Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758863AbaGCJjA (ORCPT ); Thu, 3 Jul 2014 05:39:00 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:52439 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030407AbaGCJYf (ORCPT ); Thu, 3 Jul 2014 05:24:35 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Thomas Gleixner , Rui Xiang , Luis Henriques Subject: [PATCH 3.11 158/198] nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off Date: Thu, 3 Jul 2014 10:20:01 +0100 Message-Id: <1404379241-8590-159-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1404379241-8590-1-git-send-email-luis.henriques@canonical.com> References: <1404379241-8590-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.13 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner commit 0e576acbc1d9600cf2d9b4a141a2554639959d50 upstream. If CONFIG_NO_HZ=n tick_nohz_get_sleep_length() returns NSEC_PER_SEC/HZ. If CONFIG_NO_HZ=y and the nohz functionality is disabled via the command line option "nohz=off" or not enabled due to missing hardware support, then tick_nohz_get_sleep_length() returns 0. That happens because ts->sleep_length is never set in that case. Set it to NSEC_PER_SEC/HZ when the NOHZ mode is inactive. Reported-by: Michal Hocko Reported-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: Rui Xiang Signed-off-by: Luis Henriques --- kernel/time/tick-sched.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index e8a1516cc0a3..9e62bdc9b095 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -714,8 +714,10 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) return false; } - if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE)) + if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE)) { + ts->sleep_length = (ktime_t) { .tv64 = NSEC_PER_SEC/HZ }; return false; + } if (need_resched()) return false; -- 1.9.1 -- 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/