From patchwork Thu Feb 6 05:39:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 11367661 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 458F91398 for ; Thu, 6 Feb 2020 05:39:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F2B0E214AF for ; Thu, 6 Feb 2020 05:39:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gf3ZYuJX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2B0E214AF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0F9126B0003; Thu, 6 Feb 2020 00:39:27 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 0A9CE6B0006; Thu, 6 Feb 2020 00:39:27 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F01596B0007; Thu, 6 Feb 2020 00:39:26 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0198.hostedemail.com [216.40.44.198]) by kanga.kvack.org (Postfix) with ESMTP id D4D656B0003 for ; Thu, 6 Feb 2020 00:39:26 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 90CF8282C for ; Thu, 6 Feb 2020 05:39:26 +0000 (UTC) X-FDA: 76458599532.21.song37_5257a7ab1fe1b X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,bhe@redhat.com,:linux-kernel@vger.kernel.org::akpm@linux-foundation.org:richardw.yang@linux.intel.com:david@redhat.com:mhocko@suse.com:osalvador@suse.de:bhe@redhat.com,RULES_HIT:30012:30054:30070:30090,0,RBL:207.211.31.120:@redhat.com:.lbl8.mailshell.net-62.18.0.100 66.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:29,LUA_SUMMARY:none X-HE-Tag: song37_5257a7ab1fe1b X-Filterd-Recvd-Size: 3797 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Thu, 6 Feb 2020 05:39:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580967565; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=+ZgCDJ3lYDHO7PerX7DHQHL7BbjicVXkT8EFJG70WMU=; b=gf3ZYuJXHiNGRlxW1iral6tsOt3oVAS6LOfGPIbJglk8X26jOc5PP7xpGRWhfLjdqbOiNM eFIDF8CKML6pb/xNgLxHOY0JwueWYF+vT4mgFvOU8uAIDRMGGedHt1MEw+rq+KQfXg5rk9 t4q5wlQdYYQWd2pY3izv1H3YM4VkomA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-137-IzDqwx8BMTm_-srL3eoidw-1; Thu, 06 Feb 2020 00:39:21 -0500 X-MC-Unique: IzDqwx8BMTm_-srL3eoidw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 25DF31800D42; Thu, 6 Feb 2020 05:39:20 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-19.pek2.redhat.com [10.72.12.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id A1F0185732; Thu, 6 Feb 2020 05:39:14 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, richardw.yang@linux.intel.com, david@redhat.com, mhocko@suse.com, osalvador@suse.de, bhe@redhat.com Subject: [PATCH] mm/hotplug: Adjust shrink_zone_span() to keep the old logic Date: Thu, 6 Feb 2020 13:39:12 +0800 Message-Id: <20200206053912.1211-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 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: In commit 950b68d9178b ("mm/memory_hotplug: don't check for "all holes" in shrink_zone_span()"), the zone->zone_start_pfn/->spanned_pages resetting is moved into the if()/else if() branches, if the zone becomes empty. However the 2nd resetting code block may cause misunderstanding. So take the resetting codes out of the conditional checking and handling branches just as the old code does, the find_smallest_section_pfn()and find_biggest_section_pfn() searching have done the the same thing as the old for loop did, the logic is kept the same as the old code. This can remove the possible confusion. Signed-off-by: Baoquan He Reviewed-by: Wei Yang Acked-by: David Hildenbrand Nacked-by: David Hildenbrand --- mm/memory_hotplug.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 089b6c826a9e..475d0d68a32c 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -398,7 +398,7 @@ static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { - unsigned long pfn; + unsigned long pfn = zone->zone_start_pfn; int nid = zone_to_nid(zone); zone_span_writelock(zone); @@ -414,9 +414,6 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, if (pfn) { zone->spanned_pages = zone_end_pfn(zone) - pfn; zone->zone_start_pfn = pfn; - } else { - zone->zone_start_pfn = 0; - zone->spanned_pages = 0; } } else if (zone_end_pfn(zone) == end_pfn) { /* @@ -429,10 +426,11 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, start_pfn); if (pfn) zone->spanned_pages = pfn - zone->zone_start_pfn + 1; - else { - zone->zone_start_pfn = 0; - zone->spanned_pages = 0; - } + } + + if (!pfn) { + zone->zone_start_pfn = 0; + zone->spanned_pages = 0; } zone_span_writeunlock(zone); }