Merge branch 'fix/misc' into for-linus

[pandora-kernel.git] / arch / x86 / kernel / setup_percpu.c

diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index bad2fd2..29a3eef 100644 (file)
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -156,19 +156,34 @@ static struct page * __init pcpul_get_page(unsigned int cpu, int pageno)
        return virt_to_page(pcpul_map[cpu].ptr + off);
 }
 
-static ssize_t __init setup_pcpu_lpage(size_t static_size)
+static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
 {
        size_t map_size, dyn_size;
        unsigned int cpu;
        int i, j;
        ssize_t ret;
 
-       /*
-        * If large page isn't supported, there's no benefit in doing
-        * this.  Also, on non-NUMA, embedding is better.
-        */
-       if (!cpu_has_pse || !pcpu_need_numa())
+       if (!chosen) {
+               size_t vm_size = VMALLOC_END - VMALLOC_START;
+               size_t tot_size = num_possible_cpus() * PMD_SIZE;
+
+               /* on non-NUMA, embedding is better */
+               if (!pcpu_need_numa())
+                       return -EINVAL;
+
+               /* don't consume more than 20% of vmalloc area */
+               if (tot_size > vm_size / 5) {
+                       pr_info("PERCPU: too large chunk size %zuMB for "
+                               "large page remap\n", tot_size >> 20);
+                       return -EINVAL;
+               }
+       }
+
+       /* need PSE */
+       if (!cpu_has_pse) {
+               pr_warning("PERCPU: lpage allocator requires PSE\n");
                return -EINVAL;
+       }
 
        /*
         * Currently supports only single page.  Supporting multiple
@@ -191,8 +206,11 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size)
                pcpul_map[cpu].cpu = cpu;
                pcpul_map[cpu].ptr = pcpu_alloc_bootmem(cpu, PMD_SIZE,
                                                        PMD_SIZE);
-               if (!pcpul_map[cpu].ptr)
+               if (!pcpul_map[cpu].ptr) {
+                       pr_warning("PERCPU: failed to allocate large page "
+                                  "for cpu%u\n", cpu);
                        goto enomem;
+               }
 
                /*
                 * Only use pcpul_size bytes and give back the rest.
@@ -297,7 +315,7 @@ void *pcpu_lpage_remapped(void *kaddr)
        return NULL;
 }
 #else
-static ssize_t __init setup_pcpu_lpage(size_t static_size)
+static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
 {
        return -EINVAL;
 }
@@ -311,7 +329,7 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size)
  * mapping so that it can use PMD mapping without additional TLB
  * pressure.
  */
-static ssize_t __init setup_pcpu_embed(size_t static_size)
+static ssize_t __init setup_pcpu_embed(size_t static_size, bool chosen)
 {
        size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
 
@@ -320,7 +338,7 @@ static ssize_t __init setup_pcpu_embed(size_t static_size)
         * this.  Also, embedding allocation doesn't play well with
         * NUMA.
         */
-       if (!cpu_has_pse || pcpu_need_numa())
+       if (!chosen && (!cpu_has_pse || pcpu_need_numa()))
                return -EINVAL;
 
        return pcpu_embed_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE,
@@ -370,8 +388,11 @@ static ssize_t __init setup_pcpu_4k(size_t static_size)
                        void *ptr;
 
                        ptr = pcpu_alloc_bootmem(cpu, PAGE_SIZE, PAGE_SIZE);
-                       if (!ptr)
+                       if (!ptr) {
+                               pr_warning("PERCPU: failed to allocate "
+                                          "4k page for cpu%u\n", cpu);
                                goto enomem;
+                       }
 
                        memcpy(ptr, __per_cpu_load + i * PAGE_SIZE, PAGE_SIZE);
                        pcpu4k_pages[j++] = virt_to_page(ptr);
@@ -395,6 +416,16 @@ out_free_ar:
        return ret;
 }
 
+/* for explicit first chunk allocator selection */
+static char pcpu_chosen_alloc[16] __initdata;
+
+static int __init percpu_alloc_setup(char *str)
+{
+       strncpy(pcpu_chosen_alloc, str, sizeof(pcpu_chosen_alloc) - 1);
+       return 0;
+}
+early_param("percpu_alloc", percpu_alloc_setup);
+
 static inline void setup_percpu_segment(int cpu)
 {
 #ifdef CONFIG_X86_32
@@ -408,11 +439,6 @@ static inline void setup_percpu_segment(int cpu)
 #endif
 }
 
-/*
- * Great future plan:
- * Declare PDA itself and support (irqstack,tss,pgd) as per cpu data.
- * Always point %gs to its beginning
- */
 void __init setup_per_cpu_areas(void)
 {
        size_t static_size = __per_cpu_end - __per_cpu_start;
@@ -429,9 +455,26 @@ void __init setup_per_cpu_areas(void)
         * of large page mappings.  Please read comments on top of
         * each allocator for details.
         */
-       ret = setup_pcpu_lpage(static_size);
-       if (ret < 0)
-               ret = setup_pcpu_embed(static_size);
+       ret = -EINVAL;
+       if (strlen(pcpu_chosen_alloc)) {
+               if (strcmp(pcpu_chosen_alloc, "4k")) {
+                       if (!strcmp(pcpu_chosen_alloc, "lpage"))
+                               ret = setup_pcpu_lpage(static_size, true);
+                       else if (!strcmp(pcpu_chosen_alloc, "embed"))
+                               ret = setup_pcpu_embed(static_size, true);
+                       else
+                               pr_warning("PERCPU: unknown allocator %s "
+                                          "specified\n", pcpu_chosen_alloc);
+                       if (ret < 0)
+                               pr_warning("PERCPU: %s allocator failed (%zd), "
+                                          "falling back to 4k\n",
+                                          pcpu_chosen_alloc, ret);
+               }
+       } else {
+               ret = setup_pcpu_lpage(static_size, false);
+               if (ret < 0)
+                       ret = setup_pcpu_embed(static_size, false);
+       }
        if (ret < 0)
                ret = setup_pcpu_4k(static_size);
        if (ret < 0)