Date: Tue, 8 Mar 2005 11:28:34 -0500 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-hackers@FreeBSD.org, kamalp@acm.org Cc: hackers@FreeBSD.org Subject: Re: using segmentation to manage memory in FreeBSD Message-ID: <200503081128.34407.jhb@FreeBSD.org> In-Reply-To: <20050308162021.67813.qmail@web52702.mail.yahoo.com> References: <20050308162021.67813.qmail@web52702.mail.yahoo.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tuesday 08 March 2005 11:20 am, Kamal R. Prasad wrote: > --- John Baldwin <jhb@FreeBSD.org> wrote: > > On Tuesday 08 March 2005 09:05 am, Ravi Krishna > > > > wrote: > > > Hi all! > > [snip] > > > Segments just provide a base + offset into the > > virtual address space that is > > backed by the TLB mappings, so to make this > > practically useful would be a lot > > more work than would first appear because your > > segments have to map virtually > > contiguous memory. > > If I had a processor with no MMU, but only memory > protection and a segment register, can I port freebsd > onto that architecture? I mean, use the segment > register to provide for non-conflicting process > spaces. Well, it is theoretically possible, yes, but practically speaking I'd think it would be a lot of work. The entire vm system assumes paging. If you had a way of emulating some rather large pages using segmentation then perhaps you could do that. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200503081128.34407.jhb>