Re: [PATCH 1/4] kernel-shark: Define addPlugin method for KsPluginManager

[Yordan Karadzhov <ykaradzhov@vmware.com>]

On 11.03.19 г. 14:31 ч., Slavomir Kaslev wrote:
> On Fri, Mar 8, 2019 at 7:14 PM Yordan Karadzhov <ykaradzhov@vmware.com> wrote:
>>
>> The method can be used to register and load a user-defined plugin.
>> All other previously loaded plugins will be reloaded.
>>
>> Signed-off-by: Yordan Karadzhov <ykaradzhov@vmware.com>
>> ---
>>   kernel-shark/src/KsUtils.cpp | 17 +++++++++++++++++
>>   kernel-shark/src/KsUtils.hpp |  3 +++
>>   2 files changed, 20 insertions(+)
>>
>> diff --git a/kernel-shark/src/KsUtils.cpp b/kernel-shark/src/KsUtils.cpp
>> index d7b1753..4d05bda 100644
>> --- a/kernel-shark/src/KsUtils.cpp
>> +++ b/kernel-shark/src/KsUtils.cpp
>> @@ -596,6 +596,23 @@ void KsPluginManager::unregisterPlugin(const QString &plugin)
>>          }
>>   }
>>
>> +/** @brief Add to the list and load a user-provided plugin. All other
>> + *        previously loaded plugins will be reloaded.
>> + *
>> + * @param fileName: the library file (.so) of the plugin.
>> +*/
>> +void KsPluginManager::addPlugin(const QString &fileName)
>> +{
>> +       kshark_context *kshark_ctx(nullptr);
>> +
>> +       if (!kshark_instance(&kshark_ctx))
>> +               return;
>> +
>> +       kshark_handle_plugins(kshark_ctx, KSHARK_PLUGIN_CLOSE);
>> +       registerPlugin(fileName);
>> +       kshark_handle_plugins(kshark_ctx, KSHARK_PLUGIN_INIT);
>> +}
> 
> Calling addPlugin() several times in a row will reinitialize all
> already registered plugins several times and lead to quadratic
> complexity. This seems wrong to me.
> 
> Maybe we should split adding plugins from (re-)initializing them so
> that one can add several plugins and then have initialized once when
> they are actually needed to run. Wdyt?
> 

Hi Slavi,

KsPluginManager is a helper class for the GUI. It only does what the GUI 
is supposed to do. Currently the dialog that allows to load user plugins 
provides loading only one plugin at a time, so the KsPluginManager 
provides only this functionality.

So the questions is: do we want a dialog that loads multiple plugins 
with one click?

On the other hand we do encourage the users to use the KernelShark 
library for making custom applications. This is the motivation for 
having the C API, but KsPluginManager it is not part of this API. 
KsPluginManager operates on top of the API and is intended to be used 
only by the GUI code.

Indeed the C API itself separates adding plugins from there initializing.

Thanks a lot!
Y.


> --Slavi 
> 
>> +
>>   /** Unload all plugins. */
>>   void KsPluginManager::unloadAll()
>>   {
>> diff --git a/kernel-shark/src/KsUtils.hpp b/kernel-shark/src/KsUtils.hpp
>> index cb95b4f..ae7f6d1 100644
>> --- a/kernel-shark/src/KsUtils.hpp
>> +++ b/kernel-shark/src/KsUtils.hpp
>> @@ -210,6 +210,9 @@ public:
>>
>>          void registerPlugin(const QString &plugin);
>>          void unregisterPlugin(const QString &plugin);
>> +
>> +       void addPlugin(const QString &fileName);
>> +
>>          void unloadAll();
>>
>>          void updatePlugins(QVector<int> pluginId);
>> --
>> 2.19.1
>>
> 
>