Re: RE: on load control / process swapping

[Matt Dillon <dillon@earth.backplane.com>]

    We've talked about implementing O_DIRECT.  I think it's a good idea.

    In regards to the particular case of scanning a huge multi-gigabyte
    file, FreeBSD has a sequential detection heuristic which does a
    pretty good job preventing cache blow-aways by depressing the priority
    of the data as it is read or written.  FreeBSD will still try to cache
    a good chunk, but it won't sacrifice all available memory.  If you
    access the data via the VM system, through mmap, you get even more 
    control through the madvise() syscall.

						-Matt

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