Messages in this thread | | | Date | Tue, 19 Sep 2006 11:02:14 -0700 | From | Martin Bligh <> | Subject | Re: [PATCH] Linux Kernel Markers |
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>>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.
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