1 files changed, 0 insertions, 235 deletions
diff --git a/debian/patches-rt/0003-sched-Fix-balance_callback.patch b/debian/patches-rt/0003-sched-Fix-balance_callback.patch
deleted file mode 100644
index 3448f4fc1..000000000
--- a/debian/patches-rt/0003-sched-Fix-balance_callback.patch
+++ /dev/null
@@ -1,235 +0,0 @@
-From 0d544cc765b0ebf25038748d52d2e76f256a1e56 Mon Sep 17 00:00:00 2001
-From: Peter Zijlstra <peterz@infradead.org>
-Date: Fri, 23 Oct 2020 12:12:00 +0200
-Subject: [PATCH 003/296] sched: Fix balance_callback()
-Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.35-rt39.tar.xz
-
-The intent of balance_callback() has always been to delay executing
-balancing operations until the end of the current rq->lock section.
-This is because balance operations must often drop rq->lock, and that
-isn't safe in general.
-
-However, as noted by Scott, there were a few holes in that scheme;
-balance_callback() was called after rq->lock was dropped, which means
-another CPU can interleave and touch the callback list.
-
-Rework code to call the balance callbacks before dropping rq->lock
-where possible, and otherwise splice the balance list onto a local
-stack.
-
-This guarantees that the balance list must be empty when we take
-rq->lock. IOW, we'll only ever run our own balance callbacks.
-
-Reported-by: Scott Wood <swood@redhat.com>
-Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
-Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
----
- kernel/sched/core.c  | 119 +++++++++++++++++++++++++++----------------
- kernel/sched/sched.h |   3 ++
- 2 files changed, 78 insertions(+), 44 deletions(-)
-
-diff --git a/kernel/sched/core.c b/kernel/sched/core.c
-index 3a150445e0cb..56f9a850c9bf 100644
---- a/kernel/sched/core.c
-+++ b/kernel/sched/core.c
-@@ -3487,6 +3487,69 @@ static inline void finish_task(struct task_struct *prev)
- #endif
- }
- 
-+#ifdef CONFIG_SMP
-+
-+static void do_balance_callbacks(struct rq *rq, struct callback_head *head)
-+{
-+	void (*func)(struct rq *rq);
-+	struct callback_head *next;
-+
-+	lockdep_assert_held(&rq->lock);
-+
-+	while (head) {
-+		func = (void (*)(struct rq *))head->func;
-+		next = head->next;
-+		head->next = NULL;
-+		head = next;
-+
-+		func(rq);
-+	}
-+}
-+
-+static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
-+{
-+	struct callback_head *head = rq->balance_callback;
-+
-+	lockdep_assert_held(&rq->lock);
-+	if (head)
-+		rq->balance_callback = NULL;
-+
-+	return head;
-+}
-+
-+static void __balance_callbacks(struct rq *rq)
-+{
-+	do_balance_callbacks(rq, splice_balance_callbacks(rq));
-+}
-+
-+static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
-+{
-+	unsigned long flags;
-+
-+	if (unlikely(head)) {
-+		raw_spin_lock_irqsave(&rq->lock, flags);
-+		do_balance_callbacks(rq, head);
-+		raw_spin_unlock_irqrestore(&rq->lock, flags);
-+	}
-+}
-+
-+#else
-+
-+static inline void __balance_callbacks(struct rq *rq)
-+{
-+}
-+
-+static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
-+{
-+	return NULL;
-+}
-+
-+static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
-+{
-+}
-+
-+#endif
-+
- static inline void
- prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf)
- {
-@@ -3512,6 +3575,7 @@ static inline void finish_lock_switch(struct rq *rq)
- 	 * prev into current:
- 	 */
- 	spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
-+	__balance_callbacks(rq);
- 	raw_spin_unlock_irq(&rq->lock);
- }
- 
-@@ -3653,43 +3717,6 @@ static struct rq *finish_task_switch(struct task_struct *prev)
- 	return rq;
- }
- 
--#ifdef CONFIG_SMP
--
--/* rq->lock is NOT held, but preemption is disabled */
--static void __balance_callback(struct rq *rq)
--{
--	struct callback_head *head, *next;
--	void (*func)(struct rq *rq);
--	unsigned long flags;
--
--	raw_spin_lock_irqsave(&rq->lock, flags);
--	head = rq->balance_callback;
--	rq->balance_callback = NULL;
--	while (head) {
--		func = (void (*)(struct rq *))head->func;
--		next = head->next;
--		head->next = NULL;
--		head = next;
--
--		func(rq);
--	}
--	raw_spin_unlock_irqrestore(&rq->lock, flags);
--}
--
--static inline void balance_callback(struct rq *rq)
--{
--	if (unlikely(rq->balance_callback))
--		__balance_callback(rq);
--}
--
--#else
--
--static inline void balance_callback(struct rq *rq)
--{
--}
--
--#endif
--
- /**
-  * schedule_tail - first thing a freshly forked thread must call.
-  * @prev: the thread we just switched away from.
-@@ -3709,7 +3736,6 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev)
- 	 */
- 
- 	rq = finish_task_switch(prev);
--	balance_callback(rq);
- 	preempt_enable();
- 
- 	if (current->set_child_tid)
-@@ -4525,10 +4551,11 @@ static void __sched notrace __schedule(bool preempt)
- 		rq = context_switch(rq, prev, next, &rf);
- 	} else {
- 		rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
--		rq_unlock_irq(rq, &rf);
--	}
- 
--	balance_callback(rq);
-+		rq_unpin_lock(rq, &rf);
-+		__balance_callbacks(rq);
-+		raw_spin_unlock_irq(&rq->lock);
-+	}
- }
- 
- void __noreturn do_task_dead(void)
-@@ -4940,9 +4967,11 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
- out_unlock:
- 	/* Avoid rq from going away on us: */
- 	preempt_disable();
--	__task_rq_unlock(rq, &rf);
- 
--	balance_callback(rq);
-+	rq_unpin_lock(rq, &rf);
-+	__balance_callbacks(rq);
-+	raw_spin_unlock(&rq->lock);
-+
- 	preempt_enable();
- }
- #else
-@@ -5216,6 +5245,7 @@ static int __sched_setscheduler(struct task_struct *p,
- 	int retval, oldprio, oldpolicy = -1, queued, running;
- 	int new_effective_prio, policy = attr->sched_policy;
- 	const struct sched_class *prev_class;
-+	struct callback_head *head;
- 	struct rq_flags rf;
- 	int reset_on_fork;
- 	int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
-@@ -5454,6 +5484,7 @@ static int __sched_setscheduler(struct task_struct *p,
- 
- 	/* Avoid rq from going away on us: */
- 	preempt_disable();
-+	head = splice_balance_callbacks(rq);
- 	task_rq_unlock(rq, p, &rf);
- 
- 	if (pi) {
-@@ -5462,7 +5493,7 @@ static int __sched_setscheduler(struct task_struct *p,
- 	}
- 
- 	/* Run balance callbacks after we've adjusted the PI chain: */
--	balance_callback(rq);
-+	balance_callbacks(rq, head);
- 	preempt_enable();
- 
- 	return 0;
-diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
-index fac1b121d113..5e03f3210318 100644
---- a/kernel/sched/sched.h
-+++ b/kernel/sched/sched.h
-@@ -1216,6 +1216,9 @@ static inline void rq_pin_lock(struct rq *rq, struct rq_flags *rf)
- 	rq->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
- 	rf->clock_update_flags = 0;
- #endif
-+#ifdef CONFIG_SMP
-+	SCHED_WARN_ON(rq->balance_callback);
-+#endif
- }
- 
- static inline void rq_unpin_lock(struct rq *rq, struct rq_flags *rf)
--- 
-2.30.2
-