From ba8a9d07954397f0645cf62bcc1ef536e8e7ba24 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 10 Jul 2019 12:28:15 -0700 Subject: [PATCH] Btrfs: delete the entire async bio submission framework Now that we're not using btrfs_schedule_bio() anymore, delete all the code that supported it. Reviewed-by: Josef Bacik Reviewed-by: Nikolay Borisov Signed-off-by: Chris Mason Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 1 - fs/btrfs/disk-io.c | 13 +--- fs/btrfs/super.c | 1 - fs/btrfs/volumes.c | 210 ----------------------------------------------------- fs/btrfs/volumes.h | 11 --- 5 files changed, 1 insertion(+), 235 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index d486703..d5c9fbe 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -723,7 +723,6 @@ struct btrfs_fs_info { struct btrfs_workqueue *endio_meta_write_workers; struct btrfs_workqueue *endio_write_workers; struct btrfs_workqueue *endio_freespace_worker; - struct btrfs_workqueue *submit_workers; struct btrfs_workqueue *caching_workers; struct btrfs_workqueue *readahead_workers; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index bad8386..18f80b3 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1989,7 +1989,6 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info) btrfs_destroy_workqueue(fs_info->rmw_workers); btrfs_destroy_workqueue(fs_info->endio_write_workers); btrfs_destroy_workqueue(fs_info->endio_freespace_worker); - btrfs_destroy_workqueue(fs_info->submit_workers); btrfs_destroy_workqueue(fs_info->delayed_workers); btrfs_destroy_workqueue(fs_info->caching_workers); btrfs_destroy_workqueue(fs_info->readahead_workers); @@ -2154,16 +2153,6 @@ static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info, fs_info->caching_workers = btrfs_alloc_workqueue(fs_info, "cache", flags, max_active, 0); - /* - * a higher idle thresh on the submit workers makes it much more - * likely that bios will be send down in a sane order to the - * devices - */ - fs_info->submit_workers = - btrfs_alloc_workqueue(fs_info, "submit", flags, - min_t(u64, fs_devices->num_devices, - max_active), 64); - fs_info->fixup_workers = btrfs_alloc_workqueue(fs_info, "fixup", flags, 1, 0); @@ -2202,7 +2191,7 @@ static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info, btrfs_alloc_workqueue(fs_info, "qgroup-rescan", flags, 1, 0); if (!(fs_info->workers && fs_info->delalloc_workers && - fs_info->submit_workers && fs_info->flush_workers && + fs_info->flush_workers && fs_info->endio_workers && fs_info->endio_meta_workers && fs_info->endio_meta_write_workers && fs_info->endio_repair_workers && diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 144933c..d5d15a1 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1669,7 +1669,6 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info, btrfs_workqueue_set_max(fs_info->workers, new_pool_size); btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size); - btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size); btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size); btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size); btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size); diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index eb92b4b..f03ad53 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -397,8 +397,6 @@ static struct btrfs_device *__alloc_device(void) INIT_LIST_HEAD(&dev->dev_alloc_list); INIT_LIST_HEAD(&dev->post_commit_list); - spin_lock_init(&dev->io_lock); - atomic_set(&dev->reada_in_flight, 0); atomic_set(&dev->dev_stats_ccnt, 0); btrfs_device_data_ordered_init(dev); @@ -501,212 +499,6 @@ error: return ret; } -static void requeue_list(struct btrfs_pending_bios *pending_bios, - struct bio *head, struct bio *tail) -{ - - struct bio *old_head; - - old_head = pending_bios->head; - pending_bios->head = head; - if (pending_bios->tail) - tail->bi_next = old_head; - else - pending_bios->tail = tail; -} - -/* - * we try to collect pending bios for a device so we don't get a large - * number of procs sending bios down to the same device. This greatly - * improves the schedulers ability to collect and merge the bios. - * - * But, it also turns into a long list of bios to process and that is sure - * to eventually make the worker thread block. The solution here is to - * make some progress and then put this work struct back at the end of - * the list if the block device is congested. This way, multiple devices - * can make progress from a single worker thread. - */ -static noinline void run_scheduled_bios(struct btrfs_device *device) -{ - struct btrfs_fs_info *fs_info = device->fs_info; - struct bio *pending; - struct backing_dev_info *bdi; - struct btrfs_pending_bios *pending_bios; - struct bio *tail; - struct bio *cur; - int again = 0; - unsigned long num_run; - unsigned long batch_run = 0; - unsigned long last_waited = 0; - int force_reg = 0; - int sync_pending = 0; - struct blk_plug plug; - - /* - * this function runs all the bios we've collected for - * a particular device. We don't want to wander off to - * another device without first sending all of these down. - * So, setup a plug here and finish it off before we return - */ - blk_start_plug(&plug); - - bdi = device->bdev->bd_bdi; - -loop: - spin_lock(&device->io_lock); - -loop_lock: - num_run = 0; - - /* take all the bios off the list at once and process them - * later on (without the lock held). But, remember the - * tail and other pointers so the bios can be properly reinserted - * into the list if we hit congestion - */ - if (!force_reg && device->pending_sync_bios.head) { - pending_bios = &device->pending_sync_bios; - force_reg = 1; - } else { - pending_bios = &device->pending_bios; - force_reg = 0; - } - - pending = pending_bios->head; - tail = pending_bios->tail; - WARN_ON(pending && !tail); - - /* - * if pending was null this time around, no bios need processing - * at all and we can stop. Otherwise it'll loop back up again - * and do an additional check so no bios are missed. - * - * device->running_pending is used to synchronize with the - * schedule_bio code. - */ - if (device->pending_sync_bios.head == NULL && - device->pending_bios.head == NULL) { - again = 0; - device->running_pending = 0; - } else { - again = 1; - device->running_pending = 1; - } - - pending_bios->head = NULL; - pending_bios->tail = NULL; - - spin_unlock(&device->io_lock); - - while (pending) { - - rmb(); - /* we want to work on both lists, but do more bios on the - * sync list than the regular list - */ - if ((num_run > 32 && - pending_bios != &device->pending_sync_bios && - device->pending_sync_bios.head) || - (num_run > 64 && pending_bios == &device->pending_sync_bios && - device->pending_bios.head)) { - spin_lock(&device->io_lock); - requeue_list(pending_bios, pending, tail); - goto loop_lock; - } - - cur = pending; - pending = pending->bi_next; - cur->bi_next = NULL; - - BUG_ON(atomic_read(&cur->__bi_cnt) == 0); - - /* - * if we're doing the sync list, record that our - * plug has some sync requests on it - * - * If we're doing the regular list and there are - * sync requests sitting around, unplug before - * we add more - */ - if (pending_bios == &device->pending_sync_bios) { - sync_pending = 1; - } else if (sync_pending) { - blk_finish_plug(&plug); - blk_start_plug(&plug); - sync_pending = 0; - } - - btrfsic_submit_bio(cur); - num_run++; - batch_run++; - - cond_resched(); - - /* - * we made progress, there is more work to do and the bdi - * is now congested. Back off and let other work structs - * run instead - */ - if (pending && bdi_write_congested(bdi) && batch_run > 8 && - fs_info->fs_devices->open_devices > 1) { - struct io_context *ioc; - - ioc = current->io_context; - - /* - * the main goal here is that we don't want to - * block if we're going to be able to submit - * more requests without blocking. - * - * This code does two great things, it pokes into - * the elevator code from a filesystem _and_ - * it makes assumptions about how batching works. - */ - if (ioc && ioc->nr_batch_requests > 0 && - time_before(jiffies, ioc->last_waited + HZ/50UL) && - (last_waited == 0 || - ioc->last_waited == last_waited)) { - /* - * we want to go through our batch of - * requests and stop. So, we copy out - * the ioc->last_waited time and test - * against it before looping - */ - last_waited = ioc->last_waited; - cond_resched(); - continue; - } - spin_lock(&device->io_lock); - requeue_list(pending_bios, pending, tail); - device->running_pending = 1; - - spin_unlock(&device->io_lock); - btrfs_queue_work(fs_info->submit_workers, - &device->work); - goto done; - } - } - - cond_resched(); - if (again) - goto loop; - - spin_lock(&device->io_lock); - if (device->pending_bios.head || device->pending_sync_bios.head) - goto loop_lock; - spin_unlock(&device->io_lock); - -done: - blk_finish_plug(&plug); -} - -static void pending_bios_fn(struct btrfs_work *work) -{ - struct btrfs_device *device; - - device = container_of(work, struct btrfs_device, work); - run_scheduled_bios(device); -} - static bool device_path_matched(const char *path, struct btrfs_device *device) { int found; @@ -6628,8 +6420,6 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info, else generate_random_uuid(dev->uuid); - btrfs_init_work(&dev->work, pending_bios_fn, NULL, NULL); - return dev; } diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index bc2bbaa..9b5fba4 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -18,10 +18,6 @@ extern struct mutex uuid_mutex; #define BTRFS_STRIPE_LEN SZ_64K struct buffer_head; -struct btrfs_pending_bios { - struct bio *head; - struct bio *tail; -}; struct btrfs_io_geometry { /* remaining bytes before crossing a stripe */ @@ -68,13 +64,6 @@ struct btrfs_device { u64 generation; - spinlock_t io_lock ____cacheline_aligned; - int running_pending; - /* regular prio bios */ - struct btrfs_pending_bios pending_bios; - /* sync bios */ - struct btrfs_pending_bios pending_sync_bios; - struct block_device *bdev; /* the mode sent to blkdev_get */ -- 2.7.4