--- /home/rookie/perforce/smpng/attilio_smpng/kern/kern_intr.c	Thu Jun  7 23:33:11 2007
+++ kern_intr.c	Sat Sep 15 16:41:44 2007
@@ -669,6 +669,7 @@
 	struct thread *td;
 	struct thread *ctd;
 	struct proc *p;
+	u_char cpri, pri;
 
 	/*
 	 * If no ithread or no handlers, then we have a stray interrupt.
@@ -703,18 +704,28 @@
 	 * put it on the runqueue.
 	 */
 	it->it_need = 1;
+	thread_lock(ctd);
+	cpri = ctd->td_priority;
+	thread_unlock(ctd);
 	thread_lock(td);
 	if (TD_AWAITING_INTR(td)) {
 		CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid,
 		    p->p_comm);
 		TD_CLR_IWAIT(td);
-		sched_add(td, SRQ_INTR);
+		if (cpri >= td->td_priority)
+			sched_add(td, SRQ_INTR);
 	} else {
 		CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
 		    __func__, p->p_pid, p->p_comm, it->it_need, td->td_state);
 	}
-	thread_unlock(td);
-
+	if (cpri < td->td_priority) {
+		td->td_vmfriend = ctd;
+		thread_unlock(td);
+		thread_lock(ctd);
+		cpu_switch(ctd, td, ctd->td_lock);
+		thread_unlock(ctd);
+	} else
+		thread_unlock(td);
 	return (0);
 }
 #else
--- /home/rookie/perforce/smpng/attilio_smpng/kern/kern_synch.c	Thu Jun  7 23:33:13 2007
+++ kern_synch.c	Sat Sep 15 20:25:34 2007
@@ -439,7 +439,18 @@
 	if ((flags & SW_VOL) && (td->td_proc->p_flag & P_SA))
 		newtd = thread_switchout(td, flags, newtd);
 #endif
-	sched_switch(td, newtd, flags);
+	if (td->td_vmfriend != NULL) {
+		KASSERT(td->td_pflags & TDP_ITHREAD,
+		    ("%s: td_vmfriend set for %p (%s) non interrupt thread\n",
+		    __func__, td, td->td_proc->p_comm));
+		KASSERT(newtd == NULL, ("%s: newtd expected to be NULL here\n",
+		    __func__));
+
+		newtd = td->td_vmfriend;
+		td->td_vmfriend = NULL;
+		cpu_switch(td, newtd, td->td_lock);
+	} else
+		sched_switch(td, newtd, flags);
 	CTR3(KTR_SCHED, "mi_switch: running %p(%s) prio %d",
 	    td, td->td_proc->p_comm, td->td_priority);
 
--- /home/rookie/perforce/smpng/attilio_smpng/sys/proc.h	Wed Aug  1 17:43:29 2007
+++ proc.h	Sat Sep 15 02:34:35 2007
@@ -261,6 +261,7 @@
 	u_long		td_profil_addr;	/* (k) Temporary addr until AST. */
 	u_int		td_profil_ticks; /* (k) Temporary ticks until AST. */
 	char		td_name[MAXCOMLEN + 1];	/* (*) Thread name. */
+	struct thread	*td_vmfriend;	/* (t) */
 #define	td_endzero td_base_pri
 
 /* Copied during fork1() or thread_sched_upcall(). */