Date: Tue, 7 Aug 2001 21:12:55 -0700 (PDT) From: Julian Elischer <julian@elischer.org> To: craig <craiglei@pasia.com.cn> Cc: tlambert2@mindspring.com, freebsd-hackers@FreeBSD.ORG Subject: Re: Why page enable in Kernel space? Message-ID: <Pine.BSF.4.21.0108072111150.70956-100000@InterJet.elischer.org> In-Reply-To: <002001c11fab$19acaca0$051a0a0a@fd.com>
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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
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