xfs: improve metadata I/O merging in the elevator
Change all async metadata buffers to use [READ|WRITE]_META I/O types
so that the I/O doesn't get issued immediately. This allows merging of
adjacent metadata requests but still prioritises them over bulk data.
This shows a 10-15% improvement in sequential create speed of small
files.
Don't include the log buffers in this classification - leave them as
sync types so they are issued immediately.
Signed-off-by: Dave Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index a509f4a..a34c7b5 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -55,6 +55,7 @@
XBF_FS_MANAGED = (1 << 8), /* filesystem controls freeing memory */
XBF_ORDERED = (1 << 11), /* use ordered writes */
XBF_READ_AHEAD = (1 << 12), /* asynchronous read-ahead */
+ XBF_LOG_BUFFER = (1 << 13), /* this is a buffer used for the log */
/* flags used only as arguments to access routines */
XBF_LOCK = (1 << 14), /* lock requested */