Date: Fri, 30 Jun 2000 08:34:16 -0400 (EDT) From: Kenneth Wayne Culver <culverk@wam.umd.edu> To: Paul Herman <pherman@frenchfries.net> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: what is active/inactive memory (was Re: memory leak?) Message-ID: <Pine.GSO.4.21.0006300832590.7155-100000@rac1.wam.umd.edu> In-Reply-To: <Pine.BSF.4.21.0006300712200.224-100000@bagabeedaboo.security.at12.de>
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Well, yeah, I think we're doing VM next week. Either way, thanks... :-) I wish this class was based on -CURRENT instead of 2.2.x though.. I know the -CURRENT code so much better than the 2.2.x code. ================================================================= | Kenneth Culver | FreeBSD: The best NT upgrade | | Unix Systems Administrator | ICQ #: 24767726 | | and student at The | AIM: muythaibxr | | The University of Maryland, | Website: (Under Construction) | | College Park. | http://www.wam.umd.edu/~culverk/| ================================================================= On Fri, 30 Jun 2000, Paul Herman wrote: > On Thu, 29 Jun 2000, Kenneth Wayne Culver wrote: > > > Hope I wasn't too mean :-) hehe... I think actually that we are covering > > the vm system (at least in 2.2.5, kinda old, but I'm sure that knowing > > 2.2.x's system, I could bring my self up to date on -CURRENT's vm > > system) pretty soon in this class. I can't wait. > > Then be careful of those trick questions which just bit me :) After > all, strictly speaking, there is no single concept in the kernel of > what "active" memory is, which you can see in <sys/vmmeter.h> > > 1) vmmeter->v_active_count: the one top(1) reports (pages with a > non-zero reference count.) > > 2) vmtotal->t_avm: reported by vmstat(8) (virtual pages used by > programs running in the last 20 seconds) > > 3) vmtotal->t_arm: reported by systat(1) (resident pages used > by programs running in the last 20 seconds) > > 1) and 3) are probably the most useful. In most cases, there is more > memory available to you than just "Inactive + Cache + Free", becase > some of the active memory (in the 1st sense) isn't really active (in > the 3rd sense), as would be the case with the original poster's memory > leak problem. This is clear to see with systat(1). > > So, be careful if you only have a multiple choice test!... It seems > nowadays most people just use top, so if you need only one answer to > "what is active/inactive memory" I guess 1) wins. :) "which objects > can be found in the active/inactive queue" on the other hand, would be > much easier to answer. > > -Paul. > > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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