From owner-svn-src-all@FreeBSD.ORG Thu Jan 23 19:39:30 2014 Return-Path: Delivered-To: svn-src-all@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 ESMTPS id B1B84788; Thu, 23 Jan 2014 19:39:30 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 839F411FD; Thu, 23 Jan 2014 19:39:30 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 01566B983; Thu, 23 Jan 2014 14:39:29 -0500 (EST) From: John Baldwin To: Adrian Chadd Subject: Re: svn commit: r260898 - head/sys/kern Date: Thu, 23 Jan 2014 14:30:46 -0500 User-Agent: KMail/1.13.5 (FreeBSD/8.4-CBSD-20130906; KDE/4.5.5; amd64; ; ) References: <201401200159.s0K1xa5X012123@svn.freebsd.org> <0F26E4E1-5D75-413E-B92B-AA7092B87D89@FreeBSD.org> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201401231430.46532.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Thu, 23 Jan 2014 14:39:29 -0500 (EST) Cc: "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" , Rui Paulo , Neel Natu X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Jan 2014 19:39:30 -0000 On Thursday, January 23, 2014 2:35:54 am Adrian Chadd wrote: > On 22 January 2014 20:34, Rui Paulo wrote: > > On 22 Jan 2014, at 20:05, Adrian Chadd wrote: > > > >> .. Make it be an offset into the table rather than a pointer, then we can do dirty rcu style hacks to just replace and grow the table as we need more memory. > >> > >> Don't we have a standard way to pull memory from the top of the physmem area early on for allocations like this? > > > > Perhaps a bit overkill for this problem? > > We already have platform dependent ways of doing this in the VM init > path for exactly this - structures needed early at boot. > > It may be overkill but it may also be the cleanest way to allow > boot-time tuned things based on early available information, which we > may want to do when it's time to boot a single kernel on a 2-core atom > board or a 256 core intel/amd server board. The number of witness structures (WITNESS_COUNT) should not vary in those cases. -- John Baldwin