Btrfs: Limit the number of async bio submission kthreads to the number of devices

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 56c54a4..99bd9f9 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1348,7 +1348,9 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         * cannot dynamically grow.
         */
        btrfs_init_workers(&fs_info->workers, fs_info->thread_pool_size);
-       btrfs_init_workers(&fs_info->submit_workers, fs_info->thread_pool_size);
+       btrfs_init_workers(&fs_info->submit_workers,
+                          min_t(u64, fs_devices->num_devices,
+                          fs_info->thread_pool_size));
 
        /* 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