diff --git a/sys/arm/arm/vm_machdep.c b/sys/arm/arm/vm_machdep.c
index 1a907cc..6bd5799 100644
--- a/sys/arm/arm/vm_machdep.c
+++ b/sys/arm/arm/vm_machdep.c
@@ -119,9 +119,6 @@ cpu_fork(register struct thread *td1, register struct proc *p2,
 #ifdef __XSCALE__
 #ifndef CPU_XSCALE_CORE3
 	pmap_use_minicache(td2->td_kstack, td2->td_kstack_pages * PAGE_SIZE);
-	if (td2->td_altkstack)
-		pmap_use_minicache(td2->td_altkstack, td2->td_altkstack_pages *
-		    PAGE_SIZE);
 #endif
 #endif
 	td2->td_pcb = pcb2;
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 4e2eaa9..9cda110 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_kdtrace.h"
 #include "opt_ktrace.h"
+#include "opt_kstack_pages.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -276,25 +277,28 @@ norfproc_fail:
 
 	mem_charged = 0;
 	vm2 = NULL;
+	if (pages == 0)
+		pages = KSTACK_PAGES;
 	/* Allocate new proc. */
 	newproc = uma_zalloc(proc_zone, M_WAITOK);
-	if (TAILQ_EMPTY(&newproc->p_threads)) {
-		td2 = thread_alloc();
+	if (TAILQ_EMPTY(&newproc->p_threads))
+		td2 = NULL;
+	else
+		td2 = FIRST_THREAD_IN_PROC(newproc);
+	if (td2 && pages != td2->td_kstack_pages) {
+		thread_unlink(td2);
+		thread_free(td2);
+		td2 = NULL;
+	}
+	if (!td2) {
+		td2 = thread_alloc(pages);
 		if (td2 == NULL) {
 			error = ENOMEM;
 			goto fail1;
 		}
 		proc_linkup(newproc, td2);
-	} else
-		td2 = FIRST_THREAD_IN_PROC(newproc);
-
-	/* Allocate and switch to an alternate kstack if specified. */
-	if (pages != 0) {
-		if (!vm_thread_new_altkstack(td2, pages)) {
-			error = ENOMEM;
-			goto fail1;
-		}
 	}
+
 	if ((flags & RFMEM) == 0) {
 		vm2 = vmspace_fork(p1->p_vmspace, &mem_charged);
 		if (vm2 == NULL) {
diff --git a/sys/kern/kern_kthread.c b/sys/kern/kern_kthread.c
index 1092832..3c5248e 100644
--- a/sys/kern/kern_kthread.c
+++ b/sys/kern/kern_kthread.c
@@ -256,7 +256,7 @@ kthread_add(void (*func)(void *), void *arg, struct proc *p,
 	}
 
 	/* Initialize our new td  */
-	newtd = thread_alloc();
+	newtd = thread_alloc(pages);
 	if (newtd == NULL)
 		return (ENOMEM);
 
@@ -282,9 +282,6 @@ kthread_add(void (*func)(void *), void *arg, struct proc *p,
 
 	newtd->td_pflags |= TDP_KTHREAD;
 	newtd->td_ucred = crhold(p->p_ucred);
-	/* Allocate and switch to an alternate kstack if specified. */
-	if (pages != 0)
-		vm_thread_new_altkstack(newtd, pages);
 
 	/* this code almost the same as create_thread() in kern_thr.c */
 	PROC_LOCK(p);
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index cdbc012..e012a3e 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -203,14 +203,6 @@ proc_dtor(void *mem, int size, void *arg)
 #endif
 		/* Free all OSD associated to this thread. */
 		osd_thread_exit(td);
-
-		/* Dispose of an alternate kstack, if it exists.
-		 * XXX What if there are more than one thread in the proc?
-		 *     The first thread in the proc is special and not
-		 *     freed, so you gotta do this here.
-		 */
-		if (((p->p_flag & P_KTHREAD) != 0) && (td->td_altkstack != 0))
-			vm_thread_dispose_altkstack(td);
 	}
 	EVENTHANDLER_INVOKE(process_dtor, p);
 	if (p->p_ksi != NULL)
@@ -767,8 +759,6 @@ fill_kinfo_proc_only(struct proc *p, struct kinfo_proc *kp)
 		FOREACH_THREAD_IN_PROC(p, td0) {
 			if (!TD_IS_SWAPPED(td0))
 				kp->ki_rssize += td0->td_kstack_pages;
-			if (td0->td_altkstack_obj != NULL)
-				kp->ki_rssize += td0->td_altkstack_pages;
 		}
 		kp->ki_swrss = vm->vm_swrss;
 		kp->ki_tsize = vm->vm_tsize;
diff --git a/sys/kern/kern_thr.c b/sys/kern/kern_thr.c
index c478c63..630069b 100644
--- a/sys/kern/kern_thr.c
+++ b/sys/kern/kern_thr.c
@@ -176,7 +176,7 @@ create_thread(struct thread *td, mcontext_t *ctx,
 	}
 
 	/* Initialize our td */
-	newtd = thread_alloc();
+	newtd = thread_alloc(0);
 	if (newtd == NULL)
 		return (ENOMEM);
 
diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index d47bd8c..f23fc84 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -283,7 +283,7 @@ thread_reap(void)
  * Allocate a thread.
  */
 struct thread *
-thread_alloc(void)
+thread_alloc(int pages)
 {
 	struct thread *td;
 
@@ -291,7 +291,7 @@ thread_alloc(void)
 
 	td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
 	KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
-	if (!vm_thread_new(td, 0)) {
+	if (!vm_thread_new(td, pages)) {
 		uma_zfree(thread_zone, td);
 		return (NULL);
 	}
@@ -312,8 +312,6 @@ thread_free(struct thread *td)
 		cpuset_rel(td->td_cpuset);
 	td->td_cpuset = NULL;
 	cpu_thread_free(td);
-	if (td->td_altkstack != 0)
-		vm_thread_dispose_altkstack(td);
 	if (td->td_kstack != 0)
 		vm_thread_dispose(td);
 	uma_zfree(thread_zone, td);
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index b65db62..084c098 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -267,9 +267,6 @@ struct thread {
 	struct vm_object *td_kstack_obj;/* (a) Kstack object. */
 	vm_offset_t	td_kstack;	/* (a) Kernel VA of kstack. */
 	int		td_kstack_pages; /* (a) Size of the kstack. */
-	struct vm_object *td_altkstack_obj;/* (a) Alternate kstack object. */
-	vm_offset_t	td_altkstack;	/* (a) Kernel VA of alternate kstack. */
-	int		td_altkstack_pages; /* (a) Size of alternate kstack. */
 	volatile u_int	td_critnest;	/* (k*) Critical section nest level. */
 	struct mdthread td_md;		/* (k) Any machine-dependent fields. */
 	struct td_sched	*td_sched;	/* (*) Scheduler-specific data. */
@@ -850,7 +847,7 @@ 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(void);
+struct	thread *thread_alloc(int pages);
 void	thread_exit(void) __dead2;
 void	thread_free(struct thread *td);
 void	thread_link(struct thread *td, struct proc *p);
diff --git a/sys/vm/vm_extern.h b/sys/vm/vm_extern.h
index 53f7694..65b6c8e 100644
--- a/sys/vm/vm_extern.h
+++ b/sys/vm/vm_extern.h
@@ -80,9 +80,7 @@ int vm_fault_quick(caddr_t v, int prot);
 struct sf_buf *vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset);
 void vm_imgact_unmap_page(struct sf_buf *sf);
 void vm_thread_dispose(struct thread *td);
-void vm_thread_dispose_altkstack(struct thread *td);
 int vm_thread_new(struct thread *td, int pages);
-int vm_thread_new_altkstack(struct thread *td, int pages);
 void vm_thread_swapin(struct thread *td);
 void vm_thread_swapout(struct thread *td);
 #endif				/* _KERNEL */
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c
index 9e43a3f..4863d94 100644
--- a/sys/vm/vm_glue.c
+++ b/sys/vm/vm_glue.c
@@ -468,37 +468,6 @@ vm_thread_swapin(struct thread *td)
 }
 
 /*
- * Set up a variable-sized alternate kstack.
- */
-int
-vm_thread_new_altkstack(struct thread *td, int pages)
-{
-
-	td->td_altkstack = td->td_kstack;
-	td->td_altkstack_obj = td->td_kstack_obj;
-	td->td_altkstack_pages = td->td_kstack_pages;
-
-	return (vm_thread_new(td, pages));
-}
-
-/*
- * Restore the original kstack.
- */
-void
-vm_thread_dispose_altkstack(struct thread *td)
-{
-
-	vm_thread_dispose(td);
-
-	td->td_kstack = td->td_altkstack;
-	td->td_kstack_obj = td->td_altkstack_obj;
-	td->td_kstack_pages = td->td_altkstack_pages;
-	td->td_altkstack = 0;
-	td->td_altkstack_obj = NULL;
-	td->td_altkstack_pages = 0;
-}
-
-/*
  * Implement fork's actions on an address space.
  * Here we arrange for the address space to be copied or referenced,
  * allocate a user struct (pcb and kernel stack), then call the