diff options
| -rw-r--r-- | fs/btrfs/async-thread.c | 133 | ||||
| -rw-r--r-- | fs/btrfs/async-thread.h | 9 | ||||
| -rw-r--r-- | fs/btrfs/disk-io.c | 22 |
3 files changed, 132 insertions, 32 deletions
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index 019e8af449a..f10c895224a 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -48,6 +48,9 @@ struct btrfs_worker_thread { /* number of things on the pending list */ atomic_t num_pending; + /* reference counter for this struct */ + atomic_t refs; + unsigned long sequence; /* protects the pending list. */ @@ -93,6 +96,31 @@ static void check_busy_worker(struct btrfs_worker_thread *worker) } } +static void check_pending_worker_creates(struct btrfs_worker_thread *worker) +{ + struct btrfs_workers *workers = worker->workers; + unsigned long flags; + + rmb(); + if (!workers->atomic_start_pending) + return; + + spin_lock_irqsave(&workers->lock, flags); + if (!workers->atomic_start_pending) + goto out; + + workers->atomic_start_pending = 0; + if (workers->num_workers >= workers->max_workers) + goto out; + + spin_unlock_irqrestore(&workers->lock, flags); + btrfs_start_workers(workers, 1); + return; + +out: + spin_unlock_irqrestore(&workers->lock, flags); +} + static noinline int run_ordered_completions(struct btrfs_workers *workers, struct btrfs_work *work) { @@ -140,6 +168,36 @@ static noinline int run_ordered_completions(struct btrfs_workers *workers, return 0; } +static void put_worker(struct btrfs_worker_thread *worker) +{ + if (atomic_dec_and_test(&worker->refs)) + kfree(worker); +} + +static int try_worker_shutdown(struct btrfs_worker_thread *worker) +{ + int freeit = 0; + + spin_lock_irq(&worker->lock); + spin_lock_irq(&worker->workers->lock); + if (worker->workers->num_workers > 1 && + worker->idle && + !worker->working && + !list_empty(&worker->worker_list) && + list_empty(&worker->prio_pending) && + list_empty(&worker->pending)) { + freeit = 1; + list_del_init(&worker->worker_list); + worker->workers->num_workers--; + } + spin_unlock_irq(&worker->workers->lock); + spin_unlock_irq(&worker->lock); + + if (freeit) + put_worker(worker); + return freeit; +} + /* * main loop for servicing work items */ @@ -175,6 +233,8 @@ again_locked: */ run_ordered_completions(worker->workers, work); + check_pending_worker_creates(worker); + spin_lock_irq(&worker->lock); check_idle_worker(worker); } @@ -226,8 +286,13 @@ again_locked: worker->working = 0; spin_unlock_irq(&worker->lock); - if (!kthread_should_stop()) - schedule(); + if (!kthread_should_stop()) { + schedule_timeout(HZ * 120); + if (!worker->working && + try_worker_shutdown(worker)) { + return 0; + } + } } __set_current_state(TASK_RUNNING); } @@ -242,16 +307,30 @@ int btrfs_stop_workers(struct btrfs_workers *workers) { struct list_head *cur; struct btrfs_worker_thread *worker; + int can_stop; + spin_lock_irq(&workers->lock); list_splice_init(&workers->idle_list, &workers->worker_list); while (!list_empty(&workers->worker_list)) { cur = workers->worker_list.next; worker = list_entry(cur, struct btrfs_worker_thread, worker_list); - kthread_stop(worker->task); - list_del(&worker->worker_list); - kfree(worker); + + atomic_inc(&worker->refs); + workers->num_workers -= 1; + if (!list_empty(&worker->worker_list)) { + list_del_init(&worker->worker_list); + put_worker(worker); + can_stop = 1; + } else + can_stop = 0; + spin_unlock_irq(&workers->lock); + if (can_stop) + kthread_stop(worker->task); + spin_lock_irq(&workers->lock); + put_worker(worker); } + spin_unlock_irq(&workers->lock); return 0; } @@ -270,6 +349,8 @@ void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max) workers->idle_thresh = 32; workers->name = name; workers->ordered = 0; + workers->atomic_start_pending = 0; + workers->atomic_worker_start = 0; } /* @@ -294,6 +375,7 @@ int btrfs_start_workers(struct btrfs_workers *workers, int num_workers) INIT_LIST_HEAD(&worker->worker_list); spin_lock_init(&worker->lock); atomic_set(&worker->num_pending, 0); + atomic_set(&worker->refs, 1); worker->workers = workers; worker->task = kthread_run(worker_loop, worker, "btrfs-%s-%d", workers->name, @@ -303,7 +385,6 @@ int btrfs_start_workers(struct btrfs_workers *workers, int num_workers) kfree(worker); goto fail; } - spin_lock_irq(&workers->lock); list_add_tail(&worker->worker_list, &workers->idle_list); worker->idle = 1; @@ -367,6 +448,7 @@ static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers) { struct btrfs_worker_thread *worker; unsigned long flags; + struct list_head *fallback; again: spin_lock_irqsave(&workers->lock, flags); @@ -376,19 +458,10 @@ again: if (!worker) { spin_lock_irqsave(&workers->lock, flags); if (workers->num_workers >= workers->max_workers) { - struct list_head *fallback = NULL; - /* - * we have failed to find any workers, just - * return the force one - */ - if (!list_empty(&workers->worker_list)) - fallback = workers->worker_list.next; - if (!list_empty(&workers->idle_list)) - fallback = workers->idle_list.next; - BUG_ON(!fallback); - worker = list_entry(fallback, - struct btrfs_worker_thread, worker_list); - spin_unlock_irqrestore(&workers->lock, flags); + goto fallback; + } else if (workers->atomic_worker_start) { + workers->atomic_start_pending = 1; + goto fallback; } else { spin_unlock_irqrestore(&workers->lock, flags); /* we're below the limit, start another worker */ @@ -397,6 +470,22 @@ again: } } return worker; + +fallback: + fallback = NULL; + /* + * we have failed to find any workers, just + * return the first one we can find. + */ + if (!list_empty(&workers->worker_list)) + fallback = workers->worker_list.next; + if (!list_empty(&workers->idle_list)) + fallback = workers->idle_list.next; + BUG_ON(!fallback); + worker = list_entry(fallback, + struct btrfs_worker_thread, worker_list); + spin_unlock_irqrestore(&workers->lock, flags); + return worker; } /* @@ -435,9 +524,9 @@ int btrfs_requeue_work(struct btrfs_work *work) worker->working = 1; } - spin_unlock_irqrestore(&worker->lock, flags); if (wake) wake_up_process(worker->task); + spin_unlock_irqrestore(&worker->lock, flags); out: return 0; @@ -492,10 +581,10 @@ int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work) wake = 1; worker->working = 1; - spin_unlock_irqrestore(&worker->lock, flags); - if (wake) wake_up_process(worker->task); + spin_unlock_irqrestore(&worker->lock, flags); + out: return 0; } diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h index 1b511c109db..a562ad8d83a 100644 --- a/fs/btrfs/async-thread.h +++ b/fs/btrfs/async-thread.h @@ -73,6 +73,15 @@ struct btrfs_workers { /* force completions in the order they were queued */ int ordered; + /* more workers required, but in an interrupt handler */ + int atomic_start_pending; + + /* + * are we allowed to sleep while starting workers or are we required + * to start them at a later time? + */ + int atomic_worker_start; + /* list with all the work threads. The workers on the idle thread * may be actively servicing jobs, but they haven't yet hit the * idle thresh limit above. diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 3cf4cfa575c..20cefc6f22c 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1682,7 +1682,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, err = -EINVAL; goto fail_iput; } - +printk("thread pool is %d\n", fs_info->thread_pool_size); /* * we need to start all the end_io workers up front because the * queue work function gets called at interrupt time, and so it @@ -1727,20 +1727,22 @@ struct btrfs_root *open_ctree(struct super_block *sb, fs_info->endio_workers.idle_thresh = 4; fs_info->endio_meta_workers.idle_thresh = 4; - fs_info->endio_write_workers.idle_thresh = 64; - fs_info->endio_meta_write_workers.idle_thresh = 64; + fs_info->endio_write_workers.idle_thresh = 2; + fs_info->endio_meta_write_workers.idle_thresh = 2; + + fs_info->endio_workers.atomic_worker_start = 1; + fs_info->endio_meta_workers.atomic_worker_start = 1; + fs_info->endio_write_workers.atomic_worker_start = 1; + fs_info->endio_meta_write_workers.atomic_worker_start = 1; btrfs_start_workers(&fs_info->workers, 1); btrfs_start_workers(&fs_info->submit_workers, 1); btrfs_start_workers(&fs_info->delalloc_workers, 1); btrfs_start_workers(&fs_info->fixup_workers, 1); - btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size); - btrfs_start_workers(&fs_info->endio_meta_workers, - fs_info->thread_pool_size); - btrfs_start_workers(&fs_info->endio_meta_write_workers, - fs_info->thread_pool_size); - btrfs_start_workers(&fs_info->endio_write_workers, - fs_info->thread_pool_size); + btrfs_start_workers(&fs_info->endio_workers, 1); + btrfs_start_workers(&fs_info->endio_meta_workers, 1); + btrfs_start_workers(&fs_info->endio_meta_write_workers, 1); + btrfs_start_workers(&fs_info->endio_write_workers, 1); fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super); fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages, |