Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933004AbbGVNu2 (ORCPT ); Wed, 22 Jul 2015 09:50:28 -0400 Received: from mail4.hitachi.co.jp ([133.145.228.5]:40096 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753084AbbGVNu0 (ORCPT ); Wed, 22 Jul 2015 09:50:26 -0400 Message-ID: <55AF9F9B.5080003@hitachi.com> Date: Wed, 22 Jul 2015 22:50:19 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Tom Zanussi , rostedt@goodmis.org CC: daniel.wagner@bmw-carit.de, namhyung@kernel.org, josh@joshtriplett.org, andi@firstfloor.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 13/22] tracing: Add hist trigger support for clearing a trace References: <5c71e4c084d18cec2cd28d73878413c592686f47.1437066836.git.tom.zanussi@linux.intel.com> In-Reply-To: <5c71e4c084d18cec2cd28d73878413c592686f47.1437066836.git.tom.zanussi@linux.intel.com> Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4683 Lines: 139 On 2015/07/17 2:22, Tom Zanussi wrote: > 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 By the way, since pause/cont/clear is not the trigger but the commands (which executed immediately), I think it should be a write fops of "hist" special file. e.g. to clear the histogram, write 0 to hist # echo 0 > event/hist And pause/cont will be 1 and 2. # echo 1 > event/hist <- pause and # echo 2 > event/hist <- continue What would you think ? Thanks, > > Signed-off-by: Tom Zanussi > --- > kernel/trace/trace.c | 4 +++- > kernel/trace/trace_events_hist.c | 25 ++++++++++++++++++++++++- > 2 files changed, 27 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 547bbc8..27daa28 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -3791,7 +3791,7 @@ static const char readme_msg[] = > "\t [:values= "\t [:sort=field1,field2,...]\n" > "\t [:size=#entries]\n" > - "\t [:pause][:continue]\n" > + "\t [:pause][:continue][:clear]\n" > "\t [if ]\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" > @@ -3826,6 +3826,8 @@ 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' param will clear the contents of a running hist\n" > + "\t trigger and leave its current paused/active state.\n\n" > #endif > ; > > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c > index 3ae58e7..d8259fe 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -80,6 +80,7 @@ struct hist_trigger_attrs { > char *sort_key_str; > bool pause; > bool cont; > + bool clear; > unsigned int map_bits; > }; > > @@ -188,6 +189,8 @@ 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; > @@ -888,6 +891,24 @@ 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); > + > + atomic64_set(&hist_data->total_hits, 0); > + atomic64_set(&hist_data->drops, 0); > + > + 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) > @@ -902,6 +923,8 @@ 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; > @@ -1003,7 +1026,7 @@ 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) > -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/