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Path: sserve!newshost.anu.edu.au!munnari.oz.au!bruce.cs.monash.edu.au!harbinger.cc.monash.edu.au!msuinfo!agate!howland.reston.ans.net!europa.eng.gtefsd.com!news.msfc.nasa.gov!cs.utk.edu!cs.utk.edu!moore From: moore@cs.utk.edu (Keith Moore) Newsgroups: comp.os.386bsd.development Subject: Re: Notes on the *new* FreeBSD V1.1 VM system Date: 1 Mar 1994 03:46:00 GMT Organization: Univ. of Tenn. Computer Science, Knoxville Lines: 23 Distribution: world Message-ID: <2kudpoINNbhd@CS.UTK.EDU> References: <BcxpGux.dysonj@delphi.com> <2ke3ss$l0d@u.cc.utah.edu> <Ja4p+zR.dysonj@delphi.com> <2kfcur$dd1@germany.eu.net> <2kgdcd$mls@usenet.pa.dec.com> <2kkqib$h2h@Germany.EU.net> <CLutBp.4K9@flatlin.ka.sub.org> <RA0Jn4G.dysonj@delphi.com> Reply-To: moore@cs.utk.edu NNTP-Posting-Host: wilma.cs.utk.edu In article <RA0Jn4G.dysonj@delphi.com>, John Dyson <dysonj@delphi.com> writes: > Christoph Badura <bad@flatlin.ka.sub.org> writes: > > >Getting it right means, not overcommiting VM and not killing random > >processes. Damn straight. Let's not have FreeBSD go the way of AIX. I don't think this is that hard...all you need is a count of the number of unallocated pages of swap space. When someone allocates more pages, you decrement the count; if there's not enough room, fail. When pages are freed, you add them back to the available page count. The performance impact is minimal except perhaps on multiprocessor systems where you have to get exclusive access to the counter. You can still wait until you get a fault on the new page (and need to find a place to put the data that was there) before finding where it goes on the disk. -- Keith Moore / U.Tenn CS Dept / 107 Ayres Hall / Knoxville TN 37996-1301 Internet: moore@cs.utk.edu BITNET: moore@utkvx Preserve the fourth amendment! Say HELL NO to key escrow!