Adding debian version 5.10.209-2.debian/5.10.209-2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 74 insertions, 0 deletions

diff --git a/debian/patches-rt/0137-tasklets-Replace-spin-wait-in-tasklet_kill.patch b/debian/patches-rt/0137-tasklets-Replace-spin-wait-in-tasklet_kill.patch
new file mode 100644
index 000000000..619e62b2a
--- /dev/null
+++ b/debian/patches-rt/0137-tasklets-Replace-spin-wait-in-tasklet_kill.patch
@@ -0,0 +1,74 @@
+From cc2fc16258410420e97a4873f760cffabcff49b0 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 9 Mar 2021 09:42:09 +0100
+Subject: [PATCH 137/323] tasklets: Replace spin wait in tasklet_kill()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+tasklet_kill() spin waits for TASKLET_STATE_SCHED to be cleared invoking
+yield() from inside the loop. yield() is an ill defined mechanism and the
+result might still be wasting CPU cycles in a tight loop which is
+especially painful in a guest when the CPU running the tasklet is scheduled
+out.
+
+tasklet_kill() is used in teardown paths and not performance critical at
+all. Replace the spin wait with wait_var_event().
+
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/softirq.c | 23 +++++++++++++++--------
+ 1 file changed, 15 insertions(+), 8 deletions(-)
+
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index 06bca024ce45..ecc3ac4091c8 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -530,6 +530,16 @@ void __tasklet_hi_schedule(struct tasklet_struct *t)
+ }
+ EXPORT_SYMBOL(__tasklet_hi_schedule);
+ 
++static inline bool tasklet_clear_sched(struct tasklet_struct *t)
++{
++	if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) {
++		wake_up_var(&t->state);
++		return true;
++	}
++
++	return false;
++}
++
+ static void tasklet_action_common(struct softirq_action *a,
+ 				  struct tasklet_head *tl_head,
+ 				  unsigned int softirq_nr)
+@@ -549,8 +559,7 @@ static void tasklet_action_common(struct softirq_action *a,
+ 
+ 		if (tasklet_trylock(t)) {
+ 			if (!atomic_read(&t->count)) {
+-				if (!test_and_clear_bit(TASKLET_STATE_SCHED,
+-							&t->state))
++				if (!tasklet_clear_sched(t))
+ 					BUG();
+ 				if (t->use_callback)
+ 					t->callback(t);
+@@ -610,13 +619,11 @@ void tasklet_kill(struct tasklet_struct *t)
+ 	if (in_interrupt())
+ 		pr_notice("Attempt to kill tasklet from interrupt\n");
+ 
+-	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
+-		do {
+-			yield();
+-		} while (test_bit(TASKLET_STATE_SCHED, &t->state));
+-	}
++	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
++		wait_var_event(&t->state, !test_bit(TASKLET_STATE_SCHED, &t->state));
++
+ 	tasklet_unlock_wait(t);
+-	clear_bit(TASKLET_STATE_SCHED, &t->state);
++	tasklet_clear_sched(t);
+ }
+ EXPORT_SYMBOL(tasklet_kill);
+ 
+-- 
+2.43.0
+