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| author | Steven Rostedt <rostedt@goodmis.org> | 2012-11-15 11:34:21 -0500 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2012-11-17 19:31:03 +0100 |
| commit | c0e980a4bd7fc5c9b748f2f0209d2a48c0fdf0ab (patch) | |
| tree | 39eda738087b5bda53b0cb06c9549656266a03c2 /kernel/irq_work.c | |
| parent | 00b42959106a9ca1c2899e591ae4e9a83ad6af05 (diff) | |
| download | lwn-c0e980a4bd7fc5c9b748f2f0209d2a48c0fdf0ab.tar.gz lwn-c0e980a4bd7fc5c9b748f2f0209d2a48c0fdf0ab.zip | |
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>
Diffstat (limited to 'kernel/irq_work.c')
| -rw-r--r-- | kernel/irq_work.c | 51 |
1 files changed, 45 insertions, 6 deletions
diff --git a/kernel/irq_work.c b/kernel/irq_work.c index b3c113a14727..4ed17490f629 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -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 */ |