From 42f8570f437b65aaf3ef176a38ad7d7fc5847d8b Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Mon, 17 Dec 2012 10:01:23 -0500 Subject: [PATCH] workqueue: use new hashtable implementation Switch workqueues to use the new hashtable implementation. This reduces the amount of generic unrelated code in the workqueues. This patch depends on d9b482c ("hashtable: introduce a small and naive hashtable") which was merged in v3.6. Acked-by: Tejun Heo Signed-off-by: Sasha Levin Signed-off-by: Tejun Heo --- kernel/workqueue.c | 86 ++++++++-------------------------------------- 1 file changed, 15 insertions(+), 71 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index fbc6576a83c3..acd417be8199 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -41,6 +41,7 @@ #include #include #include +#include #include "workqueue_sched.h" @@ -82,8 +83,6 @@ enum { NR_WORKER_POOLS = 2, /* # worker pools per gcwq */ 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 */ @@ -180,7 +179,7 @@ struct global_cwq { unsigned int flags; /* L: GCWQ_* flags */ /* workers are chained either in busy_hash or pool idle_list */ - struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE]; + DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER); /* L: hash of busy workers */ struct worker_pool pools[NR_WORKER_POOLS]; @@ -285,8 +284,7 @@ EXPORT_SYMBOL_GPL(system_freezable_wq); (pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++) #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) + hash_for_each(gcwq->busy_hash, i, pos, worker, hentry) static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask, unsigned int sw) @@ -858,63 +856,6 @@ static inline void worker_clr_flags(struct worker *worker, unsigned int flags) 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]; -} - -/** - * __find_worker_executing_work - find worker which is executing a work - * @gcwq: gcwq of interest - * @bwh: hash head as returned by busy_worker_head() - * @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. - * - * 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 hlist_head *bwh, - struct work_struct *work) -{ - struct worker *worker; - struct hlist_node *tmp; - - hlist_for_each_entry(worker, tmp, bwh, hentry) - if (worker->current_work == work) - return worker; - return NULL; -} - /** * find_worker_executing_work - find worker which is executing a work * @gcwq: gcwq of interest @@ -934,8 +875,14 @@ static struct worker *__find_worker_executing_work(struct global_cwq *gcwq, 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); + struct worker *worker; + struct hlist_node *tmp; + + hash_for_each_possible(gcwq->busy_hash, worker, tmp, hentry, (unsigned long)work) + if (worker->current_work == work) + return worker; + + return NULL; } /** @@ -2166,7 +2113,6 @@ __acquires(&gcwq->lock) struct cpu_workqueue_struct *cwq = get_work_cwq(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; int work_color; @@ -2198,7 +2144,7 @@ __acquires(&gcwq->lock) * 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(gcwq, work); if (unlikely(collision)) { move_linked_works(work, &collision->scheduled, NULL); return; @@ -2206,7 +2152,7 @@ __acquires(&gcwq->lock) /* claim and dequeue */ debug_work_deactivate(work); - hlist_add_head(&worker->hentry, bwh); + hash_add(gcwq->busy_hash, &worker->hentry, (unsigned long)worker); worker->current_work = work; worker->current_cwq = cwq; work_color = get_work_color(work); @@ -2264,7 +2210,7 @@ __acquires(&gcwq->lock) 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); @@ -3831,7 +3777,6 @@ out_unlock: static int __init init_workqueues(void) { unsigned int cpu; - int i; /* make sure we have enough bits for OFFQ CPU number */ BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT)) < @@ -3849,8 +3794,7 @@ static int __init init_workqueues(void) gcwq->cpu = cpu; gcwq->flags |= GCWQ_DISASSOCIATED; - for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) - INIT_HLIST_HEAD(&gcwq->busy_hash[i]); + hash_init(gcwq->busy_hash); for_each_worker_pool(pool, gcwq) { pool->gcwq = gcwq;