mirror of https://gitee.com/openkylin/linux.git
ae0def05ed
intel_pmu_handle_irq() has a warning in it if it does too many loops. It is a WARN_ONCE(), but the perf_event_print_debug() call beneath it is unconditional. For the first warning, you get a nice backtrace and message, but subsequent ones just dump the PMU state with no leading messages. I doubt this is what was intended. This patch will only print the PMU state when paired with the WARN_ON() text. It effectively open-codes WARN_ONCE()'s one-time-only logic. My suspicion is that the code really just wants to make sure we do not sit in the loop and spit out a warning for every loop iteration after the 100th. From what I've seen, this is very unlikely to happen since we also clear the PMU state. After this patch, instead of seeing the PMU state dumped each time, you will just see: [57494.894540] perf_event_intel: clearing PMU state on CPU#129 [57579.539668] perf_event_intel: clearing PMU state on CPU#10 [57587.137762] perf_event_intel: clearing PMU state on CPU#134 [57623.039912] perf_event_intel: clearing PMU state on CPU#114 [57644.559943] perf_event_intel: clearing PMU state on CPU#118 ... Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20130530174559.0DB049F4@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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