diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c
--- a/sys/amd64/amd64/vm_machdep.c
+++ b/sys/amd64/amd64/vm_machdep.c
@@ -374,16 +374,6 @@
 	}
 }
 
-void
-cpu_thread_swapin(struct thread *td)
-{
-}
-
-void
-cpu_thread_swapout(struct thread *td)
-{
-}
-
 void
 cpu_thread_alloc(struct thread *td)
 {
diff --git a/sys/arm/arm/vm_machdep.c b/sys/arm/arm/vm_machdep.c
--- a/sys/arm/arm/vm_machdep.c
+++ b/sys/arm/arm/vm_machdep.c
@@ -146,16 +146,6 @@
 	td2->td_md.md_saved_cspr = PSR_SVC32_MODE;
 }
 
-void
-cpu_thread_swapin(struct thread *td)
-{
-}
-
-void
-cpu_thread_swapout(struct thread *td)
-{
-}
-
 void
 cpu_set_syscall_retval(struct thread *td, int error)
 {
diff --git a/sys/arm64/arm64/vm_machdep.c b/sys/arm64/arm64/vm_machdep.c
--- a/sys/arm64/arm64/vm_machdep.c
+++ b/sys/arm64/arm64/vm_machdep.c
@@ -137,16 +137,6 @@
 		__asm volatile("wfi" ::: "memory");
 }
 
-void
-cpu_thread_swapin(struct thread *td)
-{
-}
-
-void
-cpu_thread_swapout(struct thread *td)
-{
-}
-
 void
 cpu_set_syscall_retval(struct thread *td, int error)
 {
diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c
--- a/sys/i386/i386/vm_machdep.c
+++ b/sys/i386/i386/vm_machdep.c
@@ -374,16 +374,6 @@
 	}
 }
 
-void
-cpu_thread_swapin(struct thread *td)
-{
-}
-
-void
-cpu_thread_swapout(struct thread *td)
-{
-}
-
 void
 cpu_thread_alloc(struct thread *td)
 {
diff --git a/sys/powerpc/powerpc/vm_machdep.c b/sys/powerpc/powerpc/vm_machdep.c
--- a/sys/powerpc/powerpc/vm_machdep.c
+++ b/sys/powerpc/powerpc/vm_machdep.c
@@ -211,18 +211,6 @@
  * fixed-size KVA.
  */
 
-void
-cpu_thread_swapin(struct thread *td)
-{
-
-}
-
-void
-cpu_thread_swapout(struct thread *td)
-{
-
-}
-
 bool
 cpu_exec_vmspace_reuse(struct proc *p __unused, vm_map_t map __unused)
 {
diff --git a/sys/riscv/riscv/vm_machdep.c b/sys/riscv/riscv/vm_machdep.c
--- a/sys/riscv/riscv/vm_machdep.c
+++ b/sys/riscv/riscv/vm_machdep.c
@@ -113,16 +113,6 @@
 	while(1);
 }
 
-void
-cpu_thread_swapin(struct thread *td)
-{
-}
-
-void
-cpu_thread_swapout(struct thread *td)
-{
-}
-
 void
 cpu_set_syscall_retval(struct thread *td, int error)
 {
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1235,8 +1235,6 @@
 void	cpu_thread_clean(struct thread *);
 void	cpu_thread_exit(struct thread *);
 void	cpu_thread_free(struct thread *);
-void	cpu_thread_swapin(struct thread *);
-void	cpu_thread_swapout(struct thread *);
 struct	thread *thread_alloc(int pages);
 int	thread_check_susp(struct thread *td, bool sleep);
 void	thread_cow_get_proc(struct thread *newtd, struct proc *p);