[PATCH] x86_64: Reduce screen space needed by stack trace

Especially under Xen, where the console cannot be adjusted to more than 25
lines, it is fairly important that the information displayed during a panic
is as compact as possible. Below adjustments work towards that.

Signed-Off-By: Jan Beulich <jbeulich@novell.com>

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/traps.c

@@ -183,7 +183,6 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
 
 void show_trace(unsigned long *stack)
 {
-	unsigned long addr;
 	const unsigned cpu = safe_smp_processor_id();
 	unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
 	int i;
@@ -193,8 +192,14 @@ void show_trace(unsigned long *stack)
 
 #define HANDLE_STACK(cond) \
 	do while (cond) { \
-		addr = *stack++; \
+		unsigned long addr = *stack++; \
 		if (kernel_text_address(addr)) { \
+			if (i > 50) { \
+				printk("\n       "); \
+				i = 0; \
+			} \
+			else \
+				i += printk(" "); \
 			/* \
 			 * If the address is either in the text segment of the \
 			 * kernel, or in the region which contains vmalloc'ed \
@@ -204,16 +209,10 @@ void show_trace(unsigned long *stack)
 			 * out the call path that was taken. \
 			 */ \
 			i += printk_address(addr); \
-			if (i > 50) { \
-				printk("\n       "); \
-				i = 0; \
-			} \
-			else \
-				i += printk(" "); \
 		} \
 	} while (0)
 
-	for(i = 0; ; ) {
+	for(i = 11; ; ) {
 		const char *id;
 		unsigned long *estack_end;
 		estack_end = in_exception_stack(cpu, (unsigned long)stack,