Messages in this thread | | | Subject | Re: [PATCH 2/5] Btrfs: delete the entire async bio submission framework | From | Nikolay Borisov <> | Date | Thu, 11 Jul 2019 17:53:05 +0300 |
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On 10.07.19 г. 22:28 ч., Tejun Heo wrote: > From: Chris Mason <clm@fb.com> > > Now that we're not using btrfs_schedule_bio() anymore, delete all the > code that supported it. > > Signed-off-by: Chris Mason <clm@fb.com> > Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com> > --- > fs/btrfs/ctree.h | 1 - > fs/btrfs/disk-io.c | 13 +-- > fs/btrfs/super.c | 1 - > fs/btrfs/volumes.c | 209 --------------------------------------------- > fs/btrfs/volumes.h | 8 -- > 5 files changed, 1 insertion(+), 231 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 0a61dff27f57..21618b5b18a4 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -989,7 +989,6 @@ 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 6b1ecc27913b..323cab06f2a9 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -2028,7 +2028,6 @@ 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); > @@ -2194,16 +2193,6 @@ 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); > > @@ -2246,7 +2235,7 @@ static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info, > max_active), 8); > > 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 0645ec428b4f..b130dc43b5f1 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -1668,7 +1668,6 @@ 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 72326cc23985..fc3a16d87869 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -509,212 +509,6 @@ btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder, > 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; > @@ -6599,9 +6393,6 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info, > else > generate_random_uuid(dev->uuid); > > - btrfs_init_work(&dev->work, btrfs_submit_helper, > - pending_bios_fn, NULL, NULL); > - > return dev; > } > > diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h > index e532d095c6a4..819047621176 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; > -}; > > /* > * Use sequence counter to get consistent device stat data on > @@ -55,10 +51,6 @@ struct btrfs_device { > > 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; > >
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