On Wed, Aug 24, 2016 at 03:44:48PM +0800, Zhen Lei wrote: > To make each percpu area allocated from its local numa node. Without this > patch, all percpu areas will be allocated from the node which cpu0 belongs > to. > > Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> > --- > arch/arm64/Kconfig | 8 ++++++++ > arch/arm64/mm/numa.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 63 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index bc3f00f..2815af6 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -603,6 +603,14 @@ config USE_PERCPU_NUMA_NODE_ID > def_bool y > depends on NUMA > > +config HAVE_SETUP_PER_CPU_AREA > + def_bool y > + depends on NUMA > + > +config NEED_PER_CPU_EMBED_FIRST_CHUNK > + def_bool y > + depends on NUMA Why do we need this? Is it purely about using block mappings for the pcpu area? > source kernel/Kconfig.preempt > source kernel/Kconfig.hz > > diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c > index 7b73808..5e44ad1 100644 > --- a/arch/arm64/mm/numa.c > +++ b/arch/arm64/mm/numa.c > @@ -26,6 +26,7 @@ > #include <linux/of.h> > > #include <asm/acpi.h> > +#include <asm/sections.h> > > struct pglist_data *node_data[MAX_NUMNODES] __read_mostly; > EXPORT_SYMBOL(node_data); > @@ -131,6 +132,60 @@ void __init early_map_cpu_to_node(unsigned int cpu, int nid) > cpu_to_node_map[cpu] = nid; > } > > +#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA > +unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; > +EXPORT_SYMBOL(__per_cpu_offset); > + > +static int __init early_cpu_to_node(int cpu) > +{ > + return cpu_to_node_map[cpu]; > +} > + > +static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) > +{ > + if (early_cpu_to_node(from) == early_cpu_to_node(to)) > + return LOCAL_DISTANCE; > + else > + return REMOTE_DISTANCE; > +} Is it too early to use __node_distance here? > +static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, > + size_t align) > +{ > + int nid = early_cpu_to_node(cpu); > + > + return memblock_virt_alloc_try_nid(size, align, > + __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid); > +} > + > +static void __init pcpu_fc_free(void *ptr, size_t size) > +{ > + memblock_free_early(__pa(ptr), size); > +} > + > +void __init setup_per_cpu_areas(void) > +{ > + unsigned long delta; > + unsigned int cpu; > + int rc; > + > + /* > + * Always reserve area for module percpu variables. That's > + * what the legacy allocator did. > + */ > + rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, > + PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, > + pcpu_cpu_distance, > + pcpu_fc_alloc, pcpu_fc_free); > + if (rc < 0) > + panic("Failed to initialize percpu areas."); > + > + delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; > + for_each_possible_cpu(cpu) > + __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu]; > +} > +#endif It's a pity that this is practically identical to PowerPC. Ideally, there would be definitions of this initialisation gunk in the core code that could be reused across architectures. 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