From patchwork Tue Oct 22 22:27:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 11205407 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 D443C13BD for ; Tue, 22 Oct 2019 22:28:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8F6D207FC for ; Tue, 22 Oct 2019 22:28:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OpRegx8/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388539AbfJVW2C (ORCPT ); Tue, 22 Oct 2019 18:28:02 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:37531 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731754AbfJVW2C (ORCPT ); Tue, 22 Oct 2019 18:28:02 -0400 Received: by mail-pf1-f194.google.com with SMTP id y5so11532606pfo.4; Tue, 22 Oct 2019 15:28:01 -0700 (PDT) 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=EpjMfNVSVsAC+zZgTxazNcdbmAOhguRbD3KBWA9AopA=; b=OpRegx8/yA7uDdzCE63jc4NvmKoyTk8ZVrcfKLv5SQMX0ImZzoxw9qPH3LNvSrI1Nz XWvVc8pZ3v0wdWlObgYoUlRaLHIxxpAuaOYhPC7LQg4PUgZ69B1IbRthaPO1Se37Dc60 HxlnwMTYlox5JOFsvs3D8dOnbiKXsu52ncGtanxEFsBqIBdWYaLfeiy/hCkqSc3TgHrz sLLFKhyLj3+sfcynfbPbqiA8ax4SFEYNuFjLhocXE5tAmnK1XiHFkFB0AG+xx2a3R8kl zkorHxFffDrb/l2gX2SIH1Tr0EkHdhwtMt80HpQ8BKCVaYryAzCiacXRxAIizkadGK78 XWhg== 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=EpjMfNVSVsAC+zZgTxazNcdbmAOhguRbD3KBWA9AopA=; b=Bwl025uJk7fuvhpit/Pxc213VTjFlDoR+vmHH/n5FtnbLT1BMmNOO8a/82UCheiIK2 r4VbabpzI6MFxE7mWPexy+0EDp0E6k7iTVhPaaKjHZ5HecWujHiz/YjMhiEy3l3AbQRb iwGdMxbQyHLnTMcBhyoNb3Vxxq3hL21FZc0YbRxwSA+7e4Fq9ZxjrDmTbbTMRYFFG0/2 vNt9DD7igAcLtX6SDoOkHYWKACoaSE5U9KLoZgCY79mTjmvgUiF1yl2UjjHNu4a8VeUa WHQTZO6gGi4czzkXIWgr/acKvBmad+4jAyoswoNyqTBDPnyIEOgiMwW3VBVvmN3mv5a4 WQtA== X-Gm-Message-State: APjAAAVMzlMS5HauUNa122VwfJAMEVnQovpbW+srIPzmRxI3BJ0d0C07 Y1WMgPE8M1Yhwq/eo/vsexs= X-Google-Smtp-Source: APXvYqxWCnQaHaoeJNF2ibhbaqRhfocMXlvvK8PUJB9BSUALT2bMDQooty3xH7SndtMI5LNegn1oQQ== X-Received: by 2002:a63:1b59:: with SMTP id b25mr6351233pgm.267.1571783280678; Tue, 22 Oct 2019 15:28:00 -0700 (PDT) Received: from localhost.localdomain ([2001:470:b:9c3:9e5c:8eff:fe4f:f2d0]) by smtp.gmail.com with ESMTPSA id k123sm12623745pgk.13.2019.10.22.15.27.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Oct 2019 15:28:00 -0700 (PDT) Subject: [PATCH v12 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, 22 Oct 2019 15:27:59 -0700 Message-ID: <20191022222759.17338.47308.stgit@localhost.localdomain> In-Reply-To: <20191022221223.17338.5860.stgit@localhost.localdomain> References: <20191022221223.17338.5860.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 --- 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 d4ca03b93373..f1361dd79757 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 ed8884dc0c47..02ca4e130985 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) { }