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Newsgroups: comp.os.386bsd.development Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!howland.reston.ans.net!wupost!decwrl!raven.alaska.edu!netnews.nwnet.net!ns1.nodak.edu!plains.NoDak.edu!tinguely From: tinguely@plains.NoDak.edu (Mark Tinguely) Subject: Re: Notes on the *new* FreeBSD V1.1 VM system Sender: usenet@ns1.nodak.edu (Usenet login) Message-ID: <CLtFoC.J4t@ns1.nodak.edu> Date: Sat, 26 Feb 1994 05:09:48 GMT References: <2khcvv$han@u.cc.utah.edu> <CLqK5I.IzH@ns1.nodak.edu> <wimlCLrCxo.Fvx@netcom.com> Nntp-Posting-Host: plains.nodak.edu Organization: North Dakota State University Lines: 28 In article <wimlCLrCxo.Fvx@netcom.com> wiml@netcom.com (William Lewis) writes: >Why can't demand-paged executables act like any other open file? It might this was talked about a long time ago. major problem is in writing to executable files (there are no problems in removing or moving a running process). to fix the problems changes would have to be done to write, the pagers and the vnodes and still this would not solve the NFS problem. There was even talk about the need for VM and file buffer consistancy where copy-on-writes could be used to take care of some problems on a per page level not on a per file level. in the end, we took the minimum solution rationalizing the decision by saying that this situation does not happen too often, and we have bigger fires in the VM to fix. real-soon-now, the time would be available to fix this right. to solve it, going back to the traditional swap model of all running applications have their text in backstore, would fix all of these problems, but at an expense (note: a comment of bias). using the filesystem to hold the text of the running processes will require something more encompassing that the current text busy flag. there are a few connecting concerns to fix all these problems connecting filesystems and VM. I am glad that Terry does the evangelical work on this and many other topics. --mark.