From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754219Ab0E2AKZ (ORCPT ); Fri, 28 May 2010 20:10:25 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:57092 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752627Ab0E2AKX (ORCPT ); Fri, 28 May 2010 20:10:23 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; b=uVuH6Rlyb2dYTzfUF81BHXVXMs0eBveT/Kp2fBfOzxoze13EoAlxcgE/OB+PiHX+v9 vPbFjhbCckgqwjAFiozxuLwKuAMdwQ9OrzZ00WChBYfmAmPyX3OQXWEWvsVDHV+NUtJO D1LV1gwYWE6ILZBLQKtFN4IXEk2WipRCGWrJ4= Message-ID: <4C005B6C.4090006@gmail.com> Date: Fri, 28 May 2010 17:10:20 -0700 From: JD User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: [PATCH V3] x86, UV: BAU performance and error recovery References: <4BFFEFA1.1020307@zytor.com> <20100528164725.GA29208@suse.de> <20100528194334.GA7707@sgi.com> <20100528222321.GC25513@suse.de> <20100528233623.GA11356@sgi.com> In-Reply-To: <20100528233623.GA11356@sgi.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/28/2010 04:36 PM, Cliff Wickman wrote: > On Fri, May 28, 2010 at 03:23:21PM -0700, Greg KH wrote: > >> On Fri, May 28, 2010 at 02:43:35PM -0500, Cliff Wickman wrote: >> >>> On Fri, May 28, 2010 at 09:47:25AM -0700, Greg KH wrote: >>> >>>> On Fri, May 28, 2010 at 09:30:25AM -0700, H. Peter Anvin wrote: >>>> >>>>> On 05/28/2010 06:33 AM, Cliff Wickman wrote: >>>>> >>>>>> - adds modification of tuning variables through /proc/sgi_uv >>>>>> >>>>> Adding new directories in /proc for a proprietary architecture is >>>>> frowned upon, to put it mildly. At the very least try to find a place >>>>> in sysfs for it. >>>>> >>>>> [Cc: gregkh in order to find a place in sysfs] >>>>> >>>> Hm, what type of files are you needing here? Do they corrispond with >>>> any specific hardware devices? If so, just put them on the hardware >>>> devices in sysfs. >>>> >>>> thanks, >>>> >>>> greg k-h >>>> >>> There is an SGI-specific directory in sysfs: /sys/firmware/sgi_uv >>> though the tuning variables for the handling of the hardware Broadcast >>> Assist Unit don't fit there very logically. >>> >>> The BAU's statistics are already displayed through the UV-only >>> /proc/sgi_uv/ptc_statistics. This was deemed necessary because of the >>> potentially very large size of that file --- it is still true that a /sys file >>> is limited to one page, is it not? >>> >> It is limited to one single value, which would never be larger than a >> page, so yes, it is limited to one page. >> >> What kind of information are you showing here? Should this thing just >> be in debugfs instead? You can do whatever you want there. >> >> thanks, >> >> greg k-h >> > /proc/sgi_uv/bau_tunables would be a read/write file to display and change > nine threshold and delay values for tuning the BAU driver. > > I like debugfs, except that a distro may not build the kernel with it > configured on. The tunables should be available as administrative > options on a customer kernel, not just as a development tool. > > And in our case the distros are already building with other such writable > options in /proc/sgi_uv. We'd like to postpone a wholesale move of such > options (assuming there will be some better place) and stay with the existing > location for this release. > > I know we (the community) would like to move non-process info out of /proc. > It seems to me that we need a similar filesystem for large and/or > administrative files. That's my perspective. > > -Cliff > Would the similar filesystem you propose be backed by permanent storage, unlike /proc?