Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751524Ab3IPWnx (ORCPT ); Mon, 16 Sep 2013 18:43:53 -0400 Received: from mail-pb0-f49.google.com ([209.85.160.49]:53433 "EHLO mail-pb0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750953Ab3IPWnw (ORCPT ); Mon, 16 Sep 2013 18:43:52 -0400 From: Kevin Hilman To: Frederic Weisbecker Cc: linux-arm-kernel@lists.infradead.org, linaro-kernel@lists.linaro.org, Paul McKenney , linux-kernel@vger.kernel.org Subject: [PATCH 1/2] sched/nohz: add debugfs control over sched_tick_max_deferment Date: Mon, 16 Sep 2013 15:43:48 -0700 Message-Id: <1379371429-22214-1-git-send-email-khilman@linaro.org> X-Mailer: git-send-email 1.8.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1692 Lines: 60 Allow debugfs override of sched_tick_max_deferment in order to ease finding/fixing the remaining issues with full nohz. The value to be written is in jiffies, and -1 means the max deferment is disabled (scheduler_tick_max_deferment() returns KTIME_MAX.) Cc: Frederic Weisbecker Signed-off-by: Kevin Hilman --- kernel/sched/core.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5ac63c9..4b1fe3e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2175,6 +2175,8 @@ void scheduler_tick(void) } #ifdef CONFIG_NO_HZ_FULL +static u32 sched_tick_max_deferment = HZ; + /** * scheduler_tick_max_deferment * @@ -2193,13 +2195,25 @@ u64 scheduler_tick_max_deferment(void) struct rq *rq = this_rq(); unsigned long next, now = ACCESS_ONCE(jiffies); - next = rq->last_sched_tick + HZ; + if (sched_tick_max_deferment == -1) + return KTIME_MAX; + + next = rq->last_sched_tick + sched_tick_max_deferment; if (time_before_eq(next, now)) return 0; return jiffies_to_usecs(next - now) * NSEC_PER_USEC; } + +static __init int sched_nohz_full_init_debug(void) +{ + debugfs_create_u32("sched_tick_max_deferment", 0644, NULL, + &sched_tick_max_deferment); + + return 0; +} +late_initcall(sched_nohz_full_init_debug); #endif notrace unsigned long get_parent_ip(unsigned long addr) -- 1.8.3 -- 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/