Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752184AbbEFQFW (ORCPT ); Wed, 6 May 2015 12:05:22 -0400 Received: from mail-wg0-f54.google.com ([74.125.82.54]:33504 "EHLO mail-wg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750698AbbEFQEq (ORCPT ); Wed, 6 May 2015 12:04:46 -0400 From: Frederic Weisbecker To: Ingo Molnar Cc: LKML , Chris Metcalf , "Rafael J . Wysocki" , Peter Zijlstra , Mike Galbraith , Dave Jones , Thomas Gleixner , Oleg Nesterov , "Paul E . McKenney" , Ingo Molnar , Frederic Weisbecker , Rik van Riel , Martin Schwidefsky Subject: [PATCH 4/4] nohz: Set isolcpus when nohz_full is set Date: Wed, 6 May 2015 18:04:26 +0200 Message-Id: <1430928266-24888-5-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1430928266-24888-1-git-send-email-fweisbec@gmail.com> References: <1430928266-24888-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1736 Lines: 48 From: Chris Metcalf nohz_full is only useful with isolcpus also set, since otherwise the scheduler has to run periodically to try to determine whether to steal work from other cores. Accordingly, when booting with nohz_full=xxx on the command line, we should act as if isolcpus=xxx was also set, and set (or extend) the isolcpus set to include the nohz_full cpus. Acked-by: Mike Galbraith ["thumbs up!"] Acked-by: Rik van Riel Acked-by: Peter Zijlstra (Intel) Signed-off-by: Chris Metcalf Cc: Peter Zijlstra (Intel) Cc: Paul E. McKenney Cc: Rafael J. Wysocki Cc: Martin Schwidefsky Cc: Mike Galbraith Cc: Ingo Molnar Cc: Rik van Riel Signed-off-by: Frederic Weisbecker --- kernel/sched/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6f149f8..e95b4d8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7042,6 +7042,9 @@ void __init sched_init_smp(void) alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); alloc_cpumask_var(&fallback_doms, GFP_KERNEL); + /* nohz_full won't take effect without isolating the cpus. */ + tick_nohz_full_add_cpus_to(cpu_isolated_map); + sched_init_numa(); /* -- 2.1.4 -- 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/