From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-mw2nam12on2119.outbound.protection.outlook.com ([40.107.244.119]:4544 "EHLO NAM12-MW2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725851AbgDCEqR (ORCPT ); Fri, 3 Apr 2020 00:46:17 -0400 Subject: Re: [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA 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> <20200331140332.GA2129@MiWiFi-R3L-srv> <20200331142138.GL30449@dhcp22.suse.cz> <20200331143140.GA2402@MiWiFi-R3L-srv> From: Hoan Tran Message-ID: Date: Thu, 2 Apr 2020 21:46:05 -0700 In-Reply-To: <20200331143140.GA2402@MiWiFi-R3L-srv> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit MIME-Version: 1.0 Sender: linux-s390-owner@vger.kernel.org List-ID: To: Baoquan He , Michal Hocko Cc: Mike Rapoport , 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 All, On 3/31/20 7:31 AM, Baoquan He wrote: > On 03/31/20 at 04:21pm, Michal Hocko wrote: >> On Tue 31-03-20 22:03:32, Baoquan He wrote: >>> 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. >> >> Doing this would be a step in the right direction! I haven't checked the >> code very closely though. The below sounds way too simple to be truth I >> am afraid. First for_each_mem_pfn_range is available only for >> CONFIG_HAVE_MEMBLOCK_NODE_MAP (which is one of the reasons why I keep >> saying that I really hate that being conditional). Also I haven't really >> checked the deferred initialization path - I have a very vague >> recollection that it has been converted to the memblock api but I have >> happilly dropped all that memory. > > Thanks for your quick response and pointing out the rest suspect aspects, > I will investigate what you mentioned, see if they impact. I would like to check if we still move on with my patch to remove CONFIG_NODES_SPAN_OTHER_NODES and have another patch on top it? Thanks Hoan > >> >>> 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) >> >> -- >> Michal Hocko >> SUSE Labs >> >