Messages in this thread | | | Date | Fri, 19 Aug 2011 15:05:42 -0400 | From | Jason Baron <> | Subject | Re: [PATCH/RFC v9 2/2] Use trace events to report stalls |
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On Wed, Aug 17, 2011 at 01:36:09PM -0700, Alex Neronskiy wrote: > Signed-off-by: Alex Neronskiy <zakmagnus@chromium.org> > --- > This outputs both the numerical representation of the stall as well > as a stack trace. The trace, unlike the number, is always output, > regardless of what debug/tracing/events/watchdog/enable says. I > don't know how to hook into that. >
(adding Steve to 'cc)
Yes, it would be nice to make the dump stack contigent on the tracepoints...that's what you want?
If so, maybe we could have TP_fast_assign fill a buffer which is output via TP_printk, or else TP_printk could take an optional callback function...
Thanks,
-Jason
> kernel/trace_watchdog.h | 43 +++++++++++++++++++++++++++++++++++++++++++ > kernel/watchdog.c | 23 +++++++++++------------ > 2 files changed, 54 insertions(+), 12 deletions(-) > create mode 100644 kernel/trace_watchdog.h > > diff --git a/kernel/trace_watchdog.h b/kernel/trace_watchdog.h > new file mode 100644 > index 0000000..1401d27f > --- /dev/null > +++ b/kernel/trace_watchdog.h > @@ -0,0 +1,43 @@ > +#undef TRACE_SYSTEM > +#define TRACE_SYSTEM watchdog > + > +#if !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ) > +#define _TRACE_WATCHDOG_H > + > +#include <linux/tracepoint.h> > +#include <linux/stacktrace.h> > + > +TRACE_EVENT(soft_stall, > + TP_PROTO(unsigned long stall), > + TP_ARGS(stall), > + TP_STRUCT__entry( > + __field(unsigned long, stall) > + ), > + TP_fast_assign( > + __entry->stall = stall; > + ), > + TP_printk("Soft stall: %lums", __entry->stall) > +); > + > +#ifdef CONFIG_HARDLOCKUP_DETECTOR > +TRACE_EVENT(hard_stall, > + TP_PROTO(unsigned long stall), > + TP_ARGS(stall), > + TP_STRUCT__entry( > + __field(unsigned long, stall) > + ), > + TP_fast_assign( > + __entry->stall = stall; > + ), > + TP_printk("Hard stall: %lu", __entry->stall) > +); > +#endif /* CONFIG_HARDLOCKUP_DETECTOR */ > + > +#endif /* _TRACE_WATCHDOG_H */ > + > +#undef TRACE_INCLUDE_PATH > +#undef TRACE_INCLUDE_FILE > +#define TRACE_INCLUDE_PATH . > + > +#define TRACE_INCLUDE_FILE trace_watchdog > +#include <trace/define_trace.h> > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index d4c51cc..18385ed 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -27,6 +27,9 @@ > #include <asm/irq_regs.h> > #include <linux/perf_event.h> > > +#define CREATE_TRACE_POINTS > +#include "trace_watchdog.h" > + > int watchdog_enabled = 1; > int __read_mostly watchdog_thresh = 10; > static unsigned long worst_softstall; > @@ -208,7 +211,7 @@ void touch_softlockup_watchdog_sync(void) > > #ifdef CONFIG_HARDLOCKUP_DETECTOR > /* watchdog detector functions */ > -static void update_hardstall(unsigned long stall, int this_cpu) > +static void update_hardstall(unsigned long stall) > { > int update_stall = 0; > > @@ -222,10 +225,8 @@ static void update_hardstall(unsigned long stall, int this_cpu) > } > > if (update_stall) { > - printk(KERN_WARNING "LOCKUP may be in progress!" > - "Worst hard stall seen on CPU#%d: %lu interrupts missed\n", > - this_cpu, stall); > - dump_stack(); > + trace_hard_stall(stall); > + trace_dump_stack(); > } > } > > @@ -245,12 +246,12 @@ static int is_hardlockup(int this_cpu) > if (ints_missed >= hardlockup_thresh) > return 1; > > - update_hardstall(ints_missed, this_cpu); > + update_hardstall(ints_missed); > return 0; > } > #endif > > -static void update_softstall(unsigned long stall, int this_cpu) > +static void update_softstall(unsigned long stall) > { > int update_stall = 0; > if (stall > get_softstall_thresh() && > @@ -264,10 +265,8 @@ static void update_softstall(unsigned long stall, int this_cpu) > } > > if (update_stall) { > - printk(KERN_WARNING "LOCKUP may be in progress!" > - "Worst soft stall seen on CPU#%d: %lums\n", > - this_cpu, stall); > - dump_stack(); > + trace_soft_stall(stall); > + trace_dump_stack(); > } > } > > @@ -280,7 +279,7 @@ static int is_softlockup(unsigned long touch_ts, int this_cpu) > if (time_after(now, touch_ts + 1000 * get_softlockup_thresh())) > return stall; > > - update_softstall(stall, this_cpu); > + update_softstall(stall); > > return 0; > } > -- > 1.7.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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