Dear RT folks!
I'm pleased to announce the v5.19-rc7-rt7 patch set.
Changes since v5.19-rc7-rt6:
- Slightly update the ptrace patch (for wait_task_inactive(). There is
no change in functionality, just the code has been reordered.
Known issues
- Valentin Schneider reported a few splats on ARM64, see
https://lkml.kernel.org/r/20210810134127.1394269-1-valentin.schneider@xxxxxxx
The delta patch against v5.19-rc7-rt6 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.19/incr/patch-5.19-rc7-rt6-rt7.patch.xz
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.19-rc7-rt7
The RT patch against v5.19-rc7 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.19/older/patch-5.19-rc7-rt7.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.19/older/patches-5.19-rc7-rt7.tar.xz
Sebastian
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1d4660a1915b3..377e7d4139d87 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3299,6 +3299,40 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p,
}
#endif /* CONFIG_NUMA_BALANCING */
+#ifdef CONFIG_PREEMPT_RT
+static __always_inline bool state_mismatch(struct task_struct *p, unsigned int match_state)
+{
+ unsigned long flags;
+ bool mismatch;
+
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
+ mismatch = READ_ONCE(p->__state) != match_state &&
+ READ_ONCE(p->saved_state) != match_state;
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+ return mismatch;
+}
+static __always_inline bool state_match(struct task_struct *p, unsigned int match_state,
+ bool *wait)
+{
+ if (READ_ONCE(p->__state) == match_state)
+ return true;
+ if (READ_ONCE(p->saved_state) != match_state)
+ return false;
+ *wait = true;
+ return true;
+}
+#else
+static __always_inline bool state_mismatch(struct task_struct *p, unsigned int match_state)
+{
+ return READ_ONCE(p->__state) != match_state;
+}
+static __always_inline bool state_match(struct task_struct *p, unsigned int match_state,
+ bool *wait)
+{
+ return READ_ONCE(p->__state) == match_state;
+}
+#endif
+
/*
* wait_task_inactive - wait for a thread to unschedule.
*
@@ -3317,12 +3351,10 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p,
*/
unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state)
{
- int running, queued;
+ bool running, wait;
struct rq_flags rf;
unsigned long ncsw;
struct rq *rq;
- bool saved_state_match;
- bool update_ncsw;
for (;;) {
/*
@@ -3345,24 +3377,8 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state
* is actually now running somewhere else!
*/
while (task_running(rq, p)) {
-
- if (match_state) {
- bool mismatch = false;
-#ifndef CONFIG_PREEMPT_RT
- if (READ_ONCE(p->__state != match_state)
- mismatch = true;
-#else
- unsigned long flags;
-
- raw_spin_lock_irqsave(&p->pi_lock, flags);
- if (READ_ONCE(p->__state) != match_state &&
- READ_ONCE(p->saved_state) != match_state)
- mismatch = true;
- raw_spin_unlock_irqrestore(&p->pi_lock, flags);
-#endif
- if (mismatch)
- return 0;
- }
+ if (match_state && state_mismatch(p, match_state))
+ return 0;
cpu_relax();
}
@@ -3374,24 +3390,12 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state
rq = task_rq_lock(p, &rf);
trace_sched_wait_task(p);
running = task_running(rq, p);
- queued = task_on_rq_queued(p);
+ wait = task_on_rq_queued(p);
ncsw = 0;
- update_ncsw = false;
- saved_state_match = false;
- if (!match_state) {
- update_ncsw = true;
- } else if (READ_ONCE(p->__state) == match_state) {
- update_ncsw = true;
-#ifdef CONFIG_PREEMPT_RT
- } else if (READ_ONCE(p->saved_state) == match_state) {
- update_ncsw = true;
- saved_state_match = true;
-#endif
- }
-
- if (update_ncsw)
+ if (!match_state || state_match(p, match_state, &wait))
ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
+
task_rq_unlock(rq, p, &rf);
/*
@@ -3420,7 +3424,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state
* running right now), it's preempted, and we should
* yield - it could be a while.
*/
- if (unlikely(queued) || saved_state_match) {
+ if (unlikely(wait)) {
ktime_t to = NSEC_PER_SEC / HZ;
set_current_state(TASK_UNINTERRUPTIBLE);
diff --git a/localversion-rt b/localversion-rt
index 8fc605d806670..045478966e9f1 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt6
+-rt7
