From owner-freebsd-questions@FreeBSD.ORG Sun Apr 12 03:39:40 2015 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 95EF8370 for ; Sun, 12 Apr 2015 03:39:40 +0000 (UTC) Received: from mail-qk0-x231.google.com (mail-qk0-x231.google.com [IPv6:2607:f8b0:400d:c09::231]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4BB07FA2 for ; Sun, 12 Apr 2015 03:39:40 +0000 (UTC) Received: by qkhg7 with SMTP id g7so108395594qkh.2 for ; Sat, 11 Apr 2015 20:39:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=vtQ0czyTZFkJRHsirZYatBczU5LpEkAydOugRFc4hBk=; b=0TovKO3iD4n/on/NOTaUFskTMIEAyTvmWZXobwDogCf8bzRkTC2J4aT8ssqsj83bSw blq3ml5Ah+auOuYryIPVH3XmUN5ipSepyZVfWW7djLvXsjS3wrpLNeaPXxTrVun5qq9X 2ZNKgUgenWYzcj8x5R1zXkFkoXcUwYcIGfdaDdGIs3jdu59gvtCc8F7epegJEHjD+MEk Ntl3j00ekGf6zaN5WXhtqgkWbrgzb20EcVKjxzKIvmJH5ISHJRh0inKv31kO36vx0PfQ V8s5T/vNyp0Yoj/9b45jHGPbyuPsXta7i1P+Oen8I/bU64Yo9XVVAmFTF40s5adygnzm fpRQ== MIME-Version: 1.0 X-Received: by 10.60.35.102 with SMTP id g6mr7951208oej.7.1428809979262; Sat, 11 Apr 2015 20:39:39 -0700 (PDT) Received: by 10.202.188.213 with HTTP; Sat, 11 Apr 2015 20:39:39 -0700 (PDT) In-Reply-To: <44k2xlcugl.fsf@be-well.ilk.org> References: <5526408F.1090005@asim.lip6.fr> <44k2xlcugl.fsf@be-well.ilk.org> Date: Sun, 12 Apr 2015 10:39:39 +0700 Message-ID: Subject: Re: How FreeBSD manage more than 4GB on 32 bits architecture From: Nguyen Binh To: FreeBSD Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 Apr 2015 03:39:40 -0000 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 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" >