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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 4B1CAC33CA1 for ; Wed, 5 Feb 2020 10:01:08 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C5C092051A for ; Wed, 5 Feb 2020 10:01:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5C092051A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48CHBl6fQ5zDqRb for ; Wed, 5 Feb 2020 21:01:03 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.intel.com (client-ip=192.55.52.88; helo=mga01.intel.com; envelope-from=richardw.yang@linux.intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.intel.com Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48CH8f6PzszDqJl for ; Wed, 5 Feb 2020 20:59:13 +1100 (AEDT) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2020 01:59:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,405,1574150400"; d="scan'208";a="343395725" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga001.fm.intel.com with ESMTP; 05 Feb 2020 01:59:07 -0800 Date: Wed, 5 Feb 2020 17:59:24 +0800 From: Wei Yang To: David Hildenbrand Subject: Re: [PATCH v6 08/10] mm/memory_hotplug: Don't check for "all holes" in shrink_zone_span() Message-ID: <20200205095924.GC24162@richard> References: <20191006085646.5768-1-david@redhat.com> <20191006085646.5768-9-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191006085646.5768-9-david@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Wei Yang Cc: linux-s390@vger.kernel.org, Michal Hocko , linux-ia64@vger.kernel.org, Pavel Tatashin , linux-sh@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Wei Yang , Andrew Morton , linuxppc-dev@lists.ozlabs.org, Dan Williams , linux-arm-kernel@lists.infradead.org, Oscar Salvador Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sun, Oct 06, 2019 at 10:56:44AM +0200, David Hildenbrand wrote: >If we have holes, the holes will automatically get detected and removed >once we remove the next bigger/smaller section. The extra checks can >go. > >Cc: Andrew Morton >Cc: Oscar Salvador >Cc: Michal Hocko >Cc: David Hildenbrand >Cc: Pavel Tatashin >Cc: Dan Williams >Cc: Wei Yang >Signed-off-by: David Hildenbrand >--- > mm/memory_hotplug.c | 34 +++++++--------------------------- > 1 file changed, 7 insertions(+), 27 deletions(-) > >diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >index f294918f7211..8dafa1ba8d9f 100644 >--- a/mm/memory_hotplug.c >+++ b/mm/memory_hotplug.c >@@ -393,6 +393,9 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, > if (pfn) { > zone->zone_start_pfn = pfn; > zone->spanned_pages = zone_end_pfn - pfn; >+ } else { >+ zone->zone_start_pfn = 0; >+ zone->spanned_pages = 0; > } > } else if (zone_end_pfn == end_pfn) { > /* >@@ -405,34 +408,11 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, > start_pfn); > if (pfn) > zone->spanned_pages = pfn - zone_start_pfn + 1; >+ else { >+ zone->zone_start_pfn = 0; >+ zone->spanned_pages = 0; >+ } > } If it is me, I would like to take out these two similar logic out. For example: if () { } else if () { } else { goto out; } /* The zone has no valid section */ if (!pfn) { zone->zone_start_pfn = 0; zone->spanned_pages = 0; } out: zone_span_writeunlock(zone); Well, this is just my personal taste :-) >- >- /* >- * The section is not biggest or smallest mem_section in the zone, it >- * only creates a hole in the zone. So in this case, we need not >- * change the zone. But perhaps, the zone has only hole data. Thus >- * it check the zone has only hole or not. >- */ >- pfn = zone_start_pfn; >- for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) { >- if (unlikely(!pfn_to_online_page(pfn))) >- continue; >- >- if (page_zone(pfn_to_page(pfn)) != zone) >- continue; >- >- /* Skip range to be removed */ >- if (pfn >= start_pfn && pfn < end_pfn) >- continue; >- >- /* If we find valid section, we have nothing to do */ >- zone_span_writeunlock(zone); >- return; >- } >- >- /* The zone has no valid section */ >- zone->zone_start_pfn = 0; >- zone->spanned_pages = 0; > zone_span_writeunlock(zone); > } > >-- >2.21.0 -- Wei Yang Help you, Help me