Re: [Qemu-devel] [PATCH v4 02/17] trace: convert code to use event iterators

["Lluís Vilanova" <vilanova@ac.upc.edu>]

Daniel P Berrange writes:

> This converts the HMP/QMP monitor API implementations
> and some internal trace control methods to use the new
> trace event iterator APIs.

> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  monitor.c       | 26 ++++++++++--------
>  trace/control.c | 85 +++++++++++++++++++++++++++++++--------------------------
>  trace/qmp.c     | 16 +++++++----
>  3 files changed, 70 insertions(+), 57 deletions(-)

> diff --git a/monitor.c b/monitor.c
> index 8bb8bbf..129d37e 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -3327,13 +3327,14 @@ void info_trace_events_completion(ReadLineState *rs, int nb_args, const char *st
>      len = strlen(str);
>      readline_set_completion_index(rs, len);
>      if (nb_args == 2) {
> -        TraceEventID id;
> -        for (id = 0; id < trace_event_count(); id++) {
> -            const char *event_name = trace_event_get_name(trace_event_id(id));
> -            if (!strncmp(str, event_name, len)) {
> -                readline_add_completion(rs, event_name);
> -            }
> +        TraceEventIter iter;
> +        TraceEvent *ev;
> +        char *pattern = g_strdup_printf("%s*", str);
> +        trace_event_iter_init(&iter, pattern);
> +        while ((ev = trace_event_iter_next(&iter)) != NULL) {
> +            readline_add_completion(rs, trace_event_get_name(ev));
>          }
> +        g_free(pattern);
>      }
>  }
 
> @@ -3344,13 +3345,14 @@ void trace_event_completion(ReadLineState *rs, int nb_args, const char *str)
>      len = strlen(str);
>      readline_set_completion_index(rs, len);
>      if (nb_args == 2) {
> -        TraceEventID id;
> -        for (id = 0; id < trace_event_count(); id++) {
> -            const char *event_name = trace_event_get_name(trace_event_id(id));
> -            if (!strncmp(str, event_name, len)) {
> -                readline_add_completion(rs, event_name);
> -            }
> +        TraceEventIter iter;
> +        TraceEvent *ev;
> +        char *pattern = g_strdup_printf("%s*", str);
> +        trace_event_iter_init(&iter, pattern);
> +        while ((ev = trace_event_iter_next(&iter)) != NULL) {
> +            readline_add_completion(rs, trace_event_get_name(ev));
>          }
> +        g_free(pattern);
>      } else if (nb_args == 3) {
>          add_completion_option(rs, str, "on");
>          add_completion_option(rs, str, "off");
> diff --git a/trace/control.c b/trace/control.c
> index 1a96049..653b70c 100644
> --- a/trace/control.c
> +++ b/trace/control.c
> @@ -60,9 +60,10 @@ TraceEvent *trace_event_name(const char *name)
>  {
>      assert(name != NULL);
 
> -    TraceEventID i;
> -    for (i = 0; i < trace_event_count(); i++) {
> -        TraceEvent *ev = trace_event_id(i);
> +    TraceEventIter iter;
> +    TraceEvent *ev;
> +    trace_event_iter_init(&iter, NULL);
> +    while ((ev = trace_event_iter_next(&iter)) != NULL) {
>          if (strcmp(trace_event_get_name(ev), name) == 0) {
>              return ev;
>          }
> @@ -105,21 +106,18 @@ TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
>  {
>      assert(pat != NULL);
 
> -    TraceEventID i;
> -
> -    if (ev == NULL) {
> -        i = -1;
> -    } else {
> -        i = trace_event_get_id(ev);
> -    }
> -    i++;
> -
> -    while (i < trace_event_count()) {
> -        TraceEvent *res = trace_event_id(i);
> -        if (pattern_glob(pat, trace_event_get_name(res))) {
> -            return res;
> +    bool matched = ev ? false : true;
> +    TraceEventIter iter;
> +    TraceEvent *thisev;
> +    trace_event_iter_init(&iter, pat);
> +    while ((thisev = trace_event_iter_next(&iter)) != NULL) {
> +        if (matched) {
> +            return thisev;
> +        } else {
> +            if (ev == thisev) {
> +                matched = true;
> +            }
>          }
> -        i++;
>      }
 
>      return NULL;
> @@ -148,10 +146,11 @@ TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 
>  void trace_list_events(void)
>  {
> -    int i;
> -    for (i = 0; i < trace_event_count(); i++) {
> -        TraceEvent *res = trace_event_id(i);
> -        fprintf(stderr, "%s\n", trace_event_get_name(res));
> +    TraceEventIter iter;
> +    TraceEvent *ev;
> +    trace_event_iter_init(&iter, NULL);
> +    while ((ev = trace_event_iter_next(&iter)) != NULL) {
> +        fprintf(stderr, "%s\n", trace_event_get_name(ev));
>      }
>  }
 
> @@ -159,26 +158,32 @@ static void do_trace_enable_events(const char *line_buf)
>  {
>      const bool enable = ('-' != line_buf[0]);
>      const char *line_ptr = enable ? line_buf : line_buf + 1;
> -
> -    if (trace_event_is_pattern(line_ptr)) {
> -        TraceEvent *ev = NULL;
> -        while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
> -            if (trace_event_get_state_static(ev)) {
> -                trace_event_set_state_dynamic_init(ev, enable);
> +    TraceEventIter iter;
> +    TraceEvent *ev;
> +    bool is_pattern = trace_event_is_pattern(line_ptr);
> +
> +    trace_event_iter_init(&iter, line_ptr);
> +    while ((ev = trace_event_iter_next(&iter)) != NULL) {
> +        if (!trace_event_get_state_static(ev)) {
> +            if (!is_pattern) {
> +                error_report("WARNING: trace event '%s' is not traceable",
> +                             line_ptr);
> +                return;
>              }
> +            continue;
>          }
> -    } else {
> -        TraceEvent *ev = trace_event_name(line_ptr);
> -        if (ev == NULL) {
> -            error_report("WARNING: trace event '%s' does not exist",
> -                         line_ptr);
> -        } else if (!trace_event_get_state_static(ev)) {
> -            error_report("WARNING: trace event '%s' is not traceable",
> -                         line_ptr);
> -        } else {
> -            trace_event_set_state_dynamic_init(ev, enable);
> +
> +        /* start tracing */
> +        trace_event_set_state_dynamic(ev, enable);
> +        if (!is_pattern) {
> +            break;
>          }
>      }
> +
> +    if (!is_pattern) {
> +        error_report("WARNING: trace event '%s' does not exist",
> +                     line_ptr);
> +    }
>  }
 
>  void trace_enable_events(const char *line_buf)
> @@ -293,8 +298,10 @@ char *trace_opt_parse(const char *optarg)
 
>  void trace_init_vcpu_events(void)
>  {
> -    TraceEvent *ev = NULL;
> -    while ((ev = trace_event_pattern("*", ev)) != NULL) {
> +    TraceEventIter iter;
> +    TraceEvent *ev;
> +    trace_event_iter_init(&iter, NULL);
> +    while ((ev = trace_event_iter_next(&iter)) != NULL) {
>          if (trace_event_is_vcpu(ev) &&
>              trace_event_get_state_static(ev) &&
>              trace_event_get_state_dynamic(ev)) {
> diff --git a/trace/qmp.c b/trace/qmp.c
> index 11d2564..88a907b 100644
> --- a/trace/qmp.c
> +++ b/trace/qmp.c
> @@ -52,8 +52,10 @@ static bool check_events(bool has_vcpu, bool ignore_unavailable, bool is_pattern
>          return true;
>      } else {
>          /* error for unavailable events */
> -        TraceEvent *ev = NULL;
> -        while ((ev = trace_event_pattern(name, ev)) != NULL) {
> +        TraceEventIter iter;
> +        TraceEvent *ev;
> +        trace_event_iter_init(&iter, name);
> +        while ((ev = trace_event_iter_next(&iter)) != NULL) {
>              if (!ignore_unavailable && !trace_event_get_state_static(ev)) {
>                  error_setg(errp, "event \"%s\" is disabled", trace_event_get_name(ev));
>                  return false;
> @@ -69,6 +71,7 @@ TraceEventInfoList *qmp_trace_event_get_state(const char *name,
>  {
>      Error *err = NULL;
>      TraceEventInfoList *events = NULL;
> +    TraceEventIter iter;
>      TraceEvent *ev;
>      bool is_pattern = trace_event_is_pattern(name);
>      CPUState *cpu;
> @@ -86,8 +89,8 @@ TraceEventInfoList *qmp_trace_event_get_state(const char *name,
>      }
 
>      /* Get states (all errors checked above) */
> -    ev = NULL;
> -    while ((ev = trace_event_pattern(name, ev)) != NULL) {
> +    trace_event_iter_init(&iter, is_pattern ? name : NULL);

I think you should always pass name, otherwise a non-pattern name (when the user
wants an exact name match) will return the state of all events.


> +    while ((ev = trace_event_iter_next(&iter)) != NULL) {
>          TraceEventInfoList *elem;
>          bool is_vcpu = trace_event_is_vcpu(ev);
>          if (has_vcpu && !is_vcpu) {
> @@ -132,6 +135,7 @@ void qmp_trace_event_set_state(const char *name, bool enable,
>                                 Error **errp)
>  {
>      Error *err = NULL;
> +    TraceEventIter iter;
>      TraceEvent *ev;
>      bool is_pattern = trace_event_is_pattern(name);
>      CPUState *cpu;
> @@ -150,8 +154,8 @@ void qmp_trace_event_set_state(const char *name, bool enable,
>      }
 
>      /* Apply changes (all errors checked above) */
> -    ev = NULL;
> -    while ((ev = trace_event_pattern(name, ev)) != NULL) {
> +    trace_event_iter_init(&iter, name);
> +    while ((ev = trace_event_iter_next(&iter)) != NULL) {
>          if (!trace_event_get_state_static(ev) ||
>              (has_vcpu && !trace_event_is_vcpu(ev))) {
>              continue;
> -- 
> 2.7.4


Thanks,
  Lluis