2 files changed, 61 insertions, 14 deletions

diff --git a/init/Kconfig b/init/Kconfig
index d4e9671347ee..9b68fee8d79e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -933,6 +933,40 @@ config AIO
           by some high performance threaded applications. Disabling
           this option saves about 7k.
 
+config HAVE_PERF_COUNTERS
+        bool
+
+menu "Performance Counters"
+
+config PERF_COUNTERS
+        bool "Kernel Performance Counters"
+        depends on HAVE_PERF_COUNTERS
+        select ANON_INODES
+        help
+          Enable kernel support for performance counter hardware.
+
+          Performance counters are special hardware registers available
+          on most modern CPUs. These registers count the number of certain
+          types of hw events: such as instructions executed, cachemisses
+          suffered, or branches mis-predicted - without slowing down the
+          kernel or applications. These registers can also trigger interrupts
+          when a threshold number of events have passed - and can thus be
+          used to profile the code that runs on that CPU.
+
+          The Linux Performance Counter subsystem provides an abstraction of
+          these hardware capabilities, available via a system call. It
+          provides per task and per CPU counters, and it provides event
+          capabilities on top of those.
+
+          Say Y if unsure.
+
+config EVENT_PROFILE
+        bool "Tracepoint profile sources"
+        depends on PERF_COUNTERS && EVENT_TRACER
+        default y
+
+endmenu
+
 config VM_EVENT_COUNTERS
         default y
         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
diff --git a/init/main.c b/init/main.c
index 9d759d68d7a0..5616661eac01 100644
--- a/init/main.c
+++ b/init/main.c
@@ -534,6 +534,16 @@ void __init __weak thread_info_cache_init(void)
 {
 }
 
+/*
+ * Set up kernel memory allocators
+ */
+static void __init mm_init(void)
+{
+        mem_init();
+        kmem_cache_init();
+        vmalloc_init();
+}
+
 asmlinkage void __init start_kernel(void)
 {
         char * command_line;
@@ -575,6 +585,23 @@ asmlinkage void __init start_kernel(void)
         setup_nr_cpu_ids();
         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 
+        build_all_zonelists();
+        page_alloc_init();
+
+        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
+        parse_early_param();
+        parse_args("Booting kernel", static_command_line, __start___param,
+                   __stop___param - __start___param,
+                   &unknown_bootoption);
+        /*
+         * These use large bootmem allocations and must precede
+         * kmem_cache_init()
+         */
+        pidhash_init();
+        vfs_caches_init_early();
+        sort_main_extable();
+        trap_init();
+        mm_init();
         /*
          * Set up the scheduler prior starting any interrupts (such as the
          * timer interrupt). Full topology setup happens at smp_init()
@@ -586,26 +613,16 @@ asmlinkage void __init start_kernel(void)
          * fragile until we cpu_idle() for the first time.
          */
         preempt_disable();
-        build_all_zonelists();
-        page_alloc_init();
-        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
-        parse_early_param();
-        parse_args("Booting kernel", static_command_line, __start___param,
-                   __stop___param - __start___param,
-                   &unknown_bootoption);
         if (!irqs_disabled()) {
                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
                                 "enabled *very* early, fixing it\n");
                 local_irq_disable();
         }
-        sort_main_extable();
-        trap_init();
         rcu_init();
         /* init some links before init_ISA_irqs() */
         early_irq_init();
         init_IRQ();
         prio_tree_init();
-        pidhash_init();
         init_timers();
         hrtimers_init();
         softirq_init();
@@ -647,14 +664,10 @@ asmlinkage void __init start_kernel(void)
                 initrd_start = 0;
         }
 #endif
-        vmalloc_init();
-        vfs_caches_init_early();
         cpuset_init_early();
         page_cgroup_init();
-        mem_init();
         enable_debug_pagealloc();
         cpu_hotplug_init();
-        kmem_cache_init();
         kmemtrace_init();
         kmemleak_init();
         debug_objects_mem_init();