diff --git a/sys/contrib/vchiq/interface/compat/vchi_bsd.h b/sys/contrib/vchiq/interface/compat/vchi_bsd.h
index a02bca452756..e8886e6e9283 100644
--- a/sys/contrib/vchiq/interface/compat/vchi_bsd.h
+++ b/sys/contrib/vchiq/interface/compat/vchi_bsd.h
@@ -162,10 +162,6 @@ struct mutex {
  */
 typedef struct rwlock rwlock_t;
 
-#if defined(SX_ADAPTIVESPIN) && !defined(SX_NOADAPTIVE)
-#define SX_NOADAPTIVE SX_ADAPTIVESPIN
-#endif
-
 #define DEFINE_RWLOCK(name)				\
 	struct rwlock name;					\
 	SX_SYSINIT(name, &name, #name)
diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c
index 600a3d03558a..d0ada0956155 100644
--- a/sys/kern/kern_sx.c
+++ b/sys/kern/kern_sx.c
@@ -71,8 +71,6 @@ __FBSDID("$FreeBSD$");
 #define	ADAPTIVE_SX
 #endif
 
-CTASSERT((SX_NOADAPTIVE & LO_CLASSFLAGS) == SX_NOADAPTIVE);
-
 #ifdef HWPMC_HOOKS
 #include <sys/pmckern.h>
 PMC_SOFT_DECLARE( , , lock, failed);
@@ -233,7 +231,7 @@ sx_init_flags(struct sx *sx, const char *description, int opts)
 	int flags;
 
 	MPASS((opts & ~(SX_QUIET | SX_RECURSE | SX_NOWITNESS | SX_DUPOK |
-	    SX_NOPROFILE | SX_NOADAPTIVE | SX_NEW)) == 0);
+	    SX_NOPROFILE | SX_NEW)) == 0);
 	ASSERT_ATOMIC_LOAD_PTR(sx->sx_lock,
 	    ("%s: sx_lock not aligned for %s: %p", __func__, description,
 	    &sx->sx_lock));
@@ -252,7 +250,6 @@ sx_init_flags(struct sx *sx, const char *description, int opts)
 	if (opts & SX_NEW)
 		flags |= LO_NEW;
 
-	flags |= opts & SX_NOADAPTIVE;
 	lock_init(&sx->lock_object, &lock_class_sx, description, NULL, flags);
 	sx->sx_lock = SX_LOCK_UNLOCKED;
 	sx->sx_recurse = 0;
@@ -572,7 +569,6 @@ _sx_xlock_hard(struct sx *sx, uintptr_t x, int opts LOCK_FILE_LINE_ARG_DEF)
 	volatile struct thread *owner;
 	u_int i, n, spintries = 0;
 	enum { READERS, WRITER } sleep_reason = READERS;
-	bool adaptive;
 	bool in_critical = false;
 #endif
 #ifdef LOCK_PROFILING
@@ -642,10 +638,6 @@ _sx_xlock_hard(struct sx *sx, uintptr_t x, int opts LOCK_FILE_LINE_ARG_DEF)
 		CTR5(KTR_LOCK, "%s: %s contested (lock=%p) at %s:%d", __func__,
 		    sx->lock_object.lo_name, (void *)sx->sx_lock, file, line);
 
-#ifdef ADAPTIVE_SX
-	adaptive = ((sx->lock_object.lo_flags & SX_NOADAPTIVE) == 0);
-#endif
-
 #ifdef HWPMC_HOOKS
 	PMC_SOFT_CALL( , , lock, failed);
 #endif
@@ -669,8 +661,6 @@ _sx_xlock_hard(struct sx *sx, uintptr_t x, int opts LOCK_FILE_LINE_ARG_DEF)
 		lda.spin_cnt++;
 #endif
 #ifdef ADAPTIVE_SX
-		if (__predict_false(!adaptive))
-			goto sleepq;
 		/*
 		 * If the lock is write locked and the owner is
 		 * running on another CPU, spin until the owner stops
@@ -762,20 +752,18 @@ _sx_xlock_hard(struct sx *sx, uintptr_t x, int opts LOCK_FILE_LINE_ARG_DEF)
 		 * chain lock.  If so, drop the sleep queue lock and try
 		 * again.
 		 */
-		if (adaptive) {
-			if (!(x & SX_LOCK_SHARED)) {
-				owner = (struct thread *)SX_OWNER(x);
-				if (TD_IS_RUNNING(owner)) {
-					sleepq_release(&sx->lock_object);
-					sx_drop_critical(x, &in_critical,
-					    &extra_work);
-					continue;
-				}
-			} else if (SX_SHARERS(x) > 0 && sleep_reason == WRITER) {
+		if (!(x & SX_LOCK_SHARED)) {
+			owner = (struct thread *)SX_OWNER(x);
+			if (TD_IS_RUNNING(owner)) {
 				sleepq_release(&sx->lock_object);
-				sx_drop_critical(x, &in_critical, &extra_work);
+				sx_drop_critical(x, &in_critical,
+				    &extra_work);
 				continue;
 			}
+		} else if (SX_SHARERS(x) > 0 && sleep_reason == WRITER) {
+			sleepq_release(&sx->lock_object);
+			sx_drop_critical(x, &in_critical, &extra_work);
+			continue;
 		}
 #endif
 
@@ -1021,7 +1009,6 @@ _sx_slock_hard(struct sx *sx, int opts, uintptr_t x LOCK_FILE_LINE_ARG_DEF)
 #ifdef ADAPTIVE_SX
 	volatile struct thread *owner;
 	u_int i, n, spintries = 0;
-	bool adaptive;
 #endif
 #ifdef LOCK_PROFILING
 	uint64_t waittime = 0;
@@ -1066,10 +1053,6 @@ _sx_slock_hard(struct sx *sx, int opts, uintptr_t x LOCK_FILE_LINE_ARG_DEF)
 	lock_delay_arg_init(&lda, NULL);
 #endif
 
-#ifdef ADAPTIVE_SX
-	adaptive = ((sx->lock_object.lo_flags & SX_NOADAPTIVE) == 0);
-#endif
-
 #ifdef HWPMC_HOOKS
 	PMC_SOFT_CALL( , , lock, failed);
 #endif
@@ -1095,9 +1078,6 @@ _sx_slock_hard(struct sx *sx, int opts, uintptr_t x LOCK_FILE_LINE_ARG_DEF)
 #endif
 
 #ifdef ADAPTIVE_SX
-		if (__predict_false(!adaptive))
-			goto sleepq;
-
 		/*
 		 * If the owner is running on another CPU, spin until
 		 * the owner stops running or the state of the lock
@@ -1154,7 +1134,6 @@ _sx_slock_hard(struct sx *sx, int opts, uintptr_t x LOCK_FILE_LINE_ARG_DEF)
 					continue;
 			}
 		}
-sleepq:
 #endif
 
 		/*
@@ -1176,7 +1155,7 @@ _sx_slock_hard(struct sx *sx, int opts, uintptr_t x LOCK_FILE_LINE_ARG_DEF)
 		 * the owner stops running or the state of the lock
 		 * changes.
 		 */
-		if (!(x & SX_LOCK_SHARED) && adaptive) {
+		if (!(x & SX_LOCK_SHARED)) {
 			owner = (struct thread *)SX_OWNER(x);
 			if (TD_IS_RUNNING(owner)) {
 				sleepq_release(&sx->lock_object);
diff --git a/sys/sys/sx.h b/sys/sys/sx.h
index 817f0f97d38c..d6cd05a76c45 100644
--- a/sys/sys/sx.h
+++ b/sys/sys/sx.h
@@ -273,7 +273,6 @@ __sx_xunlock(struct sx *sx, struct thread *td, const char *file, int line)
 #define	SX_NOPROFILE		0x02
 #define	SX_NOWITNESS		0x04
 #define	SX_QUIET		0x08
-#define	SX_NOADAPTIVE		0x10
 #define	SX_RECURSE		0x20
 #define	SX_NEW			0x40