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Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Browse Source 
Pull workqueue updates from Tejun Heo:
 "Lai has been doing a lot of cleanups of workqueue and kthread_work.
  No significant behavior change.  Just a lot of cleanups all over the
  place.  Some are a bit invasive but overall nothing too dangerous"

* 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  kthread_work: remove the unused wait_queue_head
  kthread_work: wake up worker only when the worker is idle
  workqueue: use nr_node_ids instead of wq_numa_tbl_len
  workqueue: remove the misnamed out_unlock label in get_unbound_pool()
  workqueue: remove the stale comment in pwq_unbound_release_workfn()
  workqueue: move rescuer pool detachment to the end
  workqueue: unfold start_worker() into create_worker()
  workqueue: remove @wakeup from worker_set_flags()
  workqueue: remove an unneeded UNBOUND test before waking up the next worker
  workqueue: wake regular worker if need_more_worker() when rescuer leave the pool
  workqueue: alloc struct worker on its local node
  workqueue: reuse the already calculated pwq in try_to_grab_pending()
  workqueue: stronger test in process_one_work()
  workqueue: clear POOL_DISASSOCIATED in rebind_workers()
  workqueue: sanity check pool->cpu in wq_worker_sleeping()
  workqueue: clear leftover flags when detached
  workqueue: remove useless WARN_ON_ONCE()
  workqueue: use schedule_timeout_interruptible() instead of open code
  workqueue: remove the empty check in too_many_workers()
  workqueue: use "pool->cpu < 0" to stand for an unbound pool
This commit is contained in:
Linus Torvalds 2014-08-04 10:04:44 -07:00
commit c4c3f5fba0
3 changed files with 64 additions and 151 deletions
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13
include/linux/kthread.h
View File

@ -73,7 +73,6 @@ struct kthread_worker {
struct kthread_work {
struct list_head node;
kthread_work_func_t func;
wait_queue_head_t done;
struct kthread_worker *worker;
};
@ -85,7 +84,6 @@ struct kthread_work {
#define KTHREAD_WORK_INIT(work, fn) { \
.node = LIST_HEAD_INIT((work).node), \
.func = (fn), \
.done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done), \
}
#define DEFINE_KTHREAD_WORKER(worker) \
@ -95,22 +93,16 @@ struct kthread_work {
struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
/*
* kthread_worker.lock and kthread_work.done need their own lockdep class
* keys if they are defined on stack with lockdep enabled. Use the
* following macros when defining them on stack.
* kthread_worker.lock needs its own lockdep class key when defined on
* stack with lockdep enabled. Use the following macros in such cases.
*/
#ifdef CONFIG_LOCKDEP
# define KTHREAD_WORKER_INIT_ONSTACK(worker) \
({ init_kthread_worker(&worker); worker; })
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
# define KTHREAD_WORK_INIT_ONSTACK(work, fn) \
({ init_kthread_work((&work), fn); work; })
# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) \
struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
#else
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
#endif
extern void __init_kthread_worker(struct kthread_worker *worker,
@ -127,7 +119,6 @@ extern void __init_kthread_worker(struct kthread_worker *worker,
memset((work), 0, sizeof(struct kthread_work)); \
INIT_LIST_HEAD(&(work)->node); \
(work)->func = (fn); \
init_waitqueue_head(&(work)->done); \
} while (0)
int kthread_worker_fn(void *worker_ptr);

2
kernel/kthread.c
View File

@ -591,7 +591,7 @@ static void insert_kthread_work(struct kthread_worker *worker,
list_add_tail(&work->node, pos);
work->worker = worker;
if (likely(worker->task))
if (!worker->current_work && likely(worker->task))
wake_up_process(worker->task);
}

200
kernel/workqueue.c
View File

@ -265,7 +265,6 @@ struct workqueue_struct {
static struct kmem_cache *pwq_cache;
static int wq_numa_tbl_len; /* highest possible NUMA node id + 1 */
static cpumask_var_t *wq_numa_possible_cpumask;
/* possible CPUs of each node */
@ -758,13 +757,6 @@ static bool too_many_workers(struct worker_pool *pool)
int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
int nr_busy = pool->nr_workers - nr_idle;
/*
* nr_idle and idle_list may disagree if idle rebinding is in
* progress. Never return %true if idle_list is empty.
*/
if (list_empty(&pool->idle_list))
return false;
return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
}
@ -850,7 +842,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
pool = worker->pool;
/* this can only happen on the local cpu */
if (WARN_ON_ONCE(cpu != raw_smp_processor_id()))
if (WARN_ON_ONCE(cpu != raw_smp_processor_id() || pool->cpu != cpu))
return NULL;
/*
@ -874,35 +866,22 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
* worker_set_flags - set worker flags and adjust nr_running accordingly
* @worker: self
* @flags: flags to set
* @wakeup: wakeup an idle worker if necessary
*
* Set @flags in @worker->flags and adjust nr_running accordingly. If
* nr_running becomes zero and @wakeup is %true, an idle worker is
* woken up.
* Set @flags in @worker->flags and adjust nr_running accordingly.
*
* CONTEXT:
* spin_lock_irq(pool->lock)
*/
static inline void worker_set_flags(struct worker *worker, unsigned int flags,
bool wakeup)
static inline void worker_set_flags(struct worker *worker, unsigned int flags)
{
struct worker_pool *pool = worker->pool;
WARN_ON_ONCE(worker->task != current);
/*
* If transitioning into NOT_RUNNING, adjust nr_running and
* wake up an idle worker as necessary if requested by
* @wakeup.
*/
/* If transitioning into NOT_RUNNING, adjust nr_running. */
if ((flags & WORKER_NOT_RUNNING) &&
!(worker->flags & WORKER_NOT_RUNNING)) {
if (wakeup) {
if (atomic_dec_and_test(&pool->nr_running) &&
!list_empty(&pool->worklist))
wake_up_worker(pool);
} else
atomic_dec(&pool->nr_running);
atomic_dec(&pool->nr_running);
}
worker->flags |= flags;
@ -1232,7 +1211,7 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
pwq_activate_delayed_work(work);
list_del_init(&work->entry);
pwq_dec_nr_in_flight(get_work_pwq(work), get_work_color(work));
pwq_dec_nr_in_flight(pwq, get_work_color(work));
/* work->data points to pwq iff queued, point to pool */
set_work_pool_and_keep_pending(work, pool->id);
@ -1560,7 +1539,7 @@ static void worker_enter_idle(struct worker *worker)
(worker->hentry.next || worker->hentry.pprev)))
return;
/* can't use worker_set_flags(), also called from start_worker() */
/* can't use worker_set_flags(), also called from create_worker() */
worker->flags |= WORKER_IDLE;
pool->nr_idle++;
worker->last_active = jiffies;
@ -1602,11 +1581,11 @@ static void worker_leave_idle(struct worker *worker)
list_del_init(&worker->entry);
}
static struct worker *alloc_worker(void)
static struct worker *alloc_worker(int node)
{
struct worker *worker;
worker = kzalloc(sizeof(*worker), GFP_KERNEL);
worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node);
if (worker) {
INIT_LIST_HEAD(&worker->entry);
INIT_LIST_HEAD(&worker->scheduled);
@ -1670,6 +1649,9 @@ static void worker_detach_from_pool(struct worker *worker,
detach_completion = pool->detach_completion;
mutex_unlock(&pool->attach_mutex);
/* clear leftover flags without pool->lock after it is detached */
worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND);
if (detach_completion)
complete(detach_completion);
}
@ -1678,8 +1660,7 @@ static void worker_detach_from_pool(struct worker *worker,
* create_worker - create a new workqueue worker
* @pool: pool the new worker will belong to
*
* Create a new worker which is attached to @pool. The new worker must be
* started by start_worker().
* Create and start a new worker which is attached to @pool.
*
* CONTEXT:
* Might sleep. Does GFP_KERNEL allocations.
@ -1698,7 +1679,7 @@ static struct worker *create_worker(struct worker_pool *pool)
if (id < 0)
goto fail;
worker = alloc_worker();
worker = alloc_worker(pool->node);
if (!worker)
goto fail;
@ -1724,6 +1705,13 @@ static struct worker *create_worker(struct worker_pool *pool)
/* successful, attach the worker to the pool */
worker_attach_to_pool(worker, pool);
/* start the newly created worker */
spin_lock_irq(&pool->lock);
worker->pool->nr_workers++;
worker_enter_idle(worker);
wake_up_process(worker->task);
spin_unlock_irq(&pool->lock);
return worker;
fail:
@ -1733,44 +1721,6 @@ fail:
return NULL;
}
/**
* start_worker - start a newly created worker
* @worker: worker to start
*
* Make the pool aware of @worker and start it.
*
* CONTEXT:
* spin_lock_irq(pool->lock).
*/
static void start_worker(struct worker *worker)
{
worker->pool->nr_workers++;
worker_enter_idle(worker);
wake_up_process(worker->task);
}
/**
* create_and_start_worker - create and start a worker for a pool
* @pool: the target pool
*
* Grab the managership of @pool and create and start a new worker for it.
*
* Return: 0 on success. A negative error code otherwise.
*/
static int create_and_start_worker(struct worker_pool *pool)
{
struct worker *worker;
worker = create_worker(pool);
if (worker) {
spin_lock_irq(&pool->lock);
start_worker(worker);
spin_unlock_irq(&pool->lock);
}
return worker ? 0 : -ENOMEM;
}
/**
* destroy_worker - destroy a workqueue worker
* @worker: worker to be destroyed
@ -1909,23 +1859,10 @@ restart:
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
while (true) {
struct worker *worker;
worker = create_worker(pool);
if (worker) {
del_timer_sync(&pool->mayday_timer);
spin_lock_irq(&pool->lock);
start_worker(worker);
if (WARN_ON_ONCE(need_to_create_worker(pool)))
goto restart;
return true;
}
if (!need_to_create_worker(pool))
if (create_worker(pool) || !need_to_create_worker(pool))
break;
__set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(CREATE_COOLDOWN);
schedule_timeout_interruptible(CREATE_COOLDOWN);
if (!need_to_create_worker(pool))
break;
@ -1933,6 +1870,11 @@ restart:
del_timer_sync(&pool->mayday_timer);
spin_lock_irq(&pool->lock);
/*
* This is necessary even after a new worker was just successfully
* created as @pool->lock was dropped and the new worker might have
* already become busy.
*/
if (need_to_create_worker(pool))
goto restart;
return true;
@ -2020,13 +1962,7 @@ __acquires(&pool->lock)
lockdep_copy_map(&lockdep_map, &work->lockdep_map);
#endif
/*
* Ensure we're on the correct CPU. DISASSOCIATED test is
* necessary to avoid spurious warnings from rescuers servicing the
* unbound or a disassociated pool.
*/
WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) &&
!(pool->flags & POOL_DISASSOCIATED) &&
WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
raw_smp_processor_id() != pool->cpu);
/*
@ -2052,17 +1988,22 @@ __acquires(&pool->lock)
list_del_init(&work->entry);
/*
* CPU intensive works don't participate in concurrency
* management. They're the scheduler's responsibility.
* CPU intensive works don't participate in concurrency management.
* They're the scheduler's responsibility. This takes @worker out
* of concurrency management and the next code block will chain
* execution of the pending work items.
*/
if (unlikely(cpu_intensive))
worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);
worker_set_flags(worker, WORKER_CPU_INTENSIVE);
/*
* Unbound pool isn't concurrency managed and work items should be
* executed ASAP. Wake up another worker if necessary.
* Wake up another worker if necessary. The condition is always
* false for normal per-cpu workers since nr_running would always
* be >= 1 at this point. This is used to chain execution of the
* pending work items for WORKER_NOT_RUNNING workers such as the
* UNBOUND and CPU_INTENSIVE ones.
*/
if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
if (need_more_worker(pool))
wake_up_worker(pool);
/*
@ -2218,7 +2159,7 @@ recheck:
}
} while (keep_working(pool));
worker_set_flags(worker, WORKER_PREP, false);
worker_set_flags(worker, WORKER_PREP);
sleep:
/*
* pool->lock is held and there's no work to process and no need to
@ -2311,29 +2252,27 @@ repeat:
move_linked_works(work, scheduled, &n);
process_scheduled_works(rescuer);
spin_unlock_irq(&pool->lock);
worker_detach_from_pool(rescuer, pool);
spin_lock_irq(&pool->lock);
/*
* Put the reference grabbed by send_mayday(). @pool won't
* go away while we're holding its lock.
* go away while we're still attached to it.
*/
put_pwq(pwq);
/*
* Leave this pool. If keep_working() is %true, notify a
* Leave this pool. If need_more_worker() is %true, notify a
* regular worker; otherwise, we end up with 0 concurrency
* and stalling the execution.
*/
if (keep_working(pool))
if (need_more_worker(pool))
wake_up_worker(pool);
rescuer->pool = NULL;
spin_unlock(&pool->lock);
spin_lock(&wq_mayday_lock);
spin_unlock_irq(&pool->lock);
worker_detach_from_pool(rescuer, pool);
spin_lock_irq(&wq_mayday_lock);
}
spin_unlock_irq(&wq_mayday_lock);
@ -3458,7 +3397,7 @@ static void put_unbound_pool(struct worker_pool *pool)
return;
/* sanity checks */
if (WARN_ON(!(pool->flags & POOL_DISASSOCIATED)) ||
if (WARN_ON(!(pool->cpu < 0)) ||
WARN_ON(!list_empty(&pool->worklist)))
return;
@ -3524,7 +3463,7 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) {
if (wqattrs_equal(pool->attrs, attrs)) {
pool->refcnt++;
goto out_unlock;
return pool;
}
}
@ -3557,12 +3496,12 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
goto fail;
/* create and start the initial worker */
if (create_and_start_worker(pool) < 0)
if (!create_worker(pool))
goto fail;
/* install */
hash_add(unbound_pool_hash, &pool->hash_node, hash);
out_unlock:
return pool;
fail:
if (pool)
@ -3591,11 +3530,6 @@ static void pwq_unbound_release_workfn(struct work_struct *work)
if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
return;
/*
* Unlink @pwq. Synchronization against wq->mutex isn't strictly
* necessary on release but do it anyway. It's easier to verify
* and consistent with the linking path.
*/
mutex_lock(&wq->mutex);
list_del_rcu(&pwq->pwqs_node);
is_last = list_empty(&wq->pwqs);
@ -3692,10 +3626,7 @@ static void link_pwq(struct pool_workqueue *pwq)
if (!list_empty(&pwq->pwqs_node))
return;
/*
* Set the matching work_color. This is synchronized with
* wq->mutex to avoid confusing flush_workqueue().
*/
/* set the matching work_color */
pwq->work_color = wq->work_color;
/* sync max_active to the current setting */
@ -3832,7 +3763,7 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))
return -EINVAL;
pwq_tbl = kzalloc(wq_numa_tbl_len * sizeof(pwq_tbl[0]), GFP_KERNEL);
pwq_tbl = kzalloc(nr_node_ids * sizeof(pwq_tbl[0]), GFP_KERNEL);
new_attrs = alloc_workqueue_attrs(GFP_KERNEL);
tmp_attrs = alloc_workqueue_attrs(GFP_KERNEL);
if (!pwq_tbl || !new_attrs || !tmp_attrs)
@ -4080,7 +4011,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
/* allocate wq and format name */
if (flags & WQ_UNBOUND)
tbl_size = wq_numa_tbl_len * sizeof(wq->numa_pwq_tbl[0]);
tbl_size = nr_node_ids * sizeof(wq->numa_pwq_tbl[0]);
wq = kzalloc(sizeof(*wq) + tbl_size, GFP_KERNEL);
if (!wq)
@ -4122,7 +4053,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
if (flags & WQ_MEM_RECLAIM) {
struct worker *rescuer;
rescuer = alloc_worker();
rescuer = alloc_worker(NUMA_NO_NODE);
if (!rescuer)
goto err_destroy;
@ -4470,8 +4401,6 @@ static void wq_unbind_fn(struct work_struct *work)
struct worker *worker;
for_each_cpu_worker_pool(pool, cpu) {
WARN_ON_ONCE(cpu != smp_processor_id());
mutex_lock(&pool->attach_mutex);
spin_lock_irq(&pool->lock);
@ -4543,6 +4472,7 @@ static void rebind_workers(struct worker_pool *pool)
pool->attrs->cpumask) < 0);
spin_lock_irq(&pool->lock);
pool->flags &= ~POOL_DISASSOCIATED;
for_each_pool_worker(worker, pool) {
unsigned int worker_flags = worker->flags;
@ -4632,7 +4562,7 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb,
for_each_cpu_worker_pool(pool, cpu) {
if (pool->nr_workers)
continue;
if (create_and_start_worker(pool) < 0)
if (!create_worker(pool))
return NOTIFY_BAD;
}
break;
@ -4645,10 +4575,6 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb,
mutex_lock(&pool->attach_mutex);
if (pool->cpu == cpu) {
spin_lock_irq(&pool->lock);
pool->flags &= ~POOL_DISASSOCIATED;
spin_unlock_irq(&pool->lock);
rebind_workers(pool);
} else if (pool->cpu < 0) {
restore_unbound_workers_cpumask(pool, cpu);
@ -4856,10 +4782,6 @@ static void __init wq_numa_init(void)
cpumask_var_t *tbl;
int node, cpu;
/* determine NUMA pwq table len - highest node id + 1 */
for_each_node(node)
wq_numa_tbl_len = max(wq_numa_tbl_len, node + 1);
if (num_possible_nodes() <= 1)
return;
@ -4876,7 +4798,7 @@ static void __init wq_numa_init(void)
* available. Build one from cpu_to_node() which should have been
* fully initialized by now.
*/
tbl = kzalloc(wq_numa_tbl_len * sizeof(tbl[0]), GFP_KERNEL);
tbl = kzalloc(nr_node_ids * sizeof(tbl[0]), GFP_KERNEL);
BUG_ON(!tbl);
for_each_node(node)
@ -4936,7 +4858,7 @@ static int __init init_workqueues(void)
for_each_cpu_worker_pool(pool, cpu) {
pool->flags &= ~POOL_DISASSOCIATED;
BUG_ON(create_and_start_worker(pool) < 0);
BUG_ON(!create_worker(pool));
}
}