From b64a2851ba25b3410a87d3d1b751155612105c8e Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 20 Aug 2008 13:39:41 -0400 Subject: Btrfs: Wait for async bio submissions to make some progress at queue time Before, the btrfs bdi congestion function was used to test for too many async bios. This keeps that check to throttle pdflush, but also adds a check while queuing bios. Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 23a5b0aba00..2652660e607 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -138,12 +138,18 @@ int run_scheduled_bios(struct btrfs_device *device) { struct bio *pending; struct backing_dev_info *bdi; + struct btrfs_fs_info *fs_info; struct bio *tail; struct bio *cur; int again = 0; unsigned long num_run = 0; + unsigned long limit; bdi = device->bdev->bd_inode->i_mapping->backing_dev_info; + fs_info = device->dev_root->fs_info; + limit = btrfs_async_submit_limit(fs_info); + limit = limit * 2 / 3; + loop: spin_lock(&device->io_lock); @@ -179,7 +185,11 @@ loop: cur = pending; pending = pending->bi_next; cur->bi_next = NULL; - atomic_dec(&device->dev_root->fs_info->nr_async_bios); + atomic_dec(&fs_info->nr_async_bios); + + if (atomic_read(&fs_info->nr_async_bios) < limit && + waitqueue_active(&fs_info->async_submit_wait)) + wake_up(&fs_info->async_submit_wait); BUG_ON(atomic_read(&cur->bi_cnt) == 0); bio_get(cur); @@ -2135,6 +2145,7 @@ int schedule_bio(struct btrfs_root *root, struct btrfs_device *device, int rw, struct bio *bio) { int should_queue = 1; + unsigned long limit; /* don't bother with additional async steps for reads, right now */ if (!(rw & (1 << BIO_RW))) { @@ -2171,6 +2182,11 @@ int schedule_bio(struct btrfs_root *root, struct btrfs_device *device, if (should_queue) btrfs_queue_worker(&root->fs_info->submit_workers, &device->work); + + limit = btrfs_async_submit_limit(root->fs_info); + wait_event_timeout(root->fs_info->async_submit_wait, + (atomic_read(&root->fs_info->nr_async_bios) < limit), + HZ/10); return 0; } -- cgit v1.2.3