Subject: Re: File/Buffer cache consumes all memory even when constrained in sysctl
To: George Michaelson <>
From: Daniel Carosone <>
List: current-users
Date: 05/17/2004 13:00:18
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On Mon, May 17, 2004 at 10:53:29AM +1000, George Michaelson wrote:

> My take is that sysctl vm tuning is still a black art.=20

The trick you need to understand is that the min's and max's aren't
really what you might at first assume. All of {file,exec,anon} can be
below min, or above max.

In particular, they can be above max if there's nothing else demanding
that memory at the moment.

If a particular page type is below min, it will never be stolen for
something else that wants memory.  If a page type is above max, it
will be the first page stolen when something of another type wants

My guess is that your "available space for apps" (ie, totally unused
pages?) is so "low" because your apps aren't actually demanding any
more memory.  This is a Good Thing :)


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