Btrfs: set ioprio of scrub readahead to idle
Reduce ioprio class of scrub readahead threads to idle priority.
This setting is fixed. This priority has shown the best performance
during all measurements.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e176f8c..1c665eb 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -173,6 +173,9 @@
#define BTRFS_FT_XATTR 8
#define BTRFS_FT_MAX 9
+/* ioprio of readahead is set to idle */
+#define BTRFS_IOPRIO_READA (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0))
+
/*
* The key defines the order in the tree, and so it also defines (optimal)
* block layout.