[IA64] allocate percpu area in the xen va area.

To guarantee that the percpu is pinned down,
move its virtual address from the xen identity mapped area
to the xen va area which is pinned by DTR[IA64_TR_KERNEL].
Then unnecessary tlb miss fault will be avoided.
Sometimes per cpu area is accessed from very critial
point where tlb miss isn't allowed.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>

diff --git a/xen/arch/ia64/linux-xen/mm_contig.c b/xen/arch/ia64/linux-xen/mm_contig.c
index abd1c2cfb8d3971b0457d48efce03b909581ee4b..00d90faff9f7823ae6cb3d3f225ec59ae1414928 100644 (file)
--- a/xen/arch/ia64/linux-xen/mm_contig.c
+++ b/xen/arch/ia64/linux-xen/mm_contig.c
@@ -175,6 +175,39 @@ find_memory (void)
 #endif
 
 #ifdef CONFIG_SMP
+#ifdef XEN
+#include <asm/elf.h>
+
+void *percpu_area __initdata = NULL;
+
+void* __init
+per_cpu_allocate(void *xen_heap_start, unsigned long end_in_pa)
+{
+       int order = get_order(NR_CPUS * PERCPU_PAGE_SIZE);
+       unsigned long size = 1UL << (order + PAGE_SHIFT);
+       unsigned long start = ALIGN_UP((unsigned long)xen_heap_start,
+                                      PERCPU_PAGE_SIZE);
+       unsigned long end = start + size;
+
+       if (__pa(end) < end_in_pa) {
+               init_xenheap_pages(__pa(xen_heap_start), __pa(start));
+               xen_heap_start = (void*)end;
+               percpu_area = (void*)virt_to_xenva(start);
+               printk("allocate percpu area 0x%lx@0x%lx 0x%p\n",
+                      size, start, percpu_area);
+       } else {
+               panic("can't allocate percpu area. size 0x%lx\n", size);
+       }
+       return xen_heap_start;
+}
+
+static void* __init
+get_per_cpu_area(void)
+{
+       return percpu_area;
+}
+#endif
+
 /**
  * per_cpu_init - setup per-cpu variables
  *
@@ -193,13 +226,9 @@ per_cpu_init (void)
         */
        if (smp_processor_id() == 0) {
 #ifdef XEN
-               struct page_info *page;
-               page = alloc_domheap_pages(NULL,
-                                          get_order(NR_CPUS *
-                                                    PERCPU_PAGE_SIZE), 0);
-               if (page == NULL) 
+               cpu_data = get_per_cpu_area();
+               if (cpu_data == NULL) 
                        panic("can't allocate per cpu area.\n");
-               cpu_data = page_to_virt(page);
 #else
                cpu_data = __alloc_bootmem(PERCPU_PAGE_SIZE * NR_CPUS,
                                           PERCPU_PAGE_SIZE, __pa(MAX_DMA_ADDRESS));

diff --git a/xen/arch/ia64/xen/xensetup.c b/xen/arch/ia64/xen/xensetup.c
index 7ccc4051cf45203aa989289ae70451dcd8a02ff5..fb242708d35266180f25932284a377706231dc05 100644 (file)
--- a/xen/arch/ia64/xen/xensetup.c
+++ b/xen/arch/ia64/xen/xensetup.c
@@ -566,6 +566,13 @@ skip_move:
     if (vmx_enabled)
         xen_heap_start = vmx_init_env(xen_heap_start, xenheap_phys_end);
 
+    /* allocate memory for percpu area
+     * per_cpu_init() called from late_set_arch() is called after
+     * end_boot_allocate(). It's too late to allocate memory in
+     * xenva.
+     */
+    xen_heap_start = per_cpu_allocate(xen_heap_start, xenheap_phys_end);
+
     heap_desc.xen_heap_start   = xen_heap_start;
     heap_desc.xenheap_phys_end = xenheap_phys_end;
     heap_desc.kern_md          = kern_md;

diff --git a/xen/include/asm-ia64/linux-xen/asm/percpu.h b/xen/include/asm-ia64/linux-xen/asm/percpu.h
index 4e11b3cd5d4b1b6306bb8124e095e3118f3ea694..8642afe79214543a5a78c329620d70587d3e3c58 100644 (file)
--- a/xen/include/asm-ia64/linux-xen/asm/percpu.h
+++ b/xen/include/asm-ia64/linux-xen/asm/percpu.h
@@ -50,12 +50,22 @@ DECLARE_PER_CPU(unsigned long, local_per_cpu_offset);
 extern void percpu_modcopy(void *pcpudst, const void *src, unsigned long size);
 extern void setup_per_cpu_areas (void);
 extern void *per_cpu_init(void);
+#ifdef XEN
+extern void *per_cpu_allocate(void *xen_heap_start, unsigned long end_in_pa);
+#endif
 
 #else /* ! SMP */
 
 #define per_cpu(var, cpu)                      (*((void)(cpu), &per_cpu__##var))
 #define __get_cpu_var(var)                     per_cpu__##var
 #define per_cpu_init()                         (__phys_per_cpu_start)
+#ifdef XEN
+static inline void *per_cpu_allocate(void *xen_heap_start,
+                                    unsigned long end_in_pa)
+{
+       return xen_heap_start;
+}
+#endif
 
 #endif /* SMP */