From f4904815f97a934258445a8f763f6b6c48f007e7 Mon Sep 17 00:00:00 2001 From: Dietmar Eggemann Date: Fri, 2 Aug 2019 15:59:43 +0100 Subject: sched/deadline: Fix double accounting of rq/running bw in push & pull {push,pull}_dl_task() always calls {de,}activate_task() with .flags=0 which sets p->on_rq=TASK_ON_RQ_MIGRATING. {push,pull}_dl_task()->{de,}activate_task()->{de,en}queue_task()-> {de,en}queue_task_dl() calls {sub,add}_{running,rq}_bw() since p->on_rq==TASK_ON_RQ_MIGRATING. So {sub,add}_{running,rq}_bw() in {push,pull}_dl_task() is double-accounting for that task. Fix it by removing rq/running bw accounting in [push/pull]_dl_task(). Fixes: 7dd778841164 ("sched/core: Unify p->on_rq updates") Signed-off-by: Dietmar Eggemann Signed-off-by: Peter Zijlstra (Intel) Cc: Valentin Schneider Cc: Ingo Molnar Cc: Luca Abeni Cc: Daniel Bristot de Oliveira Cc: Juri Lelli Cc: Qais Yousef Link: https://lkml.kernel.org/r/20190802145945.18702-2-dietmar.eggemann@arm.com --- kernel/sched/deadline.c | 8 -------- 1 file changed, 8 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index ef5b9f6b1d42..46122edd8552 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2088,17 +2088,13 @@ retry: } deactivate_task(rq, next_task, 0); - sub_running_bw(&next_task->dl, &rq->dl); - sub_rq_bw(&next_task->dl, &rq->dl); set_task_cpu(next_task, later_rq->cpu); - add_rq_bw(&next_task->dl, &later_rq->dl); /* * Update the later_rq clock here, because the clock is used * by the cpufreq_update_util() inside __add_running_bw(). */ update_rq_clock(later_rq); - add_running_bw(&next_task->dl, &later_rq->dl); activate_task(later_rq, next_task, ENQUEUE_NOCLOCK); ret = 1; @@ -2186,11 +2182,7 @@ static void pull_dl_task(struct rq *this_rq) resched = true; deactivate_task(src_rq, p, 0); - sub_running_bw(&p->dl, &src_rq->dl); - sub_rq_bw(&p->dl, &src_rq->dl); set_task_cpu(p, this_cpu); - add_rq_bw(&p->dl, &this_rq->dl); - add_running_bw(&p->dl, &this_rq->dl); activate_task(this_rq, p, 0); dmin = p->dl.deadline; -- cgit v1.2.3 From 14f5c7b46a41a595fc61db37f55721714729e59e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 1 Aug 2019 12:41:31 +0200 Subject: sched/psi: Reduce psimon FIFO priority PSI defaults to a FIFO-99 thread, reduce this to FIFO-1. FIFO-99 is the very highest priority available to SCHED_FIFO and it not a suitable default; it would indicate the psi work is the most important work on the machine. Since Real-Time tasks will have pre-allocated memory and locked it in place, Real-Time tasks do not care about PSI. All it needs is to be above OTHER. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Johannes Weiner Tested-by: Suren Baghdasaryan Cc: Thomas Gleixner --- kernel/sched/psi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 7acc632c3b82..7fe2c5fd26b5 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -1051,7 +1051,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, if (!rcu_access_pointer(group->poll_kworker)) { struct sched_param param = { - .sched_priority = MAX_RT_PRIO - 1, + .sched_priority = 1, }; struct kthread_worker *kworker; -- cgit v1.2.3 From 04e048cf09d7b5fc995817cdc5ae1acd4482429c Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Mon, 29 Jul 2019 18:33:10 -0700 Subject: sched/psi: Do not require setsched permission from the trigger creator When a process creates a new trigger by writing into /proc/pressure/* files, permissions to write such a file should be used to determine whether the process is allowed to do so or not. Current implementation would also require such a process to have setsched capability. Setting of psi trigger thread's scheduling policy is an implementation detail and should not be exposed to the user level. Remove the permission check by using _nocheck version of the function. Suggested-by: Nick Kralevich Signed-off-by: Suren Baghdasaryan Signed-off-by: Peter Zijlstra (Intel) Cc: lizefan@huawei.com Cc: mingo@redhat.com Cc: akpm@linux-foundation.org Cc: kernel-team@android.com Cc: dennisszhou@gmail.com Cc: dennis@kernel.org Cc: hannes@cmpxchg.org Cc: axboe@kernel.dk Link: https://lkml.kernel.org/r/20190730013310.162367-1-surenb@google.com --- kernel/sched/psi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 7fe2c5fd26b5..23fbbcc414d5 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -1061,7 +1061,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, mutex_unlock(&group->trigger_lock); return ERR_CAST(kworker); } - sched_setscheduler(kworker->task, SCHED_FIFO, ¶m); + sched_setscheduler_nocheck(kworker->task, SCHED_FIFO, ¶m); kthread_init_delayed_work(&group->poll_work, psi_poll_work); rcu_assign_pointer(group->poll_kworker, kworker); -- cgit v1.2.3