powerpc/64: Fix latency tracing for lazy irq replay
Nicholas Piggin
reviewerPATCH 1/1 powerpc/64: Fix latency tracing for lazy irq replay
When returning from an exception to a soft-enabled context, pending IRQs are replayed but IRQ tracing is not reset, so a number of them can get chained together into the same IRQ-disabled trace.
Fix this by having __check_irq_replay re-set IRQ trace. This is conceptually where we respond to the next interrupt, so it fits the semantics of the IRQ tracer.
--- arch/powerpc/kernel/irq.c | 9 +++++++++ 1 file changed, 9 insertions(+)
arch/powerpc/kernel/irq.c +9 -0
@@ -138,6 +138,13 @@ notrace unsigned int __check_irq_replay(void)*/ unsigned char happened = local_paca->irq_happened; +/* +* We are responding to the next interrupt, so interrupt-off +* latencies should be reset here. +*/ +trace_hardirqs_on (); +trace_hardirqs_off (); +if (happened &PACA_IRQ_HARD_DIS ) {/* Clear bit 0 which we wouldn't clear otherwise */ local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS ;
@@ -292,6 +299,7 @@ notrace void arch_local_irq_restore(unsigned long en)#endif /* CONFIG_TRACE_IRQFLAGS */ soft_disable_set (IRQS_DISABLED ); +trace_hardirqs_off ();/* * Check if anything needs to be re-emitted. We haven't
@@ -301,6 +309,7 @@ notrace void arch_local_irq_restore(unsigned long en) replay =__check_irq_replay ();/* We can soft-enable now */ +trace_hardirqs_on ();soft_disable_set (IRQS_ENABLED );/*
Signature · 1 line
2.13.3
Michael Ellerman
AppliedQuoted 9 lines · Nicholas Piggin
When returning from an exception to a soft-enabled context, pending IRQs are replayed but IRQ tracing is not reset, so a number of them can get chained together into the same IRQ-disabled trace.
Fix this by having
__check_irq_replayre-set IRQ trace. This is conceptually where we respond to the next interrupt, so it fits the semantics of the IRQ tracer.Signed-off-by Nicholas Piggin <[email protected]>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/ff967900c9d4740f6337c6456f1111
cheers