Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750779AbWJNEz2 (ORCPT ); Sat, 14 Oct 2006 00:55:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752072AbWJNEz2 (ORCPT ); Sat, 14 Oct 2006 00:55:28 -0400 Received: from omx2-ext.sgi.com ([192.48.171.19]:39297 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S1750779AbWJNEz2 (ORCPT ); Sat, 14 Oct 2006 00:55:28 -0400 From: Paul Jackson To: Dinakar Guniguntala Cc: Simon.Derr@bull.net, Paul Jackson , linux-kernel@vger.kernel.org Date: Fri, 13 Oct 2006 21:55:17 -0700 Message-Id: <20061014045517.22007.863.sendpatchset@v0> Subject: [RFC] Cpuset: remove useless sched domain line Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2196 Lines: 62 Dinakar, (1) Does this patch look right to you? (2) I don't understand this code: * When do we ever create sched domains for cpusets that -are- cpu_exclusive? All I see here are calls to partition_sched_domains() with various permutations of pspan and cspan that are the cpus from various non-exclusive cpusets. * Why do we return (setting up no sched domains at this time) if the current cpuset's cpus covers all the non exclusive cpus of our parent, but continue on to make a sched domain just for our parent if there are other non-exclusive cpus in our sibling cpusets? ==== Remove a useless line from the sched domain setup code in cpusets. When I removed the 'is_removed()' flag test from the sched domain setup code in cpusets, as part of my July 23, 2006 patch: Cpuset: fix ABBA deadlock with cpu hotplug lock I failed to notice that this opened the door to a little bit of code simplification. A line of code that had to cover for the possibility that a cpuset marked cpu_exclusive was marked for removal could be eliminated. In the code section visible in this patch, it is now the case that cur->cpus_allowed is always a subset of pspan, so it is always a no-op to cpus_or() cur->cpus_allowed into pspan. Signed-off-by: Paul Jackson --- kernel/cpuset.c | 1 - 1 files changed, 1 deletion(-) --- 2.6.19-rc1-mm1.orig/kernel/cpuset.c 2006-10-13 21:31:16.000000000 -0700 +++ 2.6.19-rc1-mm1/kernel/cpuset.c 2006-10-13 21:32:20.000000000 -0700 @@ -783,7 +783,6 @@ static void update_cpu_domains(struct cp cpus_andnot(pspan, pspan, c->cpus_allowed); } if (!is_cpu_exclusive(cur)) { - cpus_or(pspan, pspan, cur->cpus_allowed); if (cpus_equal(pspan, cur->cpus_allowed)) return; cspan = CPU_MASK_NONE; -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401 - 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/