Merge tag 'v5.6-rc3' into sched/core, to pick up fixes and dependent patches

Signed-off-by: Ingo Molnar <mingo@kernel.org>

5 files changed, 61 insertions, 37 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 377ec26e9159..e94819d573be 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1447,17 +1447,6 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
 
 #ifdef CONFIG_SMP
 
-static inline bool is_per_cpu_kthread(struct task_struct *p)
-{
-	if (!(p->flags & PF_KTHREAD))
-		return false;
-
-	if (p->nr_cpus_allowed != 1)
-		return false;
-
-	return true;
-}
-
 /*
  * Per-CPU kthreads are allowed to run on !active && online CPUs, see
  * __set_cpus_allowed_ptr() and select_fallback_rq().
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a7e11b1bb64c..f38ff5a335d3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3516,7 +3516,6 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
  * attach_entity_load_avg - attach this entity to its cfs_rq load avg
  * @cfs_rq: cfs_rq to attach to
  * @se: sched_entity to attach
- * @flags: migration hints
  *
  * Must call update_cfs_rq_load_avg() before this, since we rely on
  * cfs_rq->avg.last_update_time being current.
@@ -5970,6 +5969,20 @@ symmetric:
 	    (available_idle_cpu(prev) || sched_idle_cpu(prev)))
 		return prev;
 
+	/*
+	 * Allow a per-cpu kthread to stack with the wakee if the
+	 * kworker thread and the tasks previous CPUs are the same.
+	 * The assumption is that the wakee queued work for the
+	 * per-cpu kthread that is now complete and the wakeup is
+	 * essentially a sync wakeup. An obvious example of this
+	 * pattern is IO completions.
+	 */
+	if (is_per_cpu_kthread(current) &&
+	    prev == smp_processor_id() &&
+	    this_rq()->nr_running <= 1) {
+		return prev;
+	}
+
 	/* Check a recently used CPU as a potential idle candidate: */
 	recent_used_cpu = p->recent_used_cpu;
 	if (recent_used_cpu != prev &&
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 9fcb2a695a41..008d6ac2342b 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -163,6 +163,12 @@ static int __init housekeeping_isolcpus_setup(char *str)
 			continue;
 		}
 
+		if (!strncmp(str, "managed_irq,", 12)) {
+			str += 12;
+			flags |= HK_FLAG_MANAGED_IRQ;
+			continue;
+		}
+
 		pr_warn("isolcpus: Error, unknown flag\n");
 		return 0;
 	}
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index db7b50bba3f1..028520702717 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1199,6 +1199,9 @@ static ssize_t psi_write(struct file *file, const char __user *user_buf,
 	if (static_branch_likely(&psi_disabled))
 		return -EOPNOTSUPP;
 
+	if (!nbytes)
+		return -EINVAL;
+
 	buf_size = min(nbytes, sizeof(buf));
 	if (copy_from_user(buf, user_buf, buf_size))
 		return -EFAULT;
@@ -1251,40 +1254,40 @@ static int psi_fop_release(struct inode *inode, struct file *file)
 	return single_release(inode, file);
 }
 
-static const struct file_operations psi_io_fops = {
-	.open           = psi_io_open,
-	.read           = seq_read,
-	.llseek         = seq_lseek,
-	.write          = psi_io_write,
-	.poll           = psi_fop_poll,
-	.release        = psi_fop_release,
+static const struct proc_ops psi_io_proc_ops = {
+	.proc_open	= psi_io_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_io_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
 };
 
-static const struct file_operations psi_memory_fops = {
-	.open           = psi_memory_open,
-	.read           = seq_read,
-	.llseek         = seq_lseek,
-	.write          = psi_memory_write,
-	.poll           = psi_fop_poll,
-	.release        = psi_fop_release,
+static const struct proc_ops psi_memory_proc_ops = {
+	.proc_open	= psi_memory_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_memory_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
 };
 
-static const struct file_operations psi_cpu_fops = {
-	.open           = psi_cpu_open,
-	.read           = seq_read,
-	.llseek         = seq_lseek,
-	.write          = psi_cpu_write,
-	.poll           = psi_fop_poll,
-	.release        = psi_fop_release,
+static const struct proc_ops psi_cpu_proc_ops = {
+	.proc_open	= psi_cpu_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_cpu_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
 };
 
 static int __init psi_proc_init(void)
 {
 	if (psi_enable) {
 		proc_mkdir("pressure", NULL);
-		proc_create("pressure/io", 0, NULL, &psi_io_fops);
-		proc_create("pressure/memory", 0, NULL, &psi_memory_fops);
-		proc_create("pressure/cpu", 0, NULL, &psi_cpu_fops);
+		proc_create("pressure/io", 0, NULL, &psi_io_proc_ops);
+		proc_create("pressure/memory", 0, NULL, &psi_memory_proc_ops);
+		proc_create("pressure/cpu", 0, NULL, &psi_cpu_proc_ops);
 	}
 	return 0;
 }
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 878910e8b299..12bf82d86156 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -896,7 +896,7 @@ struct rq {
 	 */
 	unsigned long		nr_uninterruptible;
 
-	struct task_struct	*curr;
+	struct task_struct __rcu	*curr;
 	struct task_struct	*idle;
 	struct task_struct	*stop;
 	unsigned long		next_balance;
@@ -2484,3 +2484,16 @@ static inline void membarrier_switch_mm(struct rq *rq,
 {
 }
 #endif
+
+#ifdef CONFIG_SMP
+static inline bool is_per_cpu_kthread(struct task_struct *p)
+{
+	if (!(p->flags & PF_KTHREAD))
+		return false;
+
+	if (p->nr_cpus_allowed != 1)
+		return false;
+
+	return true;
+}
+#endif