From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754233AbcFGIb7 (ORCPT ); Tue, 7 Jun 2016 04:31:59 -0400 Received: from mail-oi0-f66.google.com ([209.85.218.66]:34696 "EHLO mail-oi0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753057AbcFGIb4 (ORCPT ); Tue, 7 Jun 2016 04:31:56 -0400 MIME-Version: 1.0 In-Reply-To: <1465286898-13828-12-git-send-email-thunder.leizhen@huawei.com> References: <1465286898-13828-1-git-send-email-thunder.leizhen@huawei.com> <1465286898-13828-12-git-send-email-thunder.leizhen@huawei.com> From: Ganapatrao Kulkarni Date: Tue, 7 Jun 2016 14:01:55 +0530 Message-ID: Subject: Re: [PATCH v4 11/14] arm64/numa: support HAVE_MEMORYLESS_NODES To: Zhen Lei Cc: Catalin Marinas , Will Deacon , linux-arm-kernel , Ganapatrao Kulkarni , Robert Richter , David Daney , Rob Herring , Frank Rowand , Grant Likely , devicetree , linux-kernel , Xinwei Hu , Zefan Li , Hanjun Guo , Tianhong Ding Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 7, 2016 at 1:38 PM, Zhen Lei wrote: > Some numa nodes may have no memory. For example: > 1. cpu0 on node0 > 2. cpu1 on node1 > 3. device0 access the momory from node0 and node1 take the same time. i am wondering, if access to both nodes is same, then why you need numa. the example you are quoting is against the basic principle of "numa" what is device0 here? cpu? > > So, we can not simply classify device0 to node0 or node1, but we can > define a node2 which distances to node0 and node1 are the same. > > Signed-off-by: Zhen Lei > --- > arch/arm64/Kconfig | 4 ++++ > arch/arm64/kernel/smp.c | 1 + > arch/arm64/mm/numa.c | 43 +++++++++++++++++++++++++++++++++++++++++-- > 3 files changed, 46 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 05c1bf1..5904a62 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -581,6 +581,10 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK > def_bool y > depends on NUMA > > +config HAVE_MEMORYLESS_NODES > + def_bool y > + depends on NUMA > + > source kernel/Kconfig.preempt > source kernel/Kconfig.hz > > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index d099306..9e15297 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -620,6 +620,7 @@ static void __init of_parse_and_init_cpus(void) > } > > bootcpu_valid = true; > + early_map_cpu_to_node(0, of_node_to_nid(dn)); > > /* > * cpu_logical_map has already been > diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c > index df5c842..d73b0a0 100644 > --- a/arch/arm64/mm/numa.c > +++ b/arch/arm64/mm/numa.c > @@ -128,6 +128,14 @@ void __init early_map_cpu_to_node(unsigned int cpu, int nid) > nid = 0; > > cpu_to_node_map[cpu] = nid; > + > + /* > + * We should set the numa node of cpu0 as soon as possible, because it > + * has already been set up online before. cpu_to_node(0) will soon be > + * called. > + */ > + if (!cpu) > + set_cpu_numa_node(cpu, nid); > } > > #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA > @@ -215,6 +223,35 @@ int __init numa_add_memblk(int nid, u64 start, u64 end) > return ret; > } > > +static u64 __init alloc_node_data_from_nearest_node(int nid, const size_t size) > +{ > + int i, best_nid, distance; > + u64 pa; > + DECLARE_BITMAP(nodes_map, MAX_NUMNODES); > + > + bitmap_zero(nodes_map, MAX_NUMNODES); > + bitmap_set(nodes_map, nid, 1); > + > +find_nearest_node: > + best_nid = NUMA_NO_NODE; > + distance = INT_MAX; > + > + for_each_clear_bit(i, nodes_map, MAX_NUMNODES) > + if (numa_distance[nid][i] < distance) { > + best_nid = i; > + distance = numa_distance[nid][i]; > + } > + > + pa = memblock_alloc_nid(size, SMP_CACHE_BYTES, best_nid); > + if (!pa) { > + BUG_ON(best_nid == NUMA_NO_NODE); > + bitmap_set(nodes_map, best_nid, 1); > + goto find_nearest_node; > + } > + > + return pa; > +} > + > /** > * Initialize NODE_DATA for a node on the local memory > */ > @@ -228,7 +265,9 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn) > pr_info("Initmem setup node %d [mem %#010Lx-%#010Lx]\n", > nid, start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1); > > - nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid); > + nd_pa = memblock_alloc_nid(nd_size, SMP_CACHE_BYTES, nid); > + if (!nd_pa) > + nd_pa = alloc_node_data_from_nearest_node(nid, nd_size); > nd = __va(nd_pa); > > /* report and initialize */ > @@ -238,7 +277,7 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn) > if (tnid != nid) > pr_info(" NODE_DATA(%d) on node %d\n", nid, tnid); > > - node_data[nid] = nd; > + NODE_DATA(nid) = nd; > memset(NODE_DATA(nid), 0, sizeof(pg_data_t)); > NODE_DATA(nid)->node_id = nid; > NODE_DATA(nid)->node_start_pfn = start_pfn; > -- > 2.5.0 > > Ganapat > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel