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    SubjectRe: [PATCH] Linux Kernel Markers
    >>Ah, good point. Though ... how much do we care what the speed of
    >>insertion/removal actually is? If we can tolerate it being slow,
    >>then just sync everyone up in an IPI to freeze them out whilst
    >>doing the insert.
    >>
    >
    > I guess using IPI occasionally would be acceptable. But I think
    > using IPI for each probes will lots of overhead.

    Depends how often you're inserting/removing probes, I guess.
    Aren't these being done manually, in which case it really can't
    be that many? Still doesn't fix the problem Matieu just pointed
    out though. Humpf.

    >>How about we combine all three ideas together ...
    >>
    >>1. Load modified copy of the function in question.
    >>2. overwrite the first instruction of the routine with an int3 that
    >>does what you say (atomically)
    >>3. Then overwrite the second instruction with a jump that's faster
    >>4. Now atomically overwrite the int3 with a nop, and let the jump
    >>take over.
    >
    > That's a good solution.

    It's not exactly elegant or simple, but I guess it'd work if we have
    to go to that extent. Seems like a lot of complexity though, I'd
    rather get rid of the int3 trap if we can.

    M.
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