From owner-freebsd-stable@FreeBSD.ORG Wed Dec 24 23:10:10 2003 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A585D16A4CE for ; Wed, 24 Dec 2003 23:10:10 -0800 (PST) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 96C0D43D39 for ; Wed, 24 Dec 2003 23:10:09 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) hBP7A9LL027005; Wed, 24 Dec 2003 23:10:09 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.9p2/8.12.9/Submit) id hBP7A8nv027004; Wed, 24 Dec 2003 23:10:08 -0800 (PST) (envelope-from dillon) Date: Wed, 24 Dec 2003 23:10:08 -0800 (PST) From: Matthew Dillon Message-Id: <200312250710.hBP7A8nv027004@apollo.backplane.com> To: Paul Mather References: <200312212310.KAA04764@lightning.itga.com.au> <20031225011412.GA441@gromit.dlib.vt.edu> cc: Gregory Bond cc: freebsd-stable@freebsd.org Subject: Re: Problems reclaiming VM cache = XFree86 startup annoyance X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Dec 2003 07:10:10 -0000 :I'm not sure what is overloading the disk other than the large amounts :of paging that are initiated the moment I invoke "startx". The last :time I did this, I looked at the disk activity beforehand via "systat :-vm 1". The disks were basically idle (all < 0.05 MB/s). As soon as :I executed "startx" the swap volume became very active (90--96% busy; :3--7 MB/sec) and the "SWAP PAGER" out column steadily showed paging :activity (nothing on the "in" column). (The 4 KB/t was a tell-tale :sign the system was doing nothing but paging.) : :I guess my question is this: why so much paging? If, as someone else :has mentioned, "Cache" and "Free" pages are both "free" (i.e., :allocable memory), with the subtle distinction being that "Cache" :pages used to hold disk blocks now discarded, then why not allocate :what is needed from them? As I stated in my original thread, all the :"Inactive" memory seems to get dumped over to "Cache" when I run :"startx", and there's usually almost about 400 MB of it when this :happens. :... :Cheers, : :Paul. If it could, it would... my guess is that your box is using a shared memory video buffer and X is allocating a large swath of contiguous physical memory to accomodate it, which would force it to pageout any preexisting dirty data using that memory. That's all I can think of. -Matt Matthew Dillon