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-rw-r--r--kernel/workqueue.c161
1 files changed, 83 insertions, 78 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index ddee541ea97a..9657315405de 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -127,16 +127,16 @@ enum {
*
* PL: wq_pool_mutex protected.
*
- * PR: wq_pool_mutex protected for writes. Sched-RCU protected for reads.
+ * PR: wq_pool_mutex protected for writes. RCU protected for reads.
*
* PW: wq_pool_mutex and wq->mutex protected for writes. Either for reads.
*
* PWR: wq_pool_mutex and wq->mutex protected for writes. Either or
- * sched-RCU for reads.
+ * RCU for reads.
*
* WQ: wq->mutex protected.
*
- * WR: wq->mutex protected for writes. Sched-RCU protected for reads.
+ * WR: wq->mutex protected for writes. RCU protected for reads.
*
* MD: wq_mayday_lock protected.
*/
@@ -183,7 +183,7 @@ struct worker_pool {
atomic_t nr_running ____cacheline_aligned_in_smp;
/*
- * Destruction of pool is sched-RCU protected to allow dereferences
+ * Destruction of pool is RCU protected to allow dereferences
* from get_work_pool().
*/
struct rcu_head rcu;
@@ -212,7 +212,7 @@ struct pool_workqueue {
/*
* Release of unbound pwq is punted to system_wq. See put_pwq()
* and pwq_unbound_release_workfn() for details. pool_workqueue
- * itself is also sched-RCU protected so that the first pwq can be
+ * itself is also RCU protected so that the first pwq can be
* determined without grabbing wq->mutex.
*/
struct work_struct unbound_release_work;
@@ -266,8 +266,8 @@ struct workqueue_struct {
char name[WQ_NAME_LEN]; /* I: workqueue name */
/*
- * Destruction of workqueue_struct is sched-RCU protected to allow
- * walking the workqueues list without grabbing wq_pool_mutex.
+ * Destruction of workqueue_struct is RCU protected to allow walking
+ * the workqueues list without grabbing wq_pool_mutex.
* This is used to dump all workqueues from sysrq.
*/
struct rcu_head rcu;
@@ -359,20 +359,20 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
#include <trace/events/workqueue.h>
#define assert_rcu_or_pool_mutex() \
- RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() && \
+ RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
!lockdep_is_held(&wq_pool_mutex), \
- "sched RCU or wq_pool_mutex should be held")
+ "RCU or wq_pool_mutex should be held")
#define assert_rcu_or_wq_mutex(wq) \
- RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() && \
+ RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
!lockdep_is_held(&wq->mutex), \
- "sched RCU or wq->mutex should be held")
+ "RCU or wq->mutex should be held")
#define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \
- RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() && \
+ RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
!lockdep_is_held(&wq->mutex) && \
!lockdep_is_held(&wq_pool_mutex), \
- "sched RCU, wq->mutex or wq_pool_mutex should be held")
+ "RCU, wq->mutex or wq_pool_mutex should be held")
#define for_each_cpu_worker_pool(pool, cpu) \
for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \
@@ -384,7 +384,7 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
* @pool: iteration cursor
* @pi: integer used for iteration
*
- * This must be called either with wq_pool_mutex held or sched RCU read
+ * This must be called either with wq_pool_mutex held or RCU read
* locked. If the pool needs to be used beyond the locking in effect, the
* caller is responsible for guaranteeing that the pool stays online.
*
@@ -416,7 +416,7 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
* @pwq: iteration cursor
* @wq: the target workqueue
*
- * This must be called either with wq->mutex held or sched RCU read locked.
+ * This must be called either with wq->mutex held or RCU read locked.
* If the pwq needs to be used beyond the locking in effect, the caller is
* responsible for guaranteeing that the pwq stays online.
*
@@ -552,7 +552,7 @@ static int worker_pool_assign_id(struct worker_pool *pool)
* @wq: the target workqueue
* @node: the node ID
*
- * This must be called with any of wq_pool_mutex, wq->mutex or sched RCU
+ * This must be called with any of wq_pool_mutex, wq->mutex or RCU
* read locked.
* If the pwq needs to be used beyond the locking in effect, the caller is
* responsible for guaranteeing that the pwq stays online.
@@ -696,8 +696,8 @@ static struct pool_workqueue *get_work_pwq(struct work_struct *work)
* @work: the work item of interest
*
* Pools are created and destroyed under wq_pool_mutex, and allows read
- * access under sched-RCU read lock. As such, this function should be
- * called under wq_pool_mutex or with preemption disabled.
+ * access under RCU read lock. As such, this function should be
+ * called under wq_pool_mutex or inside of a rcu_read_lock() region.
*
* All fields of the returned pool are accessible as long as the above
* mentioned locking is in effect. If the returned pool needs to be used
@@ -841,43 +841,32 @@ static void wake_up_worker(struct worker_pool *pool)
}
/**
- * wq_worker_waking_up - a worker is waking up
+ * wq_worker_running - a worker is running again
* @task: task waking up
- * @cpu: CPU @task is waking up to
*
- * This function is called during try_to_wake_up() when a worker is
- * being awoken.
- *
- * CONTEXT:
- * spin_lock_irq(rq->lock)
+ * This function is called when a worker returns from schedule()
*/
-void wq_worker_waking_up(struct task_struct *task, int cpu)
+void wq_worker_running(struct task_struct *task)
{
struct worker *worker = kthread_data(task);
- if (!(worker->flags & WORKER_NOT_RUNNING)) {
- WARN_ON_ONCE(worker->pool->cpu != cpu);
+ if (!worker->sleeping)
+ return;
+ if (!(worker->flags & WORKER_NOT_RUNNING))
atomic_inc(&worker->pool->nr_running);
- }
+ worker->sleeping = 0;
}
/**
* wq_worker_sleeping - a worker is going to sleep
* @task: task going to sleep
*
- * This function is called during schedule() when a busy worker is
- * going to sleep. Worker on the same cpu can be woken up by
- * returning pointer to its task.
- *
- * CONTEXT:
- * spin_lock_irq(rq->lock)
- *
- * Return:
- * Worker task on @cpu to wake up, %NULL if none.
+ * This function is called from schedule() when a busy worker is
+ * going to sleep.
*/
-struct task_struct *wq_worker_sleeping(struct task_struct *task)
+void wq_worker_sleeping(struct task_struct *task)
{
- struct worker *worker = kthread_data(task), *to_wakeup = NULL;
+ struct worker *next, *worker = kthread_data(task);
struct worker_pool *pool;
/*
@@ -886,13 +875,15 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task)
* checking NOT_RUNNING.
*/
if (worker->flags & WORKER_NOT_RUNNING)
- return NULL;
+ return;
pool = worker->pool;
- /* this can only happen on the local cpu */
- if (WARN_ON_ONCE(pool->cpu != raw_smp_processor_id()))
- return NULL;
+ if (WARN_ON_ONCE(worker->sleeping))
+ return;
+
+ worker->sleeping = 1;
+ spin_lock_irq(&pool->lock);
/*
* The counterpart of the following dec_and_test, implied mb,
@@ -906,13 +897,17 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task)
* lock is safe.
*/
if (atomic_dec_and_test(&pool->nr_running) &&
- !list_empty(&pool->worklist))
- to_wakeup = first_idle_worker(pool);
- return to_wakeup ? to_wakeup->task : NULL;
+ !list_empty(&pool->worklist)) {
+ next = first_idle_worker(pool);
+ if (next)
+ wake_up_process(next->task);
+ }
+ spin_unlock_irq(&pool->lock);
}
/**
* wq_worker_last_func - retrieve worker's last work function
+ * @task: Task to retrieve last work function of.
*
* Determine the last function a worker executed. This is called from
* the scheduler to get a worker's last known identity.
@@ -1132,7 +1127,7 @@ static void put_pwq_unlocked(struct pool_workqueue *pwq)
{
if (pwq) {
/*
- * As both pwqs and pools are sched-RCU protected, the
+ * As both pwqs and pools are RCU protected, the
* following lock operations are safe.
*/
spin_lock_irq(&pwq->pool->lock);
@@ -1260,6 +1255,7 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
return 0;
+ rcu_read_lock();
/*
* The queueing is in progress, or it is already queued. Try to
* steal it from ->worklist without clearing WORK_STRUCT_PENDING.
@@ -1298,10 +1294,12 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
set_work_pool_and_keep_pending(work, pool->id);
spin_unlock(&pool->lock);
+ rcu_read_unlock();
return 1;
}
spin_unlock(&pool->lock);
fail:
+ rcu_read_unlock();
local_irq_restore(*flags);
if (work_is_canceling(work))
return -ENOENT;
@@ -1415,6 +1413,7 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
if (unlikely(wq->flags & __WQ_DRAINING) &&
WARN_ON_ONCE(!is_chained_work(wq)))
return;
+ rcu_read_lock();
retry:
if (req_cpu == WORK_CPU_UNBOUND)
cpu = wq_select_unbound_cpu(raw_smp_processor_id());
@@ -1471,10 +1470,8 @@ retry:
/* pwq determined, queue */
trace_workqueue_queue_work(req_cpu, pwq, work);
- if (WARN_ON(!list_empty(&work->entry))) {
- spin_unlock(&pwq->pool->lock);
- return;
- }
+ if (WARN_ON(!list_empty(&work->entry)))
+ goto out;
pwq->nr_in_flight[pwq->work_color]++;
work_flags = work_color_to_flags(pwq->work_color);
@@ -1492,7 +1489,9 @@ retry:
insert_work(pwq, work, worklist, work_flags);
+out:
spin_unlock(&pwq->pool->lock);
+ rcu_read_unlock();
}
/**
@@ -2277,7 +2276,7 @@ __acquires(&pool->lock)
if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
- " last function: %pf\n",
+ " last function: %ps\n",
current->comm, preempt_count(), task_pid_nr(current),
worker->current_func);
debug_show_held_locks(current);
@@ -2596,11 +2595,11 @@ static void check_flush_dependency(struct workqueue_struct *target_wq,
worker = current_wq_worker();
WARN_ONCE(current->flags & PF_MEMALLOC,
- "workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%pf",
+ "workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%ps",
current->pid, current->comm, target_wq->name, target_func);
WARN_ONCE(worker && ((worker->current_pwq->wq->flags &
(WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM),
- "workqueue: WQ_MEM_RECLAIM %s:%pf is flushing !WQ_MEM_RECLAIM %s:%pf",
+ "workqueue: WQ_MEM_RECLAIM %s:%ps is flushing !WQ_MEM_RECLAIM %s:%ps",
worker->current_pwq->wq->name, worker->current_func,
target_wq->name, target_func);
}
@@ -2974,14 +2973,14 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
might_sleep();
- local_irq_disable();
+ rcu_read_lock();
pool = get_work_pool(work);
if (!pool) {
- local_irq_enable();
+ rcu_read_unlock();
return false;
}
- spin_lock(&pool->lock);
+ spin_lock_irq(&pool->lock);
/* see the comment in try_to_grab_pending() with the same code */
pwq = get_work_pwq(work);
if (pwq) {
@@ -3013,10 +3012,11 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
lock_map_acquire(&pwq->wq->lockdep_map);
lock_map_release(&pwq->wq->lockdep_map);
}
-
+ rcu_read_unlock();
return true;
already_gone:
spin_unlock_irq(&pool->lock);
+ rcu_read_unlock();
return false;
}
@@ -3503,7 +3503,7 @@ static void rcu_free_pool(struct rcu_head *rcu)
* put_unbound_pool - put a worker_pool
* @pool: worker_pool to put
*
- * Put @pool. If its refcnt reaches zero, it gets destroyed in sched-RCU
+ * Put @pool. If its refcnt reaches zero, it gets destroyed in RCU
* safe manner. get_unbound_pool() calls this function on its failure path
* and this function should be able to release pools which went through,
* successfully or not, init_worker_pool().
@@ -3557,7 +3557,7 @@ static void put_unbound_pool(struct worker_pool *pool)
del_timer_sync(&pool->idle_timer);
del_timer_sync(&pool->mayday_timer);
- /* sched-RCU protected to allow dereferences from get_work_pool() */
+ /* RCU protected to allow dereferences from get_work_pool() */
call_rcu(&pool->rcu, rcu_free_pool);
}
@@ -4208,6 +4208,7 @@ static int init_rescuer(struct workqueue_struct *wq)
return 0;
}
+__printf(1, 4)
struct workqueue_struct *alloc_workqueue(const char *fmt,
unsigned int flags,
int max_active, ...)
@@ -4471,7 +4472,8 @@ bool workqueue_congested(int cpu, struct workqueue_struct *wq)
struct pool_workqueue *pwq;
bool ret;
- rcu_read_lock_sched();
+ rcu_read_lock();
+ preempt_disable();
if (cpu == WORK_CPU_UNBOUND)
cpu = smp_processor_id();
@@ -4482,7 +4484,8 @@ bool workqueue_congested(int cpu, struct workqueue_struct *wq)
pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
ret = !list_empty(&pwq->delayed_works);
- rcu_read_unlock_sched();
+ preempt_enable();
+ rcu_read_unlock();
return ret;
}
@@ -4508,15 +4511,15 @@ unsigned int work_busy(struct work_struct *work)
if (work_pending(work))
ret |= WORK_BUSY_PENDING;
- local_irq_save(flags);
+ rcu_read_lock();
pool = get_work_pool(work);
if (pool) {
- spin_lock(&pool->lock);
+ spin_lock_irqsave(&pool->lock, flags);
if (find_worker_executing_work(pool, work))
ret |= WORK_BUSY_RUNNING;
- spin_unlock(&pool->lock);
+ spin_unlock_irqrestore(&pool->lock, flags);
}
- local_irq_restore(flags);
+ rcu_read_unlock();
return ret;
}
@@ -4587,7 +4590,7 @@ void print_worker_info(const char *log_lvl, struct task_struct *task)
probe_kernel_read(desc, worker->desc, sizeof(desc) - 1);
if (fn || name[0] || desc[0]) {
- printk("%sWorkqueue: %s %pf", log_lvl, name, fn);
+ printk("%sWorkqueue: %s %ps", log_lvl, name, fn);
if (strcmp(name, desc))
pr_cont(" (%s)", desc);
pr_cont("\n");
@@ -4612,7 +4615,7 @@ static void pr_cont_work(bool comma, struct work_struct *work)
pr_cont("%s BAR(%d)", comma ? "," : "",
task_pid_nr(barr->task));
} else {
- pr_cont("%s %pf", comma ? "," : "", work->func);
+ pr_cont("%s %ps", comma ? "," : "", work->func);
}
}
@@ -4644,7 +4647,7 @@ static void show_pwq(struct pool_workqueue *pwq)
if (worker->current_pwq != pwq)
continue;
- pr_cont("%s %d%s:%pf", comma ? "," : "",
+ pr_cont("%s %d%s:%ps", comma ? "," : "",
task_pid_nr(worker->task),
worker == pwq->wq->rescuer ? "(RESCUER)" : "",
worker->current_func);
@@ -4700,7 +4703,7 @@ void show_workqueue_state(void)
unsigned long flags;
int pi;
- rcu_read_lock_sched();
+ rcu_read_lock();
pr_info("Showing busy workqueues and worker pools:\n");
@@ -4765,7 +4768,7 @@ void show_workqueue_state(void)
touch_nmi_watchdog();
}
- rcu_read_unlock_sched();
+ rcu_read_unlock();
}
/* used to show worker information through /proc/PID/{comm,stat,status} */
@@ -4929,7 +4932,7 @@ static void rebind_workers(struct worker_pool *pool)
*
* WRITE_ONCE() is necessary because @worker->flags may be
* tested without holding any lock in
- * wq_worker_waking_up(). Without it, NOT_RUNNING test may
+ * wq_worker_running(). Without it, NOT_RUNNING test may
* fail incorrectly leading to premature concurrency
* management operations.
*/
@@ -5152,16 +5155,16 @@ bool freeze_workqueues_busy(void)
* nr_active is monotonically decreasing. It's safe
* to peek without lock.
*/
- rcu_read_lock_sched();
+ rcu_read_lock();
for_each_pwq(pwq, wq) {
WARN_ON_ONCE(pwq->nr_active < 0);
if (pwq->nr_active) {
busy = true;
- rcu_read_unlock_sched();
+ rcu_read_unlock();
goto out_unlock;
}
}
- rcu_read_unlock_sched();
+ rcu_read_unlock();
}
out_unlock:
mutex_unlock(&wq_pool_mutex);
@@ -5356,7 +5359,8 @@ static ssize_t wq_pool_ids_show(struct device *dev,
const char *delim = "";
int node, written = 0;
- rcu_read_lock_sched();
+ get_online_cpus();
+ rcu_read_lock();
for_each_node(node) {
written += scnprintf(buf + written, PAGE_SIZE - written,
"%s%d:%d", delim, node,
@@ -5364,7 +5368,8 @@ static ssize_t wq_pool_ids_show(struct device *dev,
delim = " ";
}
written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
- rcu_read_unlock_sched();
+ rcu_read_unlock();
+ put_online_cpus();
return written;
}
generated by cgit (git 2.34.1) at 2024-05-30 10:02:42 +0000