On Tue, Jun 09, 2009 at 10:57:16PM +0000, YAMAMOTO Takashi wrote: > i want to implement them if useful. awesome. > do you have any idea what an implementation of POSIX_FADV_NOREUSE > which is not a no-op would be like? My suggestion would be to not count this hit amongst the statistics collected by whatever caching scheme is in use. Normally, every hit counts for something, and is a clue about further possible activity (or lack thereof, if the predictor is smart enough). The hint is an extra clue, and seems pretty close to directly saying "ignore this next access" without otherwise needing to complicate the predictor. > IMO, the use-once stream is a too common workload to require > an explicit hint. the VM should just handle it nicely without > hints. Agreed, and there are caching schemes that do cope well with this; ZFS promoters make much of ARC's capability in this specifically, along with their prefetching scheme. -- Dan.
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