Cache the value of curthread in the _get_sleep_lock() and _get_spin_lock()

macros and pass the value to the associated _mtx_*() functions to avoid
more curthread dereferences in the function implementations.  This provided
a very modest perf improvement in some benchmarks.

Suggested by:	rwatson
Tested by:	scottl

1 files changed, 5 insertions, 4 deletions

diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
index 7b66186..884eeda 100644
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -417,10 +417,10 @@ _mtx_trylock(struct mtx *m, int opts, const char *file, int line)
  * sleep waiting for it), or if we need to recurse on it.
  */
 void
-_mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line)
+_mtx_lock_sleep(struct mtx *m, struct thread *td, int opts, const char *file,
+    int line)
 {
 	struct turnstile *ts;
-	struct thread *td = curthread;
 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
 	struct thread *owner;
 #endif
@@ -562,7 +562,8 @@ _mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line)
  * is handled inline.
  */
 void
-_mtx_lock_spin(struct mtx *m, int opts, const char *file, int line)
+_mtx_lock_spin(struct mtx *m, struct thread *td, int opts, const char *file,
+    int line)
 {
 	int i = 0;
 
@@ -570,7 +571,7 @@ _mtx_lock_spin(struct mtx *m, int opts, const char *file, int line)
 		CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
 
 	for (;;) {
-		if (_obtain_lock(m, curthread))
+		if (_obtain_lock(m, td))
 			break;
 
 		/* Give interrupts a chance while we spin. */