From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: To: 9fans@cse.psu.edu From: Brantley Coile Date: Thu, 13 Jul 2006 09:52:04 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: [9fans] Swap considered harmful (Sorry) Topicbox-Message-UUID: 7e35b4f4-ead1-11e9-9d60-3106f5b1d025 char Ephil[] = "It's all Phil's fault"; > From: "rob pike" <;rob@plan9.bell-labs.com>; > Subject: Re: [9fans] Virtual memory in BSD and Plan9 > Date: Mon, 29 Oct 2001 07:38:17 -0500 > > I'm a radical here, but I think if a machine is paging, you've lost. > To me, VM is a pretty technique for memory management in the kernel, > something distinct from paging, which is a way to get the system > through temprorary overshoots in memory demand. > > My boss when the first Plan 9 kernel was being written was Sandy > Fraser, who had worked on Atlas, one of the first VM systems. When he > heard that I was putting VM into Plan 9 (a situation more accurately > described as building Plan 9's original memory manager around a VM > model), he literally called me on the carpet. He said that he hated > VM bitterly because of the Atlas days, in which nothing got done > because the system was always thrashing. I pointed out the > distinction between VM and paging, explained that I was implementing > VM but not paging (Phil W. put paging in a few years later), and > justified my decision by pointing out that with memory so cheap today, > there was really no reason to depend on the paging system to manage > your working set except for the occasional brief overrun on demand. > > -rob