From owner-svn-src-head@FreeBSD.ORG Tue Dec 18 10:08:01 2012 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id A1139CB8; Tue, 18 Dec 2012 10:08:01 +0000 (UTC) (envelope-from alc@rice.edu) Received: from mh11.mail.rice.edu (mh11.mail.rice.edu [128.42.199.30]) by mx1.freebsd.org (Postfix) with ESMTP id 6574D8FC12; Tue, 18 Dec 2012 10:08:01 +0000 (UTC) Received: from mh11.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh11.mail.rice.edu (Postfix) with ESMTP id 6F96B4C050A; Tue, 18 Dec 2012 03:59:33 -0600 (CST) Received: from mh11.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh11.mail.rice.edu (Postfix) with ESMTP id 6DE164C0501; Tue, 18 Dec 2012 03:59:33 -0600 (CST) X-Virus-Scanned: by amavis-2.7.0 at mh11.mail.rice.edu, auth channel Received: from mh11.mail.rice.edu ([127.0.0.1]) by mh11.mail.rice.edu (mh11.mail.rice.edu [127.0.0.1]) (amavis, port 10026) with ESMTP id Cm9SGs536314; Tue, 18 Dec 2012 03:59:33 -0600 (CST) Received: from adsl-216-63-78-18.dsl.hstntx.swbell.net (adsl-216-63-78-18.dsl.hstntx.swbell.net [216.63.78.18]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) (Authenticated sender: alc) by mh11.mail.rice.edu (Postfix) with ESMTPSA id E0F704C0233; Tue, 18 Dec 2012 03:59:32 -0600 (CST) Message-ID: <50D03E83.8060908@rice.edu> Date: Tue, 18 Dec 2012 03:59:31 -0600 From: Alan Cox User-Agent: Mozilla/5.0 (X11; FreeBSD i386; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Oleksandr Tymoshenko Subject: Re: svn commit: r243631 - in head/sys: kern sys References: <201211272119.qARLJxXV061083@svn.freebsd.org> <50C1BC90.90106@freebsd.org> <50C25A27.4060007@bluezbox.com> <50C26331.6030504@freebsd.org> <50C26AE9.4020600@bluezbox.com> <50C3A3D3.9000804@freebsd.org> <50C3AF72.4010902@rice.edu> <330405A1-312A-45A5-BB86-4969478D8BBD@bluezbox.com> In-Reply-To: <330405A1-312A-45A5-BB86-4969478D8BBD@bluezbox.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Andre Oppermann X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Dec 2012 10:08:01 -0000 On 12/17/2012 23:40, Oleksandr Tymoshenko wrote: > On 2012-12-08, at 1:21 PM, Alan Cox wrote: > >> On 12/08/2012 14:32, Andre Oppermann wrote: > .. skipped .. > >>> The trouble seems to come from NSFBUFS which is (512 + maxusers * 16) >>> resulting in a kernel map of (512 + 400 * 16) * PAGE_SIZE = 27MB. This >>> seem to be pushing it with the smaller ARM kmap layout. >>> >>> Does it boot and run when you set the tunable kern.ipc.nsfbufs=3500? >>> >>> ARM does have a direct map mode as well which doesn't require the >>> allocation >>> of sfbufs. I'm not sure which other problems that approach has. >>> >> >> Only a few (3?) platforms use it. It reduces the size of the user >> address space, and translation between physical addresses and direct map >> addresses is not computationally trivial as it is on other >> architectures, e.g., amd64, ia64. However, it does try to use large >> page mappings. >> >> >>> Hopefully alc@ (added to cc) can answer that and also why the kmap of >>> 27MB >>> manages to wrench the ARM kernel. >>> >> >> Arm does not define caps on either the buffer map size (param.h) or the >> kmem map size (vmparam.h). It would probably make sense to copy these >> definitions from i386. > > Adding caps didn't help. I did some digging and found out that although address range > 0xc0000000 .. 0xffffffff is indeed valid for ARM in general actual KVA space varies for > each specific hardware platform. This "real" KVA is defined by > pair and ifI use them instead of > in init_param2 function my pandaboard successfully boots. Since former pair is used for defining > kernel_map boundaries I believe it should be used for auto tuning as well. That makes sense. However, "virtual_avail" isn't the start of the kernel address space. The kernel map always starts at VM_MIN_KERNEL_ADDRESS. (See kmem_init().) "virtual_avail" represents the next unallocated virtual address in the kernel address space at an early point in initialization. "virtual_avail" and "virtual_end" aren't used after that, or outside the VM system. Please use vm_map_min(kernel_map) and vm_map_max(kernel_map) instead. That said, I would still add caps on the buffer map and kmem map size. As memory sizes on arm systems grow, you'll eventually need them, just like we did on i386. Alan