Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755482AbYB0LIv (ORCPT ); Wed, 27 Feb 2008 06:08:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752140AbYB0LIn (ORCPT ); Wed, 27 Feb 2008 06:08:43 -0500 Received: from e28smtp04.in.ibm.com ([59.145.155.4]:41547 "EHLO e28esmtp04.in.ibm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751671AbYB0LIm (ORCPT ); Wed, 27 Feb 2008 06:08:42 -0500 Date: Wed, 27 Feb 2008 16:38:29 +0530 From: Dhaval Giani To: Ingo Molnar , Peter Zijlstra Cc: Sudhir Kumar , Balbir Singh , Aneesh Kumar KV , Srivatsa Vaddagiri , lkml Subject: [PATCH] sched: don't allow rt_runtime_us to be zero for groups having rt tasks Message-ID: <20080227110829.GA15731@linux.vnet.ibm.com> Reply-To: Dhaval Giani MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1813 Lines: 62 This patch checks if we can set the rt_runtime_us to 0. If there is a realtime task in the group, we don't want to set the rt_runtime_us to 0 otherwise bad things will happen. Signed-off-by: Dhaval Giani --- kernel/sched.c | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+) Index: linux-2.6.25-rc3/kernel/sched.c =================================================================== --- linux-2.6.25-rc3.orig/kernel/sched.c +++ linux-2.6.25-rc3/kernel/sched.c @@ -7960,6 +7960,17 @@ static int __rt_schedulable(struct task_ return total + to_ratio(period, runtime) < global_ratio; } +/* Must be called with tasklist_lock held */ +static inline int tg_has_rt_tasks(struct task_group *tg) +{ + struct task_struct *p; + for_each_process(p) { + if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) + return 1; + } + return 0; +} + int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) { u64 rt_runtime, rt_period; @@ -7971,6 +7982,13 @@ int sched_group_set_rt_runtime(struct ta rt_runtime = rt_period; mutex_lock(&rt_constraints_mutex); + read_lock(&tasklist_lock); + if (rt_runtime_us == 0) { + if (tg_has_rt_tasks(tg)) { + err = -EINVAL; + goto unlock; + } + } if (!__rt_schedulable(tg, rt_period, rt_runtime)) { err = -EINVAL; goto unlock; @@ -7979,6 +7997,7 @@ int sched_group_set_rt_runtime(struct ta rt_runtime = RUNTIME_INF; tg->rt_runtime = rt_runtime; unlock: + read_unlock(&tasklist_lock); mutex_unlock(&rt_constraints_mutex); return err; -- regards, Dhaval -- 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/