Dear RT folks!
I'm pleased to announce the v3.18.13-rt10 patch set.
Changes since v3.18.13-rt9
- The dead lock fix for ftrace fixed by Jan Kiszka in -rt9 has now an
updated patch by Mike Galbraith.
Known issues:
- bcache is disabled.
- CPU hotplug works in general. Steven's test script however
deadlocks usually on the second invocation.
- xor / raid_pq
I had max latency jumping up to 67563us on one CPU while the next
lower max was 58us. I tracked it down to module's init code of
xor and raid_pq. Both disable preemption while measuring the
performance of the individual implementation.
The delta patch against 3.18.13-rt9 is appended below and can be found here:
https://www.kernel.org/pub/linux/kernel/projects/rt/3.18/incr/patch-3.18.13-rt9-rt10.patch.xz
The RT patch against 3.18.13 can be found here:
https://www.kernel.org/pub/linux/kernel/projects/rt/3.18/patch-3.18.13-rt10.patch.xz
The split quilt queue is available at:
https://www.kernel.org/pub/linux/kernel/projects/rt/3.18/patches-3.18.13-rt10.tar.xz
Sebastian
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 171dfacb61d4..9678fd1382a7 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -23,9 +23,7 @@
static DEFINE_PER_CPU(struct llist_head, raised_list);
static DEFINE_PER_CPU(struct llist_head, lazy_list);
-#ifdef CONFIG_PREEMPT_RT_FULL
-static DEFINE_PER_CPU(struct llist_head, hirq_work_list);
-#endif
+
/*
* Claim the entry so that no one else will poke at it.
*/
@@ -68,7 +66,7 @@ void __weak arch_irq_work_raise(void)
*/
bool irq_work_queue_on(struct irq_work *work, int cpu)
{
- bool raise_irqwork;
+ struct llist_head *list;
/* All work should have been flushed before going offline */
WARN_ON_ONCE(cpu_is_offline(cpu));
@@ -80,16 +78,12 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
if (!irq_work_claim(work))
return false;
-#ifdef CONFIG_PREEMPT_RT_FULL
- if (work->flags & IRQ_WORK_HARD_IRQ)
- raise_irqwork = llist_add(&work->llnode,
- &per_cpu(hirq_work_list, cpu));
+ if (IS_ENABLED(CONFIG_PREEMPT_RT_FULL) && !(work->flags & IRQ_WORK_HARD_IRQ))
+ list = &per_cpu(lazy_list, cpu);
else
-#endif
- raise_irqwork = llist_add(&work->llnode,
- &per_cpu(raised_list, cpu));
+ list = &per_cpu(raised_list, cpu);
- if (raise_irqwork)
+ if (llist_add(&work->llnode, list))
arch_send_call_function_single_ipi(cpu);
return true;
@@ -100,6 +94,9 @@ EXPORT_SYMBOL_GPL(irq_work_queue_on);
/* Enqueue the irq work @work on the current CPU */
bool irq_work_queue(struct irq_work *work)
{
+ struct llist_head *list;
+ bool lazy_work, realtime = IS_ENABLED(CONFIG_PREEMPT_RT_FULL);
+
/* Only queue if not already pending */
if (!irq_work_claim(work))
return false;
@@ -107,22 +104,15 @@ bool irq_work_queue(struct irq_work *work)
/* Queue the entry and raise the IPI if needed. */
preempt_disable();
-#ifdef CONFIG_PREEMPT_RT_FULL
- if (work->flags & IRQ_WORK_HARD_IRQ) {
- if (llist_add(&work->llnode, this_cpu_ptr(&hirq_work_list)))
- arch_irq_work_raise();
- } else
-#endif
- if (work->flags & IRQ_WORK_LAZY) {
- if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
- tick_nohz_tick_stopped())
-#ifdef CONFIG_PREEMPT_RT_FULL
- raise_softirq(TIMER_SOFTIRQ);
-#else
- arch_irq_work_raise();
-#endif
- } else {
- if (llist_add(&work->llnode, this_cpu_ptr(&raised_list)))
+ lazy_work = work->flags & IRQ_WORK_LAZY;
+
+ if (lazy_work || (realtime && !(work->flags & IRQ_WORK_HARD_IRQ)))
+ list = this_cpu_ptr(&lazy_list);
+ else
+ list = this_cpu_ptr(&raised_list);
+
+ if (llist_add(&work->llnode, list)) {
+ if (!lazy_work || tick_nohz_tick_stopped())
arch_irq_work_raise();
}
@@ -139,12 +129,8 @@ bool irq_work_needs_cpu(void)
raised = this_cpu_ptr(&raised_list);
lazy = this_cpu_ptr(&lazy_list);
- if (llist_empty(raised))
- if (llist_empty(lazy))
-#ifdef CONFIG_PREEMPT_RT_FULL
- if (llist_empty(this_cpu_ptr(&hirq_work_list)))
-#endif
- return false;
+ if (llist_empty(raised) && llist_empty(lazy))
+ return false;
/* All work should have been flushed before going offline */
WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
@@ -158,9 +144,7 @@ static void irq_work_run_list(struct llist_head *list)
struct irq_work *work;
struct llist_node *llnode;
-#ifndef CONFIG_PREEMPT_RT_FULL
- BUG_ON(!irqs_disabled());
-#endif
+ BUG_ON(!IS_ENABLED(CONFIG_PREEMPT_RT_FULL) && !irqs_disabled());
if (llist_empty(list))
return;
@@ -196,19 +180,17 @@ static void irq_work_run_list(struct llist_head *list)
*/
void irq_work_run(void)
{
-#ifdef CONFIG_PREEMPT_RT_FULL
- irq_work_run_list(this_cpu_ptr(&hirq_work_list));
- /*
- * NOTE: we raise softirq via IPI for safety (caller may hold locks
- * that raise_softirq needs) and execute in irq_work_tick() to move
- * the overhead from hard to soft irq context.
- */
- if (!llist_empty(this_cpu_ptr(&raised_list)))
- raise_softirq(TIMER_SOFTIRQ);
-#else
irq_work_run_list(this_cpu_ptr(&raised_list));
- irq_work_run_list(this_cpu_ptr(&lazy_list));
-#endif
+ if (IS_ENABLED(CONFIG_PREEMPT_RT_FULL)) {
+ /*
+ * NOTE: we raise softirq via IPI for safety,
+ * and execute in irq_work_tick() to move the
+ * overhead from hard to soft irq context.
+ */
+ if (!llist_empty(this_cpu_ptr(&lazy_list)))
+ raise_softirq(TIMER_SOFTIRQ);
+ } else
+ irq_work_run_list(this_cpu_ptr(&lazy_list));
}
EXPORT_SYMBOL_GPL(irq_work_run);
@@ -216,8 +198,7 @@ void irq_work_tick(void)
{
struct llist_head *raised = this_cpu_ptr(&raised_list);
- if (!llist_empty(raised) && (!arch_irq_work_has_interrupt() ||
- IS_ENABLED(CONFIG_PREEMPT_RT_FULL)))
+ if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
irq_work_run_list(raised);
irq_work_run_list(this_cpu_ptr(&lazy_list));
}
diff --git a/localversion-rt b/localversion-rt
index 22746d6390a4..d79dde624aaa 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt9
+-rt10
--
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