From owner-freebsd-questions Sun Dec 9 20:35:12 2001 Delivered-To: freebsd-questions@freebsd.org Received: from clmboh1-smtp3.columbus.rr.com (clmboh1-smtp3.columbus.rr.com [65.24.0.112]) by hub.freebsd.org (Postfix) with ESMTP id 7080E37B405 for ; Sun, 9 Dec 2001 20:35:09 -0800 (PST) Received: from potentialtech.com (dhcp065-024-023-038.columbus.rr.com [65.24.23.38]) by clmboh1-smtp3.columbus.rr.com (8.11.2/8.11.2) with ESMTP id fBA4UZ915106; Sun, 9 Dec 2001 23:30:35 -0500 (EST) Message-ID: <3C143C19.30403@potentialtech.com> Date: Sun, 09 Dec 2001 23:37:45 -0500 From: Bill Moran Organization: Potential Technology User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:0.9.3) Gecko/20010914 X-Accept-Language: en-us MIME-Version: 1.0 To: Anthony Atkielski Cc: FreeBSD Questions Subject: Re: Diminishing free memory in top References: <00ac01c1811a$cb534790$0a00000a@atkielski.com> <3C1418D2.4010209@potentialtech.com> <00c001c18124$a1f77740$0a00000a@atkielski.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Anthony Atkielski wrote: > Bill writes: > > >>If a process is restarted that exists in the >>inactive memory pool, it can start very quickly >>because most or all of its data is already >>in memory, and the system just converts the >>inactive pages to active pages. >> > > When you say "all of its data," do you mean executable code in memory, or > buffered data from a disk file? Does FreeBSD keep track of actual pages of > executable code for a specific program even across executions of that > program? If program X runs and then terminates, how does FreeBSD know some > or all of the pages it used can be reused for a subsequent invocation of > program X? Err ... frankly, you're asking questions that are over my head. If you're interested in the VM workings at that level of detail, you may have to consult the source code, or possibly "The Design & Implementation of the BSD Operating System". I do believe that executable code is "cached" as inactive pages, while buffered disk data is kept in the "buffered" category (as shown in top) but ... this is really a little over my head as to how the system actually does all this. I've been studying it for a while, but haven't quite got that level of understanding yet. -- Bill Moran Potential Technology http://www.potentialtech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message