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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 CC36EC10F27 for ; Tue, 10 Mar 2020 15:56:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8DC3920578 for ; Tue, 10 Mar 2020 15:56:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KG0do78S" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8DC3920578 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 385DE6B0006; Tue, 10 Mar 2020 11:56:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 336D76B0007; Tue, 10 Mar 2020 11:56:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2730A6B0008; Tue, 10 Mar 2020 11:56:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0074.hostedemail.com [216.40.44.74]) by kanga.kvack.org (Postfix) with ESMTP id 0E0A76B0006 for ; Tue, 10 Mar 2020 11:56:12 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id D025A181AC9CC for ; Tue, 10 Mar 2020 15:56:11 +0000 (UTC) X-FDA: 76579904142.04.sky16_7047720258d3f X-HE-Tag: sky16_7047720258d3f X-Filterd-Recvd-Size: 5268 Received: from mail-il1-f194.google.com (mail-il1-f194.google.com [209.85.166.194]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Tue, 10 Mar 2020 15:56:11 +0000 (UTC) Received: by mail-il1-f194.google.com with SMTP id j69so12433888ila.11 for ; Tue, 10 Mar 2020 08:56:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Tr7lredCK4qagSPyF18B0aZa3RIS+CcRpTq13/SAPbs=; b=KG0do78Sdwl4eSlzuPwoqC8HPB8gywLuEysq5IjZ7Nv+HzD24RnfG9tkyJaeBgoJq6 bZQ7UXUAwfhvvFS5kImBupIweO2NJuTSeCUneLvVL97osC7YoEyZpfRici88ZARhlnuU oUiDxw9HHd3Kayvua+uG1GKAeJYVfph3zOKOWyGZThHBCTyBkLtSLQ82I8q1ZCE+5xrB E/zMg6G1H3ZhdlHusg5qYkgDAPfBQJMuo1SZNDKL26ZZdMlgSEXxkqfcOfdkwWaPeFSm 9AEwsNA6i5OlAIr3Kt7IWyorgPGxd+ScRSfCvMzQfraDEta2xo4Rb7rhdVrX1IqhIPcj JXug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Tr7lredCK4qagSPyF18B0aZa3RIS+CcRpTq13/SAPbs=; b=hWEMCjQmrdKTMOrJmjtSfTqWXx7KKgBV70K1iwbkuvZ0iE29MZUfenNh8AMXOemAfA 6DW8/IWZIEGVsJzV2MbUkvOik29zaMO1dZqxoP5fUg++v+O3EGvLHUYXEmkdNM0Uhrma 6bUsY3Oeq9StC0RyejQoGDA2i++THiozkOU48mZgiSlADj585FoI6SDocT4V8iZoExpc o3U7tmnexKsK5IW2z+vtuaBPp5kwjYWwgpxllYT7bjIHeC2C06Sqg0bNHubFC1XUq30c TsUE6JtKj81/RUrVgGxxQdHIa2uy6hskEYiEiXleSmMj0uJ3Tq212HkTopMIcCruTXVX 5S0g== X-Gm-Message-State: ANhLgQ3Ehlrw/s7ET3fqJqQw4avHXPOHBEaaQ7f7RrJJ/j2n0hD2U35b 7NIs7iHrHaXI0hhDPZ6lBCNAaXEzazGZzg97a58= X-Google-Smtp-Source: ADFU+vt2gnTErHE0WI+tfeUaPeduGZt931+UCqc6VUSJgZd+DPCgj88JDgj4Hn/+GZEMNJBBsxiHdjfg5QF/jiNc9A0= X-Received: by 2002:a92:89d5:: with SMTP id w82mr160794ilk.95.1583855770528; Tue, 10 Mar 2020 08:56:10 -0700 (PDT) MIME-Version: 1.0 References: <1583853751-5525-1-git-send-email-qiwuchen55@gmail.com> In-Reply-To: <1583853751-5525-1-git-send-email-qiwuchen55@gmail.com> From: Alexander Duyck Date: Tue, 10 Mar 2020 08:55:59 -0700 Message-ID: Subject: Re: [PATCH v4] mm/page_alloc: simplify page_is_buddy() for better code readability To: qiwuchen55@gmail.com Cc: Andrew Morton , Matthew Wilcox , Vlastimil Babka , pankaj.gupta.linux@gmail.com, bhe@redhat.com, linux-mm , chenqiwu Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 10, 2020 at 8:22 AM wrote: > > From: chenqiwu > > Simplify page_is_buddy() to reduce the redundant code for better code > readability. > > Signed-off-by: chenqiwu > --- > changes in v4: > - change the return type of page_is_buddy() from int to bool. > - reflow the comment into fewer lines. > --- Looks good to me. Reviewed-by: Alexander Duyck > mm/page_alloc.c | 33 +++++++++++++-------------------- > 1 file changed, 13 insertions(+), 20 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3c4eb75..229fc8c 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -791,32 +791,25 @@ static inline void set_page_order(struct page *page, unsigned int order) > * > * For recording page's order, we use page_private(page). > */ > -static inline int page_is_buddy(struct page *page, struct page *buddy, > +static inline bool page_is_buddy(struct page *page, struct page *buddy, > unsigned int order) > { > - if (page_is_guard(buddy) && page_order(buddy) == order) { > - if (page_zone_id(page) != page_zone_id(buddy)) > - return 0; > - > - VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); > + if (!page_is_guard(buddy) && !PageBuddy(buddy)) > + return false; > > - return 1; > - } > + if (page_order(buddy) != order) > + return false; > > - if (PageBuddy(buddy) && page_order(buddy) == order) { > - /* > - * zone check is done late to avoid uselessly > - * calculating zone/node ids for pages that could > - * never merge. > - */ > - if (page_zone_id(page) != page_zone_id(buddy)) > - return 0; > + /* > + * zone check is done late to avoid uselessly calculating > + * zone/node ids for pages that could never merge. > + */ > + if (page_zone_id(page) != page_zone_id(buddy)) > + return false; > > - VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); > + VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); > > - return 1; > - } > - return 0; > + return true; > } > > #ifdef CONFIG_COMPACTION > -- > 1.9.1 >