[GIT PULL] scheduler fixes

Ingo Molnar
2016-01-08T12:50:42Z

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: 093e5840ae76f1082633503964d035f40ed0216d sched/core: Reset task's lockless wake-queues on fork()

Misc scheduler fixes.

Thanks,

Ingo

------------------>
Andrey Ryabinin (1):
sched/fair: Fix multiplication overflow on 32-bit systems

Peter Zijlstra (1):
sched/core: Fix unserialized r-m-w scribbling stuff

Sebastian Andrzej Siewior (1):
sched/core: Reset task's lockless wake-queues on fork()

Sergey Senozhatsky (1):
sched/core: Check tgid in is_global_init()

include/linux/sched.h | 16 +++++++++-------
kernel/fork.c | 1 +
kernel/sched/fair.c | 2 +-
3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index edad7a43edea..fa39434e3fdd 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1455,14 +1455,15 @@ struct task_struct {
/* Used for emulating ABI behavior of previous Linux versions */
unsigned int personality;

- unsigned in_execve:1; /* Tell the LSMs that the process is doing an
- * execve */
- unsigned in_iowait:1;
-
- /* Revert to default priority/policy when forking */
+ /* scheduler bits, serialized by scheduler locks */
unsigned sched_reset_on_fork:1;
unsigned sched_contributes_to_load:1;
unsigned sched_migrated:1;
+ unsigned :0; /* force alignment to the next boundary */
+
+ /* unserialized, strictly 'current' */
+ unsigned in_execve:1; /* bit to tell LSMs we're in execve */
+ unsigned in_iowait:1;
#ifdef CONFIG_MEMCG
unsigned memcg_may_oom:1;
#endif
@@ -2002,7 +2003,8 @@ static inline int pid_alive(const struct task_struct *p)
}

/**
- * is_global_init - check if a task structure is init
+ * is_global_init - check if a task structure is init. Since init
+ * is free to have sub-threads we need to check tgid.
* @tsk: Task structure to be checked.
*
* Check if a task structure is the first user space task the kernel created.
@@ -2011,7 +2013,7 @@ static inline int pid_alive(const struct task_struct *p)
*/
static inline int is_global_init(struct task_struct *tsk)
{
- return tsk->pid == 1;
+ return task_tgid_nr(tsk) == 1;
}

extern struct pid *cad_pid;
diff --git a/kernel/fork.c b/kernel/fork.c
index fce002ee3ddf..1155eac61687 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -380,6 +380,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
#endif
tsk->splice_pipe = NULL;
tsk->task_frag.page = NULL;
+ tsk->wake_q.next = NULL;

account_kernel_stack(ti, 1);

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 90e26b11deaa..cfdc0e61066c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2689,7 +2689,7 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
int decayed, removed = 0;

if (atomic_long_read(&cfs_rq->removed_load_avg)) {
- long r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
+ s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
sa->load_avg = max_t(long, sa->load_avg - r, 0);
sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0);
removed = 1;