From owner-freebsd-questions@FreeBSD.ORG Tue Feb 8 22:39:24 2005 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1545416A4CE for ; Tue, 8 Feb 2005 22:39:24 +0000 (GMT) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.194]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7091943D46 for ; Tue, 8 Feb 2005 22:39:23 +0000 (GMT) (envelope-from pergesu@gmail.com) Received: by wproxy.gmail.com with SMTP id 58so991517wri for ; Tue, 08 Feb 2005 14:39:22 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:references; b=Vsx8S8FsNfhBsQTp8hsZfzQO2VwRyzczCus2dWYvFEkwTO7FSSRK5xcatfh7NnKgjGgxTRf73crrUSD9Iu4WPX/NWqTO1jDRtTXjWCWKjO42IPrnEn2itA7HIbZcQYA9OS/Zj8/H0oF9mCR4PRvFuOZ4g098/YRi0evpfPy/Cr8= Received: by 10.54.44.64 with SMTP id r64mr313768wrr; Tue, 08 Feb 2005 14:39:22 -0800 (PST) Received: by 10.54.42.28 with HTTP; Tue, 8 Feb 2005 14:39:22 -0800 (PST) Message-ID: <810a540e050208143921cd416d@mail.gmail.com> Date: Tue, 8 Feb 2005 15:39:22 -0700 From: Pat Maddox To: Pat Maddox , freebsd-questions@freebsd.org In-Reply-To: <20050208222759.GA29360@falcon.midgard.homeip.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit References: <810a540e050208133310333144@mail.gmail.com> <20050208213612.GA29063@falcon.midgard.homeip.net> <810a540e050208134479b4e774@mail.gmail.com> <20050208222759.GA29360@falcon.midgard.homeip.net> Subject: Re: Inactive memory X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: Pat Maddox List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Feb 2005 22:39:24 -0000 Thanks a lot for the explanation. I think I can close top and stop worrying now :) On Tue, 8 Feb 2005 23:27:59 +0100, Erik Trulsson wrote: > On Tue, Feb 08, 2005 at 02:44:39PM -0700, Pat Maddox wrote: > > Alright, that lets me know that it's not an entirely bad thing. It > > does say, however, that it's fine as long as the free memory isn't > > REALLY low. It did get down to 13MB though, as I said. > > Don't worry. 13MB is not what I would consider as "REALLY low" (ok, > with 1GB RAM maybe it is) but anyway, the only thing to worry about is > if the system starts to swap very often - that means you need more memory. > > > > > So now I understand that it's alright for the free memory to be low. > > I don't understand how the inactive, cache, and buffered memory are > > used though. When a process uses up all the free memory, does it then > > use some from inactive, or does it use swap? > > Memory normally moves along the following path: > > Wired -> Active -> Inactive -> Cached -> Free > > and then when it gets allocated and used it moves back to Wired. > > The difference between the categories is mainly that "Inactive" and > "Cached" memory still contains data that the system might be able to > reuse, while "Free" memory is completely free and unused. > In order to use Cached or Inactive memory it might need to be flushed > first, with Inactive probably being dirty and Cached probably not. > ("Active" memory is almost certainly dirty and is therefore somewhat > more expensive to reuse. > > If you didn't understand the preceding paragraph, don't worry. It is > not really important to understand. > > For most purposes you should just consider all of "Free", "Cached", and > "Inactive" to be free memory that is available for allocation. > > > > > > > > On Tue, 8 Feb 2005 22:36:12 +0100, Erik Trulsson wrote: > > > On Tue, Feb 08, 2005 at 02:33:14PM -0700, Pat Maddox wrote: > > > > I've always got a lot of inactive memory on my machine, around 520MB > > > > or so. While doing a portupgrade, the free memory dropped to around > > > > 13MB. I'm just curious what exactly the inactive memory is. Will the > > > > OS use the inactive memory before dipping into swap? Or is that > > > > memory off limits now? If so, is there any way to free it up? I've > > > > got 1GB total on the machine. > > > > > > http://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/misc.html#TOP-FREEMEM > > -- > > Erik Trulsson > ertr1013@student.uu.se >