Allow users to append 'clear' to an existing trigger in order to have the hash table cleared.
This expands the hist trigger syntax from this: # echo hist:keys=xxx:vals=yyy:sort=zzz.descending:pause/cont \ [ if filter] >> event/trigger to this: # echo hist:keys=xxx:vals=yyy:sort=zzz.descending:pause/cont/clear \ [ if filter] >> event/trigger Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> --- kernel/trace/trace.c | 5 ++++- kernel/trace/trace_events_hist.c | 24 ++++++++++++++++++++++-- 2 files changed, 26 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b68aedb..037f6374 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3828,7 +3828,7 @@ static const char readme_msg[] = "\t [:values=<field1[,field2,...]>]\n" "\t [:sort=<field1[,field2,...]>]\n" "\t [:size=#entries]\n" - "\t [:pause][:continue]\n" + "\t [:pause][:continue][:clear]\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" @@ -3848,6 +3848,9 @@ static const char readme_msg[] = "\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" + "\t The 'clear' parameter will clear the contents of a running\n" + "\t hist trigger and leave its current paused/active state\n" + "\t unchanged.\n\n" #endif ; diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 393f32a..dc340f0 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -89,6 +89,7 @@ struct hist_trigger_attrs { char *sort_key_str; bool pause; bool cont; + bool clear; unsigned int map_bits; }; @@ -198,6 +199,8 @@ static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str) attrs->sort_key_str = kstrdup(str, GFP_KERNEL); else if (!strncmp(str, "pause", strlen("pause"))) attrs->pause = true; + else if (!strncmp(str, "clear", strlen("clear"))) + attrs->clear = true; else if (!strncmp(str, "continue", strlen("continue")) || !strncmp(str, "cont", strlen("cont"))) attrs->cont = true; @@ -896,6 +899,21 @@ static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd, return &event_hist_trigger_ops; } +static void hist_clear(struct event_trigger_data *data) +{ + struct hist_trigger_data *hist_data = data->private_data; + bool paused; + + paused = data->paused; + data->paused = true; + + synchronize_sched(); + + tracing_map_clear(hist_data->map); + + data->paused = paused; +} + static int hist_register_trigger(char *glob, struct event_trigger_ops *ops, struct event_trigger_data *data, struct trace_event_file *file) @@ -910,13 +928,15 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops, test->paused = true; else if (hist_data->attrs->cont) test->paused = false; + else if (hist_data->attrs->clear) + hist_clear(test); else ret = -EEXIST; goto out; } } - if (hist_data->attrs->cont) { + if (hist_data->attrs->cont || hist_data->attrs->clear) { ret = -ENOENT; goto out; } @@ -1015,7 +1035,7 @@ static int event_hist_trigger_func(struct event_command *cmd_ops, * triggers registered a failure too. */ if (!ret) { - if (!(attrs->pause || attrs->cont)) + if (!(attrs->pause || attrs->cont || attrs->clear)) ret = -ENOENT; goto out_free; } else if (ret < 0) -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/