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SubjectRe: [PATCH] sched: Make nr_uninterruptible count a signed value
On 05/09/2012 06:46 AM, Diwakar Tundlam wrote:

>> No that's right. nr_uninterruptible counts the number of tasks in
>> uninterruptible sleep, so deactivate_task puts a task to sleep, so we
>> need to increment the number of sleeping tasks, activate_task wakes a
>> task up so we need to decrement the number of sleeping tasks.
>
> Yep, I looked at the code for task_contributes_to_load() and I understand what it is all about.
> The ++ and -- are correct, I see it now.
>
> On the -ve values, strangely inspite of %Ld in the print statement, in my kernel, I see high unsigned values instead of -ve values for nr_uninterruptible.
>
> But the sum is always 0, though.
>
> Maybe it is an artifact of 32-bit machine displaying 64-bit print format.
> An (unsigned long)(-24) promoted to (signed long long) ends up as 4294967272.
> As seen in my output of sched_debug.


This may do some help.

Regards,
Michael Wang
---
kernel/sched/debug.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 09acaa1..ab9d53f 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -270,7 +270,7 @@ static void print_cpu(struct seq_file *m, int cpu)
rq->load.weight);
P(nr_switches);
P(nr_load_updates);
- P(nr_uninterruptible);
+ P((signed long)nr_uninterruptible);
PN(next_balance);
P(curr->pid);
PN(clock);
--
1.7.4.1


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