diff options
| -rw-r--r-- | arch/x86/kernel/setup_percpu.c | 86 |
1 files changed, 85 insertions, 1 deletions
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index 4a17c96..fd4c399 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -43,6 +43,35 @@ unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = { EXPORT_SYMBOL(__per_cpu_offset); /** + * pcpu_need_numa - determine percpu allocation needs to consider NUMA + * + * If NUMA is not configured or there is only one NUMA node available, + * there is no reason to consider NUMA. This function determines + * whether percpu allocation should consider NUMA or not. + * + * RETURNS: + * true if NUMA should be considered; otherwise, false. + */ +static bool __init pcpu_need_numa(void) +{ +#ifdef CONFIG_NEED_MULTIPLE_NODES + pg_data_t *last = NULL; + unsigned int cpu; + + for_each_possible_cpu(cpu) { + int node = early_cpu_to_node(cpu); + + if (node_online(node) && NODE_DATA(node) && + last && last != NODE_DATA(node)) + return true; + + last = NODE_DATA(node); + } +#endif + return false; +} + +/** * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu * @cpu: cpu to allocate for * @size: size allocation in bytes @@ -82,6 +111,59 @@ static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size, } /* + * Embedding allocator + * + * The first chunk is sized to just contain the static area plus + * PERCPU_DYNAMIC_RESERVE and allocated as a contiguous area using + * bootmem allocator and used as-is without being mapped into vmalloc + * area. This enables the first chunk to piggy back on the linear + * physical PMD mapping and doesn't add any additional pressure to + * TLB. + */ +static void *pcpue_ptr __initdata; +static size_t pcpue_unit_size __initdata; + +static struct page * __init pcpue_get_page(unsigned int cpu, int pageno) +{ + return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + + ((size_t)pageno << PAGE_SHIFT)); +} + +static ssize_t __init setup_pcpu_embed(size_t static_size) +{ + unsigned int cpu; + + /* + * If large page isn't supported, there's no benefit in doing + * this. Also, embedding allocation doesn't play well with + * NUMA. + */ + if (!cpu_has_pse || pcpu_need_numa()) + return -EINVAL; + + /* allocate and copy */ + pcpue_unit_size = PFN_ALIGN(static_size + PERCPU_DYNAMIC_RESERVE); + pcpue_unit_size = max(pcpue_unit_size, PCPU_MIN_UNIT_SIZE); + pcpue_ptr = pcpu_alloc_bootmem(0, num_possible_cpus() * pcpue_unit_size, + PAGE_SIZE); + if (!pcpue_ptr) + return -ENOMEM; + + for_each_possible_cpu(cpu) + memcpy(pcpue_ptr + cpu * pcpue_unit_size, __per_cpu_load, + static_size); + + /* we're ready, commit */ + pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n", + pcpue_unit_size >> PAGE_SHIFT, pcpue_ptr, static_size); + + return pcpu_setup_first_chunk(pcpue_get_page, static_size, + pcpue_unit_size, + pcpue_unit_size - static_size, pcpue_ptr, + NULL); +} + +/* * 4k page allocator * * This is the basic allocator. Static percpu area is allocated @@ -178,7 +260,9 @@ void __init setup_per_cpu_areas(void) NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); /* allocate percpu area */ - ret = setup_pcpu_4k(static_size); + ret = setup_pcpu_embed(static_size); + if (ret < 0) + ret = setup_pcpu_4k(static_size); if (ret < 0) panic("cannot allocate static percpu area (%zu bytes, err=%zd)", static_size, ret); |