workqueue: move global_cwq->lock to worker_pool
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>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 366132b..c936512 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -108,12 +108,12 @@
* 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 @@
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 @@
* 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 @@
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 @@
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 @@
/*
* 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 @@
* 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 @@
* 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 @@
* 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 @@
* 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 @@
* 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 @@
* 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 @@
* 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 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 @@
* 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 @@
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 @@
* @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 @@
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 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 @@
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 @@
* 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 @@
insert_work(cwq, work, worklist, work_flags);
- spin_unlock(&gcwq->lock);
+ spin_unlock(&pool->lock);
}
/**
@@ -1523,7 +1521,7 @@
* necessary.
*
* LOCKING:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
*/
static void worker_enter_idle(struct worker *worker)
{
@@ -1546,7 +1544,7 @@
/*
* 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 @@
* @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 @@
* 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 @@
* 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 @@
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(¤t->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 @@
*/
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 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 @@
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 *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 @@
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 @@
* 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 @@
* 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 @@
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 @@
}
}
- spin_unlock_irq(&gcwq->lock);
+ spin_unlock_irq(&pool->lock);
}
static bool send_mayday(struct work_struct *work)
@@ -1948,10 +1939,9 @@
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 @@
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 @@
* 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 @@
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 @@
}
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 @@
* 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 @@
* 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 @@
* 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 @@
* 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 @@
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 @@
/*
* 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 @@
dump_stack();
}
- spin_lock_irq(&gcwq->lock);
+ spin_lock_irq(&pool->lock);
/* clear cpu intensive status */
if (unlikely(cpu_intensive))
@@ -2285,7 +2272,7 @@
* 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 @@
{
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 @@
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 @@
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 @@
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 @@
* 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 @@
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 @@
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 @@
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 @@
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 @@
{
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 @@
}
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 @@
return true;
already_gone:
- spin_unlock_irq(&gcwq->lock);
+ spin_unlock_irq(&pool->lock);
return false;
}
@@ -3404,7 +3387,7 @@
* 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 @@
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 @@
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 @@
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 @@
{
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 @@
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 @@
* 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 @@
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 @@
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 @@
* 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 @@
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 @@
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 @@
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 @@
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);
}
}