lkml.org 
[lkml]   [2016]   [Jul]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[GIT PULL] scheduler fix
Linus,

Please pull the latest sched-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-for-linus

# HEAD: d60585c5766e9620d5d83e2b25dc042c7bdada2c sched/core: Correct off by one bug in load migration calculation

Fix a CPU hotplug related corruption of the load average that got introduced in
this merge window.

Thanks,

Ingo

------------------>
Thomas Gleixner (1):
sched/core: Correct off by one bug in load migration calculation


kernel/sched/core.c | 6 ++++--
kernel/sched/loadavg.c | 8 ++++----
kernel/sched/sched.h | 2 +-
3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 51d7105f529a..97ee9ac7e97c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5394,13 +5394,15 @@ void idle_task_exit(void)
/*
* Since this CPU is going 'away' for a while, fold any nr_active delta
* we might have. Assumes we're called after migrate_tasks() so that the
- * nr_active count is stable.
+ * nr_active count is stable. We need to take the teardown thread which
+ * is calling this into account, so we hand in adjust = 1 to the load
+ * calculation.
*
* Also see the comment "Global load-average calculations".
*/
static void calc_load_migrate(struct rq *rq)
{
- long delta = calc_load_fold_active(rq);
+ long delta = calc_load_fold_active(rq, 1);
if (delta)
atomic_long_add(delta, &calc_load_tasks);
}
diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
index b0b93fd33af9..a2d6eb71f06b 100644
--- a/kernel/sched/loadavg.c
+++ b/kernel/sched/loadavg.c
@@ -78,11 +78,11 @@ void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
loads[2] = (avenrun[2] + offset) << shift;
}

-long calc_load_fold_active(struct rq *this_rq)
+long calc_load_fold_active(struct rq *this_rq, long adjust)
{
long nr_active, delta = 0;

- nr_active = this_rq->nr_running;
+ nr_active = this_rq->nr_running - adjust;
nr_active += (long)this_rq->nr_uninterruptible;

if (nr_active != this_rq->calc_load_active) {
@@ -188,7 +188,7 @@ void calc_load_enter_idle(void)
* We're going into NOHZ mode, if there's any pending delta, fold it
* into the pending idle delta.
*/
- delta = calc_load_fold_active(this_rq);
+ delta = calc_load_fold_active(this_rq, 0);
if (delta) {
int idx = calc_load_write_idx();

@@ -389,7 +389,7 @@ void calc_global_load_tick(struct rq *this_rq)
if (time_before(jiffies, this_rq->calc_load_update))
return;

- delta = calc_load_fold_active(this_rq);
+ delta = calc_load_fold_active(this_rq, 0);
if (delta)
atomic_long_add(delta, &calc_load_tasks);

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 7cbeb92a1cb9..898c0d2f18fe 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -28,7 +28,7 @@ extern unsigned long calc_load_update;
extern atomic_long_t calc_load_tasks;

extern void calc_global_load_tick(struct rq *this_rq);
-extern long calc_load_fold_active(struct rq *this_rq);
+extern long calc_load_fold_active(struct rq *this_rq, long adjust);

#ifdef CONFIG_SMP
extern void cpu_load_update_active(struct rq *this_rq);
\
 
 \ /
  Last update: 2016-07-14 21:41    [W:0.024 / U:2.928 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site