Commit 13e099d2 authored May 14, 2012 by Peter Zijlstra Committed by Ingo Molnar May 14, 2012

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 <dtundlam@nvidia.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-gk5tm8t2n4ix2vkpns42uqqp@git.kernel.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent e44bc5c5

kernel/sched/debug.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -261,7 +261,13 @@ static void print_cpu(struct seq_file *m, int cpu)
		#endif

		#define P(x) \
		SEQ_printf(m, " .%-30s: %Ld\n", #x, (long long)(rq->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))

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