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=-8.5 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 0F06CC32753 for ; Wed, 14 Aug 2019 16:05:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CE52D2083B for ; Wed, 14 Aug 2019 16:05:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE52D2083B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6773F6B000A; Wed, 14 Aug 2019 12:05:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 600626B000C; Wed, 14 Aug 2019 12:05:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4CD236B000D; Wed, 14 Aug 2019 12:05:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0197.hostedemail.com [216.40.44.197]) by kanga.kvack.org (Postfix) with ESMTP id 2273D6B000A for ; Wed, 14 Aug 2019 12:05:02 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id C3BCB181AC9B4 for ; Wed, 14 Aug 2019 16:05:01 +0000 (UTC) X-FDA: 75821507202.21.verse05_660b0d694b627 X-HE-Tag: verse05_660b0d694b627 X-Filterd-Recvd-Size: 2930 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Wed, 14 Aug 2019 16:05:01 +0000 (UTC) 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) 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: 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