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    SubjectRe: [PATCH] Linux Kernel Markers
    > It is an interesting idea but there appears to be following hard issues 
    > (some of which you have already listed) i am not able to see how we can
    > overcome them
    > 1) We are going to have a duplicate of the whole function which means
    > any significant changes in the original function needs to be done on the
    > copy as well, you think maintainers would like this double work idea.

    No, no ... the duplicate function isn't duplicated source code, only
    object code. Either a config option via the markup macros that we've
    been discussing, or something I hack up on the fly to debug a problem
    dynamically. In terms of how the debugging-type source code is kept,
    it's no different than something like systemtap or LTT (either would
    work, and a normal diff could be used to keep out of tree stuff),
    it's just how it hooks in is different to kprobes.

    > 2) Inline functions is often the place where we need a fast path to
    > overcome the current kprobes overhead.

    You can still instrument inline functions, you just need to hook all
    the callers, not the inline itself.

    > 3) As you said it is not trivial across all the platforms to do a switch
    > to the instrumented function from the original during the execution.
    > This problem is similar to the issue we are dealing with djprobes.

    If we just freeze all kernel operations for a split second whilst we do
    this, does it matter? Or even if we don't ... there's a brief race where
    some calls are traced, and some are not ... does that even matter?
    Doesn't seem like most usages would care.


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