Scribit Jonathan S. Shapiro dies 25/04/2006 hora 13:56: > > checking that the capability is still usable seems to me to be much > > complicated > This check is already necessary in the specification.
Could you point me where it is further described in the Coyotos specification (I'm reading it a bit in random order)? > > this check would need to page in the FCRB > So does severing the FCRB. Yes, but not at the same time. When C is eventually asked to cancel the operation, it will sever the reply FCRB to itself. The capability to the FCRB then becomes a null capability. C and anything from it can be paged out, it is not needed anymore. Some time later, S notices that it's capability is null, and can recover without the need to page C in, not even the FCRB. And so on in the chain of processes involved. > > With the severing option, the check is lightweight and can be done > > while the FCRB remain paged out, if it has been. > Actually, severing requires an interprocess call to the storage > allocator. It is *much* more expensive! Severing is maybe expensive, but the check is not. Severing occurs only N times for N+1 processes involved, and only when operation is canceled. The check could occur at each heartbeat, until the operation is canceled or completed, so it needs to be *very* inexpensive. Expensively, Nowhere man -- [EMAIL PROTECTED] OpenPGP 0xD9D50D8A
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