Peter Zijlstra cd578abb24 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: 6a02ad66b2 ("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>		2014-02-21 21:49:07 +01:00
..
callchain.c	perf: Roll back callchain buffer refcount under the callchain mutex	2013-08-16 17:55:50 +02:00
core.c	perf/x86: Warn to early_printk() in case irq_work is too slow	2014-02-21 21:49:07 +01:00
hw_breakpoint.c	hw_breakpoint: Introduce "struct bp_cpuinfo"	2013-06-20 17:58:57 +02:00
internal.h	perf: Fix arch_perf_out_copy_user default	2013-11-06 12:34:25 +01:00
Makefile	uprobes: Move to kernel/events/	2012-02-22 11:08:00 +01:00
ring_buffer.c	perf: Optimize ring-buffer write by depending on control dependencies	2013-12-11 15:53:22 +01:00
uprobes.c	This pull request has a new feature to ftrace, namely the trace event	2014-01-22 16:35:21 -08:00