This is a huge performance improvement for two reasons:
1. It uses the filesystem’s asynchronous I/O support, rather than using
synchronous I/O.
2. It bypasses the page cache, removing a redundant layer of caching and
associated overhead.
---
tools/hotplug/Linux/block | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/hotplug/Linux/block b/tools/hotplug/Linux/block
index
2691b56951c9b82094471a141b9e0bed04abb929..75785f3a5422c4a5f962a4cd4f6acae5080d036d
100644
--- a/tools/hotplug/Linux/block
+++ b/tools/hotplug/Linux/block
@@ -330,7 +330,7 @@ mount it read-write in a guest domain."
else
roflag=''
fi
- do_or_die losetup $roflag "$loopdev" "$file"
+ do_or_die losetup --direct-io=on $roflag "$loopdev" "$file"
xenstore_write "$XENBUS_PATH/node" "$loopdev"
write_dev "$loopdev"
release_lock "block"
--
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab
