diff --git a/Makefile b/Makefile
index a78379891d22..c436247d750c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
VERSION = 6
PATCHLEVEL = 8
-SUBLEVEL = 3
+SUBLEVEL = 4
EXTRAVERSION =
NAME = Hurr durr I'ma ninja sloth
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 515e7958c6c1..2cc0a9606175 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -391,13 +391,6 @@ enum {
WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
WQ_UNBOUND_MAX_ACTIVE = WQ_MAX_ACTIVE,
WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
-
- /*
- * Per-node default cap on min_active. Unless explicitly set, min_active
- * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see
- * workqueue_struct->min_active definition.
- */
- WQ_DFL_MIN_ACTIVE = 8,
};
/*
@@ -440,33 +433,11 @@ extern struct workqueue_struct *system_freezable_power_efficient_wq;
* alloc_workqueue - allocate a workqueue
* @fmt: printf format for the name of the workqueue
* @flags: WQ_* flags
- * @max_active: max in-flight work items, 0 for default
+ * @max_active: max in-flight work items per CPU, 0 for default
* remaining args: args for @fmt
*
- * For a per-cpu workqueue, @max_active limits the number of in-flight work
- * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be
- * executing at most one work item for the workqueue.
- *
- * For unbound workqueues, @max_active limits the number of in-flight work items
- * for the whole system. e.g. @max_active of 16 indicates that that there can be
- * at most 16 work items executing for the workqueue in the whole system.
- *
- * As sharing the same active counter for an unbound workqueue across multiple
- * NUMA nodes can be expensive, @max_active is distributed to each NUMA node
- * according to the proportion of the number of online CPUs and enforced
- * independently.
- *
- * Depending on online CPU distribution, a node may end up with per-node
- * max_active which is significantly lower than @max_active, which can lead to
- * deadlocks if the per-node concurrency limit is lower than the maximum number
- * of interdependent work items for the workqueue.
- *
- * To guarantee forward progress regardless of online CPU distribution, the
- * concurrency limit on every node is guaranteed to be equal to or greater than
- * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means
- * that the sum of per-node max_active's may be larger than @max_active.
- *
- * For detailed information on %WQ_* flags, please refer to
+ * Allocate a workqueue with the specified parameters. For detailed
+ * information on WQ_* flags, please refer to
* Documentation/core-api/workqueue.rst.
*
* RETURNS:
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 781900b148b6..7b482a26d741 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -108,7 +108,7 @@ enum {
RESCUER_NICE_LEVEL = MIN_NICE,
HIGHPRI_NICE_LEVEL = MIN_NICE,
- WQ_NAME_LEN = 32,
+ WQ_NAME_LEN = 24,
};
/*
@@ -122,9 +122,6 @@ enum {
*
* L: pool->lock protected. Access with pool->lock held.
*
- * LN: pool->lock and wq_node_nr_active->lock protected for writes. Either for
- * reads.
- *
* K: Only modified by worker while holding pool->lock. Can be safely read by
* self, while holding pool->lock or from IRQ context if %current is the
* kworker.
@@ -146,9 +143,6 @@ enum {
*
* WR: wq->mutex protected for writes. RCU protected for reads.
*
- * WO: wq->mutex protected for writes. Updated with WRITE_ONCE() and can be read
- * with READ_ONCE() without locking.
- *
* MD: wq_mayday_lock protected.
*
* WD: Used internally by the watchdog.
@@ -246,18 +240,18 @@ struct pool_workqueue {
* pwq->inactive_works instead of pool->worklist and marked with
* WORK_STRUCT_INACTIVE.
*
- * All work items marked with WORK_STRUCT_INACTIVE do not participate in
- * nr_active and all work items in pwq->inactive_works are marked with
- * WORK_STRUCT_INACTIVE. But not all WORK_STRUCT_INACTIVE work items are
- * in pwq->inactive_works. Some of them are ready to run in
- * pool->worklist or worker->scheduled. Those work itmes are only struct
- * wq_barrier which is used for flush_work() and should not participate
- * in nr_active. For non-barrier work item, it is marked with
- * WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
+ * All work items marked with WORK_STRUCT_INACTIVE do not participate
+ * in pwq->nr_active and all work items in pwq->inactive_works are
+ * marked with WORK_STRUCT_INACTIVE. But not all WORK_STRUCT_INACTIVE
+ * work items are in pwq->inactive_works. Some of them are ready to
+ * run in pool->worklist or worker->scheduled. Those work itmes are
+ * only struct wq_barrier which is used for flush_work() and should
+ * not participate in pwq->nr_active. For non-barrier work item, it
+ * is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
*/
int nr_active; /* L: nr of active works */
+ int max_active; /* L: max active works */
struct list_head inactive_works; /* L: inactive works */
- struct list_head pending_node; /* LN: node on wq_node_nr_active->pending_pwqs */
struct list_head pwqs_node; /* WR: node on wq->pwqs */
struct list_head mayday_node; /* MD: node on wq->maydays */
@@ -284,26 +278,6 @@ struct wq_flusher {
struct wq_device;
-/*
- * Unlike in a per-cpu workqueue where max_active limits its concurrency level
- * on each CPU, in an unbound workqueue, max_active applies to the whole system.
- * As sharing a single nr_active across multiple sockets can be very expensive,
- * the counting and enforcement is per NUMA node.
- *
- * The following struct is used to enforce per-node max_active. When a pwq wants
- * to start executing a work item, it should increment ->nr using
- * tryinc_node_nr_active(). If acquisition fails due to ->nr already being over
- * ->max, the pwq is queued on ->pending_pwqs. As in-flight work items finish
- * and decrement ->nr, node_activate_pending_pwq() activates the pending pwqs in
- * round-robin order.
- */
-struct wq_node_nr_active {
- int max; /* per-node max_active */
- atomic_t nr; /* per-node nr_active */
- raw_spinlock_t lock; /* nests inside pool locks */
- struct list_head pending_pwqs; /* LN: pwqs with inactive works */
-};
-
/*
* The externally visible workqueue. It relays the issued work items to
* the appropriate worker_pool through its pool_workqueues.
@@ -324,15 +298,10 @@ struct workqueue_struct {
struct worker *rescuer; /* MD: rescue worker */
int nr_drainers; /* WQ: drain in progress */
-
- /* See alloc_workqueue() function comment for info on min/max_active */
- int max_active; /* WO: max active works */
- int min_active; /* WO: min active works */
- int saved_max_active; /* WQ: saved max_active */
- int saved_min_active; /* WQ: saved min_active */
+ int saved_max_active; /* WQ: saved pwq max_active */
struct workqueue_attrs *unbound_attrs; /* PW: only for unbound wqs */
- struct pool_workqueue __rcu *dfl_pwq; /* PW: only for unbound wqs */
+ struct pool_workqueue *dfl_pwq; /* PW: only for unbound wqs */
#ifdef CONFIG_SYSFS
struct wq_device *wq_dev; /* I: for sysfs interface */
@@ -354,7 +323,6 @@ struct workqueue_struct {
/* hot fields used during command issue, aligned to cacheline */
unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */
struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */
- struct wq_node_nr_active *node_nr_active[]; /* I: per-node nr_active */
};
static struct kmem_cache *pwq_cache;
@@ -664,36 +632,6 @@ static int worker_pool_assign_id(struct worker_pool *pool)
return ret;
}
-static struct pool_workqueue __rcu **
-unbound_pwq_slot(struct workqueue_struct *wq, int cpu)
-{
- if (cpu >= 0)
- return per_cpu_ptr(wq->cpu_pwq, cpu);
- else
- return &wq->dfl_pwq;
-}
-
-/* @cpu < 0 for dfl_pwq */
-static struct pool_workqueue *unbound_pwq(struct workqueue_struct *wq, int cpu)
-{
- return rcu_dereference_check(*unbound_pwq_slot(wq, cpu),
- lockdep_is_held(&wq_pool_mutex) ||
- lockdep_is_held(&wq->mutex));
-}
-
-/**
- * unbound_effective_cpumask - effective cpumask of an unbound workqueue
- * @wq: workqueue of interest
- *
- * @wq->unbound_attrs->cpumask contains the cpumask requested by the user which
- * is masked with wq_unbound_cpumask to determine the effective cpumask. The
- * default pwq is always mapped to the pool with the current effective cpumask.
- */
-static struct cpumask *unbound_effective_cpumask(struct workqueue_struct *wq)
-{
- return unbound_pwq(wq, -1)->pool->attrs->__pod_cpumask;
-}
-
static unsigned int work_color_to_flags(int color)
{
return color << WORK_STRUCT_COLOR_SHIFT;
@@ -1463,71 +1401,6 @@ work_func_t wq_worker_last_func(struct task_struct *task)
return worker->last_func;
}
-/**
- * wq_node_nr_active - Determine wq_node_nr_active to use
- * @wq: workqueue of interest
- * @node: NUMA node, can be %NUMA_NO_NODE
- *
- * Determine wq_node_nr_active to use for @wq on @node. Returns:
- *
- * - %NULL for per-cpu workqueues as they don't need to use shared nr_active.
- *
- * - node_nr_active[nr_node_ids] if @node is %NUMA_NO_NODE.
- *
- * - Otherwise, node_nr_active[@node].
- */
-static struct wq_node_nr_active *wq_node_nr_active(struct workqueue_struct *wq,
- int node)
-{
- if (!(wq->flags & WQ_UNBOUND))
- return NULL;
-
- if (node == NUMA_NO_NODE)
- node = nr_node_ids;
-
- return wq->node_nr_active[node];
-}
-
-/**
- * wq_update_node_max_active - Update per-node max_actives to use
- * @wq: workqueue to update
- * @off_cpu: CPU that's going down, -1 if a CPU is not going down
- *
- * Update @wq->node_nr_active[]->max. @wq must be unbound. max_active is
- * distributed among nodes according to the proportions of numbers of online
- * cpus. The result is always between @wq->min_active and max_active.
- */
-static void wq_update_node_max_active(struct workqueue_struct *wq, int off_cpu)
-{
- struct cpumask *effective = unbound_effective_cpumask(wq);
- int min_active = READ_ONCE(wq->min_active);
- int max_active = READ_ONCE(wq->max_active);
- int total_cpus, node;
-
- lockdep_assert_held(&wq->mutex);
-
- if (off_cpu >= 0 && !cpumask_test_cpu(off_cpu, effective))
- off_cpu = -1;
-
- total_cpus = cpumask_weight_and(effective, cpu_online_mask);
- if (off_cpu >= 0)
- total_cpus--;
-
- for_each_node(node) {
- int node_cpus;
-
- node_cpus = cpumask_weight_and(effective, cpumask_of_node(node));
- if (off_cpu >= 0 && cpu_to_node(off_cpu) == node)
- node_cpus--;
-
- wq_node_nr_active(wq, node)->max =
- clamp(DIV_ROUND_UP(max_active * node_cpus, total_cpus),
- min_active, max_active);
- }
-
- wq_node_nr_active(wq, NUMA_NO_NODE)->max = min_active;
-}
-
/**
* get_pwq - get an extra reference on the specified pool_workqueue
* @pwq: pool_workqueue to get
@@ -1580,293 +1453,24 @@ static void put_pwq_unlocked(struct pool_workqueue *pwq)
}
}
-static bool pwq_is_empty(struct pool_workqueue *pwq)
-{
- return !pwq->nr_active && list_empty(&pwq->inactive_works);
-}
-
-static void __pwq_activate_work(struct pool_workqueue *pwq,
- struct work_struct *work)
+static void pwq_activate_inactive_work(struct work_struct *work)
{
- unsigned long *wdb = work_data_bits(work);
+ struct pool_workqueue *pwq = get_work_pwq(work);
- WARN_ON_ONCE(!(*wdb & WORK_STRUCT_INACTIVE));
trace_workqueue_activate_work(work);
if (list_empty(&pwq->pool->worklist))
pwq->pool->watchdog_ts = jiffies;
move_linked_works(work, &pwq->pool->worklist, NULL);
- __clear_bit(WORK_STRUCT_INACTIVE_BIT, wdb);
-}
-
-/**
- * pwq_activate_work - Activate a work item if inactive
- * @pwq: pool_workqueue @work belongs to
- * @work: work item to activate
- *
- * Returns %true if activated. %false if already active.
- */
-static bool pwq_activate_work(struct pool_workqueue *pwq,
- struct work_struct *work)
-{
- struct worker_pool *pool = pwq->pool;
- struct wq_node_nr_active *nna;
-
- lockdep_assert_held(&pool->lock);
-
- if (!(*work_data_bits(work) & WORK_STRUCT_INACTIVE))
- return false;
-
- nna = wq_node_nr_active(pwq->wq, pool->node);
- if (nna)
- atomic_inc(&nna->nr);
-
+ __clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
pwq->nr_active++;
- __pwq_activate_work(pwq, work);
- return true;
-}
-
-static bool tryinc_node_nr_active(struct wq_node_nr_active *nna)
-{
- int max = READ_ONCE(nna->max);
-
- while (true) {
- int old, tmp;
-
- old = atomic_read(&nna->nr);
- if (old >= max)
- return false;
- tmp = atomic_cmpxchg_relaxed(&nna->nr, old, old + 1);
- if (tmp == old)
- return true;
- }
-}
-
-/**
- * pwq_tryinc_nr_active - Try to increment nr_active for a pwq
- * @pwq: pool_workqueue of interest
- * @fill: max_active may have increased, try to increase concurrency level
- *
- * Try to increment nr_active for @pwq. Returns %true if an nr_active count is
- * successfully obtained. %false otherwise.
- */
-static bool pwq_tryinc_nr_active(struct pool_workqueue *pwq, bool fill)
-{
- struct workqueue_struct *wq = pwq->wq;
- struct worker_pool *pool = pwq->pool;
- struct wq_node_nr_active *nna = wq_node_nr_active(wq, pool->node);
- bool obtained = false;
-
- lockdep_assert_held(&pool->lock);
-
- if (!nna) {
- /* per-cpu workqueue, pwq->nr_active is sufficient */
- obtained = pwq->nr_active < READ_ONCE(wq->max_active);
- goto out;
- }
-
- /*
- * Unbound workqueue uses per-node shared nr_active $nna. If @pwq is
- * already waiting on $nna, pwq_dec_nr_active() will maintain the
- * concurrency level. Don't jump the line.
- *
- * We need to ignore the pending test after max_active has increased as
- * pwq_dec_nr_active() can only maintain the concurrency level but not
- * increase it. This is indicated by @fill.
- */
- if (!list_empty(&pwq->pending_node) && likely(!fill))
- goto out;
-
- obtained = tryinc_node_nr_active(nna);
- if (obtained)
- goto out;
-
- /*
- * Lockless acquisition failed. Lock, add ourself to $nna->pending_pwqs
- * and try again. The smp_mb() is paired with the implied memory barrier
- * of atomic_dec_return() in pwq_dec_nr_active() to ensure that either
- * we see the decremented $nna->nr or they see non-empty
- * $nna->pending_pwqs.
- */
- raw_spin_lock(&nna->lock);
-
- if (list_empty(&pwq->pending_node))
- list_add_tail(&pwq->pending_node, &nna->pending_pwqs);
- else if (likely(!fill))
- goto out_unlock;
-
- smp_mb();
-
- obtained = tryinc_node_nr_active(nna);
-
- /*
- * If @fill, @pwq might have already been pending. Being spuriously
- * pending in cold paths doesn't affect anything. Let's leave it be.
- */
- if (obtained && likely(!fill))
- list_del_init(&pwq->pending_node);
-
-out_unlock:
- raw_spin_unlock(&nna->lock);
-out:
- if (obtained)
- pwq->nr_active++;
- return obtained;
-}
-
-/**
- * pwq_activate_first_inactive - Activate the first inactive work item on a pwq
- * @pwq: pool_workqueue of interest
- * @fill: max_active may have increased, try to increase concurrency level
- *
- * Activate the first inactive work item of @pwq if available and allowed by
- * max_active limit.
- *
- * Returns %true if an inactive work item has been activated. %false if no
- * inactive work item is found or max_active limit is reached.
- */
-static bool pwq_activate_first_inactive(struct pool_workqueue *pwq, bool fill)
-{
- struct work_struct *work =
- list_first_entry_or_null(&pwq->inactive_works,
- struct work_struct, entry);
-
- if (work && pwq_tryinc_nr_active(pwq, fill)) {
- __pwq_activate_work(pwq, work);
- return true;
- } else {
- return false;
- }
-}
-
-/**
- * node_activate_pending_pwq - Activate a pending pwq on a wq_node_nr_active
- * @nna: wq_node_nr_active to activate a pending pwq for
- * @caller_pool: worker_pool the caller is locking
- *
- * Activate a pwq in @nna->pending_pwqs. Called with @caller_pool locked.
- * @caller_pool may be unlocked and relocked to lock other worker_pools.
- */
-static void node_activate_pending_pwq(struct wq_node_nr_active *nna,
- struct worker_pool *caller_pool)
-{
- struct worker_pool *locked_pool = caller_pool;
- struct pool_workqueue *pwq;
- struct work_struct *work;
-
- lockdep_assert_held(&caller_pool->lock);
-
- raw_spin_lock(&nna->lock);
-retry:
- pwq = list_first_entry_or_null(&nna->pending_pwqs,
- struct pool_workqueue, pending_node);
- if (!pwq)
- goto out_unlock;
-
- /*
- * If @pwq is for a different pool than @locked_pool, we need to lock
- * @pwq->pool->lock. Let's trylock first. If unsuccessful, do the unlock
- * / lock dance. For that, we also need to release @nna->lock as it's
- * nested inside pool locks.
- */
- if (pwq->pool != locked_pool) {
- raw_spin_unlock(&locked_pool->lock);
- locked_pool = pwq->pool;
- if (!raw_spin_trylock(&locked_pool->lock)) {
- raw_spin_unlock(&nna->lock);
- raw_spin_lock(&locked_pool->lock);
- raw_spin_lock(&nna->lock);
- goto retry;
- }
- }
-
- /*
- * $pwq may not have any inactive work items due to e.g. cancellations.
- * Drop it from pending_pwqs and see if there's another one.
- */
- work = list_first_entry_or_null(&pwq->inactive_works,
- struct work_struct, entry);
- if (!work) {
- list_del_init(&pwq->pending_node);
- goto retry;
- }
-
- /*
- * Acquire an nr_active count and activate the inactive work item. If
- * $pwq still has inactive work items, rotate it to the end of the
- * pending_pwqs so that we round-robin through them. This means that
- * inactive work items are not activated in queueing order which is fine
- * given that there has never been any ordering across different pwqs.
- */
- if (likely(tryinc_node_nr_active(nna))) {
- pwq->nr_active++;
- __pwq_activate_work(pwq, work);
-
- if (list_empty(&pwq->inactive_works))
- list_del_init(&pwq->pending_node);
- else
- list_move_tail(&pwq->pending_node, &nna->pending_pwqs);
-
- /* if activating a foreign pool, make sure it's running */
- if (pwq->pool != caller_pool)
- kick_pool(pwq->pool);
- }
-
-out_unlock:
- raw_spin_unlock(&nna->lock);
- if (locked_pool != caller_pool) {
- raw_spin_unlock(&locked_pool->lock);
- raw_spin_lock(&caller_pool->lock);
- }
}
-/**
- * pwq_dec_nr_active - Retire an active count
- * @pwq: pool_workqueue of interest
- *
- * Decrement @pwq's nr_active and try to activate the first inactive work item.
- * For unbound workqueues, this function may temporarily drop @pwq->pool->lock.
- */
-static void pwq_dec_nr_active(struct pool_workqueue *pwq)
+static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
{
- struct worker_pool *pool = pwq->pool;
- struct wq_node_nr_active *nna = wq_node_nr_active(pwq->wq, pool->node);
+ struct work_struct *work = list_first_entry(&pwq->inactive_works,
+ struct work_struct, entry);
- lockdep_assert_held(&pool->lock);
-
- /*
- * @pwq->nr_active should be decremented for both percpu and unbound
- * workqueues.
- */
- pwq->nr_active--;
-
- /*
- * For a percpu workqueue, it's simple. Just need to kick the first
- * inactive work item on @pwq itself.
- */
- if (!nna) {
- pwq_activate_first_inactive(pwq, false);
- return;
- }
-
- /*
- * If @pwq is for an unbound workqueue, it's more complicated because
- * multiple pwqs and pools may be sharing the nr_active count. When a
- * pwq needs to wait for an nr_active count, it puts itself on
- * $nna->pending_pwqs. The following atomic_dec_return()'s implied
- * memory barrier is paired with smp_mb() in pwq_tryinc_nr_active() to
- * guarantee that either we see non-empty pending_pwqs or they see
- * decremented $nna->nr.
- *
- * $nna->max may change as CPUs come online/offline and @pwq->wq's
- * max_active gets updated. However, it is guaranteed to be equal to or
- * larger than @pwq->wq->min_active which is above zero unless freezing.
- * This maintains the forward progress guarantee.
- */
- if (atomic_dec_return(&nna->nr) >= READ_ONCE(nna->max))
- return;
-
- if (!list_empty(&nna->pending_pwqs))
- node_activate_pending_pwq(nna, pool);
+ pwq_activate_inactive_work(work);
}
/**
@@ -1884,8 +1488,14 @@ static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, unsigned long work_
{
int color = get_work_color(work_data);
- if (!(work_data & WORK_STRUCT_INACTIVE))
- pwq_dec_nr_active(pwq);
+ if (!(work_data & WORK_STRUCT_INACTIVE)) {
+ pwq->nr_active--;
+ if (!list_empty(&pwq->inactive_works)) {
+ /* one down, submit an inactive one */
+ if (pwq->nr_active < pwq->max_active)
+ pwq_activate_first_inactive(pwq);
+ }
+ }
pwq->nr_in_flight[color]--;
@@ -1998,7 +1608,8 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
* management later on and cause stall. Make sure the work
* item is activated before grabbing.
*/
- pwq_activate_work(pwq, work);
+ if (*work_data_bits(work) & WORK_STRUCT_INACTIVE)
+ pwq_activate_inactive_work(work);
list_del_init(&work->entry);
pwq_dec_nr_in_flight(pwq, *work_data_bits(work));
@@ -2182,16 +1793,12 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
pwq->nr_in_flight[pwq->work_color]++;
work_flags = work_color_to_flags(pwq->work_color);
- /*
- * Limit the number of concurrently active work items to max_active.
- * @work must also queue behind existing inactive work items to maintain
- * ordering when max_active changes. See wq_adjust_max_active().
- */
- if (list_empty(&pwq->inactive_works) && pwq_tryinc_nr_active(pwq, false)) {
+ if (likely(pwq->nr_active < pwq->max_active)) {
if (list_empty(&pool->worklist))
pool->watchdog_ts = jiffies;
trace_workqueue_activate_work(work);
+ pwq->nr_active++;
insert_work(pwq, work, &pool->worklist, work_flags);
kick_pool(pool);
} else {
@@ -3420,7 +3027,7 @@ static void insert_wq_barrier(struct pool_workqueue *pwq,
barr->task = current;
- /* The barrier work item does not participate in nr_active. */
+ /* The barrier work item does not participate in pwq->nr_active. */
work_flags |= WORK_STRUCT_INACTIVE;
/*
@@ -3709,7 +3316,7 @@ void drain_workqueue(struct workqueue_struct *wq)
bool drained;
raw_spin_lock_irq(&pwq->pool->lock);
- drained = pwq_is_empty(pwq);
+ drained = !pwq->nr_active && list_empty(&pwq->inactive_works);
raw_spin_unlock_irq(&pwq->pool->lock);
if (drained)
@@ -4320,65 +3927,11 @@ static void wq_free_lockdep(struct workqueue_struct *wq)
}
#endif
-static void free_node_nr_active(struct wq_node_nr_active **nna_ar)
-{
- int node;
-
- for_each_node(node) {
- kfree(nna_ar[node]);
- nna_ar[node] = NULL;
- }
-
- kfree(nna_ar[nr_node_ids]);
- nna_ar[nr_node_ids] = NULL;
-}
-
-static void init_node_nr_active(struct wq_node_nr_active *nna)
-{
- atomic_set(&nna->nr, 0);
- raw_spin_lock_init(&nna->lock);
- INIT_LIST_HEAD(&nna->pending_pwqs);
-}
-
-/*
- * Each node's nr_active counter will be accessed mostly from its own node and
- * should be allocated in the node.
- */
-static int alloc_node_nr_active(struct wq_node_nr_active **nna_ar)
-{
- struct wq_node_nr_active *nna;
- int node;
-
- for_each_node(node) {
- nna = kzalloc_node(sizeof(*nna), GFP_KERNEL, node);
- if (!nna)
- goto err_free;
- init_node_nr_active(nna);
- nna_ar[node] = nna;
- }
-
- /* [nr_node_ids] is used as the fallback */
- nna = kzalloc_node(sizeof(*nna), GFP_KERNEL, NUMA_NO_NODE);
- if (!nna)
- goto err_free;
- init_node_nr_active(nna);
- nna_ar[nr_node_ids] = nna;
-
- return 0;
-
-err_free:
- free_node_nr_active(nna_ar);
- return -ENOMEM;
-}
-
static void rcu_free_wq(struct rcu_head *rcu)
{
struct workqueue_struct *wq =
container_of(rcu, struct workqueue_struct, rcu);
- if (wq->flags & WQ_UNBOUND)
- free_node_nr_active(wq->node_nr_active);
-
wq_free_lockdep(wq);
free_percpu(wq->cpu_pwq);
free_workqueue_attrs(wq->unbound_attrs);
@@ -4577,15 +4130,6 @@ static void pwq_release_workfn(struct kthread_work *work)
mutex_unlock(&wq_pool_mutex);
}
- if (!list_empty(&pwq->pending_node)) {
- struct wq_node_nr_active *nna =
- wq_node_nr_active(pwq->wq, pwq->pool->node);
-
- raw_spin_lock_irq(&nna->lock);
- list_del_init(&pwq->pending_node);
- raw_spin_unlock_irq(&nna->lock);
- }
-
call_rcu(&pwq->rcu, rcu_free_pwq);
/*
@@ -4598,6 +4142,50 @@ static void pwq_release_workfn(struct kthread_work *work)
}
}
+/**
+ * pwq_adjust_max_active - update a pwq's max_active to the current setting
+ * @pwq: target pool_workqueue
+ *
+ * If @pwq isn't freezing, set @pwq->max_active to the associated
+ * workqueue's saved_max_active and activate inactive work items
+ * accordingly. If @pwq is freezing, clear @pwq->max_active to zero.
+ */
+static void pwq_adjust_max_active(struct pool_workqueue *pwq)
+{
+ struct workqueue_struct *wq = pwq->wq;
+ bool freezable = wq->flags & WQ_FREEZABLE;
+ unsigned long flags;
+
+ /* for @wq->saved_max_active */
+ lockdep_assert_held(&wq->mutex);
+
+ /* fast exit for non-freezable wqs */
+ if (!freezable && pwq->max_active == wq->saved_max_active)
+ return;
+
+ /* this function can be called during early boot w/ irq disabled */
+ raw_spin_lock_irqsave(&pwq->pool->lock, flags);
+
+ /*
+ * During [un]freezing, the caller is responsible for ensuring that
+ * this function is called at least once after @workqueue_freezing
+ * is updated and visible.
+ */
+ if (!freezable || !workqueue_freezing) {
+ pwq->max_active = wq->saved_max_active;
+
+ while (!list_empty(&pwq->inactive_works) &&
+ pwq->nr_active < pwq->max_active)
+ pwq_activate_first_inactive(pwq);
+
+ kick_pool(pwq->pool);
+ } else {
+ pwq->max_active = 0;
+ }
+
+ raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
+}
+
/* initialize newly allocated @pwq which is associated with @wq and @pool */
static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
struct worker_pool *pool)
@@ -4611,7 +4199,6 @@ static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
pwq->flush_color = -1;
pwq->refcnt = 1;
INIT_LIST_HEAD(&pwq->inactive_works);
- INIT_LIST_HEAD(&pwq->pending_node);
INIT_LIST_HEAD(&pwq->pwqs_node);
INIT_LIST_HEAD(&pwq->mayday_node);
kthread_init_work(&pwq->release_work, pwq_release_workfn);
@@ -4631,6 +4218,9 @@ static void link_pwq(struct pool_workqueue *pwq)
/* set the matching work_color */
pwq->work_color = wq->work_color;
+ /* sync max_active to the current setting */
+ pwq_adjust_max_active(pwq);
+
/* link in @pwq */
list_add_rcu(&pwq->pwqs_node, &wq->pwqs);
}
@@ -4699,11 +4289,10 @@ static void wq_calc_pod_cpumask(struct workqueue_attrs *attrs, int cpu,
"possible intersect\n");
}
-/* install @pwq into @wq and return the old pwq, @cpu < 0 for dfl_pwq */
+/* install @pwq into @wq's cpu_pwq and return the old pwq */
static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq,
int cpu, struct pool_workqueue *pwq)
{
- struct pool_workqueue __rcu **slot = unbound_pwq_slot(wq, cpu);
struct pool_workqueue *old_pwq;
lockdep_assert_held(&wq_pool_mutex);
@@ -4712,8 +4301,8 @@ static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq,
/* link_pwq() can handle duplicate calls */
link_pwq(pwq);
- old_pwq = rcu_access_pointer(*slot);
- rcu_assign_pointer(*slot, pwq);
+ old_pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
+ rcu_assign_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu), pwq);
return old_pwq;
}
@@ -4813,14 +4402,14 @@ static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs);
- /* save the previous pwqs and install the new ones */
+ /* save the previous pwq and install the new one */
for_each_possible_cpu(cpu)
ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu,
ctx->pwq_tbl[cpu]);
- ctx->dfl_pwq = install_unbound_pwq(ctx->wq, -1, ctx->dfl_pwq);
- /* update node_nr_active->max */
- wq_update_node_max_active(ctx->wq, -1);
+ /* @dfl_pwq might not have been used, ensure it's linked */
+ link_pwq(ctx->dfl_pwq);
+ swap(ctx->wq->dfl_pwq, ctx->dfl_pwq);
mutex_unlock(&ctx->wq->mutex);
}
@@ -4930,7 +4519,9 @@ static void wq_update_pod(struct workqueue_struct *wq, int cpu,
/* nothing to do if the target cpumask matches the current pwq */
wq_calc_pod_cpumask(target_attrs, cpu, off_cpu);
- if (wqattrs_equal(target_attrs, unbound_pwq(wq, cpu)->pool->attrs))
+ pwq = rcu_dereference_protected(*per_cpu_ptr(wq->cpu_pwq, cpu),
+ lockdep_is_held(&wq_pool_mutex));
+ if (wqattrs_equal(target_attrs, pwq->pool->attrs))
return;
/* create a new pwq */
@@ -4948,11 +4539,10 @@ static void wq_update_pod(struct workqueue_struct *wq, int cpu,
use_dfl_pwq:
mutex_lock(&wq->mutex);
- pwq = unbound_pwq(wq, -1);
- raw_spin_lock_irq(&pwq->pool->lock);
- get_pwq(pwq);
- raw_spin_unlock_irq(&pwq->pool->lock);
- old_pwq = install_unbound_pwq(wq, cpu, pwq);
+ raw_spin_lock_irq(&wq->dfl_pwq->pool->lock);
+ get_pwq(wq->dfl_pwq);
+ raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock);
+ old_pwq = install_unbound_pwq(wq, cpu, wq->dfl_pwq);
out_unlock:
mutex_unlock(&wq->mutex);
put_pwq_unlocked(old_pwq);
@@ -4990,13 +4580,10 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq)
cpus_read_lock();
if (wq->flags & __WQ_ORDERED) {
- struct pool_workqueue *dfl_pwq;
-
ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
/* there should only be single pwq for ordering guarantee */
- dfl_pwq = rcu_access_pointer(wq->dfl_pwq);
- WARN(!ret && (wq->pwqs.next != &dfl_pwq->pwqs_node ||
- wq->pwqs.prev != &dfl_pwq->pwqs_node),
+ WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node ||
+ wq->pwqs.prev != &wq->dfl_pwq->pwqs_node),
"ordering guarantee broken for workqueue %s\n", wq->name);
} else {
ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
@@ -5071,69 +4658,6 @@ static int init_rescuer(struct workqueue_struct *wq)
return 0;
}
-/**
- * wq_adjust_max_active - update a wq's max_active to the current setting
- * @wq: target workqueue
- *
- * If @wq isn't freezing, set @wq->max_active to the saved_max_active and
- * activate inactive work items accordingly. If @wq is freezing, clear
- * @wq->max_active to zero.
- */
-static void wq_adjust_max_active(struct workqueue_struct *wq)
-{
- bool activated;
- int new_max, new_min;
-
- lockdep_assert_held(&wq->mutex);
-
- if ((wq->flags & WQ_FREEZABLE) && workqueue_freezing) {
- new_max = 0;
- new_min = 0;
- } else {
- new_max = wq->saved_max_active;
- new_min = wq->saved_min_active;
- }
-
- if (wq->max_active == new_max && wq->min_active == new_min)
- return;
-
- /*
- * Update @wq->max/min_active and then kick inactive work items if more
- * active work items are allowed. This doesn't break work item ordering
- * because new work items are always queued behind existing inactive
- * work items if there are any.
- */
- WRITE_ONCE(wq->max_active, new_max);
- WRITE_ONCE(wq->min_active, new_min);
-
- if (wq->flags & WQ_UNBOUND)
- wq_update_node_max_active(wq, -1);
-
- if (new_max == 0)
- return;
-
- /*
- * Round-robin through pwq's activating the first inactive work item
- * until max_active is filled.
- */
- do {
- struct pool_workqueue *pwq;
-
- activated = false;
- for_each_pwq(pwq, wq) {
- unsigned long flags;
-
- /* can be called during early boot w/ irq disabled */
- raw_spin_lock_irqsave(&pwq->pool->lock, flags);
- if (pwq_activate_first_inactive(pwq, true)) {
- activated = true;
- kick_pool(pwq->pool);
- }
- raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
- }
- } while (activated);
-}
-
__printf(1, 4)
struct workqueue_struct *alloc_workqueue(const char *fmt,
unsigned int flags,
@@ -5141,8 +4665,7 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
{
va_list args;
struct workqueue_struct *wq;
- size_t wq_size;
- int name_len;
+ struct pool_workqueue *pwq;
/*
* Unbound && max_active == 1 used to imply ordered, which is no longer
@@ -5158,12 +4681,7 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
flags |= WQ_UNBOUND;
/* allocate wq and format name */
- if (flags & WQ_UNBOUND)
- wq_size = struct_size(wq, node_nr_active, nr_node_ids + 1);
- else
- wq_size = sizeof(*wq);
-
- wq = kzalloc(wq_size, GFP_KERNEL);
+ wq = kzalloc(sizeof(*wq), GFP_KERNEL);
if (!wq)
return NULL;
@@ -5174,22 +4692,15 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
}
va_start(args, max_active);
- name_len = vsnprintf(wq->name, sizeof(wq->name), fmt, args);
+ vsnprintf(wq->name, sizeof(wq->name), fmt, args);
va_end(args);
- if (name_len >= WQ_NAME_LEN)
- pr_warn_once("workqueue: name exceeds WQ_NAME_LEN. Truncating to: %s\n",
- wq->name);
-
max_active = max_active ?: WQ_DFL_ACTIVE;
max_active = wq_clamp_max_active(max_active, flags, wq->name);
/* init wq */
wq->flags = flags;
- wq->max_active = max_active;
- wq->min_active = min(max_active, WQ_DFL_MIN_ACTIVE);
- wq->saved_max_active = wq->max_active;
- wq->saved_min_active = wq->min_active;
+ wq->saved_max_active = max_active;
mutex_init(&wq->mutex);
atomic_set(&wq->nr_pwqs_to_flush, 0);
INIT_LIST_HEAD(&wq->pwqs);
@@ -5200,13 +4711,8 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
wq_init_lockdep(wq);
INIT_LIST_HEAD(&wq->list);
- if (flags & WQ_UNBOUND) {
- if (alloc_node_nr_active(wq->node_nr_active) < 0)
- goto err_unreg_lockdep;
- }
-
if (alloc_and_link_pwqs(wq) < 0)
- goto err_free_node_nr_active;
+ goto err_unreg_lockdep;
if (wq_online && init_rescuer(wq) < 0)
goto err_destroy;
@@ -5222,7 +4728,8 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
mutex_lock(&wq_pool_mutex);
mutex_lock(&wq->mutex);
- wq_adjust_max_active(wq);
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
list_add_tail_rcu(&wq->list, &workqueues);
@@ -5231,9 +4738,6 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
return wq;
-err_free_node_nr_active:
- if (wq->flags & WQ_UNBOUND)
- free_node_nr_active(wq->node_nr_active);
err_unreg_lockdep:
wq_unregister_lockdep(wq);
wq_free_lockdep(wq);
@@ -5255,9 +4759,9 @@ static bool pwq_busy(struct pool_workqueue *pwq)
if (pwq->nr_in_flight[i])
return true;
- if ((pwq != rcu_access_pointer(pwq->wq->dfl_pwq)) && (pwq->refcnt > 1))
+ if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1))
return true;
- if (!pwq_is_empty(pwq))
+ if (pwq->nr_active || !list_empty(&pwq->inactive_works))
return true;
return false;
@@ -5339,12 +4843,13 @@ void destroy_workqueue(struct workqueue_struct *wq)
rcu_read_lock();
for_each_possible_cpu(cpu) {
- put_pwq_unlocked(unbound_pwq(wq, cpu));
- RCU_INIT_POINTER(*unbound_pwq_slot(wq, cpu), NULL);
+ pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
+ RCU_INIT_POINTER(*per_cpu_ptr(wq->cpu_pwq, cpu), NULL);
+ put_pwq_unlocked(pwq);
}
- put_pwq_unlocked(unbound_pwq(wq, -1));
- RCU_INIT_POINTER(*unbound_pwq_slot(wq, -1), NULL);
+ put_pwq_unlocked(wq->dfl_pwq);
+ wq->dfl_pwq = NULL;
rcu_read_unlock();
}
@@ -5355,14 +4860,15 @@ EXPORT_SYMBOL_GPL(destroy_workqueue);
* @wq: target workqueue
* @max_active: new max_active value.
*
- * Set max_active of @wq to @max_active. See the alloc_workqueue() function
- * comment.
+ * Set max_active of @wq to @max_active.
*
* CONTEXT:
* Don't call from IRQ context.
*/
void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
{
+ struct pool_workqueue *pwq;
+
/* disallow meddling with max_active for ordered workqueues */
if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
return;
@@ -5373,10 +4879,9 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
wq->flags &= ~__WQ_ORDERED;
wq->saved_max_active = max_active;
- if (wq->flags & WQ_UNBOUND)
- wq->saved_min_active = min(wq->saved_min_active, max_active);
- wq_adjust_max_active(wq);
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
}
@@ -5623,8 +5128,8 @@ static void show_pwq(struct pool_workqueue *pwq)
pr_info(" pwq %d:", pool->id);
pr_cont_pool_info(pool);
- pr_cont(" active=%d refcnt=%d%s\n",
- pwq->nr_active, pwq->refcnt,
+ pr_cont(" active=%d/%d refcnt=%d%s\n",
+ pwq->nr_active, pwq->max_active, pwq->refcnt,
!list_empty(&pwq->mayday_node) ? " MAYDAY" : "");
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
@@ -5698,7 +5203,7 @@ void show_one_workqueue(struct workqueue_struct *wq)
unsigned long flags;
for_each_pwq(pwq, wq) {
- if (!pwq_is_empty(pwq)) {
+ if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
idle = false;
break;
}
@@ -5710,7 +5215,7 @@ void show_one_workqueue(struct workqueue_struct *wq)
for_each_pwq(pwq, wq) {
raw_spin_lock_irqsave(&pwq->pool->lock, flags);
- if (!pwq_is_empty(pwq)) {
+ if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
/*
* Defer printing to avoid deadlocks in console
* drivers that queue work while holding locks
@@ -6057,10 +5562,6 @@ int workqueue_online_cpu(unsigned int cpu)
for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
wq_update_pod(wq, tcpu, cpu, true);
-
- mutex_lock(&wq->mutex);
- wq_update_node_max_active(wq, -1);
- mutex_unlock(&wq->mutex);
}
}
@@ -6089,10 +5590,6 @@ int workqueue_offline_cpu(unsigned int cpu)
for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
wq_update_pod(wq, tcpu, cpu, false);
-
- mutex_lock(&wq->mutex);
- wq_update_node_max_active(wq, cpu);
- mutex_unlock(&wq->mutex);
}
}
mutex_unlock(&wq_pool_mutex);
@@ -6180,6 +5677,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu_safe_key);
void freeze_workqueues_begin(void)
{
struct workqueue_struct *wq;
+ struct pool_workqueue *pwq;
mutex_lock(&wq_pool_mutex);
@@ -6188,7 +5686,8 @@ void freeze_workqueues_begin(void)
list_for_each_entry(wq, &workqueues, list) {
mutex_lock(&wq->mutex);
- wq_adjust_max_active(wq);
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
}
@@ -6253,6 +5752,7 @@ bool freeze_workqueues_busy(void)
void thaw_workqueues(void)
{
struct workqueue_struct *wq;
+ struct pool_workqueue *pwq;
mutex_lock(&wq_pool_mutex);
@@ -6264,7 +5764,8 @@ void thaw_workqueues(void)
/* restore max_active and repopulate worklist */
list_for_each_entry(wq, &workqueues, list) {
mutex_lock(&wq->mutex);
- wq_adjust_max_active(wq);
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
}
@@ -7186,7 +6687,7 @@ void __init workqueue_init_early(void)
WQ_FREEZABLE, 0);
system_power_efficient_wq = alloc_workqueue("events_power_efficient",
WQ_POWER_EFFICIENT, 0);
- system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_pwr_efficient",
+ system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient",
WQ_FREEZABLE | WQ_POWER_EFFICIENT,
0);
BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq ||
@@ -7373,12 +6874,8 @@ void __init workqueue_init_topology(void)
* combinations to apply per-pod sharing.
*/
list_for_each_entry(wq, &workqueues, list) {
- for_each_online_cpu(cpu)
+ for_each_online_cpu(cpu) {
wq_update_pod(wq, cpu, cpu, true);
- if (wq->flags & WQ_UNBOUND) {
- mutex_lock(&wq->mutex);
- wq_update_node_max_active(wq, -1);
- mutex_unlock(&wq->mutex);
}
}
