From owner-freebsd-current@FreeBSD.ORG Fri Aug 16 18:42:46 2013 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 8B225723; Fri, 16 Aug 2013 18:42:46 +0000 (UTC) (envelope-from neelnatu@gmail.com) Received: from mail-ie0-x236.google.com (mail-ie0-x236.google.com [IPv6:2607:f8b0:4001:c03::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 484162A1B; Fri, 16 Aug 2013 18:42:46 +0000 (UTC) Received: by mail-ie0-f182.google.com with SMTP id tp5so4067287ieb.13 for ; Fri, 16 Aug 2013 11:42:45 -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 :cc:content-type; bh=aDh5VMcGxCsYJaLneNpx4mN0c01iDboIvvZxRqGx8ik=; b=IcNlY7pkpZQjx6ja5viu+EjXA+aZUSJ+jiR+wv101Yr7YXchQ7bOduFKpEAwRxzqy9 1kHKN3l7KZH410UbYlp1MGz9z8lNBulTwBwaRtHgPrCpL3dAu/bi5SwU15ZdM5J8ZoeV gx+OBm7RlL4Y6CQL9TpbtXA+6KHbsj/uGCdJ9UnLQ3V9C2HtffcIGxwAM93DyKMJZXxh qsVPywa+LRjPkHNhc3hpLgND/UqbLM1YnnidAXyjHRqI9IEJkoYnVKpXbWQadSOdN09t yXDGINsMVk7xRBfGfh1UQtxvcYrpdxWqISe7xxmJ9B7X6CzupT48by4GTfQCRxA4+UWY Ac3A== MIME-Version: 1.0 X-Received: by 10.50.126.74 with SMTP id mw10mr216525igb.24.1376678564975; Fri, 16 Aug 2013 11:42:44 -0700 (PDT) Received: by 10.42.179.71 with HTTP; Fri, 16 Aug 2013 11:42:44 -0700 (PDT) In-Reply-To: References: <201306190832.r5J8WZFE082135@elf.torek.net> Date: Fri, 16 Aug 2013 11:42:44 -0700 Message-ID: Subject: Re: expanding past 1 TB on amd64 From: Neel Natu To: Chris Torek Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: alc@freebsd.org, freebsd-current , Neel Natu X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Aug 2013 18:42:46 -0000 Hi Chris, Alan: On Sun, Jul 21, 2013 at 1:19 AM, Chris Torek wrote: > (Apologies for delay in reply, family issues) > > I'd be fine with 4 TB instead of 16; and, at this point, with the latest > patches, it's easily tuned. The auto-sizing of the direct map is not > affected by sparse space as it keys off Maxmem, which is not actually > physical size, but rather "one past last valid physical page". > Here is the patch that I intend to commit: http://people.freebsd.org/~neel/patches/amd64_pmap_4TB.patch This patch bumps up the direct map to 4TB and the KVA to 2TB. It is identical to the patch you posted on hackers except for changing the limits: http://lists.freebsd.org/pipermail/freebsd-hackers/2013-July/043139.html Tested inside a bhyve virtual machine with a *very* sparse memory layout with a memory segment that cuddles up with the 4TB limit. best Neel > > The direct map limit might not need to be "twice kernel virtual size" but > on Intel memory-controller systems needs to be "greater than KVM size" du= e > to moving DRAM up past the PCI hole. Unless the restriction that the > direct-map area be a power of two size is removed, that winds up meaning > "twice". (Removing the restriction seems easy enough=97instead of "pa | > highbits" to obtain VA and "va &~ highbits" to obtain PA, just use "phys = + > offset" and "virt - offset". I didn't see a reason to bother with the > effort, though.) > > Chris >