From a1ba4d8ba9f06a397e97cbd67a93ee306860b40a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 1 Apr 2009 18:40:15 +0200 Subject: sched_rt: Fix overload bug on rt group scheduling Fixes an easily triggerable BUG() when setting process affinities. Make sure to count the number of migratable tasks in the same place: the root rt_rq. Otherwise the number doesn't make sense and we'll hit the BUG in set_cpus_allowed_rt(). Also, make sure we only count tasks, not groups (this is probably already taken care of by the fact that rt_se->nr_cpus_allowed will be 0 for groups, but be more explicit) Tested-by: Thomas Gleixner CC: stable@kernel.org Signed-off-by: Peter Zijlstra Acked-by: Gregory Haskins LKML-Reference: <1247067476.9777.57.camel@twins> Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 + kernel/sched_rt.c | 18 +++++++++++++++++- 2 files changed, 18 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 7c9098d186e6..a17f3d9a8bfa 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -493,6 +493,7 @@ struct rt_rq { #endif #ifdef CONFIG_SMP unsigned long rt_nr_migratory; + unsigned long rt_nr_total; int overloaded; struct plist_head pushable_tasks; #endif diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 9bf0d2a73045..3918e01994e0 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -10,6 +10,8 @@ static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) #ifdef CONFIG_RT_GROUP_SCHED +#define rt_entity_is_task(rt_se) (!(rt_se)->my_q) + static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) { return rt_rq->rq; @@ -22,6 +24,8 @@ static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) #else /* CONFIG_RT_GROUP_SCHED */ +#define rt_entity_is_task(rt_se) (1) + static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) { return container_of(rt_rq, struct rq, rt); @@ -73,7 +77,7 @@ static inline void rt_clear_overload(struct rq *rq) static void update_rt_migration(struct rt_rq *rt_rq) { - if (rt_rq->rt_nr_migratory && (rt_rq->rt_nr_running > 1)) { + if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) { if (!rt_rq->overloaded) { rt_set_overload(rq_of_rt_rq(rt_rq)); rt_rq->overloaded = 1; @@ -86,6 +90,12 @@ static void update_rt_migration(struct rt_rq *rt_rq) static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + if (!rt_entity_is_task(rt_se)) + return; + + rt_rq = &rq_of_rt_rq(rt_rq)->rt; + + rt_rq->rt_nr_total++; if (rt_se->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory++; @@ -94,6 +104,12 @@ static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + if (!rt_entity_is_task(rt_se)) + return; + + rt_rq = &rq_of_rt_rq(rt_rq)->rt; + + rt_rq->rt_nr_total--; if (rt_se->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory--; -- cgit v1.2.3 From 7793527b90d9418211f4fe8464cc1dcb1631ea1b Mon Sep 17 00:00:00 2001 From: Lucas De Marchi Date: Thu, 9 Jul 2009 13:57:20 +0200 Subject: sched: Reset sched stats on fork() The sched_stat fields are currently not reset upon fork. Ingo's recent commit 6c594c21fcb02c662f11c97be4d7d2b73060a205 did reset nr_migrations, but it didn't reset any of the others. This patch resets all sched_stat fields on fork. Signed-off-by: Lucas De Marchi Signed-off-by: Peter Zijlstra LKML-Reference: <193b0f820907090457s7a3662f4gcdecdc22fcae857b@mail.gmail.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 40 +++++++++++++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index a17f3d9a8bfa..c4549bd7e174 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2572,15 +2572,37 @@ static void __sched_fork(struct task_struct *p) p->se.avg_wakeup = sysctl_sched_wakeup_granularity; #ifdef CONFIG_SCHEDSTATS - p->se.wait_start = 0; - p->se.sum_sleep_runtime = 0; - p->se.sleep_start = 0; - p->se.block_start = 0; - p->se.sleep_max = 0; - p->se.block_max = 0; - p->se.exec_max = 0; - p->se.slice_max = 0; - p->se.wait_max = 0; + p->se.wait_start = 0; + p->se.wait_max = 0; + p->se.wait_count = 0; + p->se.wait_sum = 0; + + p->se.sleep_start = 0; + p->se.sleep_max = 0; + p->se.sum_sleep_runtime = 0; + + p->se.block_start = 0; + p->se.block_max = 0; + p->se.exec_max = 0; + p->se.slice_max = 0; + + p->se.nr_migrations_cold = 0; + p->se.nr_failed_migrations_affine = 0; + p->se.nr_failed_migrations_running = 0; + p->se.nr_failed_migrations_hot = 0; + p->se.nr_forced_migrations = 0; + p->se.nr_forced2_migrations = 0; + + p->se.nr_wakeups = 0; + p->se.nr_wakeups_sync = 0; + p->se.nr_wakeups_migrate = 0; + p->se.nr_wakeups_local = 0; + p->se.nr_wakeups_remote = 0; + p->se.nr_wakeups_affine = 0; + p->se.nr_wakeups_affine_attempts = 0; + p->se.nr_wakeups_passive = 0; + p->se.nr_wakeups_idle = 0; + #endif INIT_LIST_HEAD(&p->rt.run_list); -- cgit v1.2.3 From c20b08e3986c2dbfa6df1e880bf4f7159994d199 Mon Sep 17 00:00:00 2001 From: Fabio Checconi Date: Mon, 15 Jun 2009 20:56:38 +0200 Subject: sched: Fix rt_rq->pushable_tasks initialization in init_rt_rq() init_rt_rq() initializes only rq->rt.pushable_tasks, and not the pushable_tasks field of the passed rt_rq. The plist is not used uninitialized since the only pushable_tasks plists used are the ones of root rt_rqs; anyway reinitializing the list on every group creation corrupts the root plist, losing its previous contents. Signed-off-by: Fabio Checconi Signed-off-by: Peter Zijlstra LKML-Reference: <20090615185638.GK21741@gandalf.sssup.it> CC: Gregory Haskins Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index c4549bd7e174..efecfdad1b5f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -9093,7 +9093,7 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) #ifdef CONFIG_SMP rt_rq->rt_nr_migratory = 0; rt_rq->overloaded = 0; - plist_head_init(&rq->rt.pushable_tasks, &rq->lock); + plist_head_init(&rt_rq->pushable_tasks, &rq->lock); #endif rt_rq->rt_time = 0; -- cgit v1.2.3 From d07387b490b1c43bfcb9f3900faf96f2dafb2630 Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Fri, 10 Jul 2009 17:05:16 -0700 Subject: sched: Fix bug in SCHED_IDLE interaction with group scheduling One of the isolation modifications for SCHED_IDLE is the unitization of sleeper credit. However the check for this assumes that the sched_entity we're placing always belongs to a task. This is potentially not true with group scheduling and leaves us rummaging randomly when we try to pull the policy. Signed-off-by: Paul Turner Cc: peterz@infradead.org LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ba7fd6e9556f..7c248dc30f41 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -687,7 +687,8 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) * all of which have the same weight. */ if (sched_feat(NORMALIZED_SLEEPER) && - task_of(se)->policy != SCHED_IDLE) + (!entity_is_task(se) || + task_of(se)->policy != SCHED_IDLE)) thresh = calc_delta_fair(thresh, se); vruntime -= thresh; -- cgit v1.2.3