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-rw-r--r--kernel/workqueue.c80
1 files changed, 55 insertions, 25 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 8bd600c020e..f77afd93922 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1,19 +1,26 @@
/*
- * linux/kernel/workqueue.c
+ * kernel/workqueue.c - generic async execution with shared worker pool
*
- * Generic mechanism for defining kernel helper threads for running
- * arbitrary tasks in process context.
+ * Copyright (C) 2002 Ingo Molnar
*
- * Started by Ingo Molnar, Copyright (C) 2002
+ * Derived from the taskqueue/keventd code by:
+ * David Woodhouse <dwmw2@infradead.org>
+ * Andrew Morton
+ * Kai Petzke <wpp@marie.physik.tu-berlin.de>
+ * Theodore Ts'o <tytso@mit.edu>
*
- * Derived from the taskqueue/keventd code by:
+ * Made to use alloc_percpu by Christoph Lameter.
*
- * David Woodhouse <dwmw2@infradead.org>
- * Andrew Morton
- * Kai Petzke <wpp@marie.physik.tu-berlin.de>
- * Theodore Ts'o <tytso@mit.edu>
+ * Copyright (C) 2010 SUSE Linux Products GmbH
+ * Copyright (C) 2010 Tejun Heo <tj@kernel.org>
*
- * Made to use alloc_percpu by Christoph Lameter.
+ * This is the generic async execution mechanism. Work items as are
+ * executed in process context. The worker pool is shared and
+ * automatically managed. There is one worker pool for each CPU and
+ * one extra for works which are better served by workers which are
+ * not bound to any specific CPU.
+ *
+ * Please read Documentation/workqueue.txt for details.
*/
#include <linux/module.h>
@@ -90,7 +97,8 @@ enum {
/*
* Structure fields follow one of the following exclusion rules.
*
- * I: Set during initialization and read-only afterwards.
+ * I: Modifiable by initialization/destruction paths and read-only for
+ * everyone else.
*
* P: Preemption protected. Disabling preemption is enough and should
* only be modified and accessed from the local cpu.
@@ -198,7 +206,7 @@ typedef cpumask_var_t mayday_mask_t;
cpumask_test_and_set_cpu((cpu), (mask))
#define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask))
#define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask))
-#define alloc_mayday_mask(maskp, gfp) alloc_cpumask_var((maskp), (gfp))
+#define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp))
#define free_mayday_mask(mask) free_cpumask_var((mask))
#else
typedef unsigned long mayday_mask_t;
@@ -943,10 +951,14 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
struct global_cwq *gcwq;
struct cpu_workqueue_struct *cwq;
struct list_head *worklist;
+ unsigned int work_flags;
unsigned long flags;
debug_work_activate(work);
+ if (WARN_ON_ONCE(wq->flags & WQ_DYING))
+ return;
+
/* determine gcwq to use */
if (!(wq->flags & WQ_UNBOUND)) {
struct global_cwq *last_gcwq;
@@ -989,14 +1001,17 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
BUG_ON(!list_empty(&work->entry));
cwq->nr_in_flight[cwq->work_color]++;
+ work_flags = work_color_to_flags(cwq->work_color);
if (likely(cwq->nr_active < cwq->max_active)) {
cwq->nr_active++;
worklist = gcwq_determine_ins_pos(gcwq, cwq);
- } else
+ } else {
+ work_flags |= WORK_STRUCT_DELAYED;
worklist = &cwq->delayed_works;
+ }
- insert_work(cwq, work, worklist, work_color_to_flags(cwq->work_color));
+ insert_work(cwq, work, worklist, work_flags);
spin_unlock_irqrestore(&gcwq->lock, flags);
}
@@ -1215,6 +1230,7 @@ static void worker_leave_idle(struct worker *worker)
* bound), %false if offline.
*/
static bool worker_maybe_bind_and_lock(struct worker *worker)
+__acquires(&gcwq->lock)
{
struct global_cwq *gcwq = worker->gcwq;
struct task_struct *task = worker->task;
@@ -1488,6 +1504,8 @@ static void gcwq_mayday_timeout(unsigned long __gcwq)
* otherwise.
*/
static bool maybe_create_worker(struct global_cwq *gcwq)
+__releases(&gcwq->lock)
+__acquires(&gcwq->lock)
{
if (!need_to_create_worker(gcwq))
return false;
@@ -1662,6 +1680,7 @@ static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
struct list_head *pos = gcwq_determine_ins_pos(cwq->gcwq, cwq);
move_linked_works(work, pos, NULL);
+ __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
cwq->nr_active++;
}
@@ -1669,6 +1688,7 @@ static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
* cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
* @cwq: cwq of interest
* @color: color of work which left the queue
+ * @delayed: for a delayed work
*
* A work either has completed or is removed from pending queue,
* decrement nr_in_flight of its cwq and handle workqueue flushing.
@@ -1676,19 +1696,22 @@ static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
* CONTEXT:
* spin_lock_irq(gcwq->lock).
*/
-static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
+static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color,
+ bool delayed)
{
/* ignore uncolored works */
if (color == WORK_NO_COLOR)
return;
cwq->nr_in_flight[color]--;
- cwq->nr_active--;
- if (!list_empty(&cwq->delayed_works)) {
- /* one down, submit a delayed one */
- if (cwq->nr_active < cwq->max_active)
- cwq_activate_first_delayed(cwq);
+ if (!delayed) {
+ cwq->nr_active--;
+ if (!list_empty(&cwq->delayed_works)) {
+ /* one down, submit a delayed one */
+ if (cwq->nr_active < cwq->max_active)
+ cwq_activate_first_delayed(cwq);
+ }
}
/* is flush in progress and are we at the flushing tip? */
@@ -1725,6 +1748,8 @@ static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
* spin_lock_irq(gcwq->lock) which is released and regrabbed.
*/
static void process_one_work(struct worker *worker, struct work_struct *work)
+__releases(&gcwq->lock)
+__acquires(&gcwq->lock)
{
struct cpu_workqueue_struct *cwq = get_work_cwq(work);
struct global_cwq *gcwq = cwq->gcwq;
@@ -1823,7 +1848,7 @@ static void process_one_work(struct worker *worker, struct work_struct *work)
hlist_del_init(&worker->hentry);
worker->current_work = NULL;
worker->current_cwq = NULL;
- cwq_dec_nr_in_flight(cwq, work_color);
+ cwq_dec_nr_in_flight(cwq, work_color, false);
}
/**
@@ -2388,7 +2413,8 @@ static int try_to_grab_pending(struct work_struct *work)
debug_work_deactivate(work);
list_del_init(&work->entry);
cwq_dec_nr_in_flight(get_work_cwq(work),
- get_work_color(work));
+ get_work_color(work),
+ *work_data_bits(work) & WORK_STRUCT_DELAYED);
ret = 1;
}
}
@@ -2791,7 +2817,6 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name,
if (IS_ERR(rescuer->task))
goto err;
- wq->rescuer = rescuer;
rescuer->task->flags |= PF_THREAD_BOUND;
wake_up_process(rescuer->task);
}
@@ -2833,6 +2858,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
{
unsigned int cpu;
+ wq->flags |= WQ_DYING;
flush_workqueue(wq);
/*
@@ -2857,6 +2883,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
if (wq->flags & WQ_RESCUER) {
kthread_stop(wq->rescuer->task);
free_mayday_mask(wq->mayday_mask);
+ kfree(wq->rescuer);
}
free_cwqs(wq);
@@ -3239,6 +3266,8 @@ static int __cpuinit trustee_thread(void *__gcwq)
* multiple times. To be used by cpu_callback.
*/
static void __cpuinit wait_trustee_state(struct global_cwq *gcwq, int state)
+__releases(&gcwq->lock)
+__acquires(&gcwq->lock)
{
if (!(gcwq->trustee_state == state ||
gcwq->trustee_state == TRUSTEE_DONE)) {
@@ -3545,8 +3574,7 @@ static int __init init_workqueues(void)
spin_lock_init(&gcwq->lock);
INIT_LIST_HEAD(&gcwq->worklist);
gcwq->cpu = cpu;
- if (cpu == WORK_CPU_UNBOUND)
- gcwq->flags |= GCWQ_DISASSOCIATED;
+ gcwq->flags |= GCWQ_DISASSOCIATED;
INIT_LIST_HEAD(&gcwq->idle_list);
for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)
@@ -3570,6 +3598,8 @@ static int __init init_workqueues(void)
struct global_cwq *gcwq = get_gcwq(cpu);
struct worker *worker;
+ if (cpu != WORK_CPU_UNBOUND)
+ gcwq->flags &= ~GCWQ_DISASSOCIATED;
worker = create_worker(gcwq, true);
BUG_ON(!worker);
spin_lock_irq(&gcwq->lock);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-14 22:42:43 +0000