Re: "objtrm" problem probably found (was Re: Stuck in "objtrm")

[Poul-Henning Kamp]

In message <[EMAIL PROTECTED]>, John-Mark Gurney writes:
>Matthew Dillon scribbled this message on Jul 12:
>>     p.s.  I'm pretty sure that the lock prefix costs nothing on a UP system,
>>     and probably wouldn't be noticed on an SMP system either because the
>>     write-allocation overhead is already pretty bad.  But I haven't tested
>>     it.
>
>actually, I'm not so sure, it guarantees that NO other bus operation
>will succeed while this is happening... what happens if a pci bus
>mastering card makes a modification to this value?  sure, it normally
>won't happen, but it can... and w/o the lock prefix, this CAN happen
>from what I understand of the architecture...

it locks EVERYTHING.

--
Poul-Henning Kamp             FreeBSD coreteam member
[EMAIL PROTECTED]               "Real hackers run -current on their laptop."
FreeBSD -- It will take a long time before progress goes too far!


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