[PATCH] ppc64: reduce stack overflow warning threshold

Reduce the stack overflow warning from 4kB to 2kB now that its been in and
tested for a while.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ppc64/kernel/irq.c

@@ -586,13 +586,13 @@ void do_IRQ(struct pt_regs *regs)
 	irq_enter();
 
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
-	/* Debugging check for stack overflow: is there less than 4KB free? */
+	/* Debugging check for stack overflow: is there less than 2KB free? */
 	{
 		long sp;
 
 		sp = __get_SP() & (THREAD_SIZE-1);
 
-		if (unlikely(sp < (sizeof(struct thread_info) + 4096))) {
+		if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
 			printk("do_IRQ: stack overflow: %ld\n",
 				sp - sizeof(struct thread_info));
 			dump_stack();
@@ -629,13 +629,13 @@ void do_IRQ(struct pt_regs *regs)
 	irq_enter();
 
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
-	/* Debugging check for stack overflow: is there less than 4KB free? */
+	/* Debugging check for stack overflow: is there less than 2KB free? */
 	{
 		long sp;
 
 		sp = __get_SP() & (THREAD_SIZE-1);
 
-		if (unlikely(sp < (sizeof(struct thread_info) + 4096))) {
+		if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
 			printk("do_IRQ: stack overflow: %ld\n",
 				sp - sizeof(struct thread_info));
 			dump_stack();