Messages in this thread Patch in this message | | | From | Tom Zanussi <> | Subject | [PATCH v11 13/28] tracing: Add hist trigger support for pausing and continuing a trace | Date | Thu, 22 Oct 2015 13:14:17 -0500 |
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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
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> --- kernel/trace/trace.c | 7 ++++++- kernel/trace/trace_events_hist.c | 26 +++++++++++++++++++++++--- 2 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index efa8d05..a223959 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3802,6 +3802,7 @@ 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, and the value of a\n" @@ -3816,7 +3817,11 @@ static const char readme_msg[] = "\t used to specify more or fewer than the default 2048 entries\n" "\t for the hashtable size.\n\n" "\t Reading the 'hist' file for the event will dump the hash\n" - "\t table in its entirety to stdout." + "\t table in its entirety to stdout.\n\n" + "\t The 'pause' parameter 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 4fc3136..8753c3b 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; -- 1.9.3
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