Re: [PATCH 2/7] kernel-shark-qt: Add Plugin event handlers to session.

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 29 Aug 2018 19:42:19 +0300
"Yordan Karadzhov (VMware)" <y.karadz@gmail.com> wrote:

> Plugin event handlers are added to the Session context descriptor.
> The handlers are used to execute plugin-specific actions (callback
> function) during the processing of the trace data.
> 
> Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
> ---
>  kernel-shark-qt/src/libkshark.c | 24 ++++++++++++++++++++++++
>  kernel-shark-qt/src/libkshark.h | 12 ++++++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/kernel-shark-qt/src/libkshark.c b/kernel-shark-qt/src/libkshark.c
> index b4a76ae..3d9f0d5 100644
> --- a/kernel-shark-qt/src/libkshark.c
> +++ b/kernel-shark-qt/src/libkshark.c
> @@ -33,6 +33,9 @@ static bool kshark_default_context(struct kshark_context **context)
>  	if (!kshark_ctx)
>  		return false;
>  
> +	kshark_ctx->event_handlers = NULL;
> +	kshark_ctx->plugins = NULL;
> +
>  	kshark_ctx->show_task_filter = tracecmd_filter_id_hash_alloc();
>  	kshark_ctx->hide_task_filter = tracecmd_filter_id_hash_alloc();
>  
> @@ -217,6 +220,12 @@ void kshark_free(struct kshark_context *kshark_ctx)
>  	tracecmd_filter_id_hash_free(kshark_ctx->show_event_filter);
>  	tracecmd_filter_id_hash_free(kshark_ctx->hide_event_filter);
>  
> +	if(kshark_ctx->plugins) {
> +		kshark_handle_plugins(kshark_ctx, KSHARK_PLUGIN_UNLOAD);
> +		kshark_free_plugin_list(kshark_ctx->plugins);
> +		kshark_free_event_handler_list(kshark_ctx->event_handlers);
> +	}
> +
>  	kshark_free_task_list(kshark_ctx);
>  
>  	if (seq.buffer)
> @@ -564,6 +573,7 @@ static void free_rec_list(struct rec_list **rec_list, int n_cpus,
>  static size_t get_records(struct kshark_context *kshark_ctx,
>  			  struct rec_list ***rec_list, enum rec_type type)
>  {
> +	struct kshark_event_handler *evt_handler;
>  	struct event_filter *adv_filter;
>  	struct kshark_task_list *task;
>  	struct tep_record *rec;
> @@ -608,6 +618,20 @@ static size_t get_records(struct kshark_context *kshark_ctx,
>  
>  				entry = &temp_rec->entry;
>  				kshark_set_entry_values(kshark_ctx, rec, entry);
> +
> +				/* Execute all plugin-provided actions (if any). */
> +				evt_handler = kshark_ctx->event_handlers;
> +				while ((evt_handler =
> +						find_event_handler(evt_handler,
> +								   entry->event_id))) {

Note, the 80 character line limit is a guideline and not a rule. Part
of that guideline states "If breaking up the line makes the code less
readable, then it should not be broken up". The above makes the code
less readable ;-)

				while ((evt_handler = find_event_handler(evt_handler, entry->event_id))) {

Is fine. Or if you do want to break it, it can be broken as:

				while ((evt_handler = find_event_handler(evt_handler,
									 entry->event_id))) {



> +					evt_handler->event_func(kshark_ctx,
> +								rec, entry);
> +
> +					if ((evt_handler = evt_handler->next))
> +						entry->visible &=
> +							~KS_PLUGIN_UNTOUCHED_MASK;

Same here. Don't be too strict with the 80 char limit.

-- Steve

> +				}
> +
>  				pid = entry->pid;
>  				/* Apply event filtering. */
>  				ret = FILTER_MATCH;
> diff --git a/kernel-shark-qt/src/libkshark.h b/kernel-shark-qt/src/libkshark.h
> index fda133c..203c812 100644
> --- a/kernel-shark-qt/src/libkshark.h
> +++ b/kernel-shark-qt/src/libkshark.h
> @@ -29,6 +29,9 @@ extern "C" {
>  #include "event-parse.h"
>  #include "trace-filter-hash.h"
>  
> +// KernelShark
> +#include "libkshark-plugin.h"
> +
>  /**
>   * Kernel Shark entry contains all information from one trace record needed
>   * in order to  visualize the time-series of trace records. The part of the
> @@ -124,6 +127,9 @@ struct kshark_context {
>  
>  	/** List of Plugins. */
>  	struct kshark_plugin_list	*plugins;
> +
> +	/** List of Plugin Event handlers. */
> +	struct kshark_event_handler	*event_handlers;
>  };
>  
>  bool kshark_instance(struct kshark_context **kshark_ctx);
> @@ -160,6 +166,12 @@ enum kshark_filter_masks {
>  
>  	/** Special mask used whene filtering events. */
>  	KS_EVENT_VIEW_FILTER_MASK	= 1 << 2,
> +
> +	/**
> +	 * Use this mask to check if the content of the entry has been accessed
> +	 * by a plugin-defined function.
> +	 */
> +	KS_PLUGIN_UNTOUCHED_MASK	= 1 << 7
>  };
>  
>  /** Filter type identifier. */