Re: [PATCH RFC 00/11] lock monitor: Separate features related tolock

[Hitoshi Mitake]

On 03/17/10 18:52, Ingo Molnar wrote:
>
> * Frederic Weisbecker<fweisbec@xxxxxxxxx>  wrote:
>
>>> You add chained indirect calls into all lock ops, that's got to hurt.
>>
>> Well, the idea was not bad at the first glance. It was separating 
lockdep
>> and lock events codes.
>>
>> But indeed, the indirect calls plus the locking are not good for 
such a fast
>> path.
>
> What would be nice to have is some sort of dynamic patching approach 
to enable
> _both_ lockdep, lockstat and perf lock.
>
> If TRACE_EVENT() tracepoints were patchable we could use them. (but 
they arent
> right now)

I'll try it!

And I have a question related to this dynamic patching approach for lockdep.
If dynamic proving turning on/off is provided,
lockdep will be confused by inconsistency of lock acquiring log.

Will the sequence,

lock_acquire(l) -> turning off -> lock_release(l) -> turning on -> 
lock_acquire(l)

detected as double acquiring?

Should turning on/off lockdep be done in the time
when every processes have no lock?

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