The following commit has been merged into the sched/core branch of tip:
Commit-ID: f9fc8cad9728124cefe8844fb53d1814c92c6bfc
Gitweb: https://git.kernel.org/tip/f9fc8cad9728124cefe8844fb53d1814c92c6bfc
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 06 Sep 2022 12:39:55 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 07 Sep 2022 21:53:49 +02:00
sched: Add TASK_ANY for wait_task_inactive()
Now that wait_task_inactive()'s @match_state argument is a mask (like
ttwu()) it is possible to replace the special !match_state case with
an 'all-states' value such that any blocked state will match.
Suggested-by: Ingo Molnar (mingo@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/YxhkzfuFTvRnpUaH@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
---
drivers/powercap/idle_inject.c | 2 +-
fs/coredump.c | 2 +-
include/linux/sched.h | 2 ++
kernel/sched/core.c | 16 ++++++++--------
4 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c
index a20bf12..999e218 100644
--- a/drivers/powercap/idle_inject.c
+++ b/drivers/powercap/idle_inject.c
@@ -254,7 +254,7 @@ void idle_inject_stop(struct idle_inject_device *ii_dev)
iit = per_cpu_ptr(&idle_inject_thread, cpu);
iit->should_run = 0;
- wait_task_inactive(iit->tsk, 0);
+ wait_task_inactive(iit->tsk, TASK_ANY);
}
cpu_hotplug_enable();
diff --git a/fs/coredump.c b/fs/coredump.c
index 9f4aae2..3d9054c 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -412,7 +412,7 @@ static int coredump_wait(int exit_code, struct core_state *core_state)
*/
ptr = core_state->dumper.next;
while (ptr != NULL) {
- wait_task_inactive(ptr->task, 0);
+ wait_task_inactive(ptr->task, TASK_ANY);
ptr = ptr->next;
}
}
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e7b2f8a..0facaad 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -101,6 +101,8 @@ struct task_group;
#define TASK_RTLOCK_WAIT 0x1000
#define TASK_STATE_MAX 0x2000
+#define TASK_ANY (TASK_STATE_MAX-1)
+
/* Convenience macros for the sake of set_current_state: */
#define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
#define TASK_STOPPED (TASK_WAKEKILL | __TASK_STOPPED)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 43d71c6..ea26526 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3253,12 +3253,12 @@ out:
/*
* wait_task_inactive - wait for a thread to unschedule.
*
- * If @match_state is nonzero, it's the @p->state value just checked and
- * not expected to change. If it changes, i.e. @p might have woken up,
- * then return zero. When we succeed in waiting for @p to be off its CPU,
- * we return a positive number (its total switch count). If a second call
- * a short while later returns the same number, the caller can be sure that
- * @p has remained unscheduled the whole time.
+ * Wait for the thread to block in any of the states set in @match_state.
+ * If it changes, i.e. @p might have woken up, then return zero. When we
+ * succeed in waiting for @p to be off its CPU, we return a positive number
+ * (its total switch count). If a second call a short while later returns the
+ * same number, the caller can be sure that @p has remained unscheduled the
+ * whole time.
*
* The caller must ensure that the task *will* unschedule sometime soon,
* else this function might spin for a *long* time. This function can't
@@ -3294,7 +3294,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state
* is actually now running somewhere else!
*/
while (task_on_cpu(rq, p)) {
- if (match_state && !(READ_ONCE(p->__state) & match_state))
+ if (!(READ_ONCE(p->__state) & match_state))
return 0;
cpu_relax();
}
@@ -3309,7 +3309,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state
running = task_on_cpu(rq, p);
queued = task_on_rq_queued(p);
ncsw = 0;
- if (!match_state || (READ_ONCE(p->__state) & match_state))
+ if (READ_ONCE(p->__state) & match_state)
ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
task_rq_unlock(rq, p, &rf);
|