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workqueue: move global_cwq->lock to worker_pool

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Move gcwq->lock to pool->lock.  The conversion is mostly
straight-forward.  Things worth noting are

* In many places, this removes the need to use gcwq completely.  pool
  is used directly instead.  get_std_worker_pool() is added to help
  some of these conversions.  This also leaves get_work_gcwq() without
  any user.  Removed.

* In hotplug and freezer paths, the pools belonging to a CPU are often
  processed together.  This patch makes those paths hold locks of all
  pools, with highpri lock nested inside, to keep the conversion
  straight-forward.  These nested lockings will be removed by
  following patches.

This is part of an effort to remove global_cwq and make worker_pool
the top level abstraction, which in turn will help implementing worker
pools with user-specified attributes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
This commit is contained in:
Tejun Heo 2013-01-24 11:01:33 -08:00
parent ec22ca5eab
commit d565ed6309
1 changed files with 154 additions and 162 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

316
kernel/workqueue.c
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@ -108,12 +108,12 @@ enum {
* P: Preemption protected. Disabling preemption is enough and should
* only be modified and accessed from the local cpu.
*
* L: gcwq->lock protected. Access with gcwq->lock held.
* L: pool->lock protected. Access with pool->lock held.
*
* X: During normal operation, modification requires gcwq->lock and
* should be done only from local cpu. Either disabling preemption
* on local cpu or grabbing gcwq->lock is enough for read access.
* If POOL_DISASSOCIATED is set, it's identical to L.
* X: During normal operation, modification requires pool->lock and should
* be done only from local cpu. Either disabling preemption on local
* cpu or grabbing pool->lock is enough for read access. If
* POOL_DISASSOCIATED is set, it's identical to L.
*
* F: wq->flush_mutex protected.
*
@ -124,6 +124,7 @@ enum {
struct worker_pool {
struct global_cwq *gcwq; /* I: the owning gcwq */
spinlock_t lock; /* the pool lock */
unsigned int cpu; /* I: the associated cpu */
int id; /* I: pool ID */
unsigned int flags; /* X: flags */
@ -152,8 +153,6 @@ struct worker_pool {
* target workqueues.
*/
struct global_cwq {
spinlock_t lock; /* the gcwq lock */
struct worker_pool pools[NR_STD_WORKER_POOLS];
/* normal and highpri pools */
} ____cacheline_aligned_in_smp;
@ -487,6 +486,13 @@ static struct worker_pool *worker_pool_by_id(int pool_id)
return idr_find(&worker_pool_idr, pool_id);
}
static struct worker_pool *get_std_worker_pool(int cpu, bool highpri)
{
struct global_cwq *gcwq = get_gcwq(cpu);
return &gcwq->pools[highpri];
}
static atomic_t *get_pool_nr_running(struct worker_pool *pool)
{
int cpu = pool->cpu;
@ -628,13 +634,6 @@ static int get_work_pool_id(struct work_struct *work)
return pool ? pool->id : WORK_OFFQ_POOL_NONE;
}
static struct global_cwq *get_work_gcwq(struct work_struct *work)
{
struct worker_pool *pool = get_work_pool(work);
return pool ? pool->gcwq : NULL;
}
static void mark_work_canceling(struct work_struct *work)
{
unsigned long pool_id = get_work_pool_id(work);
@ -653,7 +652,7 @@ static bool work_is_canceling(struct work_struct *work)
/*
* Policy functions. These define the policies on how the global worker
* pools are managed. Unless noted otherwise, these functions assume that
* they're being called with gcwq->lock held.
* they're being called with pool->lock held.
*/
static bool __need_more_worker(struct worker_pool *pool)
@ -738,7 +737,7 @@ static struct worker *first_worker(struct worker_pool *pool)
* Wake up the first idle worker of @pool.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void wake_up_worker(struct worker_pool *pool)
{
@ -813,7 +812,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task,
* NOT_RUNNING is clear. This means that we're bound to and
* running on the local cpu w/ rq lock held and preemption
* disabled, which in turn means that none else could be
* manipulating idle_list, so dereferencing idle_list without gcwq
* manipulating idle_list, so dereferencing idle_list without pool
* lock is safe.
*/
if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist))
@ -832,7 +831,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task,
* woken up.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock)
* spin_lock_irq(pool->lock)
*/
static inline void worker_set_flags(struct worker *worker, unsigned int flags,
bool wakeup)
@ -869,7 +868,7 @@ static inline void worker_set_flags(struct worker *worker, unsigned int flags,
* Clear @flags in @worker->flags and adjust nr_running accordingly.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock)
* spin_lock_irq(pool->lock)
*/
static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
{
@ -918,7 +917,7 @@ static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
* function.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*
* RETURNS:
* Pointer to worker which is executing @work if found, NULL
@ -954,7 +953,7 @@ static struct worker *find_worker_executing_work(struct worker_pool *pool,
* nested inside outer list_for_each_entry_safe().
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void move_linked_works(struct work_struct *work, struct list_head *head,
struct work_struct **nextp)
@ -1007,7 +1006,7 @@ static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
* decrement nr_in_flight of its cwq and handle workqueue flushing.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
{
@ -1071,7 +1070,7 @@ static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
unsigned long *flags)
{
struct global_cwq *gcwq;
struct worker_pool *pool;
local_irq_save(*flags);
@ -1096,19 +1095,19 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
* The queueing is in progress, or it is already queued. Try to
* steal it from ->worklist without clearing WORK_STRUCT_PENDING.
*/
gcwq = get_work_gcwq(work);
if (!gcwq)
pool = get_work_pool(work);
if (!pool)
goto fail;
spin_lock(&gcwq->lock);
spin_lock(&pool->lock);
if (!list_empty(&work->entry)) {
/*
* This work is queued, but perhaps we locked the wrong gcwq.
* In that case we must see the new value after rmb(), see
* insert_work()->wmb().
* This work is queued, but perhaps we locked the wrong
* pool. In that case we must see the new value after
* rmb(), see insert_work()->wmb().
*/
smp_rmb();
if (gcwq == get_work_gcwq(work)) {
if (pool == get_work_pool(work)) {
debug_work_deactivate(work);
/*
@ -1126,11 +1125,11 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
cwq_dec_nr_in_flight(get_work_cwq(work),
get_work_color(work));
spin_unlock(&gcwq->lock);
spin_unlock(&pool->lock);
return 1;
}
}
spin_unlock(&gcwq->lock);
spin_unlock(&pool->lock);
fail:
local_irq_restore(*flags);
if (work_is_canceling(work))
@ -1150,7 +1149,7 @@ fail:
* @extra_flags is or'd to work_struct flags.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void insert_work(struct cpu_workqueue_struct *cwq,
struct work_struct *work, struct list_head *head,
@ -1193,23 +1192,22 @@ static bool is_chained_work(struct workqueue_struct *wq)
for_each_gcwq_cpu(cpu) {
struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
struct worker_pool *pool = cwq->pool;
struct global_cwq *gcwq = pool->gcwq;
struct worker *worker;
struct hlist_node *pos;
int i;
spin_lock_irqsave(&gcwq->lock, flags);
spin_lock_irqsave(&pool->lock, flags);
for_each_busy_worker(worker, i, pos, pool) {
if (worker->task != current)
continue;
spin_unlock_irqrestore(&gcwq->lock, flags);
spin_unlock_irqrestore(&pool->lock, flags);
/*
* I'm @worker, no locking necessary. See if @work
* is headed to the same workqueue.
*/
return worker->current_cwq->wq == wq;
}
spin_unlock_irqrestore(&gcwq->lock, flags);
spin_unlock_irqrestore(&pool->lock, flags);
}
return false;
}
@ -1217,7 +1215,8 @@ static bool is_chained_work(struct workqueue_struct *wq)
static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
struct work_struct *work)
{
struct global_cwq *gcwq;
bool highpri = wq->flags & WQ_HIGHPRI;
struct worker_pool *pool;
struct cpu_workqueue_struct *cwq;
struct list_head *worklist;
unsigned int work_flags;
@ -1238,7 +1237,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
WARN_ON_ONCE(!is_chained_work(wq)))
return;
/* determine gcwq to use */
/* determine pool to use */
if (!(wq->flags & WQ_UNBOUND)) {
struct worker_pool *last_pool;
@ -1251,38 +1250,37 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
* work needs to be queued on that cpu to guarantee
* non-reentrancy.
*/
gcwq = get_gcwq(cpu);
pool = get_std_worker_pool(cpu, highpri);
last_pool = get_work_pool(work);
if (last_pool && last_pool->gcwq != gcwq) {
struct global_cwq *last_gcwq = last_pool->gcwq;
if (last_pool && last_pool != pool) {
struct worker *worker;
spin_lock(&last_gcwq->lock);
spin_lock(&last_pool->lock);
worker = find_worker_executing_work(last_pool, work);
if (worker && worker->current_cwq->wq == wq)
gcwq = last_gcwq;
pool = last_pool;
else {
/* meh... not running there, queue here */
spin_unlock(&last_gcwq->lock);
spin_lock(&gcwq->lock);
spin_unlock(&last_pool->lock);
spin_lock(&pool->lock);
}
} else {
spin_lock(&gcwq->lock);
spin_lock(&pool->lock);
}
} else {
gcwq = get_gcwq(WORK_CPU_UNBOUND);
spin_lock(&gcwq->lock);
pool = get_std_worker_pool(WORK_CPU_UNBOUND, highpri);
spin_lock(&pool->lock);
}
/* gcwq determined, get cwq and queue */
cwq = get_cwq(gcwq->pools[0].cpu, wq);
/* pool determined, get cwq and queue */
cwq = get_cwq(pool->cpu, wq);
trace_workqueue_queue_work(req_cpu, cwq, work);
if (WARN_ON(!list_empty(&work->entry))) {
spin_unlock(&gcwq->lock);
spin_unlock(&pool->lock);
return;
}
@ -1300,7 +1298,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
insert_work(cwq, work, worklist, work_flags);
spin_unlock(&gcwq->lock);
spin_unlock(&pool->lock);
}
/**
@ -1523,7 +1521,7 @@ EXPORT_SYMBOL_GPL(mod_delayed_work);
* necessary.
*
* LOCKING:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void worker_enter_idle(struct worker *worker)
{
@ -1546,7 +1544,7 @@ static void worker_enter_idle(struct worker *worker)
/*
* Sanity check nr_running. Because gcwq_unbind_fn() releases
* gcwq->lock between setting %WORKER_UNBOUND and zapping
* pool->lock between setting %WORKER_UNBOUND and zapping
* nr_running, the warning may trigger spuriously. Check iff
* unbind is not in progress.
*/
@ -1562,7 +1560,7 @@ static void worker_enter_idle(struct worker *worker)
* @worker is leaving idle state. Update stats.
*
* LOCKING:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void worker_leave_idle(struct worker *worker)
{
@ -1597,7 +1595,7 @@ static void worker_leave_idle(struct worker *worker)
* guarantee the scheduling requirement described in the first paragraph.
*
* CONTEXT:
* Might sleep. Called without any lock but returns with gcwq->lock
* Might sleep. Called without any lock but returns with pool->lock
* held.
*
* RETURNS:
@ -1605,10 +1603,9 @@ 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)
__acquires(&pool->lock)
{
struct worker_pool *pool = worker->pool;
struct global_cwq *gcwq = pool->gcwq;
struct task_struct *task = worker->task;
while (true) {
@ -1621,14 +1618,14 @@ __acquires(&gcwq->lock)
if (!(pool->flags & POOL_DISASSOCIATED))
set_cpus_allowed_ptr(task, get_cpu_mask(pool->cpu));
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
if (pool->flags & POOL_DISASSOCIATED)
return false;
if (task_cpu(task) == pool->cpu &&
cpumask_equal(&current->cpus_allowed,
get_cpu_mask(pool->cpu)))
return true;
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
/*
* We've raced with CPU hot[un]plug. Give it a breather
@ -1647,15 +1644,13 @@ __acquires(&gcwq->lock)
*/
static void idle_worker_rebind(struct worker *worker)
{
struct global_cwq *gcwq = worker->pool->gcwq;
/* CPU may go down again inbetween, clear UNBOUND only on success */
if (worker_maybe_bind_and_lock(worker))
worker_clr_flags(worker, WORKER_UNBOUND);
/* rebind complete, become available again */
list_add(&worker->entry, &worker->pool->idle_list);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&worker->pool->lock);
}
/*
@ -1667,12 +1662,11 @@ static void idle_worker_rebind(struct worker *worker)
static void busy_worker_rebind_fn(struct work_struct *work)
{
struct worker *worker = container_of(work, struct worker, rebind_work);
struct global_cwq *gcwq = worker->pool->gcwq;
if (worker_maybe_bind_and_lock(worker))
worker_clr_flags(worker, WORKER_UNBOUND);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&worker->pool->lock);
}
/**
@ -1704,10 +1698,10 @@ static void rebind_workers(struct global_cwq *gcwq)
struct hlist_node *pos;
int i;
lockdep_assert_held(&gcwq->lock);
for_each_worker_pool(pool, gcwq)
for_each_worker_pool(pool, gcwq) {
lockdep_assert_held(&pool->assoc_mutex);
lockdep_assert_held(&pool->lock);
}
/* dequeue and kick idle ones */
for_each_worker_pool(pool, gcwq) {
@ -1785,19 +1779,18 @@ static struct worker *alloc_worker(void)
*/
static struct worker *create_worker(struct worker_pool *pool)
{
struct global_cwq *gcwq = pool->gcwq;
const char *pri = std_worker_pool_pri(pool) ? "H" : "";
struct worker *worker = NULL;
int id = -1;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
while (ida_get_new(&pool->worker_ida, &id)) {
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL))
goto fail;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
}
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
worker = alloc_worker();
if (!worker)
@ -1838,9 +1831,9 @@ static struct worker *create_worker(struct worker_pool *pool)
return worker;
fail:
if (id >= 0) {
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
ida_remove(&pool->worker_ida, id);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
}
kfree(worker);
return NULL;
@ -1853,7 +1846,7 @@ fail:
* Make the gcwq aware of @worker and start it.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void start_worker(struct worker *worker)
{
@ -1870,12 +1863,11 @@ static void start_worker(struct worker *worker)
* Destroy @worker and adjust @gcwq stats accordingly.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock) which is released and regrabbed.
* spin_lock_irq(pool->lock) which is released and regrabbed.
*/
static void destroy_worker(struct worker *worker)
{
struct worker_pool *pool = worker->pool;
struct global_cwq *gcwq = pool->gcwq;
int id = worker->id;
/* sanity check frenzy */
@ -1890,21 +1882,20 @@ static void destroy_worker(struct worker *worker)
list_del_init(&worker->entry);
worker->flags |= WORKER_DIE;
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
kthread_stop(worker->task);
kfree(worker);
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
ida_remove(&pool->worker_ida, id);
}
static void idle_worker_timeout(unsigned long __pool)
{
struct worker_pool *pool = (void *)__pool;
struct global_cwq *gcwq = pool->gcwq;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
if (too_many_workers(pool)) {
struct worker *worker;
@ -1923,7 +1914,7 @@ static void idle_worker_timeout(unsigned long __pool)
}
}
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
}
static bool send_mayday(struct work_struct *work)
@ -1948,10 +1939,9 @@ static bool send_mayday(struct work_struct *work)
static void gcwq_mayday_timeout(unsigned long __pool)
{
struct worker_pool *pool = (void *)__pool;
struct global_cwq *gcwq = pool->gcwq;
struct work_struct *work;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
if (need_to_create_worker(pool)) {
/*
@ -1964,7 +1954,7 @@ static void gcwq_mayday_timeout(unsigned long __pool)
send_mayday(work);
}
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
}
@ -1983,24 +1973,22 @@ static void gcwq_mayday_timeout(unsigned long __pool)
* may_start_working() true.
*
* LOCKING:
* spin_lock_irq(gcwq->lock) which may be released and regrabbed
* spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times. Does GFP_KERNEL allocations. Called only from
* manager.
*
* RETURNS:
* false if no action was taken and gcwq->lock stayed locked, true
* false if no action was taken and pool->lock stayed locked, true
* otherwise.
*/
static bool maybe_create_worker(struct worker_pool *pool)
__releases(&gcwq->lock)
__acquires(&gcwq->lock)
__releases(&pool->lock)
__acquires(&pool->lock)
{
struct global_cwq *gcwq = pool->gcwq;
if (!need_to_create_worker(pool))
return false;
restart:
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
/* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
@ -2011,7 +1999,7 @@ restart:
worker = create_worker(pool);
if (worker) {
del_timer_sync(&pool->mayday_timer);
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
start_worker(worker);
BUG_ON(need_to_create_worker(pool));
return true;
@ -2028,7 +2016,7 @@ restart:
}
del_timer_sync(&pool->mayday_timer);
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
if (need_to_create_worker(pool))
goto restart;
return true;
@ -2042,11 +2030,11 @@ restart:
* IDLE_WORKER_TIMEOUT.
*
* LOCKING:
* spin_lock_irq(gcwq->lock) which may be released and regrabbed
* spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times. Called only from manager.
*
* RETURNS:
* false if no action was taken and gcwq->lock stayed locked, true
* false if no action was taken and pool->lock stayed locked, true
* otherwise.
*/
static bool maybe_destroy_workers(struct worker_pool *pool)
@ -2085,12 +2073,12 @@ static bool maybe_destroy_workers(struct worker_pool *pool)
* and may_start_working() is true.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock) which may be released and regrabbed
* spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times. Does GFP_KERNEL allocations.
*
* RETURNS:
* false if no action was taken and gcwq->lock stayed locked, true if
* some action was taken.
* spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times. Does GFP_KERNEL allocations.
*/
static bool manage_workers(struct worker *worker)
{
@ -2112,10 +2100,10 @@ static bool manage_workers(struct worker *worker)
* manager against CPU hotplug.
*
* assoc_mutex would always be free unless CPU hotplug is in
* progress. trylock first without dropping @gcwq->lock.
* progress. trylock first without dropping @pool->lock.
*/
if (unlikely(!mutex_trylock(&pool->assoc_mutex))) {
spin_unlock_irq(&pool->gcwq->lock);
spin_unlock_irq(&pool->lock);
mutex_lock(&pool->assoc_mutex);
/*
* CPU hotplug could have happened while we were waiting
@ -2162,15 +2150,14 @@ static bool manage_workers(struct worker *worker)
* call this function to process a work.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock) which is released and regrabbed.
* spin_lock_irq(pool->lock) which is released and regrabbed.
*/
static void process_one_work(struct worker *worker, struct work_struct *work)
__releases(&gcwq->lock)
__acquires(&gcwq->lock)
__releases(&pool->lock)
__acquires(&pool->lock)
{
struct cpu_workqueue_struct *cwq = get_work_cwq(work);
struct worker_pool *pool = worker->pool;
struct global_cwq *gcwq = pool->gcwq;
bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE;
int work_color;
struct worker *collision;
@ -2225,7 +2212,7 @@ __acquires(&gcwq->lock)
worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);
/*
* Unbound gcwq isn't concurrency managed and work items should be
* Unbound pool isn't concurrency managed and work items should be
* executed ASAP. Wake up another worker if necessary.
*/
if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
@ -2233,13 +2220,13 @@ __acquires(&gcwq->lock)
/*
* Record the last pool and clear PENDING which should be the last
* update to @work. Also, do this inside @gcwq->lock so that
* update to @work. Also, do this inside @pool->lock so that
* PENDING and queued state changes happen together while IRQ is
* disabled.
*/
set_work_pool_and_clear_pending(work, pool->id);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
lock_map_acquire_read(&cwq->wq->lockdep_map);
lock_map_acquire(&lockdep_map);
@ -2262,7 +2249,7 @@ __acquires(&gcwq->lock)
dump_stack();
}
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
/* clear cpu intensive status */
if (unlikely(cpu_intensive))
@ -2285,7 +2272,7 @@ __acquires(&gcwq->lock)
* fetches a work from the top and executes it.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock) which may be released and regrabbed
* spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times.
*/
static void process_scheduled_works(struct worker *worker)
@ -2311,16 +2298,15 @@ static int worker_thread(void *__worker)
{
struct worker *worker = __worker;
struct worker_pool *pool = worker->pool;
struct global_cwq *gcwq = pool->gcwq;
/* tell the scheduler that this is a workqueue worker */
worker->task->flags |= PF_WQ_WORKER;
woke_up:
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
/* we are off idle list if destruction or rebind is requested */
if (unlikely(list_empty(&worker->entry))) {
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
/* if DIE is set, destruction is requested */
if (worker->flags & WORKER_DIE) {
@ -2379,15 +2365,15 @@ sleep:
goto recheck;
/*
* gcwq->lock is held and there's no work to process and no
* need to manage, sleep. Workers are woken up only while
* holding gcwq->lock or from local cpu, so setting the
* current state before releasing gcwq->lock is enough to
* prevent losing any event.
* pool->lock is held and there's no work to process and no need to
* manage, sleep. Workers are woken up only while holding
* pool->lock or from local cpu, so setting the current state
* before releasing pool->lock is enough to prevent losing any
* event.
*/
worker_enter_idle(worker);
__set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
schedule();
goto woke_up;
}
@ -2443,7 +2429,6 @@ repeat:
unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu;
struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq);
struct worker_pool *pool = cwq->pool;
struct global_cwq *gcwq = pool->gcwq;
struct work_struct *work, *n;
__set_current_state(TASK_RUNNING);
@ -2465,14 +2450,14 @@ repeat:
process_scheduled_works(rescuer);
/*
* Leave this gcwq. If keep_working() is %true, notify a
* Leave this pool. If keep_working() is %true, notify a
* regular worker; otherwise, we end up with 0 concurrency
* and stalling the execution.
*/
if (keep_working(pool))
wake_up_worker(pool);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
}
/* rescuers should never participate in concurrency management */
@ -2514,7 +2499,7 @@ static void wq_barrier_func(struct work_struct *work)
* underneath us, so we can't reliably determine cwq from @target.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
struct wq_barrier *barr,
@ -2524,7 +2509,7 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
unsigned int linked = 0;
/*
* debugobject calls are safe here even with gcwq->lock locked
* debugobject calls are safe here even with pool->lock locked
* as we know for sure that this will not trigger any of the
* checks and call back into the fixup functions where we
* might deadlock.
@ -2597,9 +2582,9 @@ static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
for_each_cwq_cpu(cpu, wq) {
struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
struct global_cwq *gcwq = cwq->pool->gcwq;
struct worker_pool *pool = cwq->pool;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
if (flush_color >= 0) {
BUG_ON(cwq->flush_color != -1);
@ -2616,7 +2601,7 @@ static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
cwq->work_color = work_color;
}
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
}
if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush))
@ -2813,9 +2798,9 @@ reflush:
struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
bool drained;
spin_lock_irq(&cwq->pool->gcwq->lock);
spin_lock_irq(&cwq->pool->lock);
drained = !cwq->nr_active && list_empty(&cwq->delayed_works);
spin_unlock_irq(&cwq->pool->gcwq->lock);
spin_unlock_irq(&cwq->pool->lock);
if (drained)
continue;
@ -2838,25 +2823,23 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
{
struct worker *worker = NULL;
struct worker_pool *pool;
struct global_cwq *gcwq;
struct cpu_workqueue_struct *cwq;
might_sleep();
pool = get_work_pool(work);
if (!pool)
return false;
gcwq = pool->gcwq;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
if (!list_empty(&work->entry)) {
/*
* See the comment near try_to_grab_pending()->smp_rmb().
* If it was re-queued to a different gcwq under us, we
* If it was re-queued to a different pool under us, we
* are not going to wait.
*/
smp_rmb();
cwq = get_work_cwq(work);
if (unlikely(!cwq || gcwq != cwq->pool->gcwq))
if (unlikely(!cwq || pool != cwq->pool))
goto already_gone;
} else {
worker = find_worker_executing_work(pool, work);
@ -2866,7 +2849,7 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
}
insert_wq_barrier(cwq, barr, work, worker);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
/*
* If @max_active is 1 or rescuer is in use, flushing another work
@ -2882,7 +2865,7 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
return true;
already_gone:
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
return false;
}
@ -3404,7 +3387,7 @@ EXPORT_SYMBOL_GPL(destroy_workqueue);
* increased.
*
* CONTEXT:
* spin_lock_irq(gcwq->lock).
* spin_lock_irq(pool->lock).
*/
static void cwq_set_max_active(struct cpu_workqueue_struct *cwq, int max_active)
{
@ -3438,15 +3421,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
for_each_cwq_cpu(cpu, wq) {
struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
struct worker_pool *pool = cwq->pool;
struct global_cwq *gcwq = pool->gcwq;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
if (!(wq->flags & WQ_FREEZABLE) ||
!(pool->flags & POOL_FREEZING))
cwq_set_max_active(cwq, max_active);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
}
spin_unlock(&workqueue_lock);
@ -3489,22 +3471,20 @@ EXPORT_SYMBOL_GPL(workqueue_congested);
unsigned int work_busy(struct work_struct *work)
{
struct worker_pool *pool = get_work_pool(work);
struct global_cwq *gcwq;
unsigned long flags;
unsigned int ret = 0;
if (!pool)
return 0;
gcwq = pool->gcwq;
spin_lock_irqsave(&gcwq->lock, flags);
spin_lock_irqsave(&pool->lock, flags);
if (work_pending(work))
ret |= WORK_BUSY_PENDING;
if (find_worker_executing_work(pool, work))
ret |= WORK_BUSY_RUNNING;
spin_unlock_irqrestore(&gcwq->lock, flags);
spin_unlock_irqrestore(&pool->lock, flags);
return ret;
}
@ -3532,7 +3512,10 @@ static void gcwq_claim_assoc_and_lock(struct global_cwq *gcwq)
for_each_worker_pool(pool, gcwq)
mutex_lock_nested(&pool->assoc_mutex, pool - gcwq->pools);
spin_lock_irq(&gcwq->lock);
local_irq_disable();
for_each_worker_pool(pool, gcwq)
spin_lock_nested(&pool->lock, pool - gcwq->pools);
}
/* release manager positions */
@ -3540,7 +3523,10 @@ static void gcwq_release_assoc_and_unlock(struct global_cwq *gcwq)
{
struct worker_pool *pool;
spin_unlock_irq(&gcwq->lock);
for_each_worker_pool(pool, gcwq)
spin_unlock(&pool->lock);
local_irq_enable();
for_each_worker_pool(pool, gcwq)
mutex_unlock(&pool->assoc_mutex);
}
@ -3621,9 +3607,9 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb,
if (!worker)
return NOTIFY_BAD;
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
start_worker(worker);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
}
break;
@ -3709,7 +3695,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu);
* gcwq->worklist.
*
* CONTEXT:
* Grabs and releases workqueue_lock and gcwq->lock's.
* Grabs and releases workqueue_lock and pool->lock's.
*/
void freeze_workqueues_begin(void)
{
@ -3725,9 +3711,11 @@ void freeze_workqueues_begin(void)
struct worker_pool *pool;
struct workqueue_struct *wq;
spin_lock_irq(&gcwq->lock);
local_irq_disable();
for_each_worker_pool(pool, gcwq) {
spin_lock_nested(&pool->lock, pool - gcwq->pools);
WARN_ON_ONCE(pool->flags & POOL_FREEZING);
pool->flags |= POOL_FREEZING;
}
@ -3739,7 +3727,9 @@ void freeze_workqueues_begin(void)
cwq->max_active = 0;
}
spin_unlock_irq(&gcwq->lock);
for_each_worker_pool(pool, gcwq)
spin_unlock(&pool->lock);
local_irq_enable();
}
spin_unlock(&workqueue_lock);
@ -3798,7 +3788,7 @@ out_unlock:
* frozen works are transferred to their respective gcwq worklists.
*
* CONTEXT:
* Grabs and releases workqueue_lock and gcwq->lock's.
* Grabs and releases workqueue_lock and pool->lock's.
*/
void thaw_workqueues(void)
{
@ -3814,9 +3804,11 @@ void thaw_workqueues(void)
struct worker_pool *pool;
struct workqueue_struct *wq;
spin_lock_irq(&gcwq->lock);
local_irq_disable();
for_each_worker_pool(pool, gcwq) {
spin_lock_nested(&pool->lock, pool - gcwq->pools);
WARN_ON_ONCE(!(pool->flags & POOL_FREEZING));
pool->flags &= ~POOL_FREEZING;
}
@ -3831,10 +3823,11 @@ void thaw_workqueues(void)
cwq_set_max_active(cwq, wq->saved_max_active);
}
for_each_worker_pool(pool, gcwq)
for_each_worker_pool(pool, gcwq) {
wake_up_worker(pool);
spin_unlock_irq(&gcwq->lock);
spin_unlock(&pool->lock);
}
local_irq_enable();
}
workqueue_freezing = false;
@ -3859,10 +3852,9 @@ static int __init init_workqueues(void)
struct global_cwq *gcwq = get_gcwq(cpu);
struct worker_pool *pool;
spin_lock_init(&gcwq->lock);
for_each_worker_pool(pool, gcwq) {
pool->gcwq = gcwq;
spin_lock_init(&pool->lock);
pool->cpu = cpu;
pool->flags |= POOL_DISASSOCIATED;
INIT_LIST_HEAD(&pool->worklist);
@ -3897,9 +3889,9 @@ static int __init init_workqueues(void)
worker = create_worker(pool);
BUG_ON(!worker);
spin_lock_irq(&gcwq->lock);
spin_lock_irq(&pool->lock);
start_worker(worker);
spin_unlock_irq(&gcwq->lock);
spin_unlock_irq(&pool->lock);
}
}