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-rw-r--r--kernel/cpu.c6
-rw-r--r--kernel/cpuset.c21
-rw-r--r--kernel/fork.c2
-rw-r--r--kernel/sched.c205
-rw-r--r--kernel/workqueue_sched.h16
5 files changed, 170 insertions, 80 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 97d1b426a4ac..f6e726f18491 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -235,11 +235,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
return -EINVAL;
cpu_hotplug_begin();
- set_cpu_active(cpu, false);
err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
if (err) {
- set_cpu_active(cpu, true);
-
nr_calls--;
__cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL);
printk("%s: attempt to take down CPU %u failed\n",
@@ -249,7 +246,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
if (err) {
- set_cpu_active(cpu, true);
/* CPU didn't die: tell everyone. Can't complain. */
cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu);
@@ -321,8 +317,6 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
goto out_notify;
BUG_ON(!cpu_online(cpu));
- set_cpu_active(cpu, true);
-
/* Now call notifier in preparation. */
cpu_notify(CPU_ONLINE | mod, hcpu);
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 02b9611eadde..05727dcaa80d 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2113,31 +2113,17 @@ static void scan_for_empty_cpusets(struct cpuset *root)
* but making no active use of cpusets.
*
* This routine ensures that top_cpuset.cpus_allowed tracks
- * cpu_online_map on each CPU hotplug (cpuhp) event.
+ * cpu_active_mask on each CPU hotplug (cpuhp) event.
*
* Called within get_online_cpus(). Needs to call cgroup_lock()
* before calling generate_sched_domains().
*/
-static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
- unsigned long phase, void *unused_cpu)
+void __cpuexit cpuset_update_active_cpus(void)
{
struct sched_domain_attr *attr;
cpumask_var_t *doms;
int ndoms;
- switch (phase) {
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- break;
-
- default:
- return NOTIFY_DONE;
- }
-
cgroup_lock();
mutex_lock(&callback_mutex);
cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
@@ -2148,8 +2134,6 @@ static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
/* Have scheduler rebuild the domains */
partition_sched_domains(ndoms, doms, attr);
-
- return NOTIFY_OK;
}
#ifdef CONFIG_MEMORY_HOTPLUG
@@ -2203,7 +2187,6 @@ void __init cpuset_init_smp(void)
cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
- hotcpu_notifier(cpuset_track_online_cpus, 0);
hotplug_memory_notifier(cpuset_track_online_nodes, 10);
cpuset_wq = create_singlethread_workqueue("cpuset");
diff --git a/kernel/fork.c b/kernel/fork.c
index b6cce14ba047..a82a65cef741 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -907,7 +907,7 @@ static void copy_flags(unsigned long clone_flags, struct task_struct *p)
{
unsigned long new_flags = p->flags;
- new_flags &= ~PF_SUPERPRIV;
+ new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER);
new_flags |= PF_FORKNOEXEC;
new_flags |= PF_STARTING;
p->flags = new_flags;
diff --git a/kernel/sched.c b/kernel/sched.c
index f8b8996228dd..edd5a54b95da 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -77,6 +77,7 @@
#include <asm/irq_regs.h>
#include "sched_cpupri.h"
+#include "workqueue_sched.h"
#define CREATE_TRACE_POINTS
#include <trace/events/sched.h>
@@ -2267,11 +2268,55 @@ static void update_avg(u64 *avg, u64 sample)
}
#endif
-/***
+static inline void ttwu_activate(struct task_struct *p, struct rq *rq,
+ bool is_sync, bool is_migrate, bool is_local,
+ unsigned long en_flags)
+{
+ schedstat_inc(p, se.statistics.nr_wakeups);
+ if (is_sync)
+ schedstat_inc(p, se.statistics.nr_wakeups_sync);
+ if (is_migrate)
+ schedstat_inc(p, se.statistics.nr_wakeups_migrate);
+ if (is_local)
+ schedstat_inc(p, se.statistics.nr_wakeups_local);
+ else
+ schedstat_inc(p, se.statistics.nr_wakeups_remote);
+
+ activate_task(rq, p, en_flags);
+}
+
+static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq,
+ int wake_flags, bool success)
+{
+ trace_sched_wakeup(p, success);
+ check_preempt_curr(rq, p, wake_flags);
+
+ p->state = TASK_RUNNING;
+#ifdef CONFIG_SMP
+ if (p->sched_class->task_woken)
+ p->sched_class->task_woken(rq, p);
+
+ if (unlikely(rq->idle_stamp)) {
+ u64 delta = rq->clock - rq->idle_stamp;
+ u64 max = 2*sysctl_sched_migration_cost;
+
+ if (delta > max)
+ rq->avg_idle = max;
+ else
+ update_avg(&rq->avg_idle, delta);
+ rq->idle_stamp = 0;
+ }
+#endif
+ /* if a worker is waking up, notify workqueue */
+ if ((p->flags & PF_WQ_WORKER) && success)
+ wq_worker_waking_up(p, cpu_of(rq));
+}
+
+/**
* try_to_wake_up - wake up a thread
- * @p: the to-be-woken-up thread
+ * @p: the thread to be awakened
* @state: the mask of task states that can be woken
- * @sync: do a synchronous wakeup?
+ * @wake_flags: wake modifier flags (WF_*)
*
* Put it on the run-queue if it's not already there. The "current"
* thread is always on the run-queue (except when the actual
@@ -2279,7 +2324,8 @@ static void update_avg(u64 *avg, u64 sample)
* the simpler "current->state = TASK_RUNNING" to mark yourself
* runnable without the overhead of this.
*
- * returns failure only if the task is already active.
+ * Returns %true if @p was woken up, %false if it was already running
+ * or @state didn't match @p's state.
*/
static int try_to_wake_up(struct task_struct *p, unsigned int state,
int wake_flags)
@@ -2359,38 +2405,11 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
out_activate:
#endif /* CONFIG_SMP */
- schedstat_inc(p, se.statistics.nr_wakeups);
- if (wake_flags & WF_SYNC)
- schedstat_inc(p, se.statistics.nr_wakeups_sync);
- if (orig_cpu != cpu)
- schedstat_inc(p, se.statistics.nr_wakeups_migrate);
- if (cpu == this_cpu)
- schedstat_inc(p, se.statistics.nr_wakeups_local);
- else
- schedstat_inc(p, se.statistics.nr_wakeups_remote);
- activate_task(rq, p, en_flags);
+ ttwu_activate(p, rq, wake_flags & WF_SYNC, orig_cpu != cpu,
+ cpu == this_cpu, en_flags);
success = 1;
-
out_running:
- trace_sched_wakeup(p, success);
- check_preempt_curr(rq, p, wake_flags);
-
- p->state = TASK_RUNNING;
-#ifdef CONFIG_SMP
- if (p->sched_class->task_woken)
- p->sched_class->task_woken(rq, p);
-
- if (unlikely(rq->idle_stamp)) {
- u64 delta = rq->clock - rq->idle_stamp;
- u64 max = 2*sysctl_sched_migration_cost;
-
- if (delta > max)
- rq->avg_idle = max;
- else
- update_avg(&rq->avg_idle, delta);
- rq->idle_stamp = 0;
- }
-#endif
+ ttwu_post_activation(p, rq, wake_flags, success);
out:
task_rq_unlock(rq, &flags);
put_cpu();
@@ -2399,6 +2418,37 @@ out:
}
/**
+ * try_to_wake_up_local - try to wake up a local task with rq lock held
+ * @p: the thread to be awakened
+ *
+ * Put @p on the run-queue if it's not alredy there. The caller must
+ * ensure that this_rq() is locked, @p is bound to this_rq() and not
+ * the current task. this_rq() stays locked over invocation.
+ */
+static void try_to_wake_up_local(struct task_struct *p)
+{
+ struct rq *rq = task_rq(p);
+ bool success = false;
+
+ BUG_ON(rq != this_rq());
+ BUG_ON(p == current);
+ lockdep_assert_held(&rq->lock);
+
+ if (!(p->state & TASK_NORMAL))
+ return;
+
+ if (!p->se.on_rq) {
+ if (likely(!task_running(rq, p))) {
+ schedstat_inc(rq, ttwu_count);
+ schedstat_inc(rq, ttwu_local);
+ }
+ ttwu_activate(p, rq, false, false, true, ENQUEUE_WAKEUP);
+ success = true;
+ }
+ ttwu_post_activation(p, rq, 0, success);
+}
+
+/**
* wake_up_process - Wake up a specific process
* @p: The process to be woken up.
*
@@ -3603,10 +3653,24 @@ need_resched_nonpreemptible:
clear_tsk_need_resched(prev);
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
- if (unlikely(signal_pending_state(prev->state, prev)))
+ if (unlikely(signal_pending_state(prev->state, prev))) {
prev->state = TASK_RUNNING;
- else
+ } else {
+ /*
+ * If a worker is going to sleep, notify and
+ * ask workqueue whether it wants to wake up a
+ * task to maintain concurrency. If so, wake
+ * up the task.
+ */
+ if (prev->flags & PF_WQ_WORKER) {
+ struct task_struct *to_wakeup;
+
+ to_wakeup = wq_worker_sleeping(prev, cpu);
+ if (to_wakeup)
+ try_to_wake_up_local(to_wakeup);
+ }
deactivate_task(rq, prev, DEQUEUE_SLEEP);
+ }
switch_count = &prev->nvcsw;
}
@@ -5801,20 +5865,49 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
*/
static struct notifier_block __cpuinitdata migration_notifier = {
.notifier_call = migration_call,
- .priority = 10
+ .priority = CPU_PRI_MIGRATION,
};
+static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ case CPU_DOWN_FAILED:
+ set_cpu_active((long)hcpu, true);
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
+static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_DOWN_PREPARE:
+ set_cpu_active((long)hcpu, false);
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
static int __init migration_init(void)
{
void *cpu = (void *)(long)smp_processor_id();
int err;
- /* Start one for the boot CPU: */
+ /* Initialize migration for the boot CPU */
err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
BUG_ON(err == NOTIFY_BAD);
migration_call(&migration_notifier, CPU_ONLINE, cpu);
register_cpu_notifier(&migration_notifier);
+ /* Register cpu active notifiers */
+ cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
+ cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
+
return 0;
}
early_initcall(migration_init);
@@ -7273,29 +7366,35 @@ int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
}
#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
-#ifndef CONFIG_CPUSETS
/*
- * Add online and remove offline CPUs from the scheduler domains.
- * When cpusets are enabled they take over this function.
+ * Update cpusets according to cpu_active mask. If cpusets are
+ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
+ * around partition_sched_domains().
*/
-static int update_sched_domains(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+static int __cpuexit cpuset_cpu_active(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
{
- switch (action) {
+ switch (action & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- partition_sched_domains(1, NULL, NULL);
+ cpuset_update_active_cpus();
return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
+static int __cpuexit cpuset_cpu_inactive(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_DOWN_PREPARE:
+ cpuset_update_active_cpus();
+ return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}
-#endif
static int update_runtime(struct notifier_block *nfb,
unsigned long action, void *hcpu)
@@ -7341,10 +7440,8 @@ void __init sched_init_smp(void)
mutex_unlock(&sched_domains_mutex);
put_online_cpus();
-#ifndef CONFIG_CPUSETS
- /* XXX: Theoretical race here - CPU may be hotplugged now */
- hotcpu_notifier(update_sched_domains, 0);
-#endif
+ hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
+ hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
/* RT runtime code needs to handle some hotplug events */
hotcpu_notifier(update_runtime, 0);
diff --git a/kernel/workqueue_sched.h b/kernel/workqueue_sched.h
new file mode 100644
index 000000000000..af040babb742
--- /dev/null
+++ b/kernel/workqueue_sched.h
@@ -0,0 +1,16 @@
+/*
+ * kernel/workqueue_sched.h
+ *
+ * Scheduler hooks for concurrency managed workqueue. Only to be
+ * included from sched.c and workqueue.c.
+ */
+static inline void wq_worker_waking_up(struct task_struct *task,
+ unsigned int cpu)
+{
+}
+
+static inline struct task_struct *wq_worker_sleeping(struct task_struct *task,
+ unsigned int cpu)
+{
+ return NULL;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 11:58:04 +0000