diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 14 | ||||
| -rw-r--r-- | kernel/exit.c | 12 | ||||
| -rw-r--r-- | kernel/sched/psi.c | 21 | ||||
| -rw-r--r-- | kernel/workqueue.c | 23 | ||||
| -rw-r--r-- | kernel/workqueue_internal.h | 6 |
5 files changed, 62 insertions, 14 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 3cd13a30f732..e5ede6918050 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -436,18 +436,18 @@ int perf_proc_update_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { - int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); - - if (ret || !write) - return ret; - + int ret; + int perf_cpu = sysctl_perf_cpu_time_max_percent; /* * If throttling is disabled don't allow the write: */ - if (sysctl_perf_cpu_time_max_percent == 100 || - sysctl_perf_cpu_time_max_percent == 0) + if (write && (perf_cpu == 100 || perf_cpu == 0)) return -EINVAL; + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + if (ret || !write) + return ret; + max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; update_perf_cpu_limits(); diff --git a/kernel/exit.c b/kernel/exit.c index 3fb7be001964..2639a30a8aa5 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -558,12 +558,14 @@ static struct task_struct *find_alive_thread(struct task_struct *p) return NULL; } -static struct task_struct *find_child_reaper(struct task_struct *father) +static struct task_struct *find_child_reaper(struct task_struct *father, + struct list_head *dead) __releases(&tasklist_lock) __acquires(&tasklist_lock) { struct pid_namespace *pid_ns = task_active_pid_ns(father); struct task_struct *reaper = pid_ns->child_reaper; + struct task_struct *p, *n; if (likely(reaper != father)) return reaper; @@ -579,6 +581,12 @@ static struct task_struct *find_child_reaper(struct task_struct *father) panic("Attempted to kill init! exitcode=0x%08x\n", father->signal->group_exit_code ?: father->exit_code); } + + list_for_each_entry_safe(p, n, dead, ptrace_entry) { + list_del_init(&p->ptrace_entry); + release_task(p); + } + zap_pid_ns_processes(pid_ns); write_lock_irq(&tasklist_lock); @@ -668,7 +676,7 @@ static void forget_original_parent(struct task_struct *father, exit_ptrace(father, dead); /* Can drop and reacquire tasklist_lock */ - reaper = find_child_reaper(father); + reaper = find_child_reaper(father, dead); if (list_empty(&father->children)) return; diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index fe24de3fbc93..c3484785b179 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -124,6 +124,7 @@ * sampling of the aggregate task states would be. */ +#include "../workqueue_internal.h" #include <linux/sched/loadavg.h> #include <linux/seq_file.h> #include <linux/proc_fs.h> @@ -480,9 +481,6 @@ static void psi_group_change(struct psi_group *group, int cpu, groupc->tasks[t]++; write_seqcount_end(&groupc->seq); - - if (!delayed_work_pending(&group->clock_work)) - schedule_delayed_work(&group->clock_work, PSI_FREQ); } static struct psi_group *iterate_groups(struct task_struct *task, void **iter) @@ -513,6 +511,7 @@ void psi_task_change(struct task_struct *task, int clear, int set) { int cpu = task_cpu(task); struct psi_group *group; + bool wake_clock = true; void *iter = NULL; if (!task->pid) @@ -530,8 +529,22 @@ void psi_task_change(struct task_struct *task, int clear, int set) task->psi_flags &= ~clear; task->psi_flags |= set; - while ((group = iterate_groups(task, &iter))) + /* + * Periodic aggregation shuts off if there is a period of no + * task changes, so we wake it back up if necessary. However, + * don't do this if the task change is the aggregation worker + * itself going to sleep, or we'll ping-pong forever. + */ + if (unlikely((clear & TSK_RUNNING) && + (task->flags & PF_WQ_WORKER) && + wq_worker_last_func(task) == psi_update_work)) + wake_clock = false; + + while ((group = iterate_groups(task, &iter))) { psi_group_change(group, cpu, clear, set); + if (wake_clock && !delayed_work_pending(&group->clock_work)) + schedule_delayed_work(&group->clock_work, PSI_FREQ); + } } void psi_memstall_tick(struct task_struct *task, int cpu) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 392be4b252f6..fc5d23d752a5 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -910,6 +910,26 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task) } /** + * wq_worker_last_func - retrieve worker's last work function + * + * Determine the last function a worker executed. This is called from + * the scheduler to get a worker's last known identity. + * + * CONTEXT: + * spin_lock_irq(rq->lock) + * + * Return: + * The last work function %current executed as a worker, NULL if it + * hasn't executed any work yet. + */ +work_func_t wq_worker_last_func(struct task_struct *task) +{ + struct worker *worker = kthread_data(task); + + return worker->last_func; +} + +/** * worker_set_flags - set worker flags and adjust nr_running accordingly * @worker: self * @flags: flags to set @@ -2184,6 +2204,9 @@ __acquires(&pool->lock) if (unlikely(cpu_intensive)) worker_clr_flags(worker, WORKER_CPU_INTENSIVE); + /* tag the worker for identification in schedule() */ + worker->last_func = worker->current_func; + /* we're done with it, release */ hash_del(&worker->hentry); worker->current_work = NULL; diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h index 66fbb5a9e633..cb68b03ca89a 100644 --- a/kernel/workqueue_internal.h +++ b/kernel/workqueue_internal.h @@ -53,6 +53,9 @@ struct worker { /* used only by rescuers to point to the target workqueue */ struct workqueue_struct *rescue_wq; /* I: the workqueue to rescue */ + + /* used by the scheduler to determine a worker's last known identity */ + work_func_t last_func; }; /** @@ -67,9 +70,10 @@ static inline struct worker *current_wq_worker(void) /* * Scheduler hooks for concurrency managed workqueue. Only to be used from - * sched/core.c and workqueue.c. + * sched/ and workqueue.c. */ void wq_worker_waking_up(struct task_struct *task, int cpu); struct task_struct *wq_worker_sleeping(struct task_struct *task); +work_func_t wq_worker_last_func(struct task_struct *task); #endif /* _KERNEL_WORKQUEUE_INTERNAL_H */ |