From: Steven Rostedt <rost...@goodmis.org>
In order not to offline a CPU with pending irq works, flush the
queue from CPU_DYING. The notifier is called by stop_machine on
the CPU that is going down. The code will not be called from irq context
(so things like get_irq_regs() wont work) but I'm not sure what the
requirements are for irq_work in that regard (Peter?). But irqs are
disabled and the CPU is about to go offline. Might as well flush the work.
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortma...@windriver.com>
Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
---
kernel/irq_work.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 44 insertions(+), 6 deletions(-)
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index b3c113a..cf8b657 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -12,6 +12,7 @@
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/irqflags.h>
+#include <linux/cpu.h>
#include <asm/processor.h>
/*
@@ -110,11 +111,7 @@ bool irq_work_needs_cpu(void)
return true;
}
-/*
- * Run the irq_work entries on this cpu. Requires to be ran from hardirq
- * context with local IRQs disabled.
- */
-void irq_work_run(void)
+static void __irq_work_run(void)
{
struct irq_work *work;
struct llist_head *this_list;
@@ -124,7 +121,6 @@ void irq_work_run(void)
if (llist_empty(this_list))
return;
- BUG_ON(!in_irq());
BUG_ON(!irqs_disabled());
llnode = llist_del_all(this_list);
@@ -149,6 +145,16 @@ void irq_work_run(void)
(void)cmpxchg(&work->flags, IRQ_WORK_BUSY, 0);
}
}
+
+/*
+ * Run the irq_work entries on this cpu. Requires to be ran from hardirq
+ * context with local IRQs disabled.
+ */
+void irq_work_run(void)
+{
+ BUG_ON(!in_irq());
+ __irq_work_run();
+}
EXPORT_SYMBOL_GPL(irq_work_run);
/*
@@ -163,3 +169,35 @@ void irq_work_sync(struct irq_work *work)
cpu_relax();
}
EXPORT_SYMBOL_GPL(irq_work_sync);
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int irq_work_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ long cpu = (long)hcpu;
+
+ switch (action) {
+ case CPU_DYING:
+ /* Called from stop_machine */
+ if (WARN_ON_ONCE(cpu != smp_processor_id()))
+ break;
+ __irq_work_run();
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block cpu_notify;
+
+static __init int irq_work_init_cpu_notifier(void)
+{
+ cpu_notify.notifier_call = irq_work_cpu_notify;
+ cpu_notify.priority = 0;
+ register_cpu_notifier(&cpu_notify);
+ return 0;
+}
+device_initcall(irq_work_init_cpu_notifier);
+
+#endif /* CONFIG_HOTPLUG_CPU */
--
1.7.5.4
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