[PATCH] Tweak idle thread setup semantics

This patch tweaks idle thread setup semantics a bit: instead of setting
NEED_RESCHED in init_idle(), we do an explicit schedule() before calling
into cpu_idle().

This patch, while having no negative side-effects, enables wider use of
cond_resched()s.  (which might happen in the stock kernel too, but it's
particulary important for voluntary-preempt)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/init/main.c b/init/main.c
index d324801729b..b5e421e39ed 100644
--- a/init/main.c
+++ b/init/main.c
@@ -383,6 +383,13 @@ static void noinline rest_init(void)
         numa_default_policy();
         unlock_kernel();
         preempt_enable_no_resched();
+
+        /*
+         * The boot idle thread must execute schedule()
+         * at least one to get things moving:
+         */
+        schedule();
+
         cpu_idle();
 }