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@@ -42,6 +42,35 @@ unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
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};
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EXPORT_SYMBOL(__per_cpu_offset);
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+/**
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+ * pcpu_need_numa - determine percpu allocation needs to consider NUMA
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+ *
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+ * If NUMA is not configured or there is only one NUMA node available,
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+ * there is no reason to consider NUMA. This function determines
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+ * whether percpu allocation should consider NUMA or not.
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+ *
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+ * RETURNS:
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+ * true if NUMA should be considered; otherwise, false.
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+ */
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+static bool __init pcpu_need_numa(void)
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+{
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+#ifdef CONFIG_NEED_MULTIPLE_NODES
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+ pg_data_t *last = NULL;
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+ unsigned int cpu;
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+
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+ for_each_possible_cpu(cpu) {
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+ int node = early_cpu_to_node(cpu);
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+
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+ if (node_online(node) && NODE_DATA(node) &&
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+ last && last != NODE_DATA(node))
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+ return true;
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+
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+ last = NODE_DATA(node);
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+ }
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+#endif
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+ return false;
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+}
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+
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/**
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* pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
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* @cpu: cpu to allocate for
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@@ -81,6 +110,59 @@ static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
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#endif
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}
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+/*
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+ * Embedding allocator
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+ *
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+ * The first chunk is sized to just contain the static area plus
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+ * PERCPU_DYNAMIC_RESERVE and allocated as a contiguous area using
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+ * bootmem allocator and used as-is without being mapped into vmalloc
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+ * area. This enables the first chunk to piggy back on the linear
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+ * physical PMD mapping and doesn't add any additional pressure to
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+ * TLB.
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+ */
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+static void *pcpue_ptr __initdata;
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+static size_t pcpue_unit_size __initdata;
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+
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+static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
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+{
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+ return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size
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+ + ((size_t)pageno << PAGE_SHIFT));
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+}
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+
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+static ssize_t __init setup_pcpu_embed(size_t static_size)
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+{
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+ unsigned int cpu;
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+
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+ /*
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+ * If large page isn't supported, there's no benefit in doing
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+ * this. Also, embedding allocation doesn't play well with
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+ * NUMA.
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+ */
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+ if (!cpu_has_pse || pcpu_need_numa())
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+ return -EINVAL;
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+
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+ /* allocate and copy */
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+ pcpue_unit_size = PFN_ALIGN(static_size + PERCPU_DYNAMIC_RESERVE);
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+ pcpue_unit_size = max(pcpue_unit_size, PCPU_MIN_UNIT_SIZE);
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+ pcpue_ptr = pcpu_alloc_bootmem(0, num_possible_cpus() * pcpue_unit_size,
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+ PAGE_SIZE);
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+ if (!pcpue_ptr)
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+ return -ENOMEM;
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+
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+ for_each_possible_cpu(cpu)
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+ memcpy(pcpue_ptr + cpu * pcpue_unit_size, __per_cpu_load,
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+ static_size);
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+
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+ /* we're ready, commit */
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+ pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n",
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+ pcpue_unit_size >> PAGE_SHIFT, pcpue_ptr, static_size);
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+
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+ return pcpu_setup_first_chunk(pcpue_get_page, static_size,
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+ pcpue_unit_size,
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+ pcpue_unit_size - static_size, pcpue_ptr,
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+ NULL);
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+}
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+
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/*
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* 4k page allocator
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*
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@@ -178,7 +260,9 @@ void __init setup_per_cpu_areas(void)
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NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
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/* allocate percpu area */
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- ret = setup_pcpu_4k(static_size);
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+ ret = setup_pcpu_embed(static_size);
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+ if (ret < 0)
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+ ret = setup_pcpu_4k(static_size);
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if (ret < 0)
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panic("cannot allocate static percpu area (%zu bytes, err=%zd)",
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static_size, ret);
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