From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753235Ab1ARTF7 (ORCPT ); Tue, 18 Jan 2011 14:05:59 -0500 Received: from hera.kernel.org ([140.211.167.34]:53025 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753213Ab1ARTF5 (ORCPT ); Tue, 18 Jan 2011 14:05:57 -0500 Date: Tue, 18 Jan 2011 19:05:26 GMT From: tip-bot for Mike Galbraith Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, bharata@linux.vnet.ibm.com, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, bharata@linux.vnet.ibm.com, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1294890890.8089.39.camel@marge.simson.net> References: <1294890890.8089.39.camel@marge.simson.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failure Message-ID: Git-Commit-ID: f44937718ce3b8360f72f6c68c9481712517a867 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Tue, 18 Jan 2011 19:05:27 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f44937718ce3b8360f72f6c68c9481712517a867 Gitweb: http://git.kernel.org/tip/f44937718ce3b8360f72f6c68c9481712517a867 Author: Mike Galbraith AuthorDate: Thu, 13 Jan 2011 04:54:50 +0100 Committer: Ingo Molnar CommitDate: Tue, 18 Jan 2011 15:09:42 +0100 sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failure If CONFIG_RT_GROUP_SCHED is set, __sched_setscheduler() fails due to autogroup not allocating rt_runtime. Free unused/unusable rt_se and rt_rq, redirect RT tasks to the root task group, and tell __sched_setscheduler() that it's ok. Reported-and-tested-by: Bharata B Rao Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra LKML-Reference: <1294890890.8089.39.camel@marge.simson.net> Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 ++- kernel/sched_autogroup.c | 27 +++++++++++++++++++++++++++ kernel/sched_autogroup.h | 4 ++++ 3 files changed, 33 insertions(+), 1 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index a0eb094..6cbff6b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4871,7 +4871,8 @@ recheck: * assigned. */ if (rt_bandwidth_enabled() && rt_policy(policy) && - task_group(p)->rt_bandwidth.rt_runtime == 0) { + task_group(p)->rt_bandwidth.rt_runtime == 0 && + !task_group_is_autogroup(task_group(p))) { __task_rq_unlock(rq); raw_spin_unlock_irqrestore(&p->pi_lock, flags); return -EPERM; diff --git a/kernel/sched_autogroup.c b/kernel/sched_autogroup.c index 938d52f..9fb6562 100644 --- a/kernel/sched_autogroup.c +++ b/kernel/sched_autogroup.c @@ -27,6 +27,11 @@ static inline void autogroup_destroy(struct kref *kref) { struct autogroup *ag = container_of(kref, struct autogroup, kref); +#ifdef CONFIG_RT_GROUP_SCHED + /* We've redirected RT tasks to the root task group... */ + ag->tg->rt_se = NULL; + ag->tg->rt_rq = NULL; +#endif sched_destroy_group(ag->tg); } @@ -55,6 +60,10 @@ static inline struct autogroup *autogroup_task_get(struct task_struct *p) return ag; } +#ifdef CONFIG_RT_GROUP_SCHED +static void free_rt_sched_group(struct task_group *tg); +#endif + static inline struct autogroup *autogroup_create(void) { struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL); @@ -72,6 +81,19 @@ static inline struct autogroup *autogroup_create(void) init_rwsem(&ag->lock); ag->id = atomic_inc_return(&autogroup_seq_nr); ag->tg = tg; +#ifdef CONFIG_RT_GROUP_SCHED + /* + * Autogroup RT tasks are redirected to the root task group + * so we don't have to move tasks around upon policy change, + * or flail around trying to allocate bandwidth on the fly. + * A bandwidth exception in __sched_setscheduler() allows + * the policy change to proceed. Thereafter, task_group() + * returns &root_task_group, so zero bandwidth is required. + */ + free_rt_sched_group(tg); + tg->rt_se = root_task_group.rt_se; + tg->rt_rq = root_task_group.rt_rq; +#endif tg->autogroup = ag; return ag; @@ -106,6 +128,11 @@ task_wants_autogroup(struct task_struct *p, struct task_group *tg) return true; } +static inline bool task_group_is_autogroup(struct task_group *tg) +{ + return tg != &root_task_group && tg->autogroup; +} + static inline struct task_group * autogroup_task_group(struct task_struct *p, struct task_group *tg) { diff --git a/kernel/sched_autogroup.h b/kernel/sched_autogroup.h index 5358e24..7b859ff 100644 --- a/kernel/sched_autogroup.h +++ b/kernel/sched_autogroup.h @@ -15,6 +15,10 @@ autogroup_task_group(struct task_struct *p, struct task_group *tg); static inline void autogroup_init(struct task_struct *init_task) { } static inline void autogroup_free(struct task_group *tg) { } +static inline bool task_group_is_autogroup(struct task_group *tg) +{ + return 0; +} static inline struct task_group * autogroup_task_group(struct task_struct *p, struct task_group *tg)