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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 8AC49C0044C for ; Mon, 5 Nov 2018 16:39:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58A1120866 for ; Mon, 5 Nov 2018 16:39:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58A1120866 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.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 S2387654AbeKFB7z (ORCPT ); Mon, 5 Nov 2018 20:59:55 -0500 Received: from mga05.intel.com ([192.55.52.43]:20007 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387420AbeKFB7y (ORCPT ); Mon, 5 Nov 2018 20:59:54 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Nov 2018 08:39:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,468,1534834800"; d="scan'208";a="105570113" Received: from ray.jf.intel.com (HELO [10.7.201.17]) ([10.7.201.17]) by orsmga001.jf.intel.com with ESMTP; 05 Nov 2018 08:39:23 -0800 Subject: Re: [PATCH 2/2] mm/page_alloc: use a single function to free page To: Aaron Lu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: Andrew Morton , =?UTF-8?Q?Pawe=c5=82_Staszewski?= , Jesper Dangaard Brouer , Eric Dumazet , Tariq Toukan , Ilias Apalodimas , Yoel Caspersen , Mel Gorman , Saeed Mahameed , Michal Hocko , Vlastimil Babka , Dave Hansen References: <20181105085820.6341-1-aaron.lu@intel.com> <20181105085820.6341-2-aaron.lu@intel.com> From: Dave Hansen Openpgp: preference=signencrypt Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181105085820.6341-2-aaron.lu@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/5/18 12:58 AM, Aaron Lu wrote: > We have multiple places of freeing a page, most of them doing similar > things and a common function can be used to reduce code duplicate. > > It also avoids bug fixed in one function and left in another. Haha, should have read the next patch. :) > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 91a9a6af41a2..2b330296e92a 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -4425,9 +4425,17 @@ unsigned long get_zeroed_page(gfp_t gfp_mask) > } > EXPORT_SYMBOL(get_zeroed_page); > > -void __free_pages(struct page *page, unsigned int order) > +/* > + * Free a page by reducing its ref count by @nr. > + * If its refcount reaches 0, then according to its order: > + * order0: send to PCP; > + * high order: directly send to Buddy. > + */ FWIW, I'm not a fan of comments on the function like this. Please just comment the *code* that's doing what you describe. It's easier to read and less likely to diverge from the code. The rest of the patch looks great, though.