From owner-freebsd-hackers@FreeBSD.ORG Wed Aug 27 13:16:29 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AD4661065674 for ; Wed, 27 Aug 2008 13:16:29 +0000 (UTC) (envelope-from bab@acciodata.com) Received: from mail.acciodata.com (host34.acciodata.com [207.200.31.34]) by mx1.freebsd.org (Postfix) with ESMTP id 64AF68FC08 for ; Wed, 27 Aug 2008 13:16:29 +0000 (UTC) (envelope-from bab@acciodata.com) Received: from bravo.acciodata.com (root@bravo [10.1.5.2]) by mail.acciodata.com (8.14.1/8.14.1) with ESMTP id m7RDGShr084298; Wed, 27 Aug 2008 08:16:28 -0500 (CDT) (envelope-from bab@acciodata.com) Received: from bravo.acciodata.com (bab@localhost [127.0.0.1]) by bravo.acciodata.com (8.14.2/8.14.2) with ESMTP id m7RDGRpp081167; Wed, 27 Aug 2008 08:16:27 -0500 (CDT) (envelope-from bab@bravo.acciodata.com) Received: (from bab@localhost) by bravo.acciodata.com (8.14.2/8.14.2/Submit) id m7RDGRmu081164; Wed, 27 Aug 2008 08:16:27 -0500 (CDT) (envelope-from bab) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18613.21419.16360.120533@gargle.gargle.HOWL> Date: Wed, 27 Aug 2008 08:16:27 -0500 To: freebsd-hackers@freebsd.org In-Reply-To: <48B52AEE.9080205@FreeBSD.org> References: <18612.51201.285688.628405@gargle.gargle.HOWL> <48B52AEE.9080205@FreeBSD.org> X-Mailer: VM 7.17 under 21.4 (patch 20) "Double Solitaire" XEmacs Lucid From: Barry Boes X-Mailman-Approved-At: Wed, 27 Aug 2008 14:17:10 +0000 Cc: Subject: Re: kvm on amd64 - >6G? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Barry Boes List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Aug 2008 13:16:29 -0000 I could apply such a patch to my servers, but there are two disadvantages : o who wants to apply kernel patches to mission critical servers? Isn't that a linux thing (joke!) o what about apps like the linuxulator that might not stand for this? On the tunable option : with today's kmem_size and kmem_size_max tunables, would there also be a need to tune the portion of address space available to kmem? Thanks, Barry Kris Kennaway writes: > Barry Boes wrote: > > With the advent of ZFS, Solaris users are devoting 30G or more to > > their ARC caches today. If FreeBSD 8 is going to up the KVM size, is > > there a reason to not increase the limit to something that will not be > > reached in the lifetime of 8? 100GB? > > It's easily configurable on HEAD. From an email alc sent me: > > ---- > This: > > Index: amd64/include/pmap.h > =================================================================== > --- amd64/include/pmap.h (revision 180373) > +++ amd64/include/pmap.h (working copy) > @@ -111,7 +111,7 @@ > > /* Initial number of kernel page tables. */ > #ifndef NKPT > -#define NKPT 32 > +#define NKPT 1023 > #endif > > #define NKPML4E 1 /* number of kernel PML4 > slots */ > Index: amd64/include/vmparam.h > =================================================================== > --- amd64/include/vmparam.h (revision 180373) > +++ amd64/include/vmparam.h (working copy) > @@ -163,7 +163,7 @@ > */ > > #define VM_MAX_KERNEL_ADDRESS KVADDR(KPML4I, NPDPEPG-1, > NPDEPG-1, NPTEPG-1) > -#define VM_MIN_KERNEL_ADDRESS KVADDR(KPML4I, NPDPEPG-7, 0, 0) > +#define VM_MIN_KERNEL_ADDRESS KVADDR(KPML4I, 0, 0, 0) > > #define DMAP_MIN_ADDRESS KVADDR(DMPML4I, 0, 0, 0) > #define DMAP_MAX_ADDRESS KVADDR(DMPML4I+1, 0, 0, 0) > > will now get you this: > > vm.kvm_free: 547729960960 > vm.kvm_size: 549755809792 > > on HEAD. :-) > ---- > > Kris