From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-2.mimecast.com ([205.139.110.61]:30490 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731051AbgCaOEe (ORCPT ); Tue, 31 Mar 2020 10:04:34 -0400 Date: Tue, 31 Mar 2020 22:03:32 +0800 From: Baoquan He Subject: Re: [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA Message-ID: <20200331140332.GA2129@MiWiFi-R3L-srv> References: <1585420282-25630-1-git-send-email-Hoan@os.amperecomputing.com> <20200330074246.GA14243@dhcp22.suse.cz> <20200330175100.GD30942@linux.ibm.com> <20200330182301.GM14243@dhcp22.suse.cz> <20200331081423.GE30942@linux.ibm.com> <20200331085513.GE30449@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200331085513.GE30449@dhcp22.suse.cz> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Michal Hocko Cc: Mike Rapoport , Hoan Tran , Catalin Marinas , Will Deacon , Andrew Morton , Vlastimil Babka , Oscar Salvador , Pavel Tatashin , Alexander Duyck , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , "David S. Miller" , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , "open list:MEMORY MANAGEMENT" , linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, lho@amperecomputing.com, mmorana@amperecomputing.com Hi Michal, On 03/31/20 at 10:55am, Michal Hocko wrote: > On Tue 31-03-20 11:14:23, Mike Rapoport wrote: > > Maybe I mis-read the code, but I don't see how this could happen. In the > > HAVE_MEMBLOCK_NODE_MAP=y case, free_area_init_node() calls > > calculate_node_totalpages() that ensures that node->node_zones are entirely > > within the node because this is checked in zone_spanned_pages_in_node(). > > zone_spanned_pages_in_node does chech the zone boundaries are within the > node boundaries. But that doesn't really tell anything about other > potential zones interleaving with the physical memory range. > zone->spanned_pages simply gives the physical range for the zone > including holes. Interleaving nodes are essentially a hole > (__absent_pages_in_range is going to skip those). > > That means that when free_area_init_core simply goes over the whole > physical zone range including holes and that is why we need to check > both for physical and logical holes (aka other nodes). > > The life would be so much easier if the whole thing would simply iterate > over memblocks... The memblock iterating sounds a great idea. I tried with putting the memblock iterating in the upper layer, memmap_init(), which is used for boot mem only anyway. Do you think it's doable and OK? It yes, I can work out a formal patch to make this simpler as you said. The draft code is as below. Like this it uses the existing code and involves little change. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 138a56c0f48f..558d421f294b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6007,14 +6007,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, * function. They do not exist on hotplugged memory. */ if (context == MEMMAP_EARLY) { - if (!early_pfn_valid(pfn)) { - pfn = next_pfn(pfn); - continue; - } - if (!early_pfn_in_nid(pfn, nid)) { - pfn++; - continue; - } if (overlap_memmap_init(zone, &pfn)) continue; if (defer_init(nid, pfn, end_pfn)) @@ -6130,9 +6122,17 @@ static void __meminit zone_init_free_lists(struct zone *zone) } void __meminit __weak memmap_init(unsigned long size, int nid, - unsigned long zone, unsigned long start_pfn) + unsigned long zone, unsigned long range_start_pfn) { - memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL); + unsigned long start_pfn, end_pfn; + unsigned long range_end_pfn = range_start_pfn + size; + int i; + for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) { + start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn); + end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn); + if (end_pfn > start_pfn) + memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL); + } } static int zone_batchsize(struct zone *zone)