[v3,1/7] sched: Expose move_queued_task() from core.c
Commit Message
The migrate_task_to() function exposed from kernel/sched/core.c migrates
the current task, which is silently assumed to also be its first
argument, to the specified CPU. The function uses stop_one_cpu() to
migrate the task to the target CPU, which won't work if @p is not the
current task as the stop_one_cpu() callback isn't invoked on remote
CPUs.
While this operation is useful for task_numa_migrate() in fair.c, it
would be useful if move_queued_task() in core.c was given external
linkage, as it actually can be used to migrate any task to a CPU.
A follow-on patch will call move_queued_task() from fair.c when
migrating a task in a shared runqueue to a remote CPU.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: David Vernet <void@manifault.com>
---
kernel/sched/core.c | 4 ++--
kernel/sched/sched.h | 3 +++
2 files changed, 5 insertions(+), 2 deletions(-)
@@ -2519,8 +2519,8 @@ static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
*
* Returns (locked) new rq. Old rq's lock is released.
*/
-static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
- struct task_struct *p, int new_cpu)
+struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
+ struct task_struct *p, int new_cpu)
{
lockdep_assert_rq_held(rq);
@@ -1763,6 +1763,9 @@ init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
#ifdef CONFIG_SMP
+
+extern struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
+ struct task_struct *p, int new_cpu);
static inline void
queue_balance_callback(struct rq *rq,
struct balance_callback *head,