branch_unlikely(&page_alloc_shuffle_key)) @@ -44,6 +45,11 @@ static inline bool is_shuffle_order(int order) return order >= SHUFFLE_ORDER; } #else +static inline bool shuffle_pick_tail(void) +{ + return false; +} + static inline void shuffle_free_memory(pg_data_t *pgdat) { }