x86: remove static boot_cpu_pda array v2

  * Remove the boot_cpu_pda array and pointer table from the data section.
    Allocate the pointer table and array during init.  do_boot_cpu()
    will reallocate the pda in node local memory and if the cpu is being
    brought up before the bootmem array is released (after_bootmem = 0),
    then it will free the initial pda.  This will happen for all cpus
    present at system startup.

    This removes 512k + 32k bytes from the data section.

For inclusion into sched-devel/latest tree.

Based on:
	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
    +   sched-devel/latest  .../mingo/linux-2.6-sched-devel.git

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 57 insertions, 16 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 913af838c3c..dd12c1c84a8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -101,6 +101,50 @@ static inline void setup_cpumask_of_cpu(void) { }
  */
 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
 EXPORT_SYMBOL(__per_cpu_offset);
+static inline void setup_cpu_pda_map(void) { }
+
+#elif !defined(CONFIG_SMP)
+static inline void setup_cpu_pda_map(void) { }
+
+#else /* CONFIG_SMP && CONFIG_X86_64 */
+
+/*
+ * Allocate cpu_pda pointer table and array via alloc_bootmem.
+ */
+static void __init setup_cpu_pda_map(void)
+{
+        char *pda;
+        struct x8664_pda **new_cpu_pda;
+        unsigned long size;
+        int cpu;
+
+        size = roundup(sizeof(struct x8664_pda), cache_line_size());
+
+        /* allocate cpu_pda array and pointer table */
+        {
+                unsigned long tsize = nr_cpu_ids * sizeof(void *);
+                unsigned long asize = size * (nr_cpu_ids - 1);
+
+                tsize = roundup(tsize, cache_line_size());
+                new_cpu_pda = alloc_bootmem(tsize + asize);
+                pda = (char *)new_cpu_pda + tsize;
+        }
+
+        /* initialize pointer table to static pda's */
+        for_each_possible_cpu(cpu) {
+                if (cpu == 0) {
+                        /* leave boot cpu pda in place */
+                        new_cpu_pda[0] = cpu_pda(0);
+                        continue;
+                }
+                new_cpu_pda[cpu] = (struct x8664_pda *)pda;
+                new_cpu_pda[cpu]->in_bootmem = 1;
+                pda += size;
+        }
+
+        /* point to new pointer table */
+        _cpu_pda = new_cpu_pda;
+}
 #endif
 
 /*
@@ -110,46 +154,43 @@ EXPORT_SYMBOL(__per_cpu_offset);
  */
 void __init setup_per_cpu_areas(void)
 {
-        int i, highest_cpu = 0;
-        unsigned long size;
+        ssize_t size = PERCPU_ENOUGH_ROOM;
+        char *ptr;
+        int cpu;
 
 #ifdef CONFIG_HOTPLUG_CPU
         prefill_possible_map();
+#else
+        nr_cpu_ids = num_processors;
 #endif
 
+        /* Setup cpu_pda map */
+        setup_cpu_pda_map();
+
         /* Copy section for each CPU (we discard the original) */
         size = PERCPU_ENOUGH_ROOM;
         printk(KERN_INFO "PERCPU: Allocating %lu bytes of per cpu data\n",
                           size);
 
-        for_each_possible_cpu(i) {
-                char *ptr;
+        for_each_possible_cpu(cpu) {
 #ifndef CONFIG_NEED_MULTIPLE_NODES
                 ptr = alloc_bootmem_pages(size);
 #else
-                int node = early_cpu_to_node(i);
+                int node = early_cpu_to_node(cpu);
                 if (!node_online(node) || !NODE_DATA(node)) {
                         ptr = alloc_bootmem_pages(size);
                         printk(KERN_INFO
                                "cpu %d has no node %d or node-local memory\n",
-                                i, node);
+                                cpu, node);
                 }
                 else
                         ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);
 #endif
-                if (!ptr)
-                        panic("Cannot allocate cpu data for CPU %d\n", i);
-#ifdef CONFIG_X86_64
-                cpu_pda(i)->data_offset = ptr - __per_cpu_start;
-#else
-                __per_cpu_offset[i] = ptr - __per_cpu_start;
-#endif
+                per_cpu_offset(cpu) = ptr - __per_cpu_start;
                 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
 
-                highest_cpu = i;
         }
 
-        nr_cpu_ids = highest_cpu + 1;
         printk(KERN_DEBUG "NR_CPUS: %d, nr_cpu_ids: %d, nr_node_ids %d\n",
                 NR_CPUS, nr_cpu_ids, nr_node_ids);
 
@@ -199,7 +240,7 @@ void __cpuinit numa_set_node(int cpu, int node)
 {
         int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);
 
-        if (node != NUMA_NO_NODE)
+        if (cpu_pda(cpu) && node != NUMA_NO_NODE)
                 cpu_pda(cpu)->nodenumber = node;
 
         if (cpu_to_node_map)