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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 4BEB5C41514 for ; Wed, 14 Aug 2019 16:05:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2269F216F4 for ; Wed, 14 Aug 2019 16:05:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565798703; bh=aj8zMwQBj3aBE59hJyKXruEZDOwZMHzGHgnv1cUF8sY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=sYzoy2qrCStKeYpvu4LDo/UwvaJ8N5RzFCCZG5ZBsCy9f74kTX6jr2YiwuiD8jS+I Bz3NwuHB0eMbUsv7ezarFWbWID383ksTdnNM9ZBDQLA9+pUR5MDxcceKbg+HfBL1SV oI+xDNCtvA38DW4dr+MBvv9r6g/SJRXmwB6L6lXQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728164AbfHNQFC (ORCPT ); Wed, 14 Aug 2019 12:05:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:37012 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726047AbfHNQFB (ORCPT ); Wed, 14 Aug 2019 12:05:01 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 01A52AB92; Wed, 14 Aug 2019 16:05:00 +0000 (UTC) Date: Wed, 14 Aug 2019 18:04:58 +0200 From: Michal Hocko To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Oscar Salvador , Pavel Tatashin , Dan Williams Subject: Re: [PATCH v2 2/5] mm/memory_hotplug: Drop PageReserved() check in online_pages_range() Message-ID: <20190814160458.GH17933@dhcp22.suse.cz> References: <20190814154109.3448-1-david@redhat.com> <20190814154109.3448-3-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190814154109.3448-3-david@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 14-08-19 17:41:06, David Hildenbrand wrote: > move_pfn_range_to_zone() will set all pages to PG_reserved via > memmap_init_zone(). The only way a page could no longer be reserved > would be if a MEM_GOING_ONLINE notifier would clear PG_reserved - which > is not done (the online_page callback is used for that purpose by > e.g., Hyper-V instead). walk_system_ram_range() will never call > online_pages_range() with duplicate PFNs, so drop the PageReserved() check. > > This seems to be a leftover from ancient times where the memmap was > initialized when adding memory and we wanted to check for already > onlined memory. > > Cc: Andrew Morton > Cc: Oscar Salvador > Cc: Michal Hocko > Cc: Pavel Tatashin > Cc: Dan Williams > Signed-off-by: David Hildenbrand Thanks for spliting that up. Acked-by: Michal Hocko > --- > mm/memory_hotplug.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 3706a137d880..10ad970f3f14 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -653,9 +653,7 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, > { > unsigned long onlined_pages = *(unsigned long *)arg; > > - if (PageReserved(pfn_to_page(start_pfn))) > - onlined_pages += online_pages_blocks(start_pfn, nr_pages); > - > + onlined_pages += online_pages_blocks(start_pfn, nr_pages); > online_mem_sections(start_pfn, start_pfn + nr_pages); > > *(unsigned long *)arg = onlined_pages; > -- > 2.21.0 > -- Michal Hocko SUSE Labs