From patchwork Tue Nov 19 21:46:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 11252705 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 7E1371390 for ; Tue, 19 Nov 2019 21:46:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 549E8222D3 for ; Tue, 19 Nov 2019 21:46:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="WgWSDZCj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727533AbfKSVqX (ORCPT ); Tue, 19 Nov 2019 16:46:23 -0500 Received: from mail-yb1-f194.google.com ([209.85.219.194]:39912 "EHLO mail-yb1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727324AbfKSVqW (ORCPT ); Tue, 19 Nov 2019 16:46:22 -0500 Received: by mail-yb1-f194.google.com with SMTP id q18so9488413ybq.6; Tue, 19 Nov 2019 13:46:22 -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=vRTdXLGlIRX6PGjWF3qAFy+h5lzWEe6Gf9rZrQkRSH8=; b=WgWSDZCjU99nDR/Ua2n8iB18ALMc/dFJq2zLttN5xPF9rSVRdWE12dMQtDlvWvG3jv 798h2jjMb4GbzHd0P9klx1E+K2bhfYNG8SWGBXktYAsd9uGuQHaMNb0KjUOiOQtLhGS3 SkSqAxUo8ULMfPW/1qUevG1/REvajb+2lF+BmmsEKloR+i9yj/SvNTkj2rVHH+O2f7CI ED4NGpZQaZZ9Vmc/1wFwDFN+PdF4YHsnHryvZ+PYAWkuwIcx6TUYj7dUKyfiCtBGwFKF HTEqRxmKBnVqeKMNJhEbghLIzGmh10s2umgd0WFA9Fn23xmIOk7o2AaNx8Jd+1gs6cZH AxiA== 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=vRTdXLGlIRX6PGjWF3qAFy+h5lzWEe6Gf9rZrQkRSH8=; b=ZBq8i1Uy64iObRYGpXRj/D/IgM45P/SHeVC3dY5qzMhfHjSS3zkChafYOSraXL9lWE uLx4oNdzxjVtSJ1wo7EVYHL70GAOZuP86qF3qdoTAmmy2S0+RSbdtMUq9lR0ZIf7olU8 JVL1cEbtF0ikLjVmbuW7uJR6UMT7vtnX49h3j6EJr730RzzTUICkOT0w0FqdAlT+kQqr Iyf2MQue0E20Kt1aHKVBIk7o/knJbw0yr//aLwuEpLKoLtHhFtDKIK6xgn1Cx2ye9vnq izyvk0hQ0BZOen/HX5FGyrUjO/hkNvtXiU0td2NhIY40MBmCSW8xPGRgF5BltJlv32CD roow== X-Gm-Message-State: APjAAAXIu55vPwoGeRwDKNrmU1uWueiu9b+IZEg73b4jCCLVxB7ZrMMz eBfUFdPEpbEYgOjeM287pTg= X-Google-Smtp-Source: APXvYqyleTGX6pFKhJehM88FqwxssAv+dmjEsyIqaIpXVPihHZ2q/HqdLxwGH+S2RuhmnV2pMAZX9g== X-Received: by 2002:a25:d0d7:: with SMTP id h206mr58288ybg.315.1574199981544; Tue, 19 Nov 2019 13:46:21 -0800 (PST) Received: from localhost.localdomain ([2001:470:b:9c3:9e5c:8eff:fe4f:f2d0]) by smtp.gmail.com with ESMTPSA id b63sm10099456ywc.94.2019.11.19.13.46.19 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 19 Nov 2019 13:46:20 -0800 (PST) Subject: [PATCH v14 1/6] 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: Tue, 19 Nov 2019 13:46:18 -0800 Message-ID: <20191119214618.24996.30818.stgit@localhost.localdomain> In-Reply-To: <20191119214454.24996.66289.stgit@localhost.localdomain> References: <20191119214454.24996.66289.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: David Hildenbrand Reviewed-by: Dan Williams Signed-off-by: Alexander Duyck Acked-by: Mel Gorman --- 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 62dcd6b76c80..32e9cc092656 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) { }