On Mon, 21 Dec 2009, Tristan Ball wrote:
Yes, primarily since if there is no more memory immediately available,
performance when starting new processes would suck. You need to reserve
some working space for processes and short term requirements.
Why is that a given? There are several systems that steal from cache under
memory pressure. Earlier versions of solaris that I've dealt with a little
managed with quite a bit less that 1G free. On this system, "lotsfree" is
sitting at 127mb, which seems reasonable, and isn't it "lotsfree" and the
related variables and page-reclaim logic that maintain that pool of free
memory for new allocations?
It ain't necessarily so but any time you need to run "reclaim" logic,
there is CPU time expended and the CPU caches tend to get thrashed.
Without constraints, the cache would expand to the total amount of
file data encountered. It is much better to avoid any thrashing.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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