Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755410Ab1C3A6q (ORCPT ); Tue, 29 Mar 2011 20:58:46 -0400 Received: from relay2.sgi.com ([192.48.179.30]:36444 "HELO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1753889Ab1C3A6p (ORCPT ); Tue, 29 Mar 2011 20:58:45 -0400 Message-ID: <4D928046.9010702@sgi.com> Date: Tue, 29 Mar 2011 17:58:46 -0700 From: Mike Travis User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Andrew Morton Cc: Thomas Gleixner , Jack Steiner , Lee Schermerhorn , Andy Shevchenko , LKML Subject: Re: [PATCH] bitmap, irq: Add smp_affinity_list interface to /proc/irq References: <4D926F6C.8010705@sgi.com> <20110329165612.bd6ad7e4.akpm@linux-foundation.org> <20110329174314.80cf7b50.akpm@linux-foundation.org> <4D927E86.90400@sgi.com> <20110329175614.0c41ae8c.akpm@linux-foundation.org> In-Reply-To: <20110329175614.0c41ae8c.akpm@linux-foundation.org> 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 Content-Length: 1823 Lines: 48 Andrew Morton wrote: > On Tue, 29 Mar 2011 17:51:18 -0700 Mike Travis wrote: > >>> Also, the patch adds a new interface which duplicates an existing one, >>> only the formats are different, yes? This is, of course, bad. >>> >>> The only justification we've seen for being bad is "Manually adjusting >>> the smp_affinity for IRQ's becomes unwieldy when the cpu count is >>> large". A more thorough description of how painful this is might help >>> motivate people to do bad things to the kernel. >>> >>> Also, if it's just a matter of an alternative presentation of the data, >>> why not implement the desired user interface with a little userspace >>> tool then feed the results down into the existing kernel interface? >>> >> Setting smp affinity to cpus 256 to 263 would be: >> >> echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity >> >> instead of: >> >> echo 256-263 > smp_affinity_list >> >> Think about what it looks like for cpus around say, 4088 to 4095. >> >> We already have many alternate "list" interfaces: >> >> /sys/devices/system/cpu/cpuX/indexY/shared_cpu_list >> /sys/devices/system/cpu/cpuX/topology/thread_siblings_list >> /sys/devices/system/cpu/cpuX/topology/core_siblings_list >> /sys/devices/system/node/nodeX/cpulist >> /sys/devices/pci***/***/local_cpulist >> >> etc. >> >> This just expands on that same philosophy. > > You mean that if someone had written a stupid little tool to convert a > list of tuples into a bitmap, we wouldn't have needed to add all that > crap to the kernel? > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/