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    SubjectRe: [PATCH v3] printk: add console output tracing
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    On Thu, 2011-11-24 at 20:03 +0100, Johannes Berg wrote:
    > From: Johannes Berg <johannes.berg@intel.com>
    >
    > Add a printk.console trace point to record any printk
    > messages into the trace, regardless of the current
    > console loglevel. This can help correlate (existing)
    > printk debugging with other tracing.
    >

    Looks like this patch got lost in the x-mas parade.

    Is this the last version of the patch?

    In the thread I also see:

    Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
    Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Acked-by-me (Thomas Gleixner)

    -- Steve


    > Signed-off-by: Johannes Berg <johannes.berg@intel.com>
    > ---
    > v2: remove extra file
    > v3: simplify length of __dynamic_array, thanks Frederic
    >
    > include/trace/events/printk.h | 41 +++++++++++++++++++++++++++++++++++++++++
    > kernel/printk.c | 5 +++++
    > 2 files changed, 46 insertions(+)
    >
    > --- /dev/null 1970-01-01 00:00:00.000000000 +0000
    > +++ b/include/trace/events/printk.h 2011-11-24 20:02:21.000000000 +0100
    > @@ -0,0 +1,41 @@
    > +#undef TRACE_SYSTEM
    > +#define TRACE_SYSTEM printk
    > +
    > +#if !defined(_TRACE_PRINTK_H) || defined(TRACE_HEADER_MULTI_READ)
    > +#define _TRACE_PRINTK_H
    > +
    > +#include <linux/tracepoint.h>
    > +
    > +TRACE_EVENT_CONDITION(console,
    > + TP_PROTO(const char *log_buf, unsigned start, unsigned end,
    > + unsigned log_buf_len),
    > +
    > + TP_ARGS(log_buf, start, end, log_buf_len),
    > +
    > + TP_CONDITION(start != end),
    > +
    > + TP_STRUCT__entry(
    > + __dynamic_array(char, msg, end - start + 1)
    > + ),
    > +
    > + TP_fast_assign(
    > + if ((start & (log_buf_len - 1)) > (end & (log_buf_len - 1))) {
    > + memcpy(__get_dynamic_array(msg),
    > + log_buf + (start & (log_buf_len - 1)),
    > + log_buf_len - (start & (log_buf_len - 1)));
    > + memcpy((char *)__get_dynamic_array(msg) +
    > + log_buf_len - (start & (log_buf_len - 1)),
    > + log_buf, end & (log_buf_len - 1));
    > + } else
    > + memcpy(__get_dynamic_array(msg),
    > + log_buf + (start & (log_buf_len - 1)),
    > + end - start);
    > + ((char *)__get_dynamic_array(msg))[end - start] = 0;
    > + ),
    > +
    > + TP_printk("%s", __get_str(msg))
    > +);
    > +#endif /* _TRACE_PRINTK_H */
    > +
    > +/* This part must be outside protection */
    > +#include <trace/define_trace.h>
    > --- a/kernel/printk.c 2011-11-24 09:38:53.000000000 +0100
    > +++ b/kernel/printk.c 2011-11-24 09:42:37.000000000 +0100
    > @@ -44,6 +44,9 @@
    >
    > #include <asm/uaccess.h>
    >
    > +#define CREATE_TRACE_POINTS
    > +#include <trace/events/printk.h>
    > +
    > /*
    > * Architectures can override it:
    > */
    > @@ -542,6 +545,8 @@ MODULE_PARM_DESC(ignore_loglevel, "ignor
    > static void _call_console_drivers(unsigned start,
    > unsigned end, int msg_log_level)
    > {
    > + trace_console(&LOG_BUF(0), start, end, log_buf_len);
    > +
    > if ((msg_log_level < console_loglevel || ignore_loglevel) &&
    > console_drivers && start != end) {
    > if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
    >




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