From owner-freebsd-hackers Tue Aug 7 19: 1: 3 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from InterJet.elischer.org (c421509-a.pinol1.sfba.home.com [24.7.86.9]) by hub.freebsd.org (Postfix) with ESMTP id 2F5FB37B401 for ; Tue, 7 Aug 2001 19:00:59 -0700 (PDT) (envelope-from julian@elischer.org) Received: from localhost (localhost.elischer.org [127.0.0.1]) by InterJet.elischer.org (8.9.1a/8.9.1) with ESMTP id VAA72737; Tue, 7 Aug 2001 21:12:55 -0700 (PDT) Date: Tue, 7 Aug 2001 21:12:55 -0700 (PDT) From: Julian Elischer To: craig Cc: tlambert2@mindspring.com, freebsd-hackers@FreeBSD.ORG Subject: Re: Why page enable in Kernel space? In-Reply-To: <002001c11fab$19acaca0$051a0a0a@fd.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Wed, 8 Aug 2001, craig wrote: > In general a address in a process is just a linear address which refer > to physical address indirectly by page directory. This is reasonable > in user space. However is it necessary to do such thing in kernel? It > is sure to have penalty when converting a linear address to physical > thing. Is it worth doing such thing in kernel. > > I think the performance is the most important in kernel, other thing > is second. I remember in linux linear address is real physical address > in kernel space(is it true?). Why freebsd does not do in the same way? To add a bit more.. the kernel uses 4MB of linear physical memory for it's text. (this saves a lot of TLBs but still requires paging to be on. > > > craiglei > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message