Re: [PATCH 3/3] tracing/function-return-tracer: add the overrunfield

[Steven Rostedt]

On Tue, 18 Nov 2008, Ingo Molnar wrote:
> > > 
> > > that reminds me: ti->ret_stack[] should be moved to task->ret_stack[]. 
> > > That way we decouple its size from any kernel stack size limits. 
> > > (thread-info resides at one end of the kernel stack, on x86)
> > 
> > Yeah, I recommended that to Frederic to save space. But that can be 
> > dangerous. Using task instead would be safer with the downside of 
> > making the task struct even bigger.
> 
> We almost never put new stuff into thread_info - we have the lockdep 
> lock stack in the task structure too, for similar reasons.

Yeah, it was just a recommendation, and perhaps not a good one ;-)

Frederic, it is better if you move the array from the thread info to the 
task struct. It will take up more memory but it is a hell of a lot safer. 
The pro here definitely outways the con.

-- Steve

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