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From: "Tzvetomir (Ceco) Stoyanov" <>
To: Steven Rostedt <>
Cc: Linux Trace Devel <>
Subject: Re: Ideals for tep plugin options
Date: Thu, 9 Jan 2020 15:21:32 +0200
Message-ID: <> (raw)
In-Reply-To: <20200106113026.75893f92@gandalf.local.home>

Hi Steven,

On Mon, Jan 6, 2020 at 6:30 PM Steven Rostedt <> wrote:
> Hi Tzvetomir,
> I was looking at the plugin options, and I believe it needs to be
> updated.
> 1) the tep_plugin_option structure:
>   - rename "file" to "plugin"
>   - remove "plugin_alias"
> 2) Currently we have the following plugin option functions exported in
> trace-cmd:
>  char **tep_plugin_list_options(void);
>  void tep_plugin_free_options_list(char **list);
>  int tep_plugin_add_options(const char *name,
>                            struct tep_plugin_option *options);
>  int tep_plugin_add_option(const char *name, const char *val);
>  void tep_plugin_remove_options(struct tep_plugin_option *options);
>  void tep_plugin_print_options(struct trace_seq *s);
>  void tep_print_plugins(struct trace_seq *s,
>                         const char *prefix, const char *suffix,
>                         const struct tep_plugin_list *list);
> What we should only have is:
>  int tep_plugin_add_options(const char *plugin,
>                           struct tep_plugin_option *options);
>  int tep_plugin_set_option(const char *plugin, const char *name,
>                           const char *val);
>  int tep_plugin_remove_options(struct tep_plugin_option *options);
>  struct tep_plugin_option const * const tep_plugin_options_list(void);
> Where:
>   tep_plugin_add_options() is basically the same as we have now. But we
>     should change it so that if "plugin" is already registered, it
>     should fail with -EBUSY.
>  tep_plugin_set_option() lets us update the option. If "plugin" is
>    NULL, then it will ignore that value, and will set all options with
>    "name" to "val", regardless of what plugin it belongs to.
>  tep_plugin_remove_options() is basically the same as what we have now,
>    and removes the options from the list.
>  tep_plugin_options_list() returns an immutable list of all the
>    registered plugin options. This is the list that the application can
>    use to see what options are registered, as well as their default
>    (and current) values.
> Does this make sense?

Yes, it makes sense. I'll submit a patch set with these changes, in
the kernel tree.
I'm going to add also a check at the plugin loading time, if it is
already loaded -
the old one will be unloaded before the new one is registered.

> -- Steve

Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center

      reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-06 16:30 Steven Rostedt
2020-01-09 13:21 ` Tzvetomir (Ceco) Stoyanov [this message]

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