On 01/31/2018 04:06 PM, Nikolay Borisov wrote:
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 1a462ab85c49..4759e988b0df 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1100,6 +1100,8 @@ struct btrfs_fs_info { spinlock_t ref_verify_lock; struct rb_root block_tree; #endif + /* Policy to balance read across mirrored devices */ + int read_mirror_policy;make that member enum btrfs_read_mirror_type
yep. Will do. ::
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index a61715677b67..39ba59832f38 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -5269,7 +5269,13 @@ static int find_live_mirror(struct btrfs_fs_info *fs_info, else num = map->num_stripes;- optimal = first + current->pid % num;+ switch(fs_info->read_mirror_policy) { + case BTRFS_READ_MIRROR_DEFAULT: + case BTRFS_READ_MIRROR_BY_PID: + default: + optimal = first + current->pid % num; + break; + }Why not factor out this code in a separate function with descriptive name and some documentation. It seems you have plans how to extend this mechanism further so let's try and make it maintainable from the get-go.
This is in fact restoring the original design, will add comments. In the long term we may have up couple of more choices (like LBA), will move it to a function. Thanks, Anand -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
