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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 3E5DEC433E3 for ; Tue, 28 Jul 2020 14:24:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F89020775 for ; Tue, 28 Jul 2020 14:24:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GtVsFuqy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730368AbgG1OYI (ORCPT ); Tue, 28 Jul 2020 10:24:08 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:32134 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730307AbgG1OYI (ORCPT ); Tue, 28 Jul 2020 10:24:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595946246; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=06rCqpwu1j4S1S47vgUTPXYPKKso17TGQwzOaoYSYfs=; b=GtVsFuqyRfS1RkT25da+EhuUFf5MK+pGegTD127A0pLyWVLsTtxR3jny/u2SUL9VKue0wR zjkYY8l6DX8mAQJRrLoC7J+CTbzHM0/D8/VS0/RR8HLuez7E+VJ6vt9Qjh1l+QjbHxeH2N rsZkLJZxu1iQGHes548R3D8PVHuaLK4= 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-166-XL5fGaBiOsyWEWGpA51xEg-1; Tue, 28 Jul 2020 10:24:02 -0400 X-MC-Unique: XL5fGaBiOsyWEWGpA51xEg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8B54D1B18BC1; Tue, 28 Jul 2020 14:23:54 +0000 (UTC) Received: from localhost (ovpn-12-117.pek2.redhat.com [10.72.12.117]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 303B41010427; Tue, 28 Jul 2020 14:23:51 +0000 (UTC) Date: Tue, 28 Jul 2020 22:23:48 +0800 From: Baoquan He To: Mike Rapoport Cc: Andrew Morton , Andy Lutomirski , Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Christoph Hellwig , Dave Hansen , Ingo Molnar , Marek Szyprowski , Max Filippov , Michael Ellerman , Michal Simek , Mike Rapoport , Palmer Dabbelt , Paul Mackerras , Paul Walmsley , Peter Zijlstra , Russell King , Stafford Horne , Thomas Gleixner , Will Deacon , Yoshinori Sato , clang-built-linux@googlegroups.com, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-c6x-dev@linux-c6x.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, linuxppc-dev@lists.ozlabs.org, openrisc@lists.librecores.org, sparclinux@vger.kernel.org, uclinux-h8-devel@lists.sourceforge.jp, x86@kernel.org Subject: Re: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved Message-ID: <20200728142348.GE10792@MiWiFi-R3L-srv> References: <20200728051153.1590-1-rppt@kernel.org> <20200728051153.1590-15-rppt@kernel.org> <20200728110254.GA14854@MiWiFi-R3L-srv> <20200728141504.GC3655207@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200728141504.GC3655207@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On 07/28/20 at 05:15pm, Mike Rapoport wrote: > On Tue, Jul 28, 2020 at 07:02:54PM +0800, Baoquan He wrote: > > On 07/28/20 at 08:11am, Mike Rapoport wrote: > > > From: Mike Rapoport > > > > > > numa_clear_kernel_node_hotplug() function first traverses numa_meminfo > > > regions to set node ID in memblock.reserved and than traverses > > > memblock.reserved to update reserved_nodemask to include node IDs that were > > > set in the first loop. > > > > > > Remove redundant traversal over memblock.reserved and update > > > reserved_nodemask while iterating over numa_meminfo. > > > > > > Signed-off-by: Mike Rapoport > > > --- > > > arch/x86/mm/numa.c | 26 ++++++++++---------------- > > > 1 file changed, 10 insertions(+), 16 deletions(-) > > > > > > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c > > > index 8ee952038c80..4078abd33938 100644 > > > --- a/arch/x86/mm/numa.c > > > +++ b/arch/x86/mm/numa.c > > > @@ -498,31 +498,25 @@ static void __init numa_clear_kernel_node_hotplug(void) > > > * and use those ranges to set the nid in memblock.reserved. > > > * This will split up the memblock regions along node > > > * boundaries and will set the node IDs as well. > > > + * > > > + * The nid will also be set in reserved_nodemask which is later > > > + * used to clear MEMBLOCK_HOTPLUG flag. > > > + * > > > + * [ Note, when booting with mem=nn[kMG] or in a kdump kernel, > > > + * numa_meminfo might not include all memblock.reserved > > > + * memory ranges, because quirks such as trim_snb_memory() > > > + * reserve specific pages for Sandy Bridge graphics. > > > + * These ranges will remain with nid == MAX_NUMNODES. ] > > > */ > > > for (i = 0; i < numa_meminfo.nr_blks; i++) { > > > struct numa_memblk *mb = numa_meminfo.blk + i; > > > int ret; > > > > > > ret = memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid); > > > + node_set(mb->nid, reserved_nodemask); > > > > Really? This will set all node id into reserved_nodemask. But in the > > current code, it's setting nid into memblock reserved region which > > interleaves with numa_memoinfo, then get those nid and set it in > > reserved_nodemask. This is so different, with my understanding. Please > > correct me if I am wrong. > > You are right, I've missed the intersections of numa_meminfo with > memblock.reserved. > > x86 interaction with membock is so, hmm, interesting... Yeah, numa_clear_kernel_node_hotplug() intends to find out any memory node which has reserved memory, then make it as unmovable. Setting all node id into reserved_nodemask will break the use case of hot removing hotpluggable boot memory after system bootup.