2 files changed, 24 insertions, 2 deletions

diff --git a/init/Kconfig b/init/Kconfig
index ada48441aff8..c6d95f8ea055 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -396,6 +396,22 @@ config RCU_FANOUT_EXACT
 
           Say N if unsure.
 
+config RCU_FAST_NO_HZ
+        bool "Accelerate last non-dyntick-idle CPU's grace periods"
+        depends on TREE_RCU && NO_HZ && SMP
+        default n
+        help
+          This option causes RCU to attempt to accelerate grace periods
+          in order to allow the final CPU to enter dynticks-idle state
+          more quickly.  On the other hand, this option increases the
+          overhead of the dynticks-idle checking, particularly on systems
+          with large numbers of CPUs.
+
+          Say Y if energy efficiency is critically important, particularly
+                if you have relatively few CPUs.
+
+          Say N if you are unsure.
+
 config TREE_RCU_TRACE
         def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
         select DEBUG_FS
@@ -1099,7 +1115,7 @@ config MMAP_ALLOW_UNINITIALIZED
           See Documentation/nommu-mmap.txt for more information.
 
 config PROFILING
-        bool "Profiling support (EXPERIMENTAL)"
+        bool "Profiling support"
         help
           Say Y here to enable the extended profiling support mechanisms used
           by profilers such as OProfile.
@@ -1249,4 +1265,8 @@ source "block/Kconfig"
 config PREEMPT_NOTIFIERS
         bool
 
+config PADATA
+        depends on SMP
+        bool
+
 source "kernel/Kconfig.locks"
diff --git a/init/main.c b/init/main.c
index dac44a9356a5..c75dcd6eef09 100644
--- a/init/main.c
+++ b/init/main.c
@@ -416,7 +416,9 @@ static noinline void __init_refok rest_init(void)
         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
         numa_default_policy();
         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
+        rcu_read_lock();
         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
+        rcu_read_unlock();
         unlock_kernel();
 
         /*
@@ -657,9 +659,9 @@ asmlinkage void __init start_kernel(void)
         proc_caches_init();
         buffer_init();
         key_init();
+        radix_tree_init();
         security_init();
         vfs_caches_init(totalram_pages);
-        radix_tree_init();
         signals_init();
         /* rootfs populating might need page-writeback */
         page_writeback_init();