diff -Naurp -X /home/jbarnes/dontdiff 240-node-history-migration.patch/arch/ia64/sn/kernel/sn2/sn2_smp.c 250-node-history.patch/arch/ia64/sn/kernel/sn2/sn2_smp.c
--- 240-node-history-migration.patch/arch/ia64/sn/kernel/sn2/sn2_smp.c	Thu Jan 29 10:18:56 2004
+++ 250-node-history.patch/arch/ia64/sn/kernel/sn2/sn2_smp.c	Thu Jan 29 10:42:37 2004
@@ -4,7 +4,7 @@
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
- *
+ * 
  * Copyright (C) 2000-2003 Silicon Graphics, Inc. All rights reserved.
  */
 
@@ -26,6 +26,8 @@
 #include <asm/delay.h>
 #include <asm/io.h>
 #include <asm/smp.h>
+#include <asm/numa.h>
+#include <asm/bitops.h>
 #include <asm/hw_irq.h>
 #include <asm/current.h>
 #include <asm/sn/sn_cpuid.h>
@@ -34,6 +36,13 @@
 #include <asm/sn/nodepda.h>
 #include <asm/sn/rw_mmr.h>
 
+/* When nodemask_t is available, delete the following definitions */
+#define NODEMASK_WORDCOUNT       ((NR_NODES+(BITS_PER_LONG-1))/BITS_PER_LONG)
+#define NODE_MASK_ALL    { [0 ... ((NR_NODES+BITS_PER_LONG-1)/BITS_PER_LONG)-1] = ~0UL }
+#define NODE_MASK_NONE   { [0 ... ((NR_NODES+BITS_PER_LONG-1)/BITS_PER_LONG)-1] = 0 }
+typedef unsigned long   nodemask_t[NODEMASK_WORDCOUNT];
+
+
 void sn2_ptc_deadlock_recovery(unsigned long data0, unsigned long data1);
 
 
@@ -66,14 +75,52 @@ wait_piowc(void)
  *
  * Purges the translation caches of all processors of the given virtual address
  * range.
+ *
+ * Note:
+ * 	- cpu_vm_mask is a bit mask that indicates which cpus have loaded the context.
+ * 	- cpu_vm_mask is converted into a nodemask of the nodes containing the
+ * 	  cpus in cpu_vm_mask.
+ *	- if only one bit is set in cpu_vm_mask & it is the current cpu,
+ *	  then only the local TLB needs to be flushed. This flushing can be done
+ *	  using ptc.l. This is the common case & avoids the global spinlock.
+ *	- if multiple cpus have loaded the context, then flushing has to be
+ *	  done with ptc.g/MMRs under protection of the global ptc_lock.
  */
 
 void
 sn2_global_tlb_purge (unsigned long start, unsigned long end, unsigned long nbits)
 {
-	int			cnode, mycnode, nasid, flushed=0;
+	int			i, cnode, mynasid, cpu, lcpu=0, nasid, flushed=0;
 	volatile unsigned	long	*ptc0, *ptc1;
 	unsigned long		flags=0, data0, data1;
+	struct mm_struct	*mm=current->active_mm;
+	nodemask_t		nodes_flushed=NODE_MASK_NONE;
+	short			nasids[NR_NODES], nix;
+
+	for (i=0, cpu=find_first_bit(&mm->cpu_vm_mask, NR_CPUS); cpu < NR_CPUS;
+			i++, cpu=find_next_bit(&mm->cpu_vm_mask, NR_CPUS, ++cpu)) {
+		cnode = cpu_to_node(cpu);
+		__set_bit(cnode, nodes_flushed);
+		lcpu = cpu;
+	}
+
+	preempt_disable();
+
+	if (likely(i == 1 && lcpu == smp_processor_id())) {
+		do {
+			asm volatile ("ptc.l %0,%1" :: "r"(start), "r"(nbits<<2) : "memory");
+			start += (1UL << nbits);
+		} while (start < end);
+		ia64_srlz_i();
+		preempt_enable();
+		return;
+	}
+
+	nix = 0;
+	for (cnode=find_first_bit(&nodes_flushed, NR_NODES); cnode < NR_NODES; 
+			cnode=find_next_bit(&nodes_flushed, NR_NODES, ++cnode))
+		nasids[nix++] = cnodeid_to_nasid(cnode);
+
 
 	data0 = (1UL<<SH_PTC_0_A_SHFT) |
 		(nbits<<SH_PTC_0_PS_SHFT) |
@@ -83,20 +130,18 @@ sn2_global_tlb_purge (unsigned long star
 	ptc0 = (long*)GLOBAL_MMR_PHYS_ADDR(0, SH_PTC_0);
 	ptc1 = (long*)GLOBAL_MMR_PHYS_ADDR(0, SH_PTC_1);
 
-	mycnode = numa_node_id();
+	mynasid = smp_physical_node_id();
 
 	spin_lock_irqsave(&sn2_global_ptc_lock, flags);
 
 	do {
 		data1 = start | (1UL<<SH_PTC_1_START_SHFT);
-		for (cnode = 0; cnode < numnodes; cnode++) {
-			if (is_headless_node(cnode))
-				continue;
-			if (cnode == mycnode) {
+		for (i=0; i<nix; i++) {
+			nasid = nasids[i];
+			if (likely(nasid == mynasid)) {
 				ia64_ptcga(start, nbits<<2);
 				ia64_srlz_i();
 			} else {
-				nasid = cnodeid_to_nasid(cnode);
 				ptc0 = CHANGE_NASID(nasid, ptc0);
 				ptc1 = CHANGE_NASID(nasid, ptc1);
 				pio_atomic_phys_write_mmrs(ptc0, data0, ptc1, data1);
@@ -114,6 +159,7 @@ sn2_global_tlb_purge (unsigned long star
 
 	spin_unlock_irqrestore(&sn2_global_ptc_lock, flags);
 
+	preempt_enable();
 }
 
 /*
diff -Naurp -X /home/jbarnes/dontdiff 240-node-history-migration.patch/include/asm-ia64/mmu_context.h 250-node-history.patch/include/asm-ia64/mmu_context.h
--- 240-node-history-migration.patch/include/asm-ia64/mmu_context.h	Sun Jan 25 18:29:59 2004
+++ 250-node-history.patch/include/asm-ia64/mmu_context.h	Thu Jan 29 10:34:40 2004
@@ -21,6 +21,7 @@
 
 # ifndef __ASSEMBLY__
 
+#include <linux/config.h>
 #include <linux/compiler.h>
 #include <linux/percpu.h>
 #include <linux/sched.h>
@@ -106,6 +107,9 @@ get_mmu_context (struct mm_struct *mm)
 		/* re-check, now that we've got the lock: */
 		context = mm->context;
 		if (context == 0) {
+#ifdef CONFIG_NUMA
+			cpus_clear(mm->cpu_vm_mask);
+#endif
 			if (ia64_ctx.next >= ia64_ctx.limit)
 				wrap_mmu_context(mm);
 			mm->context = context = ia64_ctx.next++;
@@ -170,6 +174,10 @@ activate_context (struct mm_struct *mm)
 	do {
 		context = get_mmu_context(mm);
 		MMU_TRACE('A', smp_processor_id(), mm, context);
+#ifdef CONFIG_NUMA
+		if (!cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
+			cpu_set(smp_processor_id(), mm->cpu_vm_mask);
+#endif
 		reload_context(context);
 		MMU_TRACE('a', smp_processor_id(), mm, context);
 		/* in the unlikely event of a TLB-flush by another thread, redo the load: */