sched/debug: Fix printing large integers on 32-bit platforms

Some numbers like nr_running and nr_uninterruptible are fundamentally
unsigned since its impossible to have a negative amount of tasks, yet
we still print them as signed to easily recognise the underflow
condition.

rq->nr_uninterruptible has 'special' accounting and can in fact very
easily become negative on a per-cpu basis.

It was noted that since the P() macro assumes things are long long and
the promotion of unsigned 'int/long' to long long on 32bit doesn't
sign extend we print silly large numbers instead of the easier to read
signed numbers.

Therefore extend the P() macro to not require the sign extention.

Reported-by: Diwakar Tundlam <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Author: Peter Zijlstra

kernel/sched/debug.c

@@ -260,8 +260,14 @@ static void print_cpu(struct seq_file *m, int cpu)
 	SEQ_printf(m, "\ncpu#%d\n", cpu);
 #endif
 
-#define P(x) \
-	SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x))
+#define P(x)								\
+do {									\
+	if (sizeof(rq->x) == 4)						\
+		SEQ_printf(m, "  .%-30s: %ld\n", #x, (long)(rq->x));	\
+	else								\
+		SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x));\
+} while (0)
+
 #define PN(x) \
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))