Date: Sun, 12 Apr 2015 10:39:39 +0700 From: Nguyen Binh <binhtien1162@gmail.com> To: FreeBSD <freebsd-questions@freebsd.org> Subject: Re: How FreeBSD manage more than 4GB on 32 bits architecture Message-ID: <CAA7ELWbsdEdYD-VuV2eMdho0j-Qj0tO0ughtDpafn2rN-tnz4Q@mail.gmail.com> In-Reply-To: <44k2xlcugl.fsf@be-well.ilk.org> References: <5526408F.1090005@asim.lip6.fr> <44k2xlcugl.fsf@be-well.ilk.org>
next in thread | previous in thread | raw e-mail | index | archive | help
https://fr.airbnb.com/s/bergen--norway?af=3D414650&alsm=3D1&c=3Dp2v2u_d_eng= asia_102555_36584_P2sm_img_asia&gclid=3DCLjd_OPq78QCFQxvvAod0XQAwg 2015-04-09 20:16 GMT+07:00 Lowell Gilbert < freebsd-questions-local@be-well.ilk.org>: > Pierre-Yves P=C3=A9neau <Pierre-Yves.Peneau@lip6.fr> writes: > > > For my internship, I have to find a way to manage more than 4GB of > > memory with 32 bits processors. It seems that the FreeBSD kernel is the > > perfect candidate for that. According to the architecture handbook(*), > > "FreeBSD could theoretically handle memory configurations up to 8TB on = a > > 32 bit platform." > > This is quoting the Architecture Handbook's KVM memory mapping section. T= he > following sentence reads "However, since most 32 bit platforms are only > capable of mapping 4GB of ram, this is a moot point." > > > For the last two days, I was looking for documentation, articles, > > thesis, or e-mails on that topic, but I can't find relevant > > informations. Is anybody have informations on that topic ? Where should > > I start to read the source code to find my answers ? > > I'm going to guess that the idea behind that comment is that FreeBSD's pa= ge > tables can hold 2G (2^31) entries. At a 4k page size, that would give you > 8TB of memory. But that only helps you if the hardware is physically > capable of reading from more than 4G different locations. > > Therefore, the question becomes: what kind of hardware are you going to u= se > that can keep track of those locations? > > As a side note, I would also recommend the book "The Design and > Implementation of the FreeBSD Operating System," now out in a new edition= . > > Good luck. > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAA7ELWbsdEdYD-VuV2eMdho0j-Qj0tO0ughtDpafn2rN-tnz4Q>