Re: [PATCH v2] tracing/filters: Improve subsystem filter

[Li Zefan <lizf@cn.fujitsu.com>]

>> Proposal 2:
>>
>>   # cat filter
>>   irq_handler_entry: irq == 5
>>   irq_handler_exit: none
>>   softirq_entry: vec == 1
>>   softirq_exit: vec == 2
> 
> I like proposal 2, it is very intuitive.
> 

Me too.

>> Which do you think is better? Or do you have some better idea?
>>
>> And in the failure case:
>>
>>   # echo 'irq == not_num' > filter
>>   bash: echo: write error: Invalid argument
>>
>> 1:
>>   # cat filter
>>   (still shows filters in each event like above)
>>
>> or shows error message (the current behavior)
> 
> No need to show error messages of failed filter modifications in the 
> "filter" file.
> 
>> 2:
>>   # cat filter
>>   irq == not_num
>>   ^
>>   parse_error: Couldn't find or set field in one of a subsystem's events
> 
> This looks good, BUT, it is too much. If you want to implement an error 
> message like the above, it should probably be a "pr_info()" thing.
> 

Yeah, I think it's too much too, but that's exactly what we have.
And I posted a patch to remove those error messages, but Tom and
Frederic didn't seem to like it:

	http://lkml.org/lkml/2009/6/17/89