#include <linux/debug_locks.h>
#include <linux/lockdep.h>
#include <linux/idr.h>
+#include <linux/jhash.h>
+#include <linux/hashtable.h>
+#include <linux/rculist.h>
-#include "workqueue_sched.h"
+#include "workqueue_internal.h"
enum {
/*
- * global_cwq flags
+ * worker_pool flags
*
- * A bound gcwq is either associated or disassociated with its CPU.
+ * A bound pool is either associated or disassociated with its CPU.
* While associated (!DISASSOCIATED), all workers are bound to the
* CPU and none has %WORKER_UNBOUND set and concurrency management
* is in effect.
*
* While DISASSOCIATED, the cpu may be offline and all workers have
* %WORKER_UNBOUND set and concurrency management disabled, and may
- * be executing on any CPU. The gcwq behaves as an unbound one.
+ * be executing on any CPU. The pool behaves as an unbound one.
*
- * Note that DISASSOCIATED can be flipped only while holding
- * assoc_mutex of all pools on the gcwq to avoid changing binding
- * state while create_worker() is in progress.
+ * Note that DISASSOCIATED should be flipped only while holding
+ * manager_mutex to avoid changing binding state while
+ * create_worker() is in progress.
*/
- GCWQ_DISASSOCIATED = 1 << 0, /* cpu can't serve workers */
- GCWQ_FREEZING = 1 << 1, /* freeze in progress */
-
- /* pool flags */
POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */
- POOL_MANAGING_WORKERS = 1 << 1, /* managing workers */
+ POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */
+ POOL_FREEZING = 1 << 3, /* freeze in progress */
/* worker flags */
WORKER_STARTED = 1 << 0, /* started */
WORKER_PREP = 1 << 3, /* preparing to run works */
WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */
WORKER_UNBOUND = 1 << 7, /* worker is unbound */
+ WORKER_REBOUND = 1 << 8, /* worker was rebound */
- WORKER_NOT_RUNNING = WORKER_PREP | WORKER_UNBOUND |
- WORKER_CPU_INTENSIVE,
+ WORKER_NOT_RUNNING = WORKER_PREP | WORKER_CPU_INTENSIVE |
+ WORKER_UNBOUND | WORKER_REBOUND,
- NR_WORKER_POOLS = 2, /* # worker pools per gcwq */
+ NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */
+ UNBOUND_POOL_HASH_ORDER = 6, /* hashed by pool->attrs */
BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */
- BUSY_WORKER_HASH_SIZE = 1 << BUSY_WORKER_HASH_ORDER,
- BUSY_WORKER_HASH_MASK = BUSY_WORKER_HASH_SIZE - 1,
MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */
IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */
* 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 GCWQ_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.
*
- * W: workqueue_lock protected.
+ * MG: pool->manager_mutex and pool->lock protected. Writes require both
+ * locks. Reads can happen under either lock.
+ *
+ * PL: wq_pool_mutex protected.
+ *
+ * PR: wq_pool_mutex protected for writes. Sched-RCU protected for reads.
+ *
+ * PW: pwq_lock protected.
+ *
+ * FR: wq->flush_mutex and pwq_lock protected for writes. Sched-RCU
+ * protected for reads.
+ *
+ * MD: wq_mayday_lock protected.
*/
-struct global_cwq;
-struct worker_pool;
-
-/*
- * The poor guys doing the actual heavy lifting. All on-duty workers
- * are either serving the manager role, on idle list or on busy hash.
- */
-struct worker {
- /* on idle list while idle, on busy hash table while busy */
- union {
- struct list_head entry; /* L: while idle */
- struct hlist_node hentry; /* L: while busy */
- };
-
- struct work_struct *current_work; /* L: work being processed */
- struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */
- struct list_head scheduled; /* L: scheduled works */
- struct task_struct *task; /* I: worker task */
- struct worker_pool *pool; /* I: the associated pool */
- /* 64 bytes boundary on 64bit, 32 on 32bit */
- unsigned long last_active; /* L: last active timestamp */
- unsigned int flags; /* X: flags */
- int id; /* I: worker id */
-
- /* for rebinding worker to CPU */
- struct work_struct rebind_work; /* L: for busy worker */
-};
+/* struct worker is defined in workqueue_internal.h */
struct worker_pool {
- struct global_cwq *gcwq; /* I: the owning gcwq */
+ spinlock_t lock; /* the pool lock */
+ int cpu; /* I: the associated cpu */
+ int id; /* I: pool ID */
unsigned int flags; /* X: flags */
struct list_head worklist; /* L: list of pending works */
struct timer_list idle_timer; /* L: worker idle timeout */
struct timer_list mayday_timer; /* L: SOS timer for workers */
- struct mutex assoc_mutex; /* protect GCWQ_DISASSOCIATED */
- struct ida worker_ida; /* L: for worker IDs */
-};
+ /* a workers is either on busy_hash or idle_list, or the manager */
+ DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
+ /* L: hash of busy workers */
-/*
- * Global per-cpu workqueue. There's one and only one for each cpu
- * and all works are queued and processed here regardless of their
- * target workqueues.
- */
-struct global_cwq {
- spinlock_t lock; /* the gcwq lock */
- unsigned int cpu; /* I: the associated cpu */
- unsigned int flags; /* L: GCWQ_* flags */
+ /* see manage_workers() for details on the two manager mutexes */
+ struct mutex manager_arb; /* manager arbitration */
+ struct mutex manager_mutex; /* manager exclusion */
+ struct idr worker_idr; /* MG: worker IDs and iteration */
- /* workers are chained either in busy_hash or pool idle_list */
- struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE];
- /* L: hash of busy workers */
+ struct workqueue_attrs *attrs; /* I: worker attributes */
+ struct hlist_node hash_node; /* PL: unbound_pool_hash node */
+ int refcnt; /* PL: refcnt for unbound pools */
+
+ /*
+ * The current concurrency level. As it's likely to be accessed
+ * from other CPUs during try_to_wake_up(), put it in a separate
+ * cacheline.
+ */
+ atomic_t nr_running ____cacheline_aligned_in_smp;
- struct worker_pool pools[NR_WORKER_POOLS];
- /* normal and highpri pools */
+ /*
+ * Destruction of pool is sched-RCU protected to allow dereferences
+ * from get_work_pool().
+ */
+ struct rcu_head rcu;
} ____cacheline_aligned_in_smp;
/*
- * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of
- * work_struct->data are used for flags and thus cwqs need to be
- * aligned at two's power of the number of flag bits.
+ * The per-pool workqueue. While queued, the lower WORK_STRUCT_FLAG_BITS
+ * of work_struct->data are used for flags and the remaining high bits
+ * point to the pwq; thus, pwqs need to be aligned at two's power of the
+ * number of flag bits.
*/
-struct cpu_workqueue_struct {
+struct pool_workqueue {
struct worker_pool *pool; /* I: the associated pool */
struct workqueue_struct *wq; /* I: the owning workqueue */
int work_color; /* L: current color */
int flush_color; /* L: flushing color */
+ int refcnt; /* L: reference count */
int nr_in_flight[WORK_NR_COLORS];
/* L: nr of in_flight works */
int nr_active; /* L: nr of active works */
int max_active; /* L: max active works */
struct list_head delayed_works; /* L: delayed works */
-};
+ struct list_head pwqs_node; /* FR: node on wq->pwqs */
+ struct list_head mayday_node; /* MD: node on wq->maydays */
+
+ /*
+ * Release of unbound pwq is punted to system_wq. See put_pwq()
+ * and pwq_unbound_release_workfn() for details. pool_workqueue
+ * itself is also sched-RCU protected so that the first pwq can be
+ * determined without grabbing pwq_lock.
+ */
+ struct work_struct unbound_release_work;
+ struct rcu_head rcu;
+} __aligned(1 << WORK_STRUCT_FLAG_BITS);
/*
* Structure used to wait for workqueue flush.
struct completion done; /* flush completion */
};
-/*
- * All cpumasks are assumed to be always set on UP and thus can't be
- * used to determine whether there's something to be done.
- */
-#ifdef CONFIG_SMP
-typedef cpumask_var_t mayday_mask_t;
-#define mayday_test_and_set_cpu(cpu, mask) \
- cpumask_test_and_set_cpu((cpu), (mask))
-#define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask))
-#define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask))
-#define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp))
-#define free_mayday_mask(mask) free_cpumask_var((mask))
-#else
-typedef unsigned long mayday_mask_t;
-#define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask))
-#define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask))
-#define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask))
-#define alloc_mayday_mask(maskp, gfp) true
-#define free_mayday_mask(mask) do { } while (0)
-#endif
+struct wq_device;
/*
- * The externally visible workqueue abstraction is an array of
- * per-CPU workqueues:
+ * The externally visible workqueue. It relays the issued work items to
+ * the appropriate worker_pool through its pool_workqueues.
*/
struct workqueue_struct {
- unsigned int flags; /* W: WQ_* flags */
- union {
- struct cpu_workqueue_struct __percpu *pcpu;
- struct cpu_workqueue_struct *single;
- unsigned long v;
- } cpu_wq; /* I: cwq's */
- struct list_head list; /* W: list of all workqueues */
+ unsigned int flags; /* PL: WQ_* flags */
+ struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwq's */
+ struct list_head pwqs; /* FR: all pwqs of this wq */
+ struct list_head list; /* PL: list of all workqueues */
struct mutex flush_mutex; /* protects wq flushing */
int work_color; /* F: current work color */
int flush_color; /* F: current flush color */
- atomic_t nr_cwqs_to_flush; /* flush in progress */
+ atomic_t nr_pwqs_to_flush; /* flush in progress */
struct wq_flusher *first_flusher; /* F: first flusher */
struct list_head flusher_queue; /* F: flush waiters */
struct list_head flusher_overflow; /* F: flush overflow list */
- mayday_mask_t mayday_mask; /* cpus requesting rescue */
+ struct list_head maydays; /* MD: pwqs requesting rescue */
struct worker *rescuer; /* I: rescue worker */
- int nr_drainers; /* W: drain in progress */
- int saved_max_active; /* W: saved cwq max_active */
+ int nr_drainers; /* PL: drain in progress */
+ int saved_max_active; /* PW: saved pwq max_active */
+
+#ifdef CONFIG_SYSFS
+ struct wq_device *wq_dev; /* I: for sysfs interface */
+#endif
#ifdef CONFIG_LOCKDEP
struct lockdep_map lockdep_map;
#endif
char name[]; /* I: workqueue name */
};
+static struct kmem_cache *pwq_cache;
+
+static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */
+static DEFINE_SPINLOCK(pwq_lock); /* protects pool_workqueues */
+static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */
+
+static LIST_HEAD(workqueues); /* PL: list of all workqueues */
+static bool workqueue_freezing; /* PL: have wqs started freezing? */
+
+/* the per-cpu worker pools */
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
+ cpu_worker_pools);
+
+static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */
+
+/* PL: hash of all unbound pools keyed by pool->attrs */
+static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER);
+
+/* I: attributes used when instantiating standard unbound pools on demand */
+static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS];
+
struct workqueue_struct *system_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_wq);
struct workqueue_struct *system_highpri_wq __read_mostly;
struct workqueue_struct *system_freezable_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_freezable_wq);
+static int worker_thread(void *__worker);
+static void copy_workqueue_attrs(struct workqueue_attrs *to,
+ const struct workqueue_attrs *from);
+
#define CREATE_TRACE_POINTS
#include <trace/events/workqueue.h>
-#define for_each_worker_pool(pool, gcwq) \
- for ((pool) = &(gcwq)->pools[0]; \
- (pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++)
+#define assert_rcu_or_pool_mutex() \
+ rcu_lockdep_assert(rcu_read_lock_sched_held() || \
+ lockdep_is_held(&wq_pool_mutex), \
+ "sched RCU or wq_pool_mutex should be held")
-#define for_each_busy_worker(worker, i, pos, gcwq) \
- for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \
- hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry)
+#define assert_rcu_or_pwq_lock() \
+ rcu_lockdep_assert(rcu_read_lock_sched_held() || \
+ lockdep_is_held(&pwq_lock), \
+ "sched RCU or pwq_lock should be held")
-static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask,
- unsigned int sw)
-{
- if (cpu < nr_cpu_ids) {
- if (sw & 1) {
- cpu = cpumask_next(cpu, mask);
- if (cpu < nr_cpu_ids)
- return cpu;
- }
- if (sw & 2)
- return WORK_CPU_UNBOUND;
- }
- return WORK_CPU_NONE;
-}
+#ifdef CONFIG_LOCKDEP
+#define assert_manager_or_pool_lock(pool) \
+ WARN_ONCE(debug_locks && \
+ !lockdep_is_held(&(pool)->manager_mutex) && \
+ !lockdep_is_held(&(pool)->lock), \
+ "pool->manager_mutex or ->lock should be held")
+#else
+#define assert_manager_or_pool_lock(pool) do { } while (0)
+#endif
-static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
- struct workqueue_struct *wq)
-{
- return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2);
-}
+#define for_each_cpu_worker_pool(pool, cpu) \
+ for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \
+ (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
+ (pool)++)
-/*
- * CPU iterators
+/**
+ * for_each_pool - iterate through all worker_pools in the system
+ * @pool: iteration cursor
+ * @pi: integer used for iteration
*
- * An extra gcwq is defined for an invalid cpu number
- * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any
- * specific CPU. The following iterators are similar to
- * for_each_*_cpu() iterators but also considers the unbound gcwq.
+ * This must be called either with wq_pool_mutex held or sched RCU read
+ * locked. If the pool needs to be used beyond the locking in effect, the
+ * caller is responsible for guaranteeing that the pool stays online.
*
- * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND
- * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND
- * for_each_cwq_cpu() : possible CPUs for bound workqueues,
- * WORK_CPU_UNBOUND for unbound workqueues
+ * The if/else clause exists only for the lockdep assertion and can be
+ * ignored.
*/
-#define for_each_gcwq_cpu(cpu) \
- for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \
- (cpu) < WORK_CPU_NONE; \
- (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3))
+#define for_each_pool(pool, pi) \
+ idr_for_each_entry(&worker_pool_idr, pool, pi) \
+ if (({ assert_rcu_or_pool_mutex(); false; })) { } \
+ else
-#define for_each_online_gcwq_cpu(cpu) \
- for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \
- (cpu) < WORK_CPU_NONE; \
- (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3))
+/**
+ * for_each_pool_worker - iterate through all workers of a worker_pool
+ * @worker: iteration cursor
+ * @wi: integer used for iteration
+ * @pool: worker_pool to iterate workers of
+ *
+ * This must be called with either @pool->manager_mutex or ->lock held.
+ *
+ * The if/else clause exists only for the lockdep assertion and can be
+ * ignored.
+ */
+#define for_each_pool_worker(worker, wi, pool) \
+ idr_for_each_entry(&(pool)->worker_idr, (worker), (wi)) \
+ if (({ assert_manager_or_pool_lock((pool)); false; })) { } \
+ else
-#define for_each_cwq_cpu(cpu, wq) \
- for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \
- (cpu) < WORK_CPU_NONE; \
- (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq)))
+/**
+ * for_each_pwq - iterate through all pool_workqueues of the specified workqueue
+ * @pwq: iteration cursor
+ * @wq: the target workqueue
+ *
+ * This must be called either with pwq_lock held or sched RCU read locked.
+ * If the pwq needs to be used beyond the locking in effect, the caller is
+ * responsible for guaranteeing that the pwq stays online.
+ *
+ * The if/else clause exists only for the lockdep assertion and can be
+ * ignored.
+ */
+#define for_each_pwq(pwq, wq) \
+ list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node) \
+ if (({ assert_rcu_or_pwq_lock(); false; })) { } \
+ else
#ifdef CONFIG_DEBUG_OBJECTS_WORK
static inline void debug_work_deactivate(struct work_struct *work) { }
#endif
-/* Serializes the accesses to the list of workqueues. */
-static DEFINE_SPINLOCK(workqueue_lock);
-static LIST_HEAD(workqueues);
-static bool workqueue_freezing; /* W: have wqs started freezing? */
-
-/*
- * The almighty global cpu workqueues. nr_running is the only field
- * which is expected to be used frequently by other cpus via
- * try_to_wake_up(). Put it in a separate cacheline.
- */
-static DEFINE_PER_CPU(struct global_cwq, global_cwq);
-static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, pool_nr_running[NR_WORKER_POOLS]);
-
-/*
- * Global cpu workqueue and nr_running counter for unbound gcwq. The
- * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its
- * workers have WORKER_UNBOUND set.
- */
-static struct global_cwq unbound_global_cwq;
-static atomic_t unbound_pool_nr_running[NR_WORKER_POOLS] = {
- [0 ... NR_WORKER_POOLS - 1] = ATOMIC_INIT(0), /* always 0 */
-};
-
-static int worker_thread(void *__worker);
-
-static int worker_pool_pri(struct worker_pool *pool)
+/* allocate ID and assign it to @pool */
+static int worker_pool_assign_id(struct worker_pool *pool)
{
- return pool - pool->gcwq->pools;
-}
+ int ret;
-static struct global_cwq *get_gcwq(unsigned int cpu)
-{
- if (cpu != WORK_CPU_UNBOUND)
- return &per_cpu(global_cwq, cpu);
- else
- return &unbound_global_cwq;
-}
+ lockdep_assert_held(&wq_pool_mutex);
-static atomic_t *get_pool_nr_running(struct worker_pool *pool)
-{
- int cpu = pool->gcwq->cpu;
- int idx = worker_pool_pri(pool);
+ do {
+ if (!idr_pre_get(&worker_pool_idr, GFP_KERNEL))
+ return -ENOMEM;
+ ret = idr_get_new(&worker_pool_idr, pool, &pool->id);
+ } while (ret == -EAGAIN);
- if (cpu != WORK_CPU_UNBOUND)
- return &per_cpu(pool_nr_running, cpu)[idx];
- else
- return &unbound_pool_nr_running[idx];
+ return ret;
}
-static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
- struct workqueue_struct *wq)
+/**
+ * first_pwq - return the first pool_workqueue of the specified workqueue
+ * @wq: the target workqueue
+ *
+ * This must be called either with pwq_lock held or sched RCU read locked.
+ * If the pwq needs to be used beyond the locking in effect, the caller is
+ * responsible for guaranteeing that the pwq stays online.
+ */
+static struct pool_workqueue *first_pwq(struct workqueue_struct *wq)
{
- if (!(wq->flags & WQ_UNBOUND)) {
- if (likely(cpu < nr_cpu_ids))
- return per_cpu_ptr(wq->cpu_wq.pcpu, cpu);
- } else if (likely(cpu == WORK_CPU_UNBOUND))
- return wq->cpu_wq.single;
- return NULL;
+ assert_rcu_or_pwq_lock();
+ return list_first_or_null_rcu(&wq->pwqs, struct pool_workqueue,
+ pwqs_node);
}
static unsigned int work_color_to_flags(int color)
}
/*
- * While queued, %WORK_STRUCT_CWQ is set and non flag bits of a work's data
- * contain the pointer to the queued cwq. Once execution starts, the flag
- * is cleared and the high bits contain OFFQ flags and CPU number.
+ * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data
+ * contain the pointer to the queued pwq. Once execution starts, the flag
+ * is cleared and the high bits contain OFFQ flags and pool ID.
*
- * set_work_cwq(), set_work_cpu_and_clear_pending(), mark_work_canceling()
- * and clear_work_data() can be used to set the cwq, cpu or clear
+ * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling()
+ * and clear_work_data() can be used to set the pwq, pool or clear
* work->data. These functions should only be called while the work is
* owned - ie. while the PENDING bit is set.
*
- * get_work_[g]cwq() can be used to obtain the gcwq or cwq corresponding to
- * a work. gcwq is available once the work has been queued anywhere after
- * initialization until it is sync canceled. cwq is available only while
- * the work item is queued.
+ * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq
+ * corresponding to a work. Pool is available once the work has been
+ * queued anywhere after initialization until it is sync canceled. pwq is
+ * available only while the work item is queued.
*
* %WORK_OFFQ_CANCELING is used to mark a work item which is being
* canceled. While being canceled, a work item may have its PENDING set
static inline void set_work_data(struct work_struct *work, unsigned long data,
unsigned long flags)
{
- BUG_ON(!work_pending(work));
+ WARN_ON_ONCE(!work_pending(work));
atomic_long_set(&work->data, data | flags | work_static(work));
}
-static void set_work_cwq(struct work_struct *work,
- struct cpu_workqueue_struct *cwq,
+static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq,
unsigned long extra_flags)
{
- set_work_data(work, (unsigned long)cwq,
- WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags);
+ set_work_data(work, (unsigned long)pwq,
+ WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags);
+}
+
+static void set_work_pool_and_keep_pending(struct work_struct *work,
+ int pool_id)
+{
+ set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT,
+ WORK_STRUCT_PENDING);
}
-static void set_work_cpu_and_clear_pending(struct work_struct *work,
- unsigned int cpu)
+static void set_work_pool_and_clear_pending(struct work_struct *work,
+ int pool_id)
{
/*
* The following wmb is paired with the implied mb in
* owner.
*/
smp_wmb();
- set_work_data(work, (unsigned long)cpu << WORK_OFFQ_CPU_SHIFT, 0);
+ set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0);
}
static void clear_work_data(struct work_struct *work)
{
- smp_wmb(); /* see set_work_cpu_and_clear_pending() */
- set_work_data(work, WORK_STRUCT_NO_CPU, 0);
+ smp_wmb(); /* see set_work_pool_and_clear_pending() */
+ set_work_data(work, WORK_STRUCT_NO_POOL, 0);
}
-static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work)
+static struct pool_workqueue *get_work_pwq(struct work_struct *work)
{
unsigned long data = atomic_long_read(&work->data);
- if (data & WORK_STRUCT_CWQ)
+ if (data & WORK_STRUCT_PWQ)
return (void *)(data & WORK_STRUCT_WQ_DATA_MASK);
else
return NULL;
}
-static struct global_cwq *get_work_gcwq(struct work_struct *work)
+/**
+ * get_work_pool - return the worker_pool a given work was associated with
+ * @work: the work item of interest
+ *
+ * Return the worker_pool @work was last associated with. %NULL if none.
+ *
+ * Pools are created and destroyed under wq_pool_mutex, and allows read
+ * access under sched-RCU read lock. As such, this function should be
+ * called under wq_pool_mutex or with preemption disabled.
+ *
+ * All fields of the returned pool are accessible as long as the above
+ * mentioned locking is in effect. If the returned pool needs to be used
+ * beyond the critical section, the caller is responsible for ensuring the
+ * returned pool is and stays online.
+ */
+static struct worker_pool *get_work_pool(struct work_struct *work)
{
unsigned long data = atomic_long_read(&work->data);
- unsigned int cpu;
+ int pool_id;
+
+ assert_rcu_or_pool_mutex();
- if (data & WORK_STRUCT_CWQ)
- return ((struct cpu_workqueue_struct *)
- (data & WORK_STRUCT_WQ_DATA_MASK))->pool->gcwq;
+ if (data & WORK_STRUCT_PWQ)
+ return ((struct pool_workqueue *)
+ (data & WORK_STRUCT_WQ_DATA_MASK))->pool;
- cpu = data >> WORK_OFFQ_CPU_SHIFT;
- if (cpu == WORK_CPU_NONE)
+ pool_id = data >> WORK_OFFQ_POOL_SHIFT;
+ if (pool_id == WORK_OFFQ_POOL_NONE)
return NULL;
- BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND);
- return get_gcwq(cpu);
+ return idr_find(&worker_pool_idr, pool_id);
+}
+
+/**
+ * get_work_pool_id - return the worker pool ID a given work is associated with
+ * @work: the work item of interest
+ *
+ * Return the worker_pool ID @work was last associated with.
+ * %WORK_OFFQ_POOL_NONE if none.
+ */
+static int get_work_pool_id(struct work_struct *work)
+{
+ unsigned long data = atomic_long_read(&work->data);
+
+ if (data & WORK_STRUCT_PWQ)
+ return ((struct pool_workqueue *)
+ (data & WORK_STRUCT_WQ_DATA_MASK))->pool->id;
+
+ return data >> WORK_OFFQ_POOL_SHIFT;
}
static void mark_work_canceling(struct work_struct *work)
{
- struct global_cwq *gcwq = get_work_gcwq(work);
- unsigned long cpu = gcwq ? gcwq->cpu : WORK_CPU_NONE;
+ unsigned long pool_id = get_work_pool_id(work);
- set_work_data(work, (cpu << WORK_OFFQ_CPU_SHIFT) | WORK_OFFQ_CANCELING,
- WORK_STRUCT_PENDING);
+ pool_id <<= WORK_OFFQ_POOL_SHIFT;
+ set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING);
}
static bool work_is_canceling(struct work_struct *work)
{
unsigned long data = atomic_long_read(&work->data);
- return !(data & WORK_STRUCT_CWQ) && (data & WORK_OFFQ_CANCELING);
+ return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING);
}
/*
* 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)
{
- return !atomic_read(get_pool_nr_running(pool));
+ return !atomic_read(&pool->nr_running);
}
/*
* running workers.
*
* Note that, because unbound workers never contribute to nr_running, this
- * function will always return %true for unbound gcwq as long as the
+ * function will always return %true for unbound pools as long as the
* worklist isn't empty.
*/
static bool need_more_worker(struct worker_pool *pool)
/* Do I need to keep working? Called from currently running workers. */
static bool keep_working(struct worker_pool *pool)
{
- atomic_t *nr_running = get_pool_nr_running(pool);
-
- return !list_empty(&pool->worklist) && atomic_read(nr_running) <= 1;
+ return !list_empty(&pool->worklist) &&
+ atomic_read(&pool->nr_running) <= 1;
}
/* Do we need a new worker? Called from manager. */
/* Do we have too many workers and should some go away? */
static bool too_many_workers(struct worker_pool *pool)
{
- bool managing = pool->flags & POOL_MANAGING_WORKERS;
+ bool managing = mutex_is_locked(&pool->manager_arb);
int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
int nr_busy = pool->nr_workers - nr_idle;
* 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)
{
* CONTEXT:
* spin_lock_irq(rq->lock)
*/
-void wq_worker_waking_up(struct task_struct *task, unsigned int cpu)
+void wq_worker_waking_up(struct task_struct *task, int cpu)
{
struct worker *worker = kthread_data(task);
if (!(worker->flags & WORKER_NOT_RUNNING)) {
- WARN_ON_ONCE(worker->pool->gcwq->cpu != cpu);
- atomic_inc(get_pool_nr_running(worker->pool));
+ WARN_ON_ONCE(worker->pool->cpu != cpu);
+ atomic_inc(&worker->pool->nr_running);
}
}
* RETURNS:
* Worker task on @cpu to wake up, %NULL if none.
*/
-struct task_struct *wq_worker_sleeping(struct task_struct *task,
- unsigned int cpu)
+struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
{
struct worker *worker = kthread_data(task), *to_wakeup = NULL;
- struct worker_pool *pool = worker->pool;
- atomic_t *nr_running = get_pool_nr_running(pool);
+ struct worker_pool *pool;
+ /*
+ * Rescuers, which may not have all the fields set up like normal
+ * workers, also reach here, let's not access anything before
+ * checking NOT_RUNNING.
+ */
if (worker->flags & WORKER_NOT_RUNNING)
return NULL;
+ pool = worker->pool;
+
/* this can only happen on the local cpu */
- BUG_ON(cpu != raw_smp_processor_id());
+ if (WARN_ON_ONCE(cpu != raw_smp_processor_id()))
+ return NULL;
/*
* The counterpart of the following dec_and_test, implied mb,
* 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))
+ if (atomic_dec_and_test(&pool->nr_running) &&
+ !list_empty(&pool->worklist))
to_wakeup = first_worker(pool);
return to_wakeup ? to_wakeup->task : NULL;
}
* 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)
*/
if ((flags & WORKER_NOT_RUNNING) &&
!(worker->flags & WORKER_NOT_RUNNING)) {
- atomic_t *nr_running = get_pool_nr_running(pool);
-
if (wakeup) {
- if (atomic_dec_and_test(nr_running) &&
+ if (atomic_dec_and_test(&pool->nr_running) &&
!list_empty(&pool->worklist))
wake_up_worker(pool);
} else
- atomic_dec(nr_running);
+ atomic_dec(&pool->nr_running);
}
worker->flags |= 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)
{
*/
if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
if (!(worker->flags & WORKER_NOT_RUNNING))
- atomic_inc(get_pool_nr_running(pool));
-}
-
-/**
- * busy_worker_head - return the busy hash head for a work
- * @gcwq: gcwq of interest
- * @work: work to be hashed
- *
- * Return hash head of @gcwq for @work.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- *
- * RETURNS:
- * Pointer to the hash head.
- */
-static struct hlist_head *busy_worker_head(struct global_cwq *gcwq,
- struct work_struct *work)
-{
- const int base_shift = ilog2(sizeof(struct work_struct));
- unsigned long v = (unsigned long)work;
-
- /* simple shift and fold hash, do we need something better? */
- v >>= base_shift;
- v += v >> BUSY_WORKER_HASH_ORDER;
- v &= BUSY_WORKER_HASH_MASK;
-
- return &gcwq->busy_hash[v];
+ atomic_inc(&pool->nr_running);
}
/**
- * __find_worker_executing_work - find worker which is executing a work
- * @gcwq: gcwq of interest
- * @bwh: hash head as returned by busy_worker_head()
+ * find_worker_executing_work - find worker which is executing a work
+ * @pool: pool of interest
* @work: work to find worker for
*
- * Find a worker which is executing @work on @gcwq. @bwh should be
- * the hash head obtained by calling busy_worker_head() with the same
- * work.
+ * Find a worker which is executing @work on @pool by searching
+ * @pool->busy_hash which is keyed by the address of @work. For a worker
+ * to match, its current execution should match the address of @work and
+ * its work function. This is to avoid unwanted dependency between
+ * unrelated work executions through a work item being recycled while still
+ * being executed.
+ *
+ * This is a bit tricky. A work item may be freed once its execution
+ * starts and nothing prevents the freed area from being recycled for
+ * another work item. If the same work item address ends up being reused
+ * before the original execution finishes, workqueue will identify the
+ * recycled work item as currently executing and make it wait until the
+ * current execution finishes, introducing an unwanted dependency.
+ *
+ * This function checks the work item address and work function to avoid
+ * false positives. Note that this isn't complete as one may construct a
+ * work function which can introduce dependency onto itself through a
+ * recycled work item. Well, if somebody wants to shoot oneself in the
+ * foot that badly, there's only so much we can do, and if such deadlock
+ * actually occurs, it should be easy to locate the culprit work function.
*
* CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
*
* RETURNS:
* Pointer to worker which is executing @work if found, NULL
* otherwise.
*/
-static struct worker *__find_worker_executing_work(struct global_cwq *gcwq,
- struct hlist_head *bwh,
- struct work_struct *work)
+static struct worker *find_worker_executing_work(struct worker_pool *pool,
+ struct work_struct *work)
{
struct worker *worker;
- struct hlist_node *tmp;
- hlist_for_each_entry(worker, tmp, bwh, hentry)
- if (worker->current_work == work)
+ hash_for_each_possible(pool->busy_hash, worker, hentry,
+ (unsigned long)work)
+ if (worker->current_work == work &&
+ worker->current_func == work->func)
return worker;
- return NULL;
-}
-/**
- * find_worker_executing_work - find worker which is executing a work
- * @gcwq: gcwq of interest
- * @work: work to find worker for
- *
- * Find a worker which is executing @work on @gcwq. This function is
- * identical to __find_worker_executing_work() except that this
- * function calculates @bwh itself.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- *
- * RETURNS:
- * Pointer to worker which is executing @work if found, NULL
- * otherwise.
- */
-static struct worker *find_worker_executing_work(struct global_cwq *gcwq,
- struct work_struct *work)
-{
- return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work),
- work);
+ return NULL;
}
/**
* 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)
*nextp = n;
}
-static void cwq_activate_delayed_work(struct work_struct *work)
+/**
+ * get_pwq - get an extra reference on the specified pool_workqueue
+ * @pwq: pool_workqueue to get
+ *
+ * Obtain an extra reference on @pwq. The caller should guarantee that
+ * @pwq has positive refcnt and be holding the matching pool->lock.
+ */
+static void get_pwq(struct pool_workqueue *pwq)
+{
+ lockdep_assert_held(&pwq->pool->lock);
+ WARN_ON_ONCE(pwq->refcnt <= 0);
+ pwq->refcnt++;
+}
+
+/**
+ * put_pwq - put a pool_workqueue reference
+ * @pwq: pool_workqueue to put
+ *
+ * Drop a reference of @pwq. If its refcnt reaches zero, schedule its
+ * destruction. The caller should be holding the matching pool->lock.
+ */
+static void put_pwq(struct pool_workqueue *pwq)
+{
+ lockdep_assert_held(&pwq->pool->lock);
+ if (likely(--pwq->refcnt))
+ return;
+ if (WARN_ON_ONCE(!(pwq->wq->flags & WQ_UNBOUND)))
+ return;
+ /*
+ * @pwq can't be released under pool->lock, bounce to
+ * pwq_unbound_release_workfn(). This never recurses on the same
+ * pool->lock as this path is taken only for unbound workqueues and
+ * the release work item is scheduled on a per-cpu workqueue. To
+ * avoid lockdep warning, unbound pool->locks are given lockdep
+ * subclass of 1 in get_unbound_pool().
+ */
+ schedule_work(&pwq->unbound_release_work);
+}
+
+static void pwq_activate_delayed_work(struct work_struct *work)
{
- struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+ struct pool_workqueue *pwq = get_work_pwq(work);
trace_workqueue_activate_work(work);
- move_linked_works(work, &cwq->pool->worklist, NULL);
+ move_linked_works(work, &pwq->pool->worklist, NULL);
__clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
- cwq->nr_active++;
+ pwq->nr_active++;
}
-static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
+static void pwq_activate_first_delayed(struct pool_workqueue *pwq)
{
- struct work_struct *work = list_first_entry(&cwq->delayed_works,
+ struct work_struct *work = list_first_entry(&pwq->delayed_works,
struct work_struct, entry);
- cwq_activate_delayed_work(work);
+ pwq_activate_delayed_work(work);
}
/**
- * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
- * @cwq: cwq of interest
+ * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
+ * @pwq: pwq of interest
* @color: color of work which left the queue
*
* A work either has completed or is removed from pending queue,
- * decrement nr_in_flight of its cwq and handle workqueue flushing.
+ * decrement nr_in_flight of its pwq 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)
+static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, int color)
{
- /* ignore uncolored works */
+ /* uncolored work items don't participate in flushing or nr_active */
if (color == WORK_NO_COLOR)
- return;
+ goto out_put;
- cwq->nr_in_flight[color]--;
+ pwq->nr_in_flight[color]--;
- cwq->nr_active--;
- if (!list_empty(&cwq->delayed_works)) {
+ pwq->nr_active--;
+ if (!list_empty(&pwq->delayed_works)) {
/* one down, submit a delayed one */
- if (cwq->nr_active < cwq->max_active)
- cwq_activate_first_delayed(cwq);
+ if (pwq->nr_active < pwq->max_active)
+ pwq_activate_first_delayed(pwq);
}
/* is flush in progress and are we at the flushing tip? */
- if (likely(cwq->flush_color != color))
- return;
+ if (likely(pwq->flush_color != color))
+ goto out_put;
/* are there still in-flight works? */
- if (cwq->nr_in_flight[color])
- return;
+ if (pwq->nr_in_flight[color])
+ goto out_put;
- /* this cwq is done, clear flush_color */
- cwq->flush_color = -1;
+ /* this pwq is done, clear flush_color */
+ pwq->flush_color = -1;
/*
- * If this was the last cwq, wake up the first flusher. It
+ * If this was the last pwq, wake up the first flusher. It
* will handle the rest.
*/
- if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush))
- complete(&cwq->wq->first_flusher->done);
+ if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush))
+ complete(&pwq->wq->first_flusher->done);
+out_put:
+ put_pwq(pwq);
}
/**
static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
unsigned long *flags)
{
- struct global_cwq *gcwq;
+ struct worker_pool *pool;
+ struct pool_workqueue *pwq;
local_irq_save(*flags);
* 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);
- if (!list_empty(&work->entry)) {
+ spin_lock(&pool->lock);
+ /*
+ * work->data is guaranteed to point to pwq only while the work
+ * item is queued on pwq->wq, and both updating work->data to point
+ * to pwq on queueing and to pool on dequeueing are done under
+ * pwq->pool->lock. This in turn guarantees that, if work->data
+ * points to pwq which is associated with a locked pool, the work
+ * item is currently queued on that pool.
+ */
+ pwq = get_work_pwq(work);
+ if (pwq && pwq->pool == pool) {
+ debug_work_deactivate(work);
+
/*
- * 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().
+ * A delayed work item cannot be grabbed directly because
+ * it might have linked NO_COLOR work items which, if left
+ * on the delayed_list, will confuse pwq->nr_active
+ * management later on and cause stall. Make sure the work
+ * item is activated before grabbing.
*/
- smp_rmb();
- if (gcwq == get_work_gcwq(work)) {
- debug_work_deactivate(work);
+ if (*work_data_bits(work) & WORK_STRUCT_DELAYED)
+ pwq_activate_delayed_work(work);
- /*
- * A delayed work item cannot be grabbed directly
- * because it might have linked NO_COLOR work items
- * which, if left on the delayed_list, will confuse
- * cwq->nr_active management later on and cause
- * stall. Make sure the work item is activated
- * before grabbing.
- */
- if (*work_data_bits(work) & WORK_STRUCT_DELAYED)
- cwq_activate_delayed_work(work);
+ list_del_init(&work->entry);
+ pwq_dec_nr_in_flight(get_work_pwq(work), get_work_color(work));
- list_del_init(&work->entry);
- cwq_dec_nr_in_flight(get_work_cwq(work),
- get_work_color(work));
+ /* work->data points to pwq iff queued, point to pool */
+ set_work_pool_and_keep_pending(work, pool->id);
- spin_unlock(&gcwq->lock);
- return 1;
- }
+ spin_unlock(&pool->lock);
+ return 1;
}
- spin_unlock(&gcwq->lock);
+ spin_unlock(&pool->lock);
fail:
local_irq_restore(*flags);
if (work_is_canceling(work))
}
/**
- * insert_work - insert a work into gcwq
- * @cwq: cwq @work belongs to
+ * insert_work - insert a work into a pool
+ * @pwq: pwq @work belongs to
* @work: work to insert
* @head: insertion point
* @extra_flags: extra WORK_STRUCT_* flags to set
*
- * Insert @work which belongs to @cwq into @gcwq after @head.
- * @extra_flags is or'd to work_struct flags.
+ * Insert @work which belongs to @pwq after @head. @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,
- unsigned int extra_flags)
+static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
+ struct list_head *head, unsigned int extra_flags)
{
- struct worker_pool *pool = cwq->pool;
+ struct worker_pool *pool = pwq->pool;
/* we own @work, set data and link */
- set_work_cwq(work, cwq, extra_flags);
-
- /*
- * Ensure that we get the right work->data if we see the
- * result of list_add() below, see try_to_grab_pending().
- */
- smp_wmb();
-
+ set_work_pwq(work, pwq, extra_flags);
list_add_tail(&work->entry, head);
+ get_pwq(pwq);
/*
- * Ensure either worker_sched_deactivated() sees the above
- * list_add_tail() or we see zero nr_running to avoid workers
- * lying around lazily while there are works to be processed.
+ * Ensure either wq_worker_sleeping() sees the above
+ * list_add_tail() or we see zero nr_running to avoid workers lying
+ * around lazily while there are works to be processed.
*/
smp_mb();
/*
* Test whether @work is being queued from another work executing on the
- * same workqueue. This is rather expensive and should only be used from
- * cold paths.
+ * same workqueue.
*/
static bool is_chained_work(struct workqueue_struct *wq)
{
- unsigned long flags;
- unsigned int cpu;
-
- for_each_gcwq_cpu(cpu) {
- struct global_cwq *gcwq = get_gcwq(cpu);
- struct worker *worker;
- struct hlist_node *pos;
- int i;
+ struct worker *worker;
- spin_lock_irqsave(&gcwq->lock, flags);
- for_each_busy_worker(worker, i, pos, gcwq) {
- if (worker->task != current)
- continue;
- spin_unlock_irqrestore(&gcwq->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);
- }
- return false;
+ worker = current_wq_worker();
+ /*
+ * Return %true iff I'm a worker execuing a work item on @wq. If
+ * I'm @worker, it's safe to dereference it without locking.
+ */
+ return worker && worker->current_pwq->wq == wq;
}
-static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
+static void __queue_work(int cpu, struct workqueue_struct *wq,
struct work_struct *work)
{
- struct global_cwq *gcwq;
- struct cpu_workqueue_struct *cwq;
+ struct pool_workqueue *pwq;
+ struct worker_pool *last_pool;
struct list_head *worklist;
unsigned int work_flags;
unsigned int req_cpu = cpu;
debug_work_activate(work);
/* if dying, only works from the same workqueue are allowed */
- if (unlikely(wq->flags & WQ_DRAINING) &&
+ if (unlikely(wq->flags & __WQ_DRAINING) &&
WARN_ON_ONCE(!is_chained_work(wq)))
return;
-
- /* determine gcwq to use */
+retry:
+ /* pwq which will be used unless @work is executing elsewhere */
if (!(wq->flags & WQ_UNBOUND)) {
- struct global_cwq *last_gcwq;
-
if (cpu == WORK_CPU_UNBOUND)
cpu = raw_smp_processor_id();
+ pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
+ } else {
+ pwq = first_pwq(wq);
+ }
- /*
- * It's multi cpu. If @work was previously on a different
- * cpu, it might still be running there, in which case the
- * work needs to be queued on that cpu to guarantee
- * non-reentrancy.
- */
- gcwq = get_gcwq(cpu);
- last_gcwq = get_work_gcwq(work);
-
- if (last_gcwq && last_gcwq != gcwq) {
- struct worker *worker;
+ /*
+ * If @work was previously on a different pool, it might still be
+ * running there, in which case the work needs to be queued on that
+ * pool to guarantee non-reentrancy.
+ */
+ last_pool = get_work_pool(work);
+ if (last_pool && last_pool != pwq->pool) {
+ struct worker *worker;
- spin_lock(&last_gcwq->lock);
+ spin_lock(&last_pool->lock);
- worker = find_worker_executing_work(last_gcwq, work);
+ worker = find_worker_executing_work(last_pool, work);
- if (worker && worker->current_cwq->wq == wq)
- gcwq = last_gcwq;
- else {
- /* meh... not running there, queue here */
- spin_unlock(&last_gcwq->lock);
- spin_lock(&gcwq->lock);
- }
+ if (worker && worker->current_pwq->wq == wq) {
+ pwq = worker->current_pwq;
} else {
- spin_lock(&gcwq->lock);
+ /* meh... not running there, queue here */
+ spin_unlock(&last_pool->lock);
+ spin_lock(&pwq->pool->lock);
}
} else {
- gcwq = get_gcwq(WORK_CPU_UNBOUND);
- spin_lock(&gcwq->lock);
+ spin_lock(&pwq->pool->lock);
+ }
+
+ /*
+ * pwq is determined and locked. For unbound pools, we could have
+ * raced with pwq release and it could already be dead. If its
+ * refcnt is zero, repeat pwq selection. Note that pwqs never die
+ * without another pwq replacing it as the first pwq or while a
+ * work item is executing on it, so the retying is guaranteed to
+ * make forward-progress.
+ */
+ if (unlikely(!pwq->refcnt)) {
+ if (wq->flags & WQ_UNBOUND) {
+ spin_unlock(&pwq->pool->lock);
+ cpu_relax();
+ goto retry;
+ }
+ /* oops */
+ WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt",
+ wq->name, cpu);
}
- /* gcwq determined, get cwq and queue */
- cwq = get_cwq(gcwq->cpu, wq);
- trace_workqueue_queue_work(req_cpu, cwq, work);
+ /* pwq determined, queue */
+ trace_workqueue_queue_work(req_cpu, pwq, work);
if (WARN_ON(!list_empty(&work->entry))) {
- spin_unlock(&gcwq->lock);
+ spin_unlock(&pwq->pool->lock);
return;
}
- cwq->nr_in_flight[cwq->work_color]++;
- work_flags = work_color_to_flags(cwq->work_color);
+ pwq->nr_in_flight[pwq->work_color]++;
+ work_flags = work_color_to_flags(pwq->work_color);
- if (likely(cwq->nr_active < cwq->max_active)) {
+ if (likely(pwq->nr_active < pwq->max_active)) {
trace_workqueue_activate_work(work);
- cwq->nr_active++;
- worklist = &cwq->pool->worklist;
+ pwq->nr_active++;
+ worklist = &pwq->pool->worklist;
} else {
work_flags |= WORK_STRUCT_DELAYED;
- worklist = &cwq->delayed_works;
+ worklist = &pwq->delayed_works;
}
- insert_work(cwq, work, worklist, work_flags);
+ insert_work(pwq, work, worklist, work_flags);
- spin_unlock(&gcwq->lock);
+ spin_unlock(&pwq->pool->lock);
}
/**
}
EXPORT_SYMBOL_GPL(queue_work_on);
-/**
- * queue_work - queue work on a workqueue
- * @wq: workqueue to use
- * @work: work to queue
- *
- * Returns %false if @work was already on a queue, %true otherwise.
- *
- * We queue the work to the CPU on which it was submitted, but if the CPU dies
- * it can be processed by another CPU.
- */
-bool queue_work(struct workqueue_struct *wq, struct work_struct *work)
-{
- return queue_work_on(WORK_CPU_UNBOUND, wq, work);
-}
-EXPORT_SYMBOL_GPL(queue_work);
-
void delayed_work_timer_fn(unsigned long __data)
{
struct delayed_work *dwork = (struct delayed_work *)__data;
- struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work);
/* should have been called from irqsafe timer with irq already off */
- __queue_work(dwork->cpu, cwq->wq, &dwork->work);
+ __queue_work(dwork->cpu, dwork->wq, &dwork->work);
}
-EXPORT_SYMBOL_GPL(delayed_work_timer_fn);
+EXPORT_SYMBOL(delayed_work_timer_fn);
static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
struct delayed_work *dwork, unsigned long delay)
{
struct timer_list *timer = &dwork->timer;
struct work_struct *work = &dwork->work;
- unsigned int lcpu;
WARN_ON_ONCE(timer->function != delayed_work_timer_fn ||
timer->data != (unsigned long)dwork);
timer_stats_timer_set_start_info(&dwork->timer);
- /*
- * This stores cwq for the moment, for the timer_fn. Note that the
- * work's gcwq is preserved to allow reentrance detection for
- * delayed works.
- */
- if (!(wq->flags & WQ_UNBOUND)) {
- struct global_cwq *gcwq = get_work_gcwq(work);
-
- /*
- * If we cannot get the last gcwq from @work directly,
- * select the last CPU such that it avoids unnecessarily
- * triggering non-reentrancy check in __queue_work().
- */
- lcpu = cpu;
- if (gcwq)
- lcpu = gcwq->cpu;
- if (lcpu == WORK_CPU_UNBOUND)
- lcpu = raw_smp_processor_id();
- } else {
- lcpu = WORK_CPU_UNBOUND;
- }
-
- set_work_cwq(work, get_cwq(lcpu, wq), 0);
-
+ dwork->wq = wq;
dwork->cpu = cpu;
timer->expires = jiffies + delay;
}
EXPORT_SYMBOL_GPL(queue_delayed_work_on);
-/**
- * queue_delayed_work - queue work on a workqueue after delay
- * @wq: workqueue to use
- * @dwork: delayable work to queue
- * @delay: number of jiffies to wait before queueing
- *
- * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
- */
-bool queue_delayed_work(struct workqueue_struct *wq,
- struct delayed_work *dwork, unsigned long delay)
-{
- return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
-}
-EXPORT_SYMBOL_GPL(queue_delayed_work);
-
/**
* mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU
* @cpu: CPU number to execute work on
}
EXPORT_SYMBOL_GPL(mod_delayed_work_on);
-/**
- * mod_delayed_work - modify delay of or queue a delayed work
- * @wq: workqueue to use
- * @dwork: work to queue
- * @delay: number of jiffies to wait before queueing
- *
- * mod_delayed_work_on() on local CPU.
- */
-bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork,
- unsigned long delay)
-{
- return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
-}
-EXPORT_SYMBOL_GPL(mod_delayed_work);
-
/**
* worker_enter_idle - enter idle state
* @worker: worker which is entering idle state
* necessary.
*
* LOCKING:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
*/
static void worker_enter_idle(struct worker *worker)
{
struct worker_pool *pool = worker->pool;
- struct global_cwq *gcwq = pool->gcwq;
- BUG_ON(worker->flags & WORKER_IDLE);
- BUG_ON(!list_empty(&worker->entry) &&
- (worker->hentry.next || worker->hentry.pprev));
+ if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) ||
+ WARN_ON_ONCE(!list_empty(&worker->entry) &&
+ (worker->hentry.next || worker->hentry.pprev)))
+ return;
/* can't use worker_set_flags(), also called from start_worker() */
worker->flags |= WORKER_IDLE;
mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);
/*
- * Sanity check nr_running. Because gcwq_unbind_fn() releases
- * gcwq->lock between setting %WORKER_UNBOUND and zapping
+ * Sanity check nr_running. Because wq_unbind_fn() releases
+ * pool->lock between setting %WORKER_UNBOUND and zapping
* nr_running, the warning may trigger spuriously. Check iff
* unbind is not in progress.
*/
- WARN_ON_ONCE(!(gcwq->flags & GCWQ_DISASSOCIATED) &&
+ WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
pool->nr_workers == pool->nr_idle &&
- atomic_read(get_pool_nr_running(pool)));
+ atomic_read(&pool->nr_running));
}
/**
* @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)
{
struct worker_pool *pool = worker->pool;
- BUG_ON(!(worker->flags & WORKER_IDLE));
+ if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE)))
+ return;
worker_clr_flags(worker, WORKER_IDLE);
pool->nr_idle--;
list_del_init(&worker->entry);
}
/**
- * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq
- * @worker: self
+ * worker_maybe_bind_and_lock - try to bind %current to worker_pool and lock it
+ * @pool: target worker_pool
+ *
+ * Bind %current to the cpu of @pool if it is associated and lock @pool.
*
* Works which are scheduled while the cpu is online must at least be
* scheduled to a worker which is bound to the cpu so that if they are
* flushed from cpu callbacks while cpu is going down, they are
* guaranteed to execute on the cpu.
*
- * This function is to be used by rogue workers and rescuers to bind
+ * This function is to be used by unbound workers and rescuers to bind
* themselves to the target cpu and may race with cpu going down or
* coming online. kthread_bind() can't be used because it may put the
* worker to already dead cpu and set_cpus_allowed_ptr() can't be used
- * verbatim as it's best effort and blocking and gcwq may be
+ * verbatim as it's best effort and blocking and pool may be
* [dis]associated in the meantime.
*
- * This function tries set_cpus_allowed() and locks gcwq and verifies the
- * binding against %GCWQ_DISASSOCIATED which is set during
+ * This function tries set_cpus_allowed() and locks pool and verifies the
+ * binding against %POOL_DISASSOCIATED which is set during
* %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker
* enters idle state or fetches works without dropping lock, it can
* 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:
- * %true if the associated gcwq is online (@worker is successfully
+ * %true if the associated pool is online (@worker is successfully
* bound), %false if offline.
*/
-static bool worker_maybe_bind_and_lock(struct worker *worker)
-__acquires(&gcwq->lock)
+static bool worker_maybe_bind_and_lock(struct worker_pool *pool)
+__acquires(&pool->lock)
{
- struct global_cwq *gcwq = worker->pool->gcwq;
- struct task_struct *task = worker->task;
-
while (true) {
/*
* The following call may fail, succeed or succeed
* without actually migrating the task to the cpu if
* it races with cpu hotunplug operation. Verify
- * against GCWQ_DISASSOCIATED.
+ * against POOL_DISASSOCIATED.
*/
- if (!(gcwq->flags & GCWQ_DISASSOCIATED))
- set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu));
+ if (!(pool->flags & POOL_DISASSOCIATED))
+ set_cpus_allowed_ptr(current, pool->attrs->cpumask);
- spin_lock_irq(&gcwq->lock);
- if (gcwq->flags & GCWQ_DISASSOCIATED)
+ spin_lock_irq(&pool->lock);
+ if (pool->flags & POOL_DISASSOCIATED)
return false;
- if (task_cpu(task) == gcwq->cpu &&
- cpumask_equal(¤t->cpus_allowed,
- get_cpu_mask(gcwq->cpu)))
+ if (task_cpu(current) == pool->cpu &&
+ cpumask_equal(¤t->cpus_allowed, pool->attrs->cpumask))
return true;
- spin_unlock_irq(&gcwq->lock);
+ spin_unlock_irq(&pool->lock);
/*
* We've raced with CPU hot[un]plug. Give it a breather
}
}
-/*
- * Rebind an idle @worker to its CPU. worker_thread() will test
- * list_empty(@worker->entry) before leaving idle and call this function.
- */
-static void idle_worker_rebind(struct worker *worker)
+static struct worker *alloc_worker(void)
{
- 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);
-}
-
-/*
- * Function for @worker->rebind.work used to rebind unbound busy workers to
- * the associated cpu which is coming back online. This is scheduled by
- * cpu up but can race with other cpu hotplug operations and may be
- * executed twice without intervening cpu down.
- */
-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);
-}
-
-/**
- * rebind_workers - rebind all workers of a gcwq to the associated CPU
- * @gcwq: gcwq of interest
- *
- * @gcwq->cpu is coming online. Rebind all workers to the CPU. Rebinding
- * is different for idle and busy ones.
- *
- * Idle ones will be removed from the idle_list and woken up. They will
- * add themselves back after completing rebind. This ensures that the
- * idle_list doesn't contain any unbound workers when re-bound busy workers
- * try to perform local wake-ups for concurrency management.
- *
- * Busy workers can rebind after they finish their current work items.
- * Queueing the rebind work item at the head of the scheduled list is
- * enough. Note that nr_running will be properly bumped as busy workers
- * rebind.
- *
- * On return, all non-manager workers are scheduled for rebind - see
- * manage_workers() for the manager special case. Any idle worker
- * including the manager will not appear on @idle_list until rebind is
- * complete, making local wake-ups safe.
- */
-static void rebind_workers(struct global_cwq *gcwq)
-{
- struct worker_pool *pool;
- struct worker *worker, *n;
- struct hlist_node *pos;
- int i;
-
- lockdep_assert_held(&gcwq->lock);
-
- for_each_worker_pool(pool, gcwq)
- lockdep_assert_held(&pool->assoc_mutex);
-
- /* dequeue and kick idle ones */
- for_each_worker_pool(pool, gcwq) {
- list_for_each_entry_safe(worker, n, &pool->idle_list, entry) {
- /*
- * idle workers should be off @pool->idle_list
- * until rebind is complete to avoid receiving
- * premature local wake-ups.
- */
- list_del_init(&worker->entry);
-
- /*
- * worker_thread() will see the above dequeuing
- * and call idle_worker_rebind().
- */
- wake_up_process(worker->task);
- }
- }
-
- /* rebind busy workers */
- for_each_busy_worker(worker, i, pos, gcwq) {
- struct work_struct *rebind_work = &worker->rebind_work;
- struct workqueue_struct *wq;
-
- if (test_and_set_bit(WORK_STRUCT_PENDING_BIT,
- work_data_bits(rebind_work)))
- continue;
-
- debug_work_activate(rebind_work);
-
- /*
- * wq doesn't really matter but let's keep @worker->pool
- * and @cwq->pool consistent for sanity.
- */
- if (worker_pool_pri(worker->pool))
- wq = system_highpri_wq;
- else
- wq = system_wq;
-
- insert_work(get_cwq(gcwq->cpu, wq), rebind_work,
- worker->scheduled.next,
- work_color_to_flags(WORK_NO_COLOR));
- }
-}
-
-static struct worker *alloc_worker(void)
-{
- struct worker *worker;
+ struct worker *worker;
worker = kzalloc(sizeof(*worker), GFP_KERNEL);
if (worker) {
INIT_LIST_HEAD(&worker->entry);
INIT_LIST_HEAD(&worker->scheduled);
- INIT_WORK(&worker->rebind_work, busy_worker_rebind_fn);
/* on creation a worker is in !idle && prep state */
worker->flags = WORKER_PREP;
}
*/
static struct worker *create_worker(struct worker_pool *pool)
{
- struct global_cwq *gcwq = pool->gcwq;
- const char *pri = worker_pool_pri(pool) ? "H" : "";
+ const char *pri = pool->attrs->nice < 0 ? "H" : "";
struct worker *worker = NULL;
int id = -1;
- spin_lock_irq(&gcwq->lock);
- while (ida_get_new(&pool->worker_ida, &id)) {
- spin_unlock_irq(&gcwq->lock);
- if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL))
- goto fail;
- spin_lock_irq(&gcwq->lock);
- }
- spin_unlock_irq(&gcwq->lock);
+ lockdep_assert_held(&pool->manager_mutex);
+
+ /*
+ * ID is needed to determine kthread name. Allocate ID first
+ * without installing the pointer.
+ */
+ idr_preload(GFP_KERNEL);
+ spin_lock_irq(&pool->lock);
+
+ id = idr_alloc(&pool->worker_idr, NULL, 0, 0, GFP_NOWAIT);
+
+ spin_unlock_irq(&pool->lock);
+ idr_preload_end();
+ if (id < 0)
+ goto fail;
worker = alloc_worker();
if (!worker)
worker->pool = pool;
worker->id = id;
- if (gcwq->cpu != WORK_CPU_UNBOUND)
+ if (pool->cpu >= 0)
worker->task = kthread_create_on_node(worker_thread,
- worker, cpu_to_node(gcwq->cpu),
- "kworker/%u:%d%s", gcwq->cpu, id, pri);
+ worker, cpu_to_node(pool->cpu),
+ "kworker/%d:%d%s", pool->cpu, id, pri);
else
worker->task = kthread_create(worker_thread, worker,
- "kworker/u:%d%s", id, pri);
+ "kworker/u%d:%d%s",
+ pool->id, id, pri);
if (IS_ERR(worker->task))
goto fail;
- if (worker_pool_pri(pool))
- set_user_nice(worker->task, HIGHPRI_NICE_LEVEL);
+ /*
+ * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
+ * online CPUs. It'll be re-applied when any of the CPUs come up.
+ */
+ set_user_nice(worker->task, pool->attrs->nice);
+ set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
+
+ /* prevent userland from meddling with cpumask of workqueue workers */
+ worker->task->flags |= PF_NO_SETAFFINITY;
/*
- * Determine CPU binding of the new worker depending on
- * %GCWQ_DISASSOCIATED. The caller is responsible for ensuring the
- * flag remains stable across this function. See the comments
- * above the flag definition for details.
- *
- * As an unbound worker may later become a regular one if CPU comes
- * online, make sure every worker has %PF_THREAD_BOUND set.
+ * The caller is responsible for ensuring %POOL_DISASSOCIATED
+ * remains stable across this function. See the comments above the
+ * flag definition for details.
*/
- if (!(gcwq->flags & GCWQ_DISASSOCIATED)) {
- kthread_bind(worker->task, gcwq->cpu);
- } else {
- worker->task->flags |= PF_THREAD_BOUND;
+ if (pool->flags & POOL_DISASSOCIATED)
worker->flags |= WORKER_UNBOUND;
- }
+
+ /* successful, commit the pointer to idr */
+ spin_lock_irq(&pool->lock);
+ idr_replace(&pool->worker_idr, worker, worker->id);
+ spin_unlock_irq(&pool->lock);
return worker;
+
fail:
if (id >= 0) {
- spin_lock_irq(&gcwq->lock);
- ida_remove(&pool->worker_ida, id);
- spin_unlock_irq(&gcwq->lock);
+ spin_lock_irq(&pool->lock);
+ idr_remove(&pool->worker_idr, id);
+ spin_unlock_irq(&pool->lock);
}
kfree(worker);
return NULL;
* start_worker - start a newly created worker
* @worker: worker to start
*
- * Make the gcwq aware of @worker and start it.
+ * Make the pool aware of @worker and start it.
*
* CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
*/
static void start_worker(struct worker *worker)
{
wake_up_process(worker->task);
}
+/**
+ * create_and_start_worker - create and start a worker for a pool
+ * @pool: the target pool
+ *
+ * Grab the managership of @pool and create and start a new worker for it.
+ */
+static int create_and_start_worker(struct worker_pool *pool)
+{
+ struct worker *worker;
+
+ mutex_lock(&pool->manager_mutex);
+
+ worker = create_worker(pool);
+ if (worker) {
+ spin_lock_irq(&pool->lock);
+ start_worker(worker);
+ spin_unlock_irq(&pool->lock);
+ }
+
+ mutex_unlock(&pool->manager_mutex);
+
+ return worker ? 0 : -ENOMEM;
+}
+
/**
* destroy_worker - destroy a workqueue worker
* @worker: worker to be destroyed
*
- * Destroy @worker and adjust @gcwq stats accordingly.
+ * Destroy @worker and adjust @pool 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;
+
+ lockdep_assert_held(&pool->manager_mutex);
+ lockdep_assert_held(&pool->lock);
/* sanity check frenzy */
- BUG_ON(worker->current_work);
- BUG_ON(!list_empty(&worker->scheduled));
+ if (WARN_ON(worker->current_work) ||
+ WARN_ON(!list_empty(&worker->scheduled)))
+ return;
if (worker->flags & WORKER_STARTED)
pool->nr_workers--;
list_del_init(&worker->entry);
worker->flags |= WORKER_DIE;
- spin_unlock_irq(&gcwq->lock);
+ idr_remove(&pool->worker_idr, worker->id);
+
+ spin_unlock_irq(&pool->lock);
kthread_stop(worker->task);
kfree(worker);
- spin_lock_irq(&gcwq->lock);
- ida_remove(&pool->worker_ida, id);
+ spin_lock_irq(&pool->lock);
}
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;
}
}
- spin_unlock_irq(&gcwq->lock);
+ spin_unlock_irq(&pool->lock);
}
-static bool send_mayday(struct work_struct *work)
+static void send_mayday(struct work_struct *work)
{
- struct cpu_workqueue_struct *cwq = get_work_cwq(work);
- struct workqueue_struct *wq = cwq->wq;
- unsigned int cpu;
+ struct pool_workqueue *pwq = get_work_pwq(work);
+ struct workqueue_struct *wq = pwq->wq;
- if (!(wq->flags & WQ_RESCUER))
- return false;
+ lockdep_assert_held(&wq_mayday_lock);
+
+ if (!wq->rescuer)
+ return;
/* mayday mayday mayday */
- cpu = cwq->pool->gcwq->cpu;
- /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */
- if (cpu == WORK_CPU_UNBOUND)
- cpu = 0;
- if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask))
+ if (list_empty(&pwq->mayday_node)) {
+ list_add_tail(&pwq->mayday_node, &wq->maydays);
wake_up_process(wq->rescuer->task);
- return true;
+ }
}
-static void gcwq_mayday_timeout(unsigned long __pool)
+static void pool_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(&wq_mayday_lock); /* for wq->maydays */
+ spin_lock(&pool->lock);
if (need_to_create_worker(pool)) {
/*
send_mayday(work);
}
- spin_unlock_irq(&gcwq->lock);
+ spin_unlock(&pool->lock);
+ spin_unlock_irq(&wq_mayday_lock);
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
}
* sent to all rescuers with works scheduled on @pool to resolve
* possible allocation deadlock.
*
- * On return, need_to_create_worker() is guaranteed to be false and
- * may_start_working() true.
+ * On return, need_to_create_worker() is guaranteed to be %false and
+ * 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);
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));
+ if (WARN_ON_ONCE(need_to_create_worker(pool)))
+ goto restart;
return true;
}
}
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;
* 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)
* manage_workers - manage worker pool
* @worker: self
*
- * Assume the manager role and manage gcwq worker pool @worker belongs
+ * Assume the manager role and manage the worker pool @worker belongs
* to. At any given time, there can be only zero or one manager per
- * gcwq. The exclusion is handled automatically by this function.
+ * pool. The exclusion is handled automatically by this function.
*
* The caller can safely start processing works on false return. On
* true return, it's guaranteed that need_to_create_worker() is false
* 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)
{
struct worker_pool *pool = worker->pool;
bool ret = false;
- if (pool->flags & POOL_MANAGING_WORKERS)
- return ret;
-
- pool->flags |= POOL_MANAGING_WORKERS;
-
/*
- * To simplify both worker management and CPU hotplug, hold off
- * management while hotplug is in progress. CPU hotplug path can't
- * grab %POOL_MANAGING_WORKERS to achieve this because that can
- * lead to idle worker depletion (all become busy thinking someone
- * else is managing) which in turn can result in deadlock under
- * extreme circumstances. Use @pool->assoc_mutex to synchronize
- * manager against CPU hotplug.
+ * Managership is governed by two mutexes - manager_arb and
+ * manager_mutex. manager_arb handles arbitration of manager role.
+ * Anyone who successfully grabs manager_arb wins the arbitration
+ * and becomes the manager. mutex_trylock() on pool->manager_arb
+ * failure while holding pool->lock reliably indicates that someone
+ * else is managing the pool and the worker which failed trylock
+ * can proceed to executing work items. This means that anyone
+ * grabbing manager_arb is responsible for actually performing
+ * manager duties. If manager_arb is grabbed and released without
+ * actual management, the pool may stall indefinitely.
*
- * assoc_mutex would always be free unless CPU hotplug is in
- * progress. trylock first without dropping @gcwq->lock.
+ * manager_mutex is used for exclusion of actual management
+ * operations. The holder of manager_mutex can be sure that none
+ * of management operations, including creation and destruction of
+ * workers, won't take place until the mutex is released. Because
+ * manager_mutex doesn't interfere with manager role arbitration,
+ * it is guaranteed that the pool's management, while may be
+ * delayed, won't be disturbed by someone else grabbing
+ * manager_mutex.
*/
- if (unlikely(!mutex_trylock(&pool->assoc_mutex))) {
- spin_unlock_irq(&pool->gcwq->lock);
- mutex_lock(&pool->assoc_mutex);
- /*
- * CPU hotplug could have happened while we were waiting
- * for assoc_mutex. Hotplug itself can't handle us
- * because manager isn't either on idle or busy list, and
- * @gcwq's state and ours could have deviated.
- *
- * As hotplug is now excluded via assoc_mutex, we can
- * simply try to bind. It will succeed or fail depending
- * on @gcwq's current state. Try it and adjust
- * %WORKER_UNBOUND accordingly.
- */
- if (worker_maybe_bind_and_lock(worker))
- worker->flags &= ~WORKER_UNBOUND;
- else
- worker->flags |= WORKER_UNBOUND;
+ if (!mutex_trylock(&pool->manager_arb))
+ return ret;
+ /*
+ * With manager arbitration won, manager_mutex would be free in
+ * most cases. trylock first without dropping @pool->lock.
+ */
+ if (unlikely(!mutex_trylock(&pool->manager_mutex))) {
+ spin_unlock_irq(&pool->lock);
+ mutex_lock(&pool->manager_mutex);
ret = true;
}
ret |= maybe_destroy_workers(pool);
ret |= maybe_create_worker(pool);
- pool->flags &= ~POOL_MANAGING_WORKERS;
- mutex_unlock(&pool->assoc_mutex);
+ mutex_unlock(&pool->manager_mutex);
+ mutex_unlock(&pool->manager_arb);
return ret;
}
* 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 pool_workqueue *pwq = get_work_pwq(work);
struct worker_pool *pool = worker->pool;
- struct global_cwq *gcwq = pool->gcwq;
- struct hlist_head *bwh = busy_worker_head(gcwq, work);
- bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE;
- work_func_t f = work->func;
+ bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE;
int work_color;
struct worker *collision;
#ifdef CONFIG_LOCKDEP
/*
* Ensure we're on the correct CPU. DISASSOCIATED test is
* necessary to avoid spurious warnings from rescuers servicing the
- * unbound or a disassociated gcwq.
+ * unbound or a disassociated pool.
*/
WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) &&
- !(gcwq->flags & GCWQ_DISASSOCIATED) &&
- raw_smp_processor_id() != gcwq->cpu);
+ !(pool->flags & POOL_DISASSOCIATED) &&
+ raw_smp_processor_id() != pool->cpu);
/*
* A single work shouldn't be executed concurrently by
* already processing the work. If so, defer the work to the
* currently executing one.
*/
- collision = __find_worker_executing_work(gcwq, bwh, work);
+ collision = find_worker_executing_work(pool, work);
if (unlikely(collision)) {
move_linked_works(work, &collision->scheduled, NULL);
return;
/* claim and dequeue */
debug_work_deactivate(work);
- hlist_add_head(&worker->hentry, bwh);
+ hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work);
worker->current_work = work;
- worker->current_cwq = cwq;
+ worker->current_func = work->func;
+ worker->current_pwq = pwq;
work_color = get_work_color(work);
list_del_init(&work->entry);
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))
wake_up_worker(pool);
/*
- * Record the last CPU and clear PENDING which should be the last
- * update to @work. Also, do this inside @gcwq->lock so that
+ * Record the last pool and clear PENDING which should be the last
+ * update to @work. Also, do this inside @pool->lock so that
* PENDING and queued state changes happen together while IRQ is
* disabled.
*/
- set_work_cpu_and_clear_pending(work, gcwq->cpu);
+ 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_read(&pwq->wq->lockdep_map);
lock_map_acquire(&lockdep_map);
trace_workqueue_execute_start(work);
- f(work);
+ worker->current_func(work);
/*
* While we must be careful to not use "work" after this, the trace
* point will only record its address.
*/
trace_workqueue_execute_end(work);
lock_map_release(&lockdep_map);
- lock_map_release(&cwq->wq->lockdep_map);
+ lock_map_release(&pwq->wq->lockdep_map);
if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
" last function: %pf\n",
- current->comm, preempt_count(), task_pid_nr(current), f);
+ current->comm, preempt_count(), task_pid_nr(current),
+ worker->current_func);
debug_show_held_locks(current);
dump_stack();
}
- spin_lock_irq(&gcwq->lock);
+ spin_lock_irq(&pool->lock);
/* clear cpu intensive status */
if (unlikely(cpu_intensive))
worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
/* we're done with it, release */
- hlist_del_init(&worker->hentry);
+ hash_del(&worker->hentry);
worker->current_work = NULL;
- worker->current_cwq = NULL;
- cwq_dec_nr_in_flight(cwq, work_color);
+ worker->current_func = NULL;
+ worker->current_pwq = NULL;
+ pwq_dec_nr_in_flight(pwq, work_color);
}
/**
* 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)
* worker_thread - the worker thread function
* @__worker: self
*
- * The gcwq worker thread function. There's a single dynamic pool of
- * these per each cpu. These workers process all works regardless of
- * their specific target workqueue. The only exception is works which
- * belong to workqueues with a rescuer which will be explained in
- * rescuer_thread().
+ * The worker thread function. All workers belong to a worker_pool -
+ * either a per-cpu one or dynamic unbound one. These workers process all
+ * work items regardless of their specific target workqueue. The only
+ * exception is work items which belong to workqueues with a rescuer which
+ * will be explained in rescuer_thread().
*/
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);
-
- /* we are off idle list if destruction or rebind is requested */
- if (unlikely(list_empty(&worker->entry))) {
- spin_unlock_irq(&gcwq->lock);
-
- /* if DIE is set, destruction is requested */
- if (worker->flags & WORKER_DIE) {
- worker->task->flags &= ~PF_WQ_WORKER;
- return 0;
- }
+ spin_lock_irq(&pool->lock);
- /* otherwise, rebind */
- idle_worker_rebind(worker);
- goto woke_up;
+ /* am I supposed to die? */
+ if (unlikely(worker->flags & WORKER_DIE)) {
+ spin_unlock_irq(&pool->lock);
+ WARN_ON_ONCE(!list_empty(&worker->entry));
+ worker->task->flags &= ~PF_WQ_WORKER;
+ return 0;
}
worker_leave_idle(worker);
* preparing to process a work or actually processing it.
* Make sure nobody diddled with it while I was sleeping.
*/
- BUG_ON(!list_empty(&worker->scheduled));
+ WARN_ON_ONCE(!list_empty(&worker->scheduled));
/*
- * When control reaches this point, we're guaranteed to have
- * at least one idle worker or that someone else has already
- * assumed the manager role.
+ * Finish PREP stage. We're guaranteed to have at least one idle
+ * worker or that someone else has already assumed the manager
+ * role. This is where @worker starts participating in concurrency
+ * management if applicable and concurrency management is restored
+ * after being rebound. See rebind_workers() for details.
*/
- worker_clr_flags(worker, WORKER_PREP);
+ worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);
do {
struct work_struct *work =
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;
}
/**
* rescuer_thread - the rescuer thread function
- * @__wq: the associated workqueue
+ * @__rescuer: self
*
* Workqueue rescuer thread function. There's one rescuer for each
- * workqueue which has WQ_RESCUER set.
+ * workqueue which has WQ_MEM_RECLAIM set.
*
- * Regular work processing on a gcwq may block trying to create a new
+ * Regular work processing on a pool may block trying to create a new
* worker which uses GFP_KERNEL allocation which has slight chance of
* developing into deadlock if some works currently on the same queue
* need to be processed to satisfy the GFP_KERNEL allocation. This is
* the problem rescuer solves.
*
- * When such condition is possible, the gcwq summons rescuers of all
- * workqueues which have works queued on the gcwq and let them process
+ * When such condition is possible, the pool summons rescuers of all
+ * workqueues which have works queued on the pool and let them process
* those works so that forward progress can be guaranteed.
*
* This should happen rarely.
*/
-static int rescuer_thread(void *__wq)
+static int rescuer_thread(void *__rescuer)
{
- struct workqueue_struct *wq = __wq;
- struct worker *rescuer = wq->rescuer;
+ struct worker *rescuer = __rescuer;
+ struct workqueue_struct *wq = rescuer->rescue_wq;
struct list_head *scheduled = &rescuer->scheduled;
- bool is_unbound = wq->flags & WQ_UNBOUND;
- unsigned int cpu;
set_user_nice(current, RESCUER_NICE_LEVEL);
+
+ /*
+ * Mark rescuer as worker too. As WORKER_PREP is never cleared, it
+ * doesn't participate in concurrency management.
+ */
+ rescuer->task->flags |= PF_WQ_WORKER;
repeat:
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
+ rescuer->task->flags &= ~PF_WQ_WORKER;
return 0;
}
- /*
- * See whether any cpu is asking for help. Unbounded
- * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND.
- */
- for_each_mayday_cpu(cpu, wq->mayday_mask) {
- 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;
+ /* see whether any pwq is asking for help */
+ spin_lock_irq(&wq_mayday_lock);
+
+ while (!list_empty(&wq->maydays)) {
+ struct pool_workqueue *pwq = list_first_entry(&wq->maydays,
+ struct pool_workqueue, mayday_node);
+ struct worker_pool *pool = pwq->pool;
struct work_struct *work, *n;
__set_current_state(TASK_RUNNING);
- mayday_clear_cpu(cpu, wq->mayday_mask);
+ list_del_init(&pwq->mayday_node);
+
+ spin_unlock_irq(&wq_mayday_lock);
/* migrate to the target cpu if possible */
+ worker_maybe_bind_and_lock(pool);
rescuer->pool = pool;
- worker_maybe_bind_and_lock(rescuer);
/*
* Slurp in all works issued via this workqueue and
* process'em.
*/
- BUG_ON(!list_empty(&rescuer->scheduled));
+ WARN_ON_ONCE(!list_empty(&rescuer->scheduled));
list_for_each_entry_safe(work, n, &pool->worklist, entry)
- if (get_work_cwq(work) == cwq)
+ if (get_work_pwq(work) == pwq)
move_linked_works(work, scheduled, &n);
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);
+ rescuer->pool = NULL;
+ spin_unlock(&pool->lock);
+ spin_lock(&wq_mayday_lock);
}
+ spin_unlock_irq(&wq_mayday_lock);
+
+ /* rescuers should never participate in concurrency management */
+ WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
schedule();
goto repeat;
}
/**
* insert_wq_barrier - insert a barrier work
- * @cwq: cwq to insert barrier into
+ * @pwq: pwq to insert barrier into
* @barr: wq_barrier to insert
* @target: target work to attach @barr to
* @worker: worker currently executing @target, NULL if @target is not executing
* after a work with LINKED flag set.
*
* Note that when @worker is non-NULL, @target may be modified
- * underneath us, so we can't reliably determine cwq from @target.
+ * underneath us, so we can't reliably determine pwq from @target.
*
* CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
*/
-static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
+static void insert_wq_barrier(struct pool_workqueue *pwq,
struct wq_barrier *barr,
struct work_struct *target, struct worker *worker)
{
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.
}
debug_work_activate(&barr->work);
- insert_work(cwq, &barr->work, head,
+ insert_work(pwq, &barr->work, head,
work_color_to_flags(WORK_NO_COLOR) | linked);
}
/**
- * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing
+ * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing
* @wq: workqueue being flushed
* @flush_color: new flush color, < 0 for no-op
* @work_color: new work color, < 0 for no-op
*
- * Prepare cwqs for workqueue flushing.
+ * Prepare pwqs for workqueue flushing.
*
- * If @flush_color is non-negative, flush_color on all cwqs should be
- * -1. If no cwq has in-flight commands at the specified color, all
- * cwq->flush_color's stay at -1 and %false is returned. If any cwq
- * has in flight commands, its cwq->flush_color is set to
- * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq
+ * If @flush_color is non-negative, flush_color on all pwqs should be
+ * -1. If no pwq has in-flight commands at the specified color, all
+ * pwq->flush_color's stay at -1 and %false is returned. If any pwq
+ * has in flight commands, its pwq->flush_color is set to
+ * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq
* wakeup logic is armed and %true is returned.
*
* The caller should have initialized @wq->first_flusher prior to
* @flush_color is negative, no flush color update is done and %false
* is returned.
*
- * If @work_color is non-negative, all cwqs should have the same
+ * If @work_color is non-negative, all pwqs should have the same
* work_color which is previous to @work_color and all will be
* advanced to @work_color.
*
* %true if @flush_color >= 0 and there's something to flush. %false
* otherwise.
*/
-static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
+static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq,
int flush_color, int work_color)
{
bool wait = false;
- unsigned int cpu;
+ struct pool_workqueue *pwq;
if (flush_color >= 0) {
- BUG_ON(atomic_read(&wq->nr_cwqs_to_flush));
- atomic_set(&wq->nr_cwqs_to_flush, 1);
+ WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush));
+ atomic_set(&wq->nr_pwqs_to_flush, 1);
}
- for_each_cwq_cpu(cpu, wq) {
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
- struct global_cwq *gcwq = cwq->pool->gcwq;
+ local_irq_disable();
+
+ for_each_pwq(pwq, wq) {
+ struct worker_pool *pool = pwq->pool;
- spin_lock_irq(&gcwq->lock);
+ spin_lock(&pool->lock);
if (flush_color >= 0) {
- BUG_ON(cwq->flush_color != -1);
+ WARN_ON_ONCE(pwq->flush_color != -1);
- if (cwq->nr_in_flight[flush_color]) {
- cwq->flush_color = flush_color;
- atomic_inc(&wq->nr_cwqs_to_flush);
+ if (pwq->nr_in_flight[flush_color]) {
+ pwq->flush_color = flush_color;
+ atomic_inc(&wq->nr_pwqs_to_flush);
wait = true;
}
}
if (work_color >= 0) {
- BUG_ON(work_color != work_next_color(cwq->work_color));
- cwq->work_color = work_color;
+ WARN_ON_ONCE(work_color != work_next_color(pwq->work_color));
+ pwq->work_color = work_color;
}
- spin_unlock_irq(&gcwq->lock);
+ spin_unlock(&pool->lock);
}
- if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush))
+ local_irq_enable();
+
+ if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush))
complete(&wq->first_flusher->done);
return wait;
* flush_workqueue - ensure that any scheduled work has run to completion.
* @wq: workqueue to flush
*
- * Forces execution of the workqueue and blocks until its completion.
- * This is typically used in driver shutdown handlers.
- *
- * We sleep until all works which were queued on entry have been handled,
- * but we are not livelocked by new incoming ones.
+ * This function sleeps until all work items which were queued on entry
+ * have finished execution, but it is not livelocked by new incoming ones.
*/
void flush_workqueue(struct workqueue_struct *wq)
{
* becomes our flush_color and work_color is advanced
* by one.
*/
- BUG_ON(!list_empty(&wq->flusher_overflow));
+ WARN_ON_ONCE(!list_empty(&wq->flusher_overflow));
this_flusher.flush_color = wq->work_color;
wq->work_color = next_color;
if (!wq->first_flusher) {
/* no flush in progress, become the first flusher */
- BUG_ON(wq->flush_color != this_flusher.flush_color);
+ WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
wq->first_flusher = &this_flusher;
- if (!flush_workqueue_prep_cwqs(wq, wq->flush_color,
+ if (!flush_workqueue_prep_pwqs(wq, wq->flush_color,
wq->work_color)) {
/* nothing to flush, done */
wq->flush_color = next_color;
}
} else {
/* wait in queue */
- BUG_ON(wq->flush_color == this_flusher.flush_color);
+ WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color);
list_add_tail(&this_flusher.list, &wq->flusher_queue);
- flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+ flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
}
} else {
/*
wq->first_flusher = NULL;
- BUG_ON(!list_empty(&this_flusher.list));
- BUG_ON(wq->flush_color != this_flusher.flush_color);
+ WARN_ON_ONCE(!list_empty(&this_flusher.list));
+ WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
while (true) {
struct wq_flusher *next, *tmp;
complete(&next->done);
}
- BUG_ON(!list_empty(&wq->flusher_overflow) &&
- wq->flush_color != work_next_color(wq->work_color));
+ WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) &&
+ wq->flush_color != work_next_color(wq->work_color));
/* this flush_color is finished, advance by one */
wq->flush_color = work_next_color(wq->flush_color);
list_splice_tail_init(&wq->flusher_overflow,
&wq->flusher_queue);
- flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+ flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
}
if (list_empty(&wq->flusher_queue)) {
- BUG_ON(wq->flush_color != wq->work_color);
+ WARN_ON_ONCE(wq->flush_color != wq->work_color);
break;
}
/*
* Need to flush more colors. Make the next flusher
- * the new first flusher and arm cwqs.
+ * the new first flusher and arm pwqs.
*/
- BUG_ON(wq->flush_color == wq->work_color);
- BUG_ON(wq->flush_color != next->flush_color);
+ WARN_ON_ONCE(wq->flush_color == wq->work_color);
+ WARN_ON_ONCE(wq->flush_color != next->flush_color);
list_del_init(&next->list);
wq->first_flusher = next;
- if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1))
+ if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1))
break;
/*
void drain_workqueue(struct workqueue_struct *wq)
{
unsigned int flush_cnt = 0;
- unsigned int cpu;
+ struct pool_workqueue *pwq;
/*
* __queue_work() needs to test whether there are drainers, is much
* hotter than drain_workqueue() and already looks at @wq->flags.
- * Use WQ_DRAINING so that queue doesn't have to check nr_drainers.
+ * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers.
*/
- spin_lock(&workqueue_lock);
+ mutex_lock(&wq_pool_mutex);
if (!wq->nr_drainers++)
- wq->flags |= WQ_DRAINING;
- spin_unlock(&workqueue_lock);
+ wq->flags |= __WQ_DRAINING;
+ mutex_unlock(&wq_pool_mutex);
reflush:
flush_workqueue(wq);
- for_each_cwq_cpu(cpu, wq) {
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+ local_irq_disable();
+
+ for_each_pwq(pwq, wq) {
bool drained;
- spin_lock_irq(&cwq->pool->gcwq->lock);
- drained = !cwq->nr_active && list_empty(&cwq->delayed_works);
- spin_unlock_irq(&cwq->pool->gcwq->lock);
+ spin_lock(&pwq->pool->lock);
+ drained = !pwq->nr_active && list_empty(&pwq->delayed_works);
+ spin_unlock(&pwq->pool->lock);
if (drained)
continue;
if (++flush_cnt == 10 ||
(flush_cnt % 100 == 0 && flush_cnt <= 1000))
- pr_warn("workqueue %s: flush on destruction isn't complete after %u tries\n",
+ pr_warn("workqueue %s: drain_workqueue() isn't complete after %u tries\n",
wq->name, flush_cnt);
+
+ local_irq_enable();
goto reflush;
}
- spin_lock(&workqueue_lock);
+ local_irq_enable();
+
+ mutex_lock(&wq_pool_mutex);
if (!--wq->nr_drainers)
- wq->flags &= ~WQ_DRAINING;
- spin_unlock(&workqueue_lock);
+ wq->flags &= ~__WQ_DRAINING;
+ mutex_unlock(&wq_pool_mutex);
}
EXPORT_SYMBOL_GPL(drain_workqueue);
static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
{
struct worker *worker = NULL;
- struct global_cwq *gcwq;
- struct cpu_workqueue_struct *cwq;
+ struct worker_pool *pool;
+ struct pool_workqueue *pwq;
might_sleep();
- gcwq = get_work_gcwq(work);
- if (!gcwq)
+
+ local_irq_disable();
+ pool = get_work_pool(work);
+ if (!pool) {
+ local_irq_enable();
return false;
+ }
- spin_lock_irq(&gcwq->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
- * are not going to wait.
- */
- smp_rmb();
- cwq = get_work_cwq(work);
- if (unlikely(!cwq || gcwq != cwq->pool->gcwq))
+ spin_lock(&pool->lock);
+ /* see the comment in try_to_grab_pending() with the same code */
+ pwq = get_work_pwq(work);
+ if (pwq) {
+ if (unlikely(pwq->pool != pool))
goto already_gone;
} else {
- worker = find_worker_executing_work(gcwq, work);
+ worker = find_worker_executing_work(pool, work);
if (!worker)
goto already_gone;
- cwq = worker->current_cwq;
+ pwq = worker->current_pwq;
}
- insert_wq_barrier(cwq, barr, work, worker);
- spin_unlock_irq(&gcwq->lock);
+ insert_wq_barrier(pwq, barr, work, worker);
+ spin_unlock_irq(&pool->lock);
/*
* If @max_active is 1 or rescuer is in use, flushing another work
* flusher is not running on the same workqueue by verifying write
* access.
*/
- if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER)
- lock_map_acquire(&cwq->wq->lockdep_map);
+ if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)
+ lock_map_acquire(&pwq->wq->lockdep_map);
else
- lock_map_acquire_read(&cwq->wq->lockdep_map);
- lock_map_release(&cwq->wq->lockdep_map);
+ lock_map_acquire_read(&pwq->wq->lockdep_map);
+ lock_map_release(&pwq->wq->lockdep_map);
return true;
already_gone:
- spin_unlock_irq(&gcwq->lock);
+ spin_unlock_irq(&pool->lock);
return false;
}
{
local_irq_disable();
if (del_timer_sync(&dwork->timer))
- __queue_work(dwork->cpu,
- get_work_cwq(&dwork->work)->wq, &dwork->work);
+ __queue_work(dwork->cpu, dwork->wq, &dwork->work);
local_irq_enable();
return flush_work(&dwork->work);
}
if (unlikely(ret < 0))
return false;
- set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work));
+ set_work_pool_and_clear_pending(&dwork->work,
+ get_work_pool_id(&dwork->work));
local_irq_restore(flags);
return ret;
}
}
EXPORT_SYMBOL(cancel_delayed_work_sync);
-/**
- * schedule_work_on - put work task on a specific cpu
- * @cpu: cpu to put the work task on
- * @work: job to be done
- *
- * This puts a job on a specific cpu
- */
-bool schedule_work_on(int cpu, struct work_struct *work)
-{
- return queue_work_on(cpu, system_wq, work);
-}
-EXPORT_SYMBOL(schedule_work_on);
-
-/**
- * schedule_work - put work task in global workqueue
- * @work: job to be done
- *
- * Returns %false if @work was already on the kernel-global workqueue and
- * %true otherwise.
- *
- * This puts a job in the kernel-global workqueue if it was not already
- * queued and leaves it in the same position on the kernel-global
- * workqueue otherwise.
- */
-bool schedule_work(struct work_struct *work)
-{
- return queue_work(system_wq, work);
-}
-EXPORT_SYMBOL(schedule_work);
-
-/**
- * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
- * @cpu: cpu to use
- * @dwork: job to be done
- * @delay: number of jiffies to wait
- *
- * After waiting for a given time this puts a job in the kernel-global
- * workqueue on the specified CPU.
- */
-bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
- unsigned long delay)
-{
- return queue_delayed_work_on(cpu, system_wq, dwork, delay);
-}
-EXPORT_SYMBOL(schedule_delayed_work_on);
-
-/**
- * schedule_delayed_work - put work task in global workqueue after delay
- * @dwork: job to be done
- * @delay: number of jiffies to wait or 0 for immediate execution
- *
- * After waiting for a given time this puts a job in the kernel-global
- * workqueue.
- */
-bool schedule_delayed_work(struct delayed_work *dwork, unsigned long delay)
-{
- return queue_delayed_work(system_wq, dwork, delay);
-}
-EXPORT_SYMBOL(schedule_delayed_work);
-
/**
* schedule_on_each_cpu - execute a function synchronously on each online CPU
* @func: the function to call
}
EXPORT_SYMBOL_GPL(execute_in_process_context);
-int keventd_up(void)
+#ifdef CONFIG_SYSFS
+/*
+ * Workqueues with WQ_SYSFS flag set is visible to userland via
+ * /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the
+ * following attributes.
+ *
+ * per_cpu RO bool : whether the workqueue is per-cpu or unbound
+ * max_active RW int : maximum number of in-flight work items
+ *
+ * Unbound workqueues have the following extra attributes.
+ *
+ * id RO int : the associated pool ID
+ * nice RW int : nice value of the workers
+ * cpumask RW mask : bitmask of allowed CPUs for the workers
+ */
+struct wq_device {
+ struct workqueue_struct *wq;
+ struct device dev;
+};
+
+static struct workqueue_struct *dev_to_wq(struct device *dev)
{
- return system_wq != NULL;
+ struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
+
+ return wq_dev->wq;
}
-static int alloc_cwqs(struct workqueue_struct *wq)
+static ssize_t wq_per_cpu_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
{
- /*
- * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS.
- * Make sure that the alignment isn't lower than that of
- * unsigned long long.
- */
- const size_t size = sizeof(struct cpu_workqueue_struct);
- const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS,
- __alignof__(unsigned long long));
+ struct workqueue_struct *wq = dev_to_wq(dev);
- if (!(wq->flags & WQ_UNBOUND))
- wq->cpu_wq.pcpu = __alloc_percpu(size, align);
- else {
- void *ptr;
+ return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND));
+}
- /*
- * Allocate enough room to align cwq and put an extra
- * pointer at the end pointing back to the originally
- * allocated pointer which will be used for free.
- */
- ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL);
- if (ptr) {
- wq->cpu_wq.single = PTR_ALIGN(ptr, align);
- *(void **)(wq->cpu_wq.single + 1) = ptr;
- }
- }
+static ssize_t wq_max_active_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct workqueue_struct *wq = dev_to_wq(dev);
- /* just in case, make sure it's actually aligned */
- BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align));
- return wq->cpu_wq.v ? 0 : -ENOMEM;
+ return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active);
}
-static void free_cwqs(struct workqueue_struct *wq)
+static ssize_t wq_max_active_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
{
- if (!(wq->flags & WQ_UNBOUND))
- free_percpu(wq->cpu_wq.pcpu);
- else if (wq->cpu_wq.single) {
- /* the pointer to free is stored right after the cwq */
- kfree(*(void **)(wq->cpu_wq.single + 1));
- }
+ struct workqueue_struct *wq = dev_to_wq(dev);
+ int val;
+
+ if (sscanf(buf, "%d", &val) != 1 || val <= 0)
+ return -EINVAL;
+
+ workqueue_set_max_active(wq, val);
+ return count;
}
-static int wq_clamp_max_active(int max_active, unsigned int flags,
- const char *name)
+static struct device_attribute wq_sysfs_attrs[] = {
+ __ATTR(per_cpu, 0444, wq_per_cpu_show, NULL),
+ __ATTR(max_active, 0644, wq_max_active_show, wq_max_active_store),
+ __ATTR_NULL,
+};
+
+static ssize_t wq_pool_id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
{
- int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;
+ struct workqueue_struct *wq = dev_to_wq(dev);
+ struct worker_pool *pool;
+ int written;
- if (max_active < 1 || max_active > lim)
- pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
- max_active, name, 1, lim);
+ rcu_read_lock_sched();
+ pool = first_pwq(wq)->pool;
+ written = scnprintf(buf, PAGE_SIZE, "%d\n", pool->id);
+ rcu_read_unlock_sched();
- return clamp_val(max_active, 1, lim);
+ return written;
}
-struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
- unsigned int flags,
- int max_active,
- struct lock_class_key *key,
- const char *lock_name, ...)
+static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
{
- va_list args, args1;
- struct workqueue_struct *wq;
- unsigned int cpu;
- size_t namelen;
+ struct workqueue_struct *wq = dev_to_wq(dev);
+ int written;
- /* determine namelen, allocate wq and format name */
- va_start(args, lock_name);
- va_copy(args1, args);
- namelen = vsnprintf(NULL, 0, fmt, args) + 1;
+ rcu_read_lock_sched();
+ written = scnprintf(buf, PAGE_SIZE, "%d\n",
+ first_pwq(wq)->pool->attrs->nice);
+ rcu_read_unlock_sched();
- wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL);
- if (!wq)
- goto err;
+ return written;
+}
- vsnprintf(wq->name, namelen, fmt, args1);
- va_end(args);
- va_end(args1);
+/* prepare workqueue_attrs for sysfs store operations */
+static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq)
+{
+ struct workqueue_attrs *attrs;
- /*
- * Workqueues which may be used during memory reclaim should
- * have a rescuer to guarantee forward progress.
- */
- if (flags & WQ_MEM_RECLAIM)
- flags |= WQ_RESCUER;
+ attrs = alloc_workqueue_attrs(GFP_KERNEL);
+ if (!attrs)
+ return NULL;
- max_active = max_active ?: WQ_DFL_ACTIVE;
- max_active = wq_clamp_max_active(max_active, flags, wq->name);
+ rcu_read_lock_sched();
+ copy_workqueue_attrs(attrs, first_pwq(wq)->pool->attrs);
+ rcu_read_unlock_sched();
+ return attrs;
+}
- /* init wq */
- wq->flags = flags;
- wq->saved_max_active = max_active;
- mutex_init(&wq->flush_mutex);
- atomic_set(&wq->nr_cwqs_to_flush, 0);
- INIT_LIST_HEAD(&wq->flusher_queue);
- INIT_LIST_HEAD(&wq->flusher_overflow);
+static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct workqueue_struct *wq = dev_to_wq(dev);
+ struct workqueue_attrs *attrs;
+ int ret;
- lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
- INIT_LIST_HEAD(&wq->list);
+ attrs = wq_sysfs_prep_attrs(wq);
+ if (!attrs)
+ return -ENOMEM;
+
+ if (sscanf(buf, "%d", &attrs->nice) == 1 &&
+ attrs->nice >= -20 && attrs->nice <= 19)
+ ret = apply_workqueue_attrs(wq, attrs);
+ else
+ ret = -EINVAL;
- if (alloc_cwqs(wq) < 0)
- goto err;
+ free_workqueue_attrs(attrs);
+ return ret ?: count;
+}
- for_each_cwq_cpu(cpu, wq) {
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
- struct global_cwq *gcwq = get_gcwq(cpu);
- int pool_idx = (bool)(flags & WQ_HIGHPRI);
+static ssize_t wq_cpumask_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct workqueue_struct *wq = dev_to_wq(dev);
+ int written;
- BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK);
- cwq->pool = &gcwq->pools[pool_idx];
- cwq->wq = wq;
- cwq->flush_color = -1;
- cwq->max_active = max_active;
- INIT_LIST_HEAD(&cwq->delayed_works);
- }
+ rcu_read_lock_sched();
+ written = cpumask_scnprintf(buf, PAGE_SIZE,
+ first_pwq(wq)->pool->attrs->cpumask);
+ rcu_read_unlock_sched();
- if (flags & WQ_RESCUER) {
- struct worker *rescuer;
+ written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
+ return written;
+}
- if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL))
- goto err;
+static ssize_t wq_cpumask_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct workqueue_struct *wq = dev_to_wq(dev);
+ struct workqueue_attrs *attrs;
+ int ret;
- wq->rescuer = rescuer = alloc_worker();
- if (!rescuer)
- goto err;
+ attrs = wq_sysfs_prep_attrs(wq);
+ if (!attrs)
+ return -ENOMEM;
- rescuer->task = kthread_create(rescuer_thread, wq, "%s",
- wq->name);
- if (IS_ERR(rescuer->task))
- goto err;
+ ret = cpumask_parse(buf, attrs->cpumask);
+ if (!ret)
+ ret = apply_workqueue_attrs(wq, attrs);
- rescuer->task->flags |= PF_THREAD_BOUND;
- wake_up_process(rescuer->task);
- }
+ free_workqueue_attrs(attrs);
+ return ret ?: count;
+}
- /*
- * workqueue_lock protects global freeze state and workqueues
- * list. Grab it, set max_active accordingly and add the new
- * workqueue to workqueues list.
- */
- spin_lock(&workqueue_lock);
+static struct device_attribute wq_sysfs_unbound_attrs[] = {
+ __ATTR(pool_id, 0444, wq_pool_id_show, NULL),
+ __ATTR(nice, 0644, wq_nice_show, wq_nice_store),
+ __ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
+ __ATTR_NULL,
+};
- if (workqueue_freezing && wq->flags & WQ_FREEZABLE)
- for_each_cwq_cpu(cpu, wq)
- get_cwq(cpu, wq)->max_active = 0;
+static struct bus_type wq_subsys = {
+ .name = "workqueue",
+ .dev_attrs = wq_sysfs_attrs,
+};
- list_add(&wq->list, &workqueues);
+static int __init wq_sysfs_init(void)
+{
+ return subsys_virtual_register(&wq_subsys, NULL);
+}
+core_initcall(wq_sysfs_init);
- spin_unlock(&workqueue_lock);
+static void wq_device_release(struct device *dev)
+{
+ struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
- return wq;
-err:
- if (wq) {
- free_cwqs(wq);
- free_mayday_mask(wq->mayday_mask);
- kfree(wq->rescuer);
- kfree(wq);
- }
- return NULL;
+ kfree(wq_dev);
}
-EXPORT_SYMBOL_GPL(__alloc_workqueue_key);
/**
- * destroy_workqueue - safely terminate a workqueue
- * @wq: target workqueue
+ * workqueue_sysfs_register - make a workqueue visible in sysfs
+ * @wq: the workqueue to register
*
- * Safely destroy a workqueue. All work currently pending will be done first.
+ * Expose @wq in sysfs under /sys/bus/workqueue/devices.
+ * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set
+ * which is the preferred method.
+ *
+ * Workqueue user should use this function directly iff it wants to apply
+ * workqueue_attrs before making the workqueue visible in sysfs; otherwise,
+ * apply_workqueue_attrs() may race against userland updating the
+ * attributes.
+ *
+ * Returns 0 on success, -errno on failure.
*/
-void destroy_workqueue(struct workqueue_struct *wq)
+int workqueue_sysfs_register(struct workqueue_struct *wq)
{
- unsigned int cpu;
+ struct wq_device *wq_dev;
+ int ret;
- /* drain it before proceeding with destruction */
- drain_workqueue(wq);
+ /*
+ * Adjusting max_active or creating new pwqs by applyting
+ * attributes breaks ordering guarantee. Disallow exposing ordered
+ * workqueues.
+ */
+ if (WARN_ON(wq->flags & __WQ_ORDERED))
+ return -EINVAL;
+
+ wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);
+ if (!wq_dev)
+ return -ENOMEM;
+
+ wq_dev->wq = wq;
+ wq_dev->dev.bus = &wq_subsys;
+ wq_dev->dev.init_name = wq->name;
+ wq_dev->dev.release = wq_device_release;
/*
- * wq list is used to freeze wq, remove from list after
- * flushing is complete in case freeze races us.
+ * unbound_attrs are created separately. Suppress uevent until
+ * everything is ready.
*/
- spin_lock(&workqueue_lock);
- list_del(&wq->list);
- spin_unlock(&workqueue_lock);
+ dev_set_uevent_suppress(&wq_dev->dev, true);
- /* sanity check */
- for_each_cwq_cpu(cpu, wq) {
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
- int i;
+ ret = device_register(&wq_dev->dev);
+ if (ret) {
+ kfree(wq_dev);
+ wq->wq_dev = NULL;
+ return ret;
+ }
- for (i = 0; i < WORK_NR_COLORS; i++)
- BUG_ON(cwq->nr_in_flight[i]);
- BUG_ON(cwq->nr_active);
- BUG_ON(!list_empty(&cwq->delayed_works));
+ if (wq->flags & WQ_UNBOUND) {
+ struct device_attribute *attr;
+
+ for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) {
+ ret = device_create_file(&wq_dev->dev, attr);
+ if (ret) {
+ device_unregister(&wq_dev->dev);
+ wq->wq_dev = NULL;
+ return ret;
+ }
+ }
}
- if (wq->flags & WQ_RESCUER) {
- kthread_stop(wq->rescuer->task);
- free_mayday_mask(wq->mayday_mask);
- kfree(wq->rescuer);
+ kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD);
+ return 0;
+}
+
+/**
+ * workqueue_sysfs_unregister - undo workqueue_sysfs_register()
+ * @wq: the workqueue to unregister
+ *
+ * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister.
+ */
+static void workqueue_sysfs_unregister(struct workqueue_struct *wq)
+{
+ struct wq_device *wq_dev = wq->wq_dev;
+
+ if (!wq->wq_dev)
+ return;
+
+ wq->wq_dev = NULL;
+ device_unregister(&wq_dev->dev);
+}
+#else /* CONFIG_SYSFS */
+static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { }
+#endif /* CONFIG_SYSFS */
+
+/**
+ * free_workqueue_attrs - free a workqueue_attrs
+ * @attrs: workqueue_attrs to free
+ *
+ * Undo alloc_workqueue_attrs().
+ */
+void free_workqueue_attrs(struct workqueue_attrs *attrs)
+{
+ if (attrs) {
+ free_cpumask_var(attrs->cpumask);
+ kfree(attrs);
}
+}
- free_cwqs(wq);
- kfree(wq);
+/**
+ * alloc_workqueue_attrs - allocate a workqueue_attrs
+ * @gfp_mask: allocation mask to use
+ *
+ * Allocate a new workqueue_attrs, initialize with default settings and
+ * return it. Returns NULL on failure.
+ */
+struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask)
+{
+ struct workqueue_attrs *attrs;
+
+ attrs = kzalloc(sizeof(*attrs), gfp_mask);
+ if (!attrs)
+ goto fail;
+ if (!alloc_cpumask_var(&attrs->cpumask, gfp_mask))
+ goto fail;
+
+ cpumask_setall(attrs->cpumask);
+ return attrs;
+fail:
+ free_workqueue_attrs(attrs);
+ return NULL;
+}
+
+static void copy_workqueue_attrs(struct workqueue_attrs *to,
+ const struct workqueue_attrs *from)
+{
+ to->nice = from->nice;
+ cpumask_copy(to->cpumask, from->cpumask);
+}
+
+/*
+ * Hacky implementation of jhash of bitmaps which only considers the
+ * specified number of bits. We probably want a proper implementation in
+ * include/linux/jhash.h.
+ */
+static u32 jhash_bitmap(const unsigned long *bitmap, int bits, u32 hash)
+{
+ int nr_longs = bits / BITS_PER_LONG;
+ int nr_leftover = bits % BITS_PER_LONG;
+ unsigned long leftover = 0;
+
+ if (nr_longs)
+ hash = jhash(bitmap, nr_longs * sizeof(long), hash);
+ if (nr_leftover) {
+ bitmap_copy(&leftover, bitmap + nr_longs, nr_leftover);
+ hash = jhash(&leftover, sizeof(long), hash);
+ }
+ return hash;
+}
+
+/* hash value of the content of @attr */
+static u32 wqattrs_hash(const struct workqueue_attrs *attrs)
+{
+ u32 hash = 0;
+
+ hash = jhash_1word(attrs->nice, hash);
+ hash = jhash_bitmap(cpumask_bits(attrs->cpumask), nr_cpu_ids, hash);
+ return hash;
+}
+
+/* content equality test */
+static bool wqattrs_equal(const struct workqueue_attrs *a,
+ const struct workqueue_attrs *b)
+{
+ if (a->nice != b->nice)
+ return false;
+ if (!cpumask_equal(a->cpumask, b->cpumask))
+ return false;
+ return true;
}
-EXPORT_SYMBOL_GPL(destroy_workqueue);
/**
- * cwq_set_max_active - adjust max_active of a cwq
- * @cwq: target cpu_workqueue_struct
- * @max_active: new max_active value.
+ * init_worker_pool - initialize a newly zalloc'd worker_pool
+ * @pool: worker_pool to initialize
*
- * Set @cwq->max_active to @max_active and activate delayed works if
- * increased.
+ * Initiailize a newly zalloc'd @pool. It also allocates @pool->attrs.
+ * Returns 0 on success, -errno on failure. Even on failure, all fields
+ * inside @pool proper are initialized and put_unbound_pool() can be called
+ * on @pool safely to release it.
+ */
+static int init_worker_pool(struct worker_pool *pool)
+{
+ spin_lock_init(&pool->lock);
+ pool->id = -1;
+ pool->cpu = -1;
+ pool->flags |= POOL_DISASSOCIATED;
+ INIT_LIST_HEAD(&pool->worklist);
+ INIT_LIST_HEAD(&pool->idle_list);
+ hash_init(pool->busy_hash);
+
+ init_timer_deferrable(&pool->idle_timer);
+ pool->idle_timer.function = idle_worker_timeout;
+ pool->idle_timer.data = (unsigned long)pool;
+
+ setup_timer(&pool->mayday_timer, pool_mayday_timeout,
+ (unsigned long)pool);
+
+ mutex_init(&pool->manager_arb);
+ mutex_init(&pool->manager_mutex);
+ idr_init(&pool->worker_idr);
+
+ INIT_HLIST_NODE(&pool->hash_node);
+ pool->refcnt = 1;
+
+ /* shouldn't fail above this point */
+ pool->attrs = alloc_workqueue_attrs(GFP_KERNEL);
+ if (!pool->attrs)
+ return -ENOMEM;
+ return 0;
+}
+
+static void rcu_free_pool(struct rcu_head *rcu)
+{
+ struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu);
+
+ idr_destroy(&pool->worker_idr);
+ free_workqueue_attrs(pool->attrs);
+ kfree(pool);
+}
+
+/**
+ * put_unbound_pool - put a worker_pool
+ * @pool: worker_pool to put
*
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * Put @pool. If its refcnt reaches zero, it gets destroyed in sched-RCU
+ * safe manner. get_unbound_pool() calls this function on its failure path
+ * and this function should be able to release pools which went through,
+ * successfully or not, init_worker_pool().
*/
-static void cwq_set_max_active(struct cpu_workqueue_struct *cwq, int max_active)
+static void put_unbound_pool(struct worker_pool *pool)
{
- cwq->max_active = max_active;
+ struct worker *worker;
+
+ mutex_lock(&wq_pool_mutex);
+ if (--pool->refcnt) {
+ mutex_unlock(&wq_pool_mutex);
+ return;
+ }
+
+ /* sanity checks */
+ if (WARN_ON(!(pool->flags & POOL_DISASSOCIATED)) ||
+ WARN_ON(!list_empty(&pool->worklist))) {
+ mutex_unlock(&wq_pool_mutex);
+ return;
+ }
+
+ /* release id and unhash */
+ if (pool->id >= 0)
+ idr_remove(&worker_pool_idr, pool->id);
+ hash_del(&pool->hash_node);
+
+ mutex_unlock(&wq_pool_mutex);
- while (!list_empty(&cwq->delayed_works) &&
- cwq->nr_active < cwq->max_active)
- cwq_activate_first_delayed(cwq);
+ /*
+ * Become the manager and destroy all workers. Grabbing
+ * manager_arb prevents @pool's workers from blocking on
+ * manager_mutex.
+ */
+ mutex_lock(&pool->manager_arb);
+ mutex_lock(&pool->manager_mutex);
+ spin_lock_irq(&pool->lock);
+
+ while ((worker = first_worker(pool)))
+ destroy_worker(worker);
+ WARN_ON(pool->nr_workers || pool->nr_idle);
+
+ spin_unlock_irq(&pool->lock);
+ mutex_unlock(&pool->manager_mutex);
+ mutex_unlock(&pool->manager_arb);
+
+ /* shut down the timers */
+ del_timer_sync(&pool->idle_timer);
+ del_timer_sync(&pool->mayday_timer);
+
+ /* sched-RCU protected to allow dereferences from get_work_pool() */
+ call_rcu_sched(&pool->rcu, rcu_free_pool);
}
+/**
+ * get_unbound_pool - get a worker_pool with the specified attributes
+ * @attrs: the attributes of the worker_pool to get
+ *
+ * Obtain a worker_pool which has the same attributes as @attrs, bump the
+ * reference count and return it. If there already is a matching
+ * worker_pool, it will be used; otherwise, this function attempts to
+ * create a new one. On failure, returns NULL.
+ */
+static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
+{
+ u32 hash = wqattrs_hash(attrs);
+ struct worker_pool *pool;
+
+ mutex_lock(&wq_pool_mutex);
+
+ /* do we already have a matching pool? */
+ hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) {
+ if (wqattrs_equal(pool->attrs, attrs)) {
+ pool->refcnt++;
+ goto out_unlock;
+ }
+ }
+
+ /* nope, create a new one */
+ pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+ if (!pool || init_worker_pool(pool) < 0)
+ goto fail;
+
+ if (workqueue_freezing)
+ pool->flags |= POOL_FREEZING;
+
+ lockdep_set_subclass(&pool->lock, 1); /* see put_pwq() */
+ copy_workqueue_attrs(pool->attrs, attrs);
+
+ if (worker_pool_assign_id(pool) < 0)
+ goto fail;
+
+ /* create and start the initial worker */
+ if (create_and_start_worker(pool) < 0)
+ goto fail;
+
+ /* install */
+ hash_add(unbound_pool_hash, &pool->hash_node, hash);
+out_unlock:
+ mutex_unlock(&wq_pool_mutex);
+ return pool;
+fail:
+ mutex_unlock(&wq_pool_mutex);
+ if (pool)
+ put_unbound_pool(pool);
+ return NULL;
+}
+
+static void rcu_free_pwq(struct rcu_head *rcu)
+{
+ kmem_cache_free(pwq_cache,
+ container_of(rcu, struct pool_workqueue, rcu));
+}
+
+/*
+ * Scheduled on system_wq by put_pwq() when an unbound pwq hits zero refcnt
+ * and needs to be destroyed.
+ */
+static void pwq_unbound_release_workfn(struct work_struct *work)
+{
+ struct pool_workqueue *pwq = container_of(work, struct pool_workqueue,
+ unbound_release_work);
+ struct workqueue_struct *wq = pwq->wq;
+ struct worker_pool *pool = pwq->pool;
+
+ if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
+ return;
+
+ /*
+ * Unlink @pwq. Synchronization against flush_mutex isn't strictly
+ * necessary on release but do it anyway. It's easier to verify
+ * and consistent with the linking path.
+ */
+ mutex_lock(&wq->flush_mutex);
+ spin_lock_irq(&pwq_lock);
+ list_del_rcu(&pwq->pwqs_node);
+ spin_unlock_irq(&pwq_lock);
+ mutex_unlock(&wq->flush_mutex);
+
+ put_unbound_pool(pool);
+ call_rcu_sched(&pwq->rcu, rcu_free_pwq);
+
+ /*
+ * If we're the last pwq going away, @wq is already dead and no one
+ * is gonna access it anymore. Free it.
+ */
+ if (list_empty(&wq->pwqs))
+ kfree(wq);
+}
+
+/**
+ * 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 delayed 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;
+
+ /* for @wq->saved_max_active */
+ lockdep_assert_held(&pwq_lock);
+
+ /* fast exit for non-freezable wqs */
+ if (!freezable && pwq->max_active == wq->saved_max_active)
+ return;
+
+ spin_lock(&pwq->pool->lock);
+
+ if (!freezable || !(pwq->pool->flags & POOL_FREEZING)) {
+ pwq->max_active = wq->saved_max_active;
+
+ while (!list_empty(&pwq->delayed_works) &&
+ pwq->nr_active < pwq->max_active)
+ pwq_activate_first_delayed(pwq);
+
+ /*
+ * Need to kick a worker after thawed or an unbound wq's
+ * max_active is bumped. It's a slow path. Do it always.
+ */
+ wake_up_worker(pwq->pool);
+ } else {
+ pwq->max_active = 0;
+ }
+
+ spin_unlock(&pwq->pool->lock);
+}
+
+static void init_and_link_pwq(struct pool_workqueue *pwq,
+ struct workqueue_struct *wq,
+ struct worker_pool *pool,
+ struct pool_workqueue **p_last_pwq)
+{
+ BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);
+
+ pwq->pool = pool;
+ pwq->wq = wq;
+ pwq->flush_color = -1;
+ pwq->refcnt = 1;
+ INIT_LIST_HEAD(&pwq->delayed_works);
+ INIT_LIST_HEAD(&pwq->mayday_node);
+ INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
+
+ mutex_lock(&wq->flush_mutex);
+ spin_lock_irq(&pwq_lock);
+
+ /*
+ * Set the matching work_color. This is synchronized with
+ * flush_mutex to avoid confusing flush_workqueue().
+ */
+ if (p_last_pwq)
+ *p_last_pwq = first_pwq(wq);
+ 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);
+
+ spin_unlock_irq(&pwq_lock);
+ mutex_unlock(&wq->flush_mutex);
+}
+
+/**
+ * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
+ * @wq: the target workqueue
+ * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
+ *
+ * Apply @attrs to an unbound workqueue @wq. If @attrs doesn't match the
+ * current attributes, a new pwq is created and made the first pwq which
+ * will serve all new work items. Older pwqs are released as in-flight
+ * work items finish. Note that a work item which repeatedly requeues
+ * itself back-to-back will stay on its current pwq.
+ *
+ * Performs GFP_KERNEL allocations. Returns 0 on success and -errno on
+ * failure.
+ */
+int apply_workqueue_attrs(struct workqueue_struct *wq,
+ const struct workqueue_attrs *attrs)
+{
+ struct pool_workqueue *pwq, *last_pwq;
+ struct worker_pool *pool;
+
+ /* only unbound workqueues can change attributes */
+ if (WARN_ON(!(wq->flags & WQ_UNBOUND)))
+ return -EINVAL;
+
+ /* creating multiple pwqs breaks ordering guarantee */
+ if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))
+ return -EINVAL;
+
+ pwq = kmem_cache_zalloc(pwq_cache, GFP_KERNEL);
+ if (!pwq)
+ return -ENOMEM;
+
+ pool = get_unbound_pool(attrs);
+ if (!pool) {
+ kmem_cache_free(pwq_cache, pwq);
+ return -ENOMEM;
+ }
+
+ init_and_link_pwq(pwq, wq, pool, &last_pwq);
+ if (last_pwq) {
+ spin_lock_irq(&last_pwq->pool->lock);
+ put_pwq(last_pwq);
+ spin_unlock_irq(&last_pwq->pool->lock);
+ }
+
+ return 0;
+}
+
+static int alloc_and_link_pwqs(struct workqueue_struct *wq)
+{
+ bool highpri = wq->flags & WQ_HIGHPRI;
+ int cpu;
+
+ if (!(wq->flags & WQ_UNBOUND)) {
+ wq->cpu_pwqs = alloc_percpu(struct pool_workqueue);
+ if (!wq->cpu_pwqs)
+ return -ENOMEM;
+
+ for_each_possible_cpu(cpu) {
+ struct pool_workqueue *pwq =
+ per_cpu_ptr(wq->cpu_pwqs, cpu);
+ struct worker_pool *cpu_pools =
+ per_cpu(cpu_worker_pools, cpu);
+
+ init_and_link_pwq(pwq, wq, &cpu_pools[highpri], NULL);
+ }
+ return 0;
+ } else {
+ return apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
+ }
+}
+
+static int wq_clamp_max_active(int max_active, unsigned int flags,
+ const char *name)
+{
+ int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;
+
+ if (max_active < 1 || max_active > lim)
+ pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
+ max_active, name, 1, lim);
+
+ return clamp_val(max_active, 1, lim);
+}
+
+struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
+ unsigned int flags,
+ int max_active,
+ struct lock_class_key *key,
+ const char *lock_name, ...)
+{
+ va_list args, args1;
+ struct workqueue_struct *wq;
+ struct pool_workqueue *pwq;
+ size_t namelen;
+
+ /* determine namelen, allocate wq and format name */
+ va_start(args, lock_name);
+ va_copy(args1, args);
+ namelen = vsnprintf(NULL, 0, fmt, args) + 1;
+
+ wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL);
+ if (!wq)
+ return NULL;
+
+ vsnprintf(wq->name, namelen, fmt, args1);
+ va_end(args);
+ va_end(args1);
+
+ max_active = max_active ?: WQ_DFL_ACTIVE;
+ max_active = wq_clamp_max_active(max_active, flags, wq->name);
+
+ /* init wq */
+ wq->flags = flags;
+ wq->saved_max_active = max_active;
+ mutex_init(&wq->flush_mutex);
+ atomic_set(&wq->nr_pwqs_to_flush, 0);
+ INIT_LIST_HEAD(&wq->pwqs);
+ INIT_LIST_HEAD(&wq->flusher_queue);
+ INIT_LIST_HEAD(&wq->flusher_overflow);
+ INIT_LIST_HEAD(&wq->maydays);
+
+ lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
+ INIT_LIST_HEAD(&wq->list);
+
+ if (alloc_and_link_pwqs(wq) < 0)
+ goto err_free_wq;
+
+ /*
+ * Workqueues which may be used during memory reclaim should
+ * have a rescuer to guarantee forward progress.
+ */
+ if (flags & WQ_MEM_RECLAIM) {
+ struct worker *rescuer;
+
+ rescuer = alloc_worker();
+ if (!rescuer)
+ goto err_destroy;
+
+ rescuer->rescue_wq = wq;
+ rescuer->task = kthread_create(rescuer_thread, rescuer, "%s",
+ wq->name);
+ if (IS_ERR(rescuer->task)) {
+ kfree(rescuer);
+ goto err_destroy;
+ }
+
+ wq->rescuer = rescuer;
+ rescuer->task->flags |= PF_NO_SETAFFINITY;
+ wake_up_process(rescuer->task);
+ }
+
+ if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
+ goto err_destroy;
+
+ /*
+ * wq_pool_mutex protects global freeze state and workqueues list.
+ * Grab it, adjust max_active and add the new @wq to workqueues
+ * list.
+ */
+ mutex_lock(&wq_pool_mutex);
+
+ spin_lock_irq(&pwq_lock);
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
+ spin_unlock_irq(&pwq_lock);
+
+ list_add(&wq->list, &workqueues);
+
+ mutex_unlock(&wq_pool_mutex);
+
+ return wq;
+
+err_free_wq:
+ kfree(wq);
+ return NULL;
+err_destroy:
+ destroy_workqueue(wq);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(__alloc_workqueue_key);
+
+/**
+ * destroy_workqueue - safely terminate a workqueue
+ * @wq: target workqueue
+ *
+ * Safely destroy a workqueue. All work currently pending will be done first.
+ */
+void destroy_workqueue(struct workqueue_struct *wq)
+{
+ struct pool_workqueue *pwq;
+
+ /* drain it before proceeding with destruction */
+ drain_workqueue(wq);
+
+ /* sanity checks */
+ spin_lock_irq(&pwq_lock);
+ for_each_pwq(pwq, wq) {
+ int i;
+
+ for (i = 0; i < WORK_NR_COLORS; i++) {
+ if (WARN_ON(pwq->nr_in_flight[i])) {
+ spin_unlock_irq(&pwq_lock);
+ return;
+ }
+ }
+
+ if (WARN_ON(pwq->refcnt > 1) ||
+ WARN_ON(pwq->nr_active) ||
+ WARN_ON(!list_empty(&pwq->delayed_works))) {
+ spin_unlock_irq(&pwq_lock);
+ return;
+ }
+ }
+ spin_unlock_irq(&pwq_lock);
+
+ /*
+ * wq list is used to freeze wq, remove from list after
+ * flushing is complete in case freeze races us.
+ */
+ mutex_lock(&wq_pool_mutex);
+ list_del_init(&wq->list);
+ mutex_unlock(&wq_pool_mutex);
+
+ workqueue_sysfs_unregister(wq);
+
+ if (wq->rescuer) {
+ kthread_stop(wq->rescuer->task);
+ kfree(wq->rescuer);
+ wq->rescuer = NULL;
+ }
+
+ if (!(wq->flags & WQ_UNBOUND)) {
+ /*
+ * The base ref is never dropped on per-cpu pwqs. Directly
+ * free the pwqs and wq.
+ */
+ free_percpu(wq->cpu_pwqs);
+ kfree(wq);
+ } else {
+ /*
+ * We're the sole accessor of @wq at this point. Directly
+ * access the first pwq and put the base ref. As both pwqs
+ * and pools are sched-RCU protected, the lock operations
+ * are safe. @wq will be freed when the last pwq is
+ * released.
+ */
+ pwq = list_first_entry(&wq->pwqs, struct pool_workqueue,
+ pwqs_node);
+ spin_lock_irq(&pwq->pool->lock);
+ put_pwq(pwq);
+ spin_unlock_irq(&pwq->pool->lock);
+ }
+}
+EXPORT_SYMBOL_GPL(destroy_workqueue);
+
/**
* workqueue_set_max_active - adjust max_active of a workqueue
* @wq: target workqueue
*/
void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
{
- unsigned int cpu;
+ struct pool_workqueue *pwq;
+
+ /* disallow meddling with max_active for ordered workqueues */
+ if (WARN_ON(wq->flags & __WQ_ORDERED))
+ return;
max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
- spin_lock(&workqueue_lock);
+ spin_lock_irq(&pwq_lock);
wq->saved_max_active = max_active;
- for_each_cwq_cpu(cpu, wq) {
- struct global_cwq *gcwq = get_gcwq(cpu);
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
- spin_lock_irq(&gcwq->lock);
-
- if (!(wq->flags & WQ_FREEZABLE) ||
- !(gcwq->flags & GCWQ_FREEZING))
- cwq_set_max_active(get_cwq(gcwq->cpu, wq), max_active);
+ spin_unlock_irq(&pwq_lock);
+}
+EXPORT_SYMBOL_GPL(workqueue_set_max_active);
- spin_unlock_irq(&gcwq->lock);
- }
+/**
+ * current_is_workqueue_rescuer - is %current workqueue rescuer?
+ *
+ * Determine whether %current is a workqueue rescuer. Can be used from
+ * work functions to determine whether it's being run off the rescuer task.
+ */
+bool current_is_workqueue_rescuer(void)
+{
+ struct worker *worker = current_wq_worker();
- spin_unlock(&workqueue_lock);
+ return worker && worker->rescue_wq;
}
-EXPORT_SYMBOL_GPL(workqueue_set_max_active);
/**
* workqueue_congested - test whether a workqueue is congested
* RETURNS:
* %true if congested, %false otherwise.
*/
-bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq)
+bool workqueue_congested(int cpu, struct workqueue_struct *wq)
{
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+ struct pool_workqueue *pwq;
+ bool ret;
- return !list_empty(&cwq->delayed_works);
-}
-EXPORT_SYMBOL_GPL(workqueue_congested);
+ rcu_read_lock_sched();
-/**
- * work_cpu - return the last known associated cpu for @work
- * @work: the work of interest
- *
- * RETURNS:
- * CPU number if @work was ever queued. WORK_CPU_NONE otherwise.
- */
-unsigned int work_cpu(struct work_struct *work)
-{
- struct global_cwq *gcwq = get_work_gcwq(work);
+ if (!(wq->flags & WQ_UNBOUND))
+ pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
+ else
+ pwq = first_pwq(wq);
+
+ ret = !list_empty(&pwq->delayed_works);
+ rcu_read_unlock_sched();
- return gcwq ? gcwq->cpu : WORK_CPU_NONE;
+ return ret;
}
-EXPORT_SYMBOL_GPL(work_cpu);
+EXPORT_SYMBOL_GPL(workqueue_congested);
/**
* work_busy - test whether a work is currently pending or running
* Test whether @work is currently pending or running. There is no
* synchronization around this function and the test result is
* unreliable and only useful as advisory hints or for debugging.
- * Especially for reentrant wqs, the pending state might hide the
- * running state.
*
* RETURNS:
* OR'd bitmask of WORK_BUSY_* bits.
*/
unsigned int work_busy(struct work_struct *work)
{
- struct global_cwq *gcwq = get_work_gcwq(work);
+ struct worker_pool *pool;
unsigned long flags;
unsigned int ret = 0;
- if (!gcwq)
- return 0;
-
- spin_lock_irqsave(&gcwq->lock, flags);
-
if (work_pending(work))
ret |= WORK_BUSY_PENDING;
- if (find_worker_executing_work(gcwq, work))
- ret |= WORK_BUSY_RUNNING;
- spin_unlock_irqrestore(&gcwq->lock, flags);
+ local_irq_save(flags);
+ pool = get_work_pool(work);
+ if (pool) {
+ spin_lock(&pool->lock);
+ if (find_worker_executing_work(pool, work))
+ ret |= WORK_BUSY_RUNNING;
+ spin_unlock(&pool->lock);
+ }
+ local_irq_restore(flags);
return ret;
}
* CPU hotplug.
*
* There are two challenges in supporting CPU hotplug. Firstly, there
- * are a lot of assumptions on strong associations among work, cwq and
- * gcwq which make migrating pending and scheduled works very
+ * are a lot of assumptions on strong associations among work, pwq and
+ * pool which make migrating pending and scheduled works very
* difficult to implement without impacting hot paths. Secondly,
- * gcwqs serve mix of short, long and very long running works making
+ * worker pools serve mix of short, long and very long running works making
* blocked draining impractical.
*
- * This is solved by allowing a gcwq to be disassociated from the CPU
+ * This is solved by allowing the pools to be disassociated from the CPU
* running as an unbound one and allowing it to be reattached later if the
* cpu comes back online.
*/
-/* claim manager positions of all pools */
-static void gcwq_claim_assoc_and_lock(struct global_cwq *gcwq)
-{
- struct worker_pool *pool;
-
- for_each_worker_pool(pool, gcwq)
- mutex_lock_nested(&pool->assoc_mutex, pool - gcwq->pools);
- spin_lock_irq(&gcwq->lock);
-}
-
-/* release manager positions */
-static void gcwq_release_assoc_and_unlock(struct global_cwq *gcwq)
+static void wq_unbind_fn(struct work_struct *work)
{
- struct worker_pool *pool;
-
- spin_unlock_irq(&gcwq->lock);
- for_each_worker_pool(pool, gcwq)
- mutex_unlock(&pool->assoc_mutex);
-}
-
-static void gcwq_unbind_fn(struct work_struct *work)
-{
- struct global_cwq *gcwq = get_gcwq(smp_processor_id());
+ int cpu = smp_processor_id();
struct worker_pool *pool;
struct worker *worker;
- struct hlist_node *pos;
- int i;
+ int wi;
- BUG_ON(gcwq->cpu != smp_processor_id());
+ for_each_cpu_worker_pool(pool, cpu) {
+ WARN_ON_ONCE(cpu != smp_processor_id());
- gcwq_claim_assoc_and_lock(gcwq);
+ mutex_lock(&pool->manager_mutex);
+ spin_lock_irq(&pool->lock);
- /*
- * We've claimed all manager positions. Make all workers unbound
- * and set DISASSOCIATED. Before this, all workers except for the
- * ones which are still executing works from before the last CPU
- * down must be on the cpu. After this, they may become diasporas.
- */
- for_each_worker_pool(pool, gcwq)
- list_for_each_entry(worker, &pool->idle_list, entry)
+ /*
+ * We've blocked all manager operations. Make all workers
+ * unbound and set DISASSOCIATED. Before this, all workers
+ * except for the ones which are still executing works from
+ * before the last CPU down must be on the cpu. After
+ * this, they may become diasporas.
+ */
+ for_each_pool_worker(worker, wi, pool)
worker->flags |= WORKER_UNBOUND;
- for_each_busy_worker(worker, i, pos, gcwq)
- worker->flags |= WORKER_UNBOUND;
-
- gcwq->flags |= GCWQ_DISASSOCIATED;
+ pool->flags |= POOL_DISASSOCIATED;
- gcwq_release_assoc_and_unlock(gcwq);
+ spin_unlock_irq(&pool->lock);
+ mutex_unlock(&pool->manager_mutex);
+ }
/*
* Call schedule() so that we cross rq->lock and thus can guarantee
/*
* Sched callbacks are disabled now. Zap nr_running. After this,
* nr_running stays zero and need_more_worker() and keep_working()
- * are always true as long as the worklist is not empty. @gcwq now
- * behaves as unbound (in terms of concurrency management) gcwq
- * which is served by workers tied to the CPU.
+ * are always true as long as the worklist is not empty. Pools on
+ * @cpu now behave as unbound (in terms of concurrency management)
+ * pools which are served by workers tied to the CPU.
*
* On return from this function, the current worker would trigger
* unbound chain execution of pending work items if other workers
* didn't already.
*/
- for_each_worker_pool(pool, gcwq)
- atomic_set(get_pool_nr_running(pool), 0);
+ for_each_cpu_worker_pool(pool, cpu)
+ atomic_set(&pool->nr_running, 0);
+}
+
+/**
+ * rebind_workers - rebind all workers of a pool to the associated CPU
+ * @pool: pool of interest
+ *
+ * @pool->cpu is coming online. Rebind all workers to the CPU.
+ */
+static void rebind_workers(struct worker_pool *pool)
+{
+ struct worker *worker;
+ int wi;
+
+ lockdep_assert_held(&pool->manager_mutex);
+
+ /*
+ * Restore CPU affinity of all workers. As all idle workers should
+ * be on the run-queue of the associated CPU before any local
+ * wake-ups for concurrency management happen, restore CPU affinty
+ * of all workers first and then clear UNBOUND. As we're called
+ * from CPU_ONLINE, the following shouldn't fail.
+ */
+ for_each_pool_worker(worker, wi, pool)
+ WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
+ pool->attrs->cpumask) < 0);
+
+ spin_lock_irq(&pool->lock);
+
+ for_each_pool_worker(worker, wi, pool) {
+ unsigned int worker_flags = worker->flags;
+
+ /*
+ * A bound idle worker should actually be on the runqueue
+ * of the associated CPU for local wake-ups targeting it to
+ * work. Kick all idle workers so that they migrate to the
+ * associated CPU. Doing this in the same loop as
+ * replacing UNBOUND with REBOUND is safe as no worker will
+ * be bound before @pool->lock is released.
+ */
+ if (worker_flags & WORKER_IDLE)
+ wake_up_process(worker->task);
+
+ /*
+ * We want to clear UNBOUND but can't directly call
+ * worker_clr_flags() or adjust nr_running. Atomically
+ * replace UNBOUND with another NOT_RUNNING flag REBOUND.
+ * @worker will clear REBOUND using worker_clr_flags() when
+ * it initiates the next execution cycle thus restoring
+ * concurrency management. Note that when or whether
+ * @worker clears REBOUND doesn't affect correctness.
+ *
+ * ACCESS_ONCE() is necessary because @worker->flags may be
+ * tested without holding any lock in
+ * wq_worker_waking_up(). Without it, NOT_RUNNING test may
+ * fail incorrectly leading to premature concurrency
+ * management operations.
+ */
+ WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND));
+ worker_flags |= WORKER_REBOUND;
+ worker_flags &= ~WORKER_UNBOUND;
+ ACCESS_ONCE(worker->flags) = worker_flags;
+ }
+
+ spin_unlock_irq(&pool->lock);
+}
+
+/**
+ * restore_unbound_workers_cpumask - restore cpumask of unbound workers
+ * @pool: unbound pool of interest
+ * @cpu: the CPU which is coming up
+ *
+ * An unbound pool may end up with a cpumask which doesn't have any online
+ * CPUs. When a worker of such pool get scheduled, the scheduler resets
+ * its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any
+ * online CPU before, cpus_allowed of all its workers should be restored.
+ */
+static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
+{
+ static cpumask_t cpumask;
+ struct worker *worker;
+ int wi;
+
+ lockdep_assert_held(&pool->manager_mutex);
+
+ /* is @cpu allowed for @pool? */
+ if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
+ return;
+
+ /* is @cpu the only online CPU? */
+ cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask);
+ if (cpumask_weight(&cpumask) != 1)
+ return;
+
+ /* as we're called from CPU_ONLINE, the following shouldn't fail */
+ for_each_pool_worker(worker, wi, pool)
+ WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
+ pool->attrs->cpumask) < 0);
}
/*
unsigned long action,
void *hcpu)
{
- unsigned int cpu = (unsigned long)hcpu;
- struct global_cwq *gcwq = get_gcwq(cpu);
+ int cpu = (unsigned long)hcpu;
struct worker_pool *pool;
+ int pi;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
- for_each_worker_pool(pool, gcwq) {
- struct worker *worker;
-
+ for_each_cpu_worker_pool(pool, cpu) {
if (pool->nr_workers)
continue;
-
- worker = create_worker(pool);
- if (!worker)
+ if (create_and_start_worker(pool) < 0)
return NOTIFY_BAD;
-
- spin_lock_irq(&gcwq->lock);
- start_worker(worker);
- spin_unlock_irq(&gcwq->lock);
}
break;
case CPU_DOWN_FAILED:
case CPU_ONLINE:
- gcwq_claim_assoc_and_lock(gcwq);
- gcwq->flags &= ~GCWQ_DISASSOCIATED;
- rebind_workers(gcwq);
- gcwq_release_assoc_and_unlock(gcwq);
+ mutex_lock(&wq_pool_mutex);
+
+ for_each_pool(pool, pi) {
+ mutex_lock(&pool->manager_mutex);
+
+ if (pool->cpu == cpu) {
+ spin_lock_irq(&pool->lock);
+ pool->flags &= ~POOL_DISASSOCIATED;
+ spin_unlock_irq(&pool->lock);
+
+ rebind_workers(pool);
+ } else if (pool->cpu < 0) {
+ restore_unbound_workers_cpumask(pool, cpu);
+ }
+
+ mutex_unlock(&pool->manager_mutex);
+ }
+
+ mutex_unlock(&wq_pool_mutex);
break;
}
return NOTIFY_OK;
unsigned long action,
void *hcpu)
{
- unsigned int cpu = (unsigned long)hcpu;
+ int cpu = (unsigned long)hcpu;
struct work_struct unbind_work;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DOWN_PREPARE:
/* unbinding should happen on the local CPU */
- INIT_WORK_ONSTACK(&unbind_work, gcwq_unbind_fn);
+ INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn);
queue_work_on(cpu, system_highpri_wq, &unbind_work);
flush_work(&unbind_work);
break;
* It is up to the caller to ensure that the cpu doesn't go offline.
* The caller must not hold any locks which would prevent @fn from completing.
*/
-long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
+long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
{
struct work_for_cpu wfc = { .fn = fn, .arg = arg };
* freeze_workqueues_begin - begin freezing workqueues
*
* Start freezing workqueues. After this function returns, all freezable
- * workqueues will queue new works to their frozen_works list instead of
- * gcwq->worklist.
+ * workqueues will queue new works to their delayed_works list instead of
+ * pool->worklist.
*
* CONTEXT:
- * Grabs and releases workqueue_lock and gcwq->lock's.
+ * Grabs and releases wq_pool_mutex, pwq_lock and pool->lock's.
*/
void freeze_workqueues_begin(void)
{
- unsigned int cpu;
+ struct worker_pool *pool;
+ struct workqueue_struct *wq;
+ struct pool_workqueue *pwq;
+ int pi;
- spin_lock(&workqueue_lock);
+ mutex_lock(&wq_pool_mutex);
- BUG_ON(workqueue_freezing);
+ WARN_ON_ONCE(workqueue_freezing);
workqueue_freezing = true;
- for_each_gcwq_cpu(cpu) {
- struct global_cwq *gcwq = get_gcwq(cpu);
- struct workqueue_struct *wq;
-
- spin_lock_irq(&gcwq->lock);
-
- BUG_ON(gcwq->flags & GCWQ_FREEZING);
- gcwq->flags |= GCWQ_FREEZING;
-
- list_for_each_entry(wq, &workqueues, list) {
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
-
- if (cwq && wq->flags & WQ_FREEZABLE)
- cwq->max_active = 0;
- }
+ /* set FREEZING */
+ for_each_pool(pool, pi) {
+ spin_lock_irq(&pool->lock);
+ WARN_ON_ONCE(pool->flags & POOL_FREEZING);
+ pool->flags |= POOL_FREEZING;
+ spin_unlock_irq(&pool->lock);
+ }
- spin_unlock_irq(&gcwq->lock);
+ /* suppress further executions by setting max_active to zero */
+ spin_lock_irq(&pwq_lock);
+ list_for_each_entry(wq, &workqueues, list) {
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
}
+ spin_unlock_irq(&pwq_lock);
- spin_unlock(&workqueue_lock);
+ mutex_unlock(&wq_pool_mutex);
}
/**
* between freeze_workqueues_begin() and thaw_workqueues().
*
* CONTEXT:
- * Grabs and releases workqueue_lock.
+ * Grabs and releases wq_pool_mutex.
*
* RETURNS:
* %true if some freezable workqueues are still busy. %false if freezing
*/
bool freeze_workqueues_busy(void)
{
- unsigned int cpu;
bool busy = false;
+ struct workqueue_struct *wq;
+ struct pool_workqueue *pwq;
- spin_lock(&workqueue_lock);
+ mutex_lock(&wq_pool_mutex);
- BUG_ON(!workqueue_freezing);
+ WARN_ON_ONCE(!workqueue_freezing);
- for_each_gcwq_cpu(cpu) {
- struct workqueue_struct *wq;
+ list_for_each_entry(wq, &workqueues, list) {
+ if (!(wq->flags & WQ_FREEZABLE))
+ continue;
/*
* nr_active is monotonically decreasing. It's safe
* to peek without lock.
*/
- list_for_each_entry(wq, &workqueues, list) {
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
-
- if (!cwq || !(wq->flags & WQ_FREEZABLE))
- continue;
-
- BUG_ON(cwq->nr_active < 0);
- if (cwq->nr_active) {
+ rcu_read_lock_sched();
+ for_each_pwq(pwq, wq) {
+ WARN_ON_ONCE(pwq->nr_active < 0);
+ if (pwq->nr_active) {
busy = true;
+ rcu_read_unlock_sched();
goto out_unlock;
}
}
+ rcu_read_unlock_sched();
}
out_unlock:
- spin_unlock(&workqueue_lock);
+ mutex_unlock(&wq_pool_mutex);
return busy;
}
* thaw_workqueues - thaw workqueues
*
* Thaw workqueues. Normal queueing is restored and all collected
- * frozen works are transferred to their respective gcwq worklists.
+ * frozen works are transferred to their respective pool worklists.
*
* CONTEXT:
- * Grabs and releases workqueue_lock and gcwq->lock's.
+ * Grabs and releases wq_pool_mutex, pwq_lock and pool->lock's.
*/
void thaw_workqueues(void)
{
- unsigned int cpu;
+ struct workqueue_struct *wq;
+ struct pool_workqueue *pwq;
+ struct worker_pool *pool;
+ int pi;
- spin_lock(&workqueue_lock);
+ mutex_lock(&wq_pool_mutex);
if (!workqueue_freezing)
goto out_unlock;
- for_each_gcwq_cpu(cpu) {
- struct global_cwq *gcwq = get_gcwq(cpu);
- struct worker_pool *pool;
- struct workqueue_struct *wq;
-
- spin_lock_irq(&gcwq->lock);
-
- BUG_ON(!(gcwq->flags & GCWQ_FREEZING));
- gcwq->flags &= ~GCWQ_FREEZING;
-
- list_for_each_entry(wq, &workqueues, list) {
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
-
- if (!cwq || !(wq->flags & WQ_FREEZABLE))
- continue;
-
- /* restore max_active and repopulate worklist */
- cwq_set_max_active(cwq, wq->saved_max_active);
- }
-
- for_each_worker_pool(pool, gcwq)
- wake_up_worker(pool);
+ /* clear FREEZING */
+ for_each_pool(pool, pi) {
+ spin_lock_irq(&pool->lock);
+ WARN_ON_ONCE(!(pool->flags & POOL_FREEZING));
+ pool->flags &= ~POOL_FREEZING;
+ spin_unlock_irq(&pool->lock);
+ }
- spin_unlock_irq(&gcwq->lock);
+ /* restore max_active and repopulate worklist */
+ spin_lock_irq(&pwq_lock);
+ list_for_each_entry(wq, &workqueues, list) {
+ for_each_pwq(pwq, wq)
+ pwq_adjust_max_active(pwq);
}
+ spin_unlock_irq(&pwq_lock);
workqueue_freezing = false;
out_unlock:
- spin_unlock(&workqueue_lock);
+ mutex_unlock(&wq_pool_mutex);
}
#endif /* CONFIG_FREEZER */
static int __init init_workqueues(void)
{
- unsigned int cpu;
- int i;
+ int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
+ int i, cpu;
- /* make sure we have enough bits for OFFQ CPU number */
- BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT)) <
- WORK_CPU_LAST);
+ /* make sure we have enough bits for OFFQ pool ID */
+ BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT)) <
+ WORK_CPU_END * NR_STD_WORKER_POOLS);
+
+ WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
+
+ pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP);
hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN);
- /* initialize gcwqs */
- for_each_gcwq_cpu(cpu) {
- struct global_cwq *gcwq = get_gcwq(cpu);
+ /* initialize CPU pools */
+ for_each_possible_cpu(cpu) {
struct worker_pool *pool;
- spin_lock_init(&gcwq->lock);
- gcwq->cpu = cpu;
- gcwq->flags |= GCWQ_DISASSOCIATED;
-
- for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)
- INIT_HLIST_HEAD(&gcwq->busy_hash[i]);
-
- for_each_worker_pool(pool, gcwq) {
- pool->gcwq = gcwq;
- INIT_LIST_HEAD(&pool->worklist);
- INIT_LIST_HEAD(&pool->idle_list);
-
- init_timer_deferrable(&pool->idle_timer);
- pool->idle_timer.function = idle_worker_timeout;
- pool->idle_timer.data = (unsigned long)pool;
-
- setup_timer(&pool->mayday_timer, gcwq_mayday_timeout,
- (unsigned long)pool);
-
- mutex_init(&pool->assoc_mutex);
- ida_init(&pool->worker_ida);
+ i = 0;
+ for_each_cpu_worker_pool(pool, cpu) {
+ BUG_ON(init_worker_pool(pool));
+ pool->cpu = cpu;
+ cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu));
+ pool->attrs->nice = std_nice[i++];
+
+ /* alloc pool ID */
+ mutex_lock(&wq_pool_mutex);
+ BUG_ON(worker_pool_assign_id(pool));
+ mutex_unlock(&wq_pool_mutex);
}
}
/* create the initial worker */
- for_each_online_gcwq_cpu(cpu) {
- struct global_cwq *gcwq = get_gcwq(cpu);
+ for_each_online_cpu(cpu) {
struct worker_pool *pool;
- if (cpu != WORK_CPU_UNBOUND)
- gcwq->flags &= ~GCWQ_DISASSOCIATED;
+ for_each_cpu_worker_pool(pool, cpu) {
+ pool->flags &= ~POOL_DISASSOCIATED;
+ BUG_ON(create_and_start_worker(pool) < 0);
+ }
+ }
- for_each_worker_pool(pool, gcwq) {
- struct worker *worker;
+ /* create default unbound wq attrs */
+ for (i = 0; i < NR_STD_WORKER_POOLS; i++) {
+ struct workqueue_attrs *attrs;
- worker = create_worker(pool);
- BUG_ON(!worker);
- spin_lock_irq(&gcwq->lock);
- start_worker(worker);
- spin_unlock_irq(&gcwq->lock);
- }
+ BUG_ON(!(attrs = alloc_workqueue_attrs(GFP_KERNEL)));
+
+ attrs->nice = std_nice[i];
+ cpumask_setall(attrs->cpumask);
+
+ unbound_std_wq_attrs[i] = attrs;
}
system_wq = alloc_workqueue("events", 0, 0);
git.openpandora.org / pandora-kernel.git / blobdiff