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irq_work: Flush work on CPU_DYING 

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 <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Steven Rostedt 2012-11-15 11:34:21 -05:00 committed by Frederic Weisbecker
parent 00b4295910
commit c0e980a4bd
1 changed files with 45 additions and 6 deletions
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51
kernel/irq_work.c
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@ -12,6 +12,8 @@
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/irqflags.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <asm/processor.h>
/*
@ -110,11 +112,7 @@ 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 +122,6 @@ 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 +146,16 @@ 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 +170,35 @@ 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 */