From owner-freebsd-hackers Tue Jul 13 11:32:53 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from lestat.nas.nasa.gov (lestat.nas.nasa.gov [129.99.50.29]) by hub.freebsd.org (Postfix) with ESMTP id CA8B914E6B; Tue, 13 Jul 1999 11:32:51 -0700 (PDT) (envelope-from thorpej@lestat.nas.nasa.gov) Received: from lestat (localhost [127.0.0.1]) by lestat.nas.nasa.gov (8.8.8/8.6.12) with ESMTP id LAA22555; Tue, 13 Jul 1999 11:32:32 -0700 (PDT) Message-Id: <199907131832.LAA22555@lestat.nas.nasa.gov> To: Matthew Dillon Cc: "Brian F. Feldman" , Noriyuki Soda , bright@rush.net, dcs@newsguy.com, freebsd-hackers@FreeBSD.ORG, jon@oaktree.co.uk, tech-userlevel@netbsd.org Subject: Re: Replacement for grep(1) (part 2) Reply-To: Jason Thorpe From: Jason Thorpe Date: Tue, 13 Jul 1999 11:32:31 -0700 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 13 Jul 1999 11:13:49 -0700 (PDT) Matthew Dillon wrote: > SysV was totally and utterly broken in regards to swap allocation. The > only major operating system that used it as a base was IRIX and SGI > found out very quickly that pre-reserving swap is a stupid idea - and > so they implemented 'virtual swap' to get around it in 5.3, and moved the > whole thing to an overcommit model in 6.4. Doh! Even solaris doesn't > overcommit - you think it actually reserves data blocks for its file-backed > swap? Bzzt! It uses an overcommit model too. You don't have to reserve the actual swap blocks. you merely have to know how many blocks total there are, and how many swap backed pages you have. you can certainly dynamically assign the actual swap blocks, for e.g. swap clustering, etc. it's really not that hard. In the case of swapping to files, NetBSD, at least, doesn't allow swapping to sparse files. The data blocks in the swap file must exist and be allocated to that file. -- Jason R. Thorpe To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message