Re: event tracing, ringbuffer and RB_MAX_SMALL_DATA

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

Steven Rostedt wrote:
> On Thu, 16 Jul 2009, Li Zefan wrote:
> 
>> Johannes Berg wrote:
>>> On Wed, 2009-07-15 at 09:08 +0800, Li Zefan wrote:
>>>
>>>> Right, the length of a dynamic array is not recorded, and this
>>>> causes 2 problems:
>>>>
>>>> - the event filter is not working properly for dynamic strings
>>>> - userspace parsers can't figure out the length of those arrays
>>>>
>>>> I had an idea some time ago, and hopefully will send out a
>>>> patch today or tomorrow. 
>>> Well except for the corner case I pointed out, you can determine the
>>> length of dynamic arrays by either
>>>  - the next dynamic array's offset or
>>>  - the length of the item.
>>>
>>> So, afaict, the simplest solution would be to not embed the length of
>>> the item in type_len if it's not divisible by four and contains dynamic
>>> members, though the latter condition might be hard to check.
>>>
>> Actually I'm going to encode the size of a dynamic array
>> in it's @offset, so the lower 16bits is offset and the
>> higher 16bits is size.
> 
> Was there a patch sent out to do this yet, or is this still something 
> being worked on?
> 

Haven't you pulled it as you said. ;)

http://lkml.org/lkml/2009/7/20/155