[GIT pull] scheduler fixes for 4.20

From: Thomas Gleixner
Date: Sun Nov 11 2018 - 03:11:30 EST


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

Two small scheduler fixes:

- Take hotplug lock in sched_init_smp(). Technically not really required,
but lockdep will complain other.

- Trivial comment fix in sched/fair


Thanks,

tglx

------------------>
Valentin Schneider (1):
sched/core: Take the hotplug lock in sched_init_smp()

Yi Wang (1):
sched/fair: Fix a comment in task_numa_fault()


kernel/sched/core.c | 5 ++++-
kernel/sched/fair.c | 4 ++--
2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fd2fce8a001b..02a20ef196a6 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5859,11 +5859,14 @@ void __init sched_init_smp(void)
/*
* There's no userspace yet to cause hotplug operations; hence all the
* CPU masks are stable and all blatant races in the below code cannot
- * happen.
+ * happen. The hotplug lock is nevertheless taken to satisfy lockdep,
+ * but there won't be any contention on it.
*/
+ cpus_read_lock();
mutex_lock(&sched_domains_mutex);
sched_init_domains(cpu_active_mask);
mutex_unlock(&sched_domains_mutex);
+ cpus_read_unlock();

/* Move init over to a non-isolated CPU */
if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ee271bb661cc..3648d0300fdf 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2400,8 +2400,8 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
local = 1;

/*
- * Retry task to preferred node migration periodically, in case it
- * case it previously failed, or the scheduler moved us.
+ * Retry to migrate task to preferred node periodically, in case it
+ * previously failed, or the scheduler moved us.
*/
if (time_after(jiffies, p->numa_migrate_retry)) {
task_numa_placement(p);