Date: Mon, 04 Oct 1999 15:22:18 +0000 From: Joseph Scott <joseph.scott@owp.csus.edu> To: Dan Mahoney <dmahoney@pe.net> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: "Top" shows large amount of "inact" RAM Message-ID: <37F8C62A.B54F705F@owp.csus.edu> References: <199910021956.MAA21292@smtp.pe.net>
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Dan Mahoney wrote: > > I have been watching the output of "top" on > my FreeBSD 3.2 system, and I was wondering > if anyone could help me undestand a little > better? > > 'top" currently shows 318 M active, 113 inactive, > 51 M wired, 13M cache, 8341 K buff, 2744K free > (this is on a dual-CPU system with 512 MB > phyiscal RAM). I also see 668K out of 512 M > of swap in use. Here's my confusion: > shouldn't the inactive RAM be getting cleared > out and reused, instead of starting to hit the > swap space? Or is my understanding of the > process unclear? Here's how I believe this works : The swap was probably used at one point where the system was actually under enough use it need to start swapping a little. That little bit is still in use because it's easier to have it in swap than having to go through the work of cleaning those pages, especially if that data may be needed again, and if there's no big push on the swap space anyway ( ie: not close to using all of it ). Same idea with the physical memory, it's cheaper to keep the dirty pages in memory until demand for physical memory grows and which time the dirty pages are cleared and whatever needs the memory now gets it. This is especially true if the data in those pages gets called again. I hope that makes sense, sometimes I have it clear in my head but it doesn't come out that way :-) -- Joseph Scott joseph.scott@owp.csus.edu Office Of Water Programs - CSU Sacramento To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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