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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH 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 0D289C3279B for ; Mon, 2 Jul 2018 19:54:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0C56208C2 for ; Mon, 2 Jul 2018 19:54:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="KqA/37ud" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B0C56208C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.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 S1753411AbeGBTy5 (ORCPT ); Mon, 2 Jul 2018 15:54:57 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:51418 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753365AbeGBTyz (ORCPT ); Mon, 2 Jul 2018 15:54:55 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w62JsQp7054146; Mon, 2 Jul 2018 19:54:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2017-10-26; bh=Aph7wy/2jJBdEm68+lX0P9wqZYlnzuuxGjOOCwNELi4=; b=KqA/37udbmVUbTyfaWS6KfqgaCrXS7okp/cmSx0WmGuxxIfgY30sWcgiuUJxXIut+/LP O9Xa8PMVRBGjRsvY9EI1K3C0SpFHznJ8fzEplt6Ot9qFtqpn39dW+aW3712Q07P1x5iL z7nPxQNj3JMOPyeceuSOzo/mD9TMtJ6cXT+ttXojBMCpIczHGkHCKjArnXET0NjWqrY7 EmIOjROV4QsuZKvO3L6DZyp/monIAe95v0zKSeO+ADcXBngp8Hj4Fy1CXkzXRG4F5kS6 ihyUqf/8TysLPbPJ9CWh9g8crVgdrPJmDIAhEwGmb54Ve4TV3/Za5hJjfniwJFT/ZoLO Mg== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2130.oracle.com with ESMTP id 2jx19snwfg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 02 Jul 2018 19:54:26 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w62JsPbE017832 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 2 Jul 2018 19:54:25 GMT Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w62JsNiB014330; Mon, 2 Jul 2018 19:54:23 GMT Received: from [192.168.1.10] (/73.69.118.222) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 02 Jul 2018 12:54:23 -0700 Subject: Re: [PATCH v3 2/2] mm/sparse: start using sparse_init_nid(), and remove old code To: Dave Hansen , steven.sistare@oracle.com, daniel.m.jordan@oracle.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, mhocko@suse.com, linux-mm@kvack.org, dan.j.williams@intel.com, jack@suse.cz, jglisse@redhat.com, jrdr.linux@gmail.com, bhe@redhat.com, gregkh@linuxfoundation.org, vbabka@suse.cz, richard.weiyang@gmail.com, rientjes@google.com, mingo@kernel.org, osalvador@techadventures.net References: <20180702020417.21281-1-pasha.tatashin@oracle.com> <20180702020417.21281-3-pasha.tatashin@oracle.com> <552d5a9b-0ca9-cc30-d8c2-33dc1cde917f@intel.com> From: Pavel Tatashin Message-ID: Date: Mon, 2 Jul 2018 15:54:19 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <552d5a9b-0ca9-cc30-d8c2-33dc1cde917f@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8942 signatures=668704 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807020222 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/02/2018 03:47 PM, Dave Hansen wrote: > On 07/01/2018 07:04 PM, Pavel Tatashin wrote: >> + for_each_present_section_nr(pnum_begin + 1, pnum_end) { >> + int nid = sparse_early_nid(__nr_to_section(pnum_end)); >> >> + if (nid == nid_begin) { >> + map_count++; >> continue; >> } > >> + sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count); >> + nid_begin = nid; >> + pnum_begin = pnum_end; >> + map_count = 1; >> } > > Ugh, this is really hard to read. Especially because the pnum "counter" > is called "pnum_end". I called it pnum_end, because that is what is passed to sparse_init_nid(), but I see your point, and I can rename pnum_end to simply pnum if that will make things look better. > > So, this is basically a loop that collects all of the adjacent sections > in a given single nid and then calls sparse_init_nid(). pnum_end in > this case is non-inclusive, so the sparse_init_nid() call is actually > for the *previous* nid that pnum_end is pointing _past_. > > This *really* needs commenting. There is a comment before sparse_init_nid() about inclusiveness: 434 /* 435 * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end) 436 * And number of present sections in this node is map_count. 437 */ 438 static void __init sparse_init_nid(int nid, unsigned long pnum_begin, 439 unsigned long pnum_end, 440 unsigned long map_count) Thank you, Pavel