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authorPeter Zijlstra <peterz@infradead.org>2014-02-11 19:01:16 +0400
committerThomas Gleixner <tglx@linutronix.de>2014-02-22 00:49:07 +0400
commitcd578abb24aa67ce468c427d3356c08ea32cf768 (patch)
tree974a97cebfc368e8bee9c1beccbbd9bda00d89ef /include/linux/irq_work.h
parent90ed5b0fa5eb96e1cbb34aebf6a9ed96ee1587ec (diff)
downloadlinux-cd578abb24aa67ce468c427d3356c08ea32cf768.tar.xz
perf/x86: Warn to early_printk() in case irq_work is too slow
On Mon, Feb 10, 2014 at 08:45:16AM -0800, Dave Hansen wrote: > The reason I coded this up was that NMIs were firing off so fast that > nothing else was getting a chance to run. With this patch, at least the > printk() would come out and I'd have some idea what was going on. It will start spewing to early_printk() (which is a lot nicer to use from NMI context too) when it fails to queue the IRQ-work because its already enqueued. It does have the false-positive for when two CPUs trigger the warn concurrently, but that should be rare and some extra clutter on the early printk shouldn't be a problem. Cc: hpa@zytor.com Cc: tglx@linutronix.de Cc: dzickus@redhat.com Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: mingo@kernel.org Fixes: 6a02ad66b2c4 ("perf/x86: Push the duration-logging printk() to IRQ context") Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140211150116.GO27965@twins.programming.kicks-ass.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/irq_work.h')
-rw-r--r--include/linux/irq_work.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index add13c8624b7..19ae05d4b8ec 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -32,7 +32,7 @@ void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
#define DEFINE_IRQ_WORK(name, _f) struct irq_work name = { .func = (_f), }
-void irq_work_queue(struct irq_work *work);
+bool irq_work_queue(struct irq_work *work);
void irq_work_run(void);
void irq_work_sync(struct irq_work *work);