From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 9 15:50:20 2009 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 7E32C106568F for ; Mon, 9 Nov 2009 15:50:20 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 518C88FC30 for ; Mon, 9 Nov 2009 15:50:20 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id DD0C046B0D; Mon, 9 Nov 2009 10:50:19 -0500 (EST) Received: from jhbbsd.hudson-trading.com (unknown [209.249.190.8]) by bigwig.baldwin.cx (Postfix) with ESMTPA id 176AD8A01F; Mon, 9 Nov 2009 10:50:19 -0500 (EST) From: John Baldwin To: freebsd-hackers@freebsd.org Date: Mon, 9 Nov 2009 09:27:04 -0500 User-Agent: KMail/1.9.7 References: <761362.20406.qm@web113204.mail.gq1.yahoo.com> In-Reply-To: <761362.20406.qm@web113204.mail.gq1.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200911090927.05010.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Mon, 09 Nov 2009 10:50:19 -0500 (EST) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=4.2 tests=AWL,BAYES_00,RDNS_NONE autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: Trever Subject: Re: Why is default value of NKPT so small? mfsroot X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Nov 2009 15:50:20 -0000 On Friday 06 November 2009 2:19:51 pm Trever wrote: > Does anyone know what the thinking is behind the default value of NKTP in /usr/src/sys/i386/include/pmap.h? > > It seems to me that it's too small, though I'm wondering if there are some considerations in changing it's value that I should know about. > > Too small because: making it a little more than twice as large (so you can get about a 300MB mfsroot to boot) means you can (by default) boot a standard FreeBSD system into memory, and I know I can't be the only one who would value that a great deal for many reasons. As it stands you have to ax things out (like depenguinator does, for example). Or you have to recompile the kernel. > > Does it have to be like this? > > Which leads me to two more questions: > - is it possible to change the NKTP value without recompiling the kernel? I think there isn't but I'll ask. > - is it possible to change the NKTP value without editing pmap.h (can I pass a variable into the kernel build process)? I keep meaning to make NKPT a kernel option for i386. Try this patch, it should let you add 'options NKPT=xxx' to your kernel config. Index: conf/options.i386 =================================================================== --- conf/options.i386 (revision 198997) +++ conf/options.i386 (working copy) @@ -12,6 +12,7 @@ MAXMEM MPTABLE_FORCE_HTT MP_WATCHDOG +NKPT opt_pmap.h PERFMON PMAP_SHPGPERPROC opt_pmap.h POWERFAIL_NMI opt_trap.h Index: i386/i386/mp_machdep.c =================================================================== --- i386/i386/mp_machdep.c (revision 198997) +++ i386/i386/mp_machdep.c (working copy) @@ -30,6 +30,7 @@ #include "opt_cpu.h" #include "opt_kstack_pages.h" #include "opt_mp_watchdog.h" +#include "opt_pmap.h" #include "opt_sched.h" #include "opt_smp.h" Index: i386/xen/mp_machdep.c =================================================================== --- i386/xen/mp_machdep.c (revision 198997) +++ i386/xen/mp_machdep.c (working copy) @@ -31,6 +31,7 @@ #include "opt_cpu.h" #include "opt_kstack_pages.h" #include "opt_mp_watchdog.h" +#include "opt_pmap.h" #include "opt_sched.h" #include "opt_smp.h" -- John Baldwin