Hi Tom, On 2015/07/17 2:22, Tom Zanussi wrote: > Allow users to append 'pause' or 'continue' to an existing trigger in > order to have it paused or to have a paused trace continue. > > This expands the hist trigger syntax from this: > # echo hist:keys=xxx:vals=yyy:sort=zzz.descending \ > [ if filter] > event/trigger > > to this: > > # echo hist:keys=xxx:vals=yyy:sort=zzz.descending:pause or cont \ > [ if filter] > event/trigger
Since the only one hist trigger can be set on one event, it seems that we don't need keys for pause/cont/clear (e.g. hist:pause is enough). Anyway, I've found an odd behavior. [root@localhost tracing]# echo 'hist:keys=parent_pid' > events/sched/sched_process_fork/trigger [root@localhost tracing]# echo 'hist:keys=common_pid:pause' > events/sched/sched_process_fork/trigger [root@localhost tracing]# cat events/sched/sched_process_fork/trigger hist:keys=parent_pid:vals=hitcount:sort=hitcount:size=2048 [paused] So, the second "pause" command can work with different keys. Moreover, I can remove it with different keys. [root@localhost tracing]# echo '!hist:keys=child_pid' > events/sched/sched_process_fork/trigger [root@localhost tracing]# cat events/sched/sched_process_fork/trigger # Available triggers: # traceon traceoff snapshot stacktrace enable_event disable_event enable_hist disable_hist hist Thank you, > > Signed-off-by: Tom Zanussi <[email protected]> > --- > kernel/trace/trace.c | 5 +++++ > kernel/trace/trace_events_hist.c | 26 +++++++++++++++++++++++--- > 2 files changed, 28 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 5dd1fc4..547bbc8 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -3791,6 +3791,7 @@ static const char readme_msg[] = > "\t [:values=<field1[,field2,...]]\n" > "\t [:sort=field1,field2,...]\n" > "\t [:size=#entries]\n" > + "\t [:pause][:continue]\n" > "\t [if <filter>]\n\n" > "\t When a matching event is hit, an entry is added to a hash\n" > "\t table using the key(s) and value(s) named. Keys and values\n" > @@ -3821,6 +3822,10 @@ static const char readme_msg[] = > "\t on. The default if unspecified is 'hitcount' and the.\n" > "\t default sort order is 'ascending'. To sort in the opposite\n" > "\t direction, append .descending' to the sort key.\n\n" > + "\t The 'pause' param can be used to pause an existing hist\n" > + "\t trigger or to start a hist trigger but not log any events\n" > + "\t until told to do so. 'continue' can be used to start or\n" > + "\t restart a paused hist trigger.\n\n" > #endif > ; > > diff --git a/kernel/trace/trace_events_hist.c > b/kernel/trace/trace_events_hist.c > index 6bf224f..3ae58e7 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -78,6 +78,8 @@ struct hist_trigger_attrs { > char *keys_str; > char *vals_str; > char *sort_key_str; > + bool pause; > + bool cont; > unsigned int map_bits; > }; > > @@ -184,6 +186,11 @@ static struct hist_trigger_attrs > *parse_hist_trigger_attrs(char *trigger_str) > attrs->vals_str = kstrdup(str, GFP_KERNEL); > else if (!strncmp(str, "sort", strlen("sort"))) > attrs->sort_key_str = kstrdup(str, GFP_KERNEL); > + else if (!strncmp(str, "pause", strlen("pause"))) > + attrs->pause = true; > + else if (!strncmp(str, "continue", strlen("continue")) || > + !strncmp(str, "cont", strlen("cont"))) > + attrs->cont = true; > else if (!strncmp(str, "size", strlen("size"))) { > int map_bits = parse_map_size(str); > > @@ -843,7 +850,10 @@ static int event_hist_trigger_print(struct seq_file *m, > if (data->filter_str) > seq_printf(m, " if %s", data->filter_str); > > - seq_puts(m, " [active]"); > + if (data->paused) > + seq_puts(m, " [paused]"); > + else > + seq_puts(m, " [active]"); > > seq_putc(m, '\n'); > > @@ -882,16 +892,25 @@ static int hist_register_trigger(char *glob, struct > event_trigger_ops *ops, > struct event_trigger_data *data, > struct trace_event_file *file) > { > + struct hist_trigger_data *hist_data = data->private_data; > struct event_trigger_data *test; > int ret = 0; > > list_for_each_entry_rcu(test, &file->triggers, list) { > if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) { > - ret = -EEXIST; > + if (hist_data->attrs->pause) > + test->paused = true; > + else if (hist_data->attrs->cont) > + test->paused = false; > + else > + ret = -EEXIST; > goto out; > } > } > > + if (hist_data->attrs->pause) > + data->paused = true; > + > if (data->ops->init) { > ret = data->ops->init(data->ops, data); > if (ret < 0) > @@ -984,7 +1003,8 @@ static int event_hist_trigger_func(struct event_command > *cmd_ops, > * triggers registered a failure too. > */ > if (!ret) { > - ret = -ENOENT; > + if (!(attrs->pause || attrs->cont)) > + ret = -ENOENT; > goto out_free; > } else if (ret < 0) > goto out_free; > -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
