From 2532fc318db0e1fe68e01407ee27634c76916e44 Mon Sep 17 00:00:00 2001 From: Tang Chen Date: Thu, 25 Aug 2016 16:35:14 +0800 Subject: [PATCH] x86/numa: Online memory-less nodes at boot time For now, x86 does not support memory-less node. A node without memory will not be onlined, and the cpus on it will be mapped to the other online nodes with memory in init_cpu_to_node(). The reason of doing this is to ensure each cpu has mapped to a node with memory, so that it will be able to allocate local memory for that cpu. But we don't have to do it in this way. In this series of patches, we are going to construct cpu <-> node mapping for all possible cpus at boot time, which is a persistent mapping. It means that the cpu will be mapped to the node which it belongs to, and will never be changed. If a node has only cpus but no memory, the cpus on it will be mapped to a memory-less node. And the memory-less node should be onlined. Allocate pgdats for all memory-less nodes and online them at boot time. Then build zonelists for these nodes. As a result, when cpus on these memory-less nodes try to allocate memory from local node, it will automatically fall back to the proper zones in the zonelists. Signed-off-by: Zhu Guihua Signed-off-by: Dou Liyang Acked-by: Ingo Molnar Cc: mika.j.penttila@gmail.com Cc: len.brown@intel.com Cc: Tang Chen Cc: rafael@kernel.org Cc: rjw@rjwysocki.net Cc: yasu.isimatu@gmail.com Cc: linux-mm@kvack.org Cc: linux-acpi@vger.kernel.org Cc: isimatu.yasuaki@jp.fujitsu.com Cc: gongzhaogang@inspur.com Cc: tj@kernel.org Cc: izumi.taku@jp.fujitsu.com Cc: cl@linux.com Cc: chen.tang@easystack.cn Cc: akpm@linux-foundation.org Cc: kamezawa.hiroyu@jp.fujitsu.com Cc: lenb@kernel.org Link: http://lkml.kernel.org/r/1472114120-3281-2-git-send-email-douly.fnst@cn.fujitsu.com Signed-off-by: Thomas Gleixner --- arch/x86/mm/numa.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index fb682108f4dc..3f35b48d1d9d 100644 --- a/arch/x86/mm/numa.c +++ b/arch/x86/mm/numa.c @@ -722,22 +722,19 @@ void __init x86_numa_init(void) numa_init(dummy_numa_init); } -static __init int find_near_online_node(int node) +static void __init init_memory_less_node(int nid) { - int n, val; - int min_val = INT_MAX; - int best_node = -1; + unsigned long zones_size[MAX_NR_ZONES] = {0}; + unsigned long zholes_size[MAX_NR_ZONES] = {0}; - for_each_online_node(n) { - val = node_distance(node, n); + /* Allocate and initialize node data. Memory-less node is now online.*/ + alloc_node_data(nid); + free_area_init_node(nid, zones_size, 0, zholes_size); - if (val < min_val) { - min_val = val; - best_node = n; - } - } - - return best_node; + /* + * All zonelists will be built later in start_kernel() after per cpu + * areas are initialized. + */ } /* @@ -766,8 +763,10 @@ void __init init_cpu_to_node(void) if (node == NUMA_NO_NODE) continue; + if (!node_online(node)) - node = find_near_online_node(node); + init_memory_less_node(node); + numa_set_node(cpu, node); } } -- 2.39.5