On Fri, Nov 27, 2015 at 12:09:44PM +0800, yalin wang wrote:
> nr_uninterruptible will be negative during running,
> this happened when dequeue a TASK_UNINTERRUPTIBLE task
> from rq1 and then wake up the task and queue it to rq2,
> then rq2->nr_uninterruptible-- will reuslt in negative value
> sometimes.
Why!? Aren't isn't signed stuff more likely affected by over/underflow
muck? I'd be more inclined to remove the signed muck altogether like:
That relies on C having defined overflow semantics for unsigned types
and the (hard) assumption that the hardware uses 2s-complement (which
the kernel assumes in many many places already).
diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
index ef7159012cf3..62cff13ed120 100644
--- a/kernel/sched/loadavg.c
+++ b/kernel/sched/loadavg.c
@@ -80,13 +80,14 @@ void get_avenrun(unsigned long *loads, unsigned long
offset, int shift)
long calc_load_fold_active(struct rq *this_rq)
{
- long nr_active, delta = 0;
+ unsigned long nr_active;
+ long delta = 0;
nr_active = this_rq->nr_running;
- nr_active += (long)this_rq->nr_uninterruptible;
+ nr_active += this_rq->nr_uninterruptible;
if (nr_active != this_rq->calc_load_active) {
- delta = nr_active - this_rq->calc_load_active;
+ delta = (long)(nr_active - this_rq->calc_load_active);
this_rq->calc_load_active = nr_active;
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 2eb2002aa336..2f9b4ce759dc 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -652,7 +652,7 @@ struct rq {
/* calc_load related fields */
unsigned long calc_load_update;
- long calc_load_active;
+ unsigned long calc_load_active;
#ifdef CONFIG_SCHED_HRTICK
#ifdef CONFIG_SMP
--
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