From owner-svn-src-all@FreeBSD.ORG Mon Jan 7 19:42:41 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id E7DD5F41; Mon, 7 Jan 2013 19:42:41 +0000 (UTC) (envelope-from alc@rice.edu) Received: from mh10.mail.rice.edu (mh10.mail.rice.edu [128.42.201.30]) by mx1.freebsd.org (Postfix) with ESMTP id AF9251D6; Mon, 7 Jan 2013 19:42:41 +0000 (UTC) Received: from mh10.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh10.mail.rice.edu (Postfix) with ESMTP id 1D0C1604C9; Mon, 7 Jan 2013 13:32:36 -0600 (CST) Received: from mh10.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh10.mail.rice.edu (Postfix) with ESMTP id 1B563603DA; Mon, 7 Jan 2013 13:32:36 -0600 (CST) X-Virus-Scanned: by amavis-2.7.0 at mh10.mail.rice.edu, auth channel Received: from mh10.mail.rice.edu ([127.0.0.1]) by mh10.mail.rice.edu (mh10.mail.rice.edu [127.0.0.1]) (amavis, port 10026) with ESMTP id rdXnTEeZlyAu; Mon, 7 Jan 2013 13:32:36 -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 mh10.mail.rice.edu (Postfix) with ESMTPSA id 1E3D5604C6; Mon, 7 Jan 2013 13:32:35 -0600 (CST) Message-ID: <50EB22D2.6090103@rice.edu> Date: Mon, 07 Jan 2013 13:32:34 -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> <50D03E83.8060908@rice.edu> <50DD081E.8000409@bluezbox.com> <50EB1841.5030006@bluezbox.com> In-Reply-To: <50EB1841.5030006@bluezbox.com> Content-Type: text/plain; charset=windows-1252 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-all@freebsd.org X-Mailman-Version: 2.1.14 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: Mon, 07 Jan 2013 19:42:42 -0000 On 01/07/2013 12:47, Oleksandr Tymoshenko wrote: > On 12/27/2012 6:46 PM, Oleksandr Tymoshenko wrote: >> On 12/18/2012 1:59 AM, Alan Cox wrote: >>> 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 >>> VM_MAX_KERNEL_ADDRESS> >>>> 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. >> >> I checked: kernel_map is not available (NULL) at this point. So we >> can't use it to >> determine real KVA size. Closest thing we can get is >> virtual_avail/virtual_end pair. >> >> Andre, could you approve attached patch for commit or suggest better >> solution? > > Any update on this one? Can I proceed with commit? > Sorry, I've been away from my e-mail since the 30th, and I'm now in the process of getting caught up. Give me a day or so to look at this. Alan