core: Make secondary spin and locks use cpu_relax()

This makes secondaries spinning waiting for a job and spinlocks
use cpu_relax() which speeds up the primary thread and thus speeds
up the boot process a bit. Also prettify a bit cpu_relax() implementation

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/core/lock.c b/core/lock.c
index 70fb994..6a8282f 100644
--- a/core/lock.c
+++ b/core/lock.c
@@ -87,9 +87,8 @@ void lock(struct lock *l)
 	for (;;) {
 		if (try_lock(l))
 			break;
-		smt_low();
+		cpu_relax();
 	}
-	smt_medium();
 }
 
 void unlock(struct lock *l)