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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 73D82C43144 for ; Fri, 29 Jun 2018 02:30:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23AB027AF1 for ; Fri, 29 Jun 2018 02:30:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lgz2ZEIT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 23AB027AF1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966760AbeF2Cal (ORCPT ); Thu, 28 Jun 2018 22:30:41 -0400 Received: from mail-qt0-f193.google.com ([209.85.216.193]:34236 "EHLO mail-qt0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936532AbeF2Cai (ORCPT ); Thu, 28 Jun 2018 22:30:38 -0400 Received: by mail-qt0-f193.google.com with SMTP id d23-v6so6663798qtp.1 for ; Thu, 28 Jun 2018 19:30:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=prJMZsopAOGvd4i4ZRQwEORKw4GozwPrjoRsWm2lbeQ=; b=lgz2ZEITaTVt04bNM0MT1SISuJTXx0Rrp9eDDycJTaX5aaZ2EjdEkQIohH1B4y5DJ1 UVtQ05IMUPPQDIkMJomg4YdUJZdcRLkstlBJEJrl0EphcxFg2qo31ZgwygThX1wsIBUS I7i4MMopE7BZN7yy/IdUjYiQBmMKyS118ZTsDrbJnogA8q3ub001IAScmRzo2y+dgS2N G1/ImPXpnQ7Cx+on6s9Qd5DXMS7oule9bzFoqJXSgqtJ3CLUNb0UU/3XXJwxNgLJ4N4y F411z6/P0abiJ8Eqsk4pIg7nfNf//HZ6Zab/BvUPZRskxzfOfDuir+diI5NAVptBt5lP uUjg== 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; bh=prJMZsopAOGvd4i4ZRQwEORKw4GozwPrjoRsWm2lbeQ=; b=IaXYH18MAvH8mNL41+DCjd2BtnAr47ZCeT1tG9YRk4GHitoDMiMTV6V0tO+5lK2OFr XGlp6pXXWJtzw3p6qFZhXWLt8nOGuASOAMM3po64q20btR227dXUTRTlN4pPhATGRUL1 eA0TY1RDURYH+jvG2+K6tjxriT/eBmTgqJUJZWJYw2eHU3Gb/RwtUUuEz1v0798rTdLW EDwKLPO7d9oY+HspzM9o6oRQJUGHfHkANHlftJoFfgF5+IXkpb57alwwoSYXNRg3EfJe pgZRfNifDu0a4Sa85oCoQOUDZLcdTZQgtyv3BlxYpRysm89eeqcY7iV1Mf3bPm/jS33I JrPw== X-Gm-Message-State: APt69E0ZcB6zlD2Y3xgLb1abW4Q9eZkXPlF3jU4dLbtvv8BHLTZlJe3d +s68Quw/YKLpBpRAnh6jnkE= X-Google-Smtp-Source: AAOMgpcqIJfzdL/03nyFApzj1RxfQp6BJ298UNev1sqy6C08/xo2E1+n4eX8mzOaHT7tnEzj84w41Q== X-Received: by 2002:aed:2a4a:: with SMTP id k10-v6mr4494886qtf.102.1530239437883; Thu, 28 Jun 2018 19:30:37 -0700 (PDT) Received: from ct7host.localdomain ([38.106.11.25]) by smtp.gmail.com with ESMTPSA id y25-v6sm6390186qtc.48.2018.06.28.19.30.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Jun 2018 19:30:37 -0700 (PDT) From: Jia He To: Russell King , Andrew Morton , Michal Hocko , Catalin Marinas , Mel Gorman , Will Deacon , Mark Rutland , "H. Peter Anvin" Cc: Pavel Tatashin , Daniel Jordan , AKASHI Takahiro , Gioh Kim , Steven Sistare , Daniel Vacek , Eugeniu Rosca , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org, James Morse , Ard Biesheuvel , Steve Capper , Thomas Gleixner , Ingo Molnar , Greg Kroah-Hartman , Kate Stewart , Philippe Ombredanne , Johannes Weiner , Kemi Wang , Petr Tesarik , YASUAKI ISHIMATSU , Andrey Ryabinin , Nikolay Borisov , richard.weiyang@gmail.com, Jia He , Jia He Subject: [PATCH v9 3/6] arm: arm64: page_alloc: reduce unnecessary binary search in memblock_next_valid_pfn() Date: Fri, 29 Jun 2018 10:29:20 +0800 Message-Id: <1530239363-2356-4-git-send-email-hejianet@gmail.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1530239363-2356-1-git-send-email-hejianet@gmail.com> References: <1530239363-2356-1-git-send-email-hejianet@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") optimized the loop in memmap_init_zone(). But there is still some room for improvement. E.g. if pfn and pfn+1 are in the same memblock region, we can simply pfn++ instead of doing the binary search in memblock_next_valid_pfn. Furthermore, if the pfn is in a *gap* of two memory region, skip to next region directly if possible. Signed-off-by: Jia He --- include/linux/early_pfn.h | 37 +++++++++++++++++++++++++++++-------- 1 file changed, 29 insertions(+), 8 deletions(-) diff --git a/include/linux/early_pfn.h b/include/linux/early_pfn.h index 1b001c7..f9e40c3 100644 --- a/include/linux/early_pfn.h +++ b/include/linux/early_pfn.h @@ -3,31 +3,52 @@ #ifndef __EARLY_PFN_H #define __EARLY_PFN_H #ifdef CONFIG_HAVE_MEMBLOCK_PFN_VALID +static int early_region_idx __init_memblock = -1; ulong __init_memblock memblock_next_valid_pfn(ulong pfn) { struct memblock_type *type = &memblock.memory; - unsigned int right = type->cnt; - unsigned int mid, left = 0; + struct memblock_region *regions = type->regions; + uint right = type->cnt; + uint mid, left = 0; + ulong start_pfn, end_pfn, next_start_pfn; phys_addr_t addr = PFN_PHYS(++pfn); + /* fast path, return pfn+1 if next pfn is in the same region */ + if (early_region_idx != -1) { + start_pfn = PFN_DOWN(regions[early_region_idx].base); + end_pfn = PFN_DOWN(regions[early_region_idx].base + + regions[early_region_idx].size); + + if (pfn >= start_pfn && pfn < end_pfn) + return pfn; + + early_region_idx++; + next_start_pfn = PFN_DOWN(regions[early_region_idx].base); + + if (pfn >= end_pfn && pfn <= next_start_pfn) + return next_start_pfn; + } + + /* slow path, do the binary searching */ do { mid = (right + left) / 2; - if (addr < type->regions[mid].base) + if (addr < regions[mid].base) right = mid; - else if (addr >= (type->regions[mid].base + - type->regions[mid].size)) + else if (addr >= (regions[mid].base + regions[mid].size)) left = mid + 1; else { - /* addr is within the region, so pfn is valid */ + early_region_idx = mid; return pfn; } } while (left < right); if (right == type->cnt) return -1UL; - else - return PHYS_PFN(type->regions[right].base); + + early_region_idx = right; + + return PHYS_PFN(regions[early_region_idx].base); } EXPORT_SYMBOL(memblock_next_valid_pfn); #endif /*CONFIG_HAVE_MEMBLOCK_PFN_VALID*/ -- 1.8.3.1