On 2016/8/26 23:43, Will Deacon wrote: > On Wed, Aug 24, 2016 at 03:44:50PM +0800, 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. >> >> 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 <thunder.leizhen@xxxxxxxxxx> >> --- >> 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 2815af6..3a2b6ed 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -611,6 +611,10 @@ 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 d93d433..4879085 100644 >> --- a/arch/arm64/kernel/smp.c >> +++ b/arch/arm64/kernel/smp.c >> @@ -619,6 +619,7 @@ static void __init of_parse_and_init_cpus(void) >> } >> >> bootcpu_valid = true; >> + early_map_cpu_to_node(0, of_node_to_nid(dn)); > > This seems unrelated? I will get off my work soon. Maybe I need put it into patch 12. > >> /* >> * cpu_logical_map has already been >> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c >> index 6853db7..114180f 100644 >> --- a/arch/arm64/mm/numa.c >> +++ b/arch/arm64/mm/numa.c >> @@ -129,6 +129,14 @@ 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); > > Likewise. > >> } >> >> #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA >> @@ -211,6 +219,35 @@ 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 >> */ >> @@ -224,7 +261,9 @@ 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); > > Why not add memblock_alloc_near_nid to the core code, and make it do > what you need there? I'm thinking about it next week. But some ARCHs like X86/IA64 have their own implementation. > > Will > > . > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html