Re: [Qemu-devel] [PATCH v4 11/17] trace: provide mechanism for registering trace events

[Lluís Vilanova]

Daniel P Berrange writes:

> Remove the notion of there being a single global array
> of trace events, by introducing a method for registering
> groups of events.

> Signed-off-by: Daniel P. Berrange <address@hidden>

Except for the calls to module_call_init() (I did not check if they're all
necessary and sufficient):

Reviewed-by: Lluís Vilanova <address@hidden>


> ---
>  include/qemu/module.h                |  2 ++
>  qemu-img.c                           |  1 +
>  qemu-io.c                            |  1 +
>  qemu-nbd.c                           |  1 +
>  scripts/tracetool/format/events_c.py |  6 ++++++
>  trace/control-internal.h             |  4 +++-
>  trace/control.c                      | 25 +++++++++++++++++++++++--
>  trace/control.h                      |  1 +
>  vl.c                                 |  2 ++
>  9 files changed, 40 insertions(+), 3 deletions(-)

> diff --git a/include/qemu/module.h b/include/qemu/module.h
> index 2370708..c700961 100644
> --- a/include/qemu/module.h
> +++ b/include/qemu/module.h
> @@ -44,6 +44,7 @@ typedef enum {
>      MODULE_INIT_OPTS,
>      MODULE_INIT_QAPI,
>      MODULE_INIT_QOM,
> +    MODULE_INIT_TRACE,
>      MODULE_INIT_MAX
>  } module_init_type;
 
> @@ -51,6 +52,7 @@ typedef enum {
>  #define opts_init(function) module_init(function, MODULE_INIT_OPTS)
>  #define qapi_init(function) module_init(function, MODULE_INIT_QAPI)
>  #define type_init(function) module_init(function, MODULE_INIT_QOM)
> +#define trace_init(function) module_init(function, MODULE_INIT_TRACE)
 
>  void register_module_init(void (*fn)(void), module_init_type type);
>  void register_dso_module_init(void (*fn)(void), module_init_type type);
> diff --git a/qemu-img.c b/qemu-img.c
> index ea52486..bbe648a 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -3824,6 +3824,7 @@ int main(int argc, char **argv)
>      signal(SIGPIPE, SIG_IGN);
>  #endif
 
> +    module_call_init(MODULE_INIT_TRACE);
>      error_set_progname(argv[0]);
>      qemu_init_exec_dir(argv[0]);
 
> diff --git a/qemu-io.c b/qemu-io.c
> index db129ea..23a229f 100644
> --- a/qemu-io.c
> +++ b/qemu-io.c
> @@ -467,6 +467,7 @@ int main(int argc, char **argv)
>      signal(SIGPIPE, SIG_IGN);
>  #endif
 
> +    module_call_init(MODULE_INIT_TRACE);
>      progname = basename(argv[0]);
>      qemu_init_exec_dir(argv[0]);
 
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 99297a5..361880b 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -533,6 +533,7 @@ int main(int argc, char **argv)
>      sa_sigterm.sa_handler = termsig_handler;
>      sigaction(SIGTERM, &sa_sigterm, NULL);
 
> +    module_call_init(MODULE_INIT_TRACE);
>      qcrypto_init(&error_fatal);
 
>      module_call_init(MODULE_INIT_QOM);
> diff --git a/scripts/tracetool/format/events_c.py 
> b/scripts/tracetool/format/events_c.py
> index 325f4e0..766bc09 100644
> --- a/scripts/tracetool/format/events_c.py
> +++ b/scripts/tracetool/format/events_c.py
> @@ -60,3 +60,9 @@ def generate(events, backend):
>      out('  NULL,',
>          '};',
>          '')
> +
> +    out('static void trace_register_events(void)',
> +        '{',
> +        '    trace_event_register_group(trace_events);',
> +        '}',
> +        'trace_init(trace_register_events)')
> diff --git a/trace/control-internal.h b/trace/control-internal.h
> index 8bfbdfb..206906a 100644
> --- a/trace/control-internal.h
> +++ b/trace/control-internal.h
> @@ -15,7 +15,6 @@
>  #include "qom/cpu.h"
 
 
> -extern TraceEvent *trace_events[];
>  extern int trace_events_enabled_count;
 
 
> @@ -83,4 +82,7 @@ static inline bool 
> trace_event_get_vcpu_state_dynamic(CPUState *vcpu,
>      return trace_event_get_vcpu_state_dynamic_by_vcpu_id(vcpu, vcpu_id);
>  }
 
> +
> +void trace_event_register_group(TraceEvent **events);
> +
>  #endif /* TRACE__CONTROL_INTERNAL_H */
> diff --git a/trace/control.c b/trace/control.c
> index 64aaede..7be654d 100644
> --- a/trace/control.c
> +++ b/trace/control.c
> @@ -29,6 +29,13 @@
 
>  int trace_events_enabled_count;
 
> +typedef struct TraceEventGroup {
> +    TraceEvent **events;
> +} TraceEventGroup;
> +
> +static TraceEventGroup *event_groups;
> +static size_t nevent_groups;
> +
>  QemuOptsList qemu_trace_opts = {
>      .name = "trace",
>      .implied_opt_name = "enable",
> @@ -50,6 +57,14 @@ QemuOptsList qemu_trace_opts = {
>  };
 
 
> +void trace_event_register_group(TraceEvent **events)
> +{
> +    event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
> +    event_groups[nevent_groups].events = events;
> +    nevent_groups++;
> +}
> +
> +
>  TraceEvent *trace_event_name(const char *name)
>  {
>      assert(name != NULL);
> @@ -100,14 +115,20 @@ static bool pattern_glob(const char *pat, const char 
> *ev)
>  void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
>  {
iter-> event = 0;
> +    iter->group = 0;
iter-> pattern = pattern;
>  }
 
>  TraceEvent *trace_event_iter_next(TraceEventIter *iter)
>  {
> -    while (trace_events[iter->event] != NULL) {
> -        TraceEvent *ev = trace_events[iter->event];
> +    while (iter->group < nevent_groups &&
> +           event_groups[iter->group].events[iter->event] != NULL) {
> +        TraceEvent *ev = event_groups[iter->group].events[iter->event];
iter-> event++;
> +        if (event_groups[iter->group].events[iter->event] == NULL) {
> +            iter->event = 0;
> +            iter->group++;
> +        }
>          if (!iter->pattern ||
>              pattern_glob(iter->pattern,
>                           trace_event_get_name(ev))) {
> diff --git a/trace/control.h b/trace/control.h
> index 21ce5f1..45ee4fb 100644
> --- a/trace/control.h
> +++ b/trace/control.h
> @@ -15,6 +15,7 @@
 
>  typedef struct TraceEventIter {
>      size_t event;
> +    size_t group;
>      const char *pattern;
>  } TraceEventIter;
 
> diff --git a/vl.c b/vl.c
> index fca0487..6aa56ce 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2979,6 +2979,8 @@ int main(int argc, char **argv, char **envp)
>      Error *err = NULL;
>      bool list_data_dirs = false;
 
> +    module_call_init(MODULE_INIT_TRACE);
> +
>      qemu_init_cpu_loop();
>      qemu_mutex_lock_iothread();
 
> -- 
> 2.7.4