Commit 34eefc06 authored Jun 27, 2013 by Dave Chinner Committed by Ben Myers Jun 27, 2013

xfs: plug directory buffer readahead



Similar to bulkstat inode chunk readahead, we need to plug directory
data buffer readahead during getdents to ensure that we can merge
adjacent readahead requests and sort out of order requests optimally
before they are dispatched. This improves the readahead efficiency
and reduces the IO load it generates as the IO patterns are
significantly better for both contiguous and fragmented directories.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

parent cbb2864a

fs/xfs/xfs_dir2_leaf.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1108,6 +1108,7 @@ xfs_dir2_leaf_readbuf(
		struct xfs_mount *mp = dp->i_mount;
		struct xfs_buf bp = bpp;
		struct xfs_bmbt_irec *map = mip->map;
		struct blk_plug plug;
		int error = 0;
		int length;
		int i;
		@@ -1236,6 +1237,7 @@ xfs_dir2_leaf_readbuf(
		/*
		* Do we need more readahead?
		*/
		blk_start_plug(&plug);
		for (mip->ra_index = mip->ra_offset = i = 0;
		mip->ra_want > mip->ra_current && i < mip->map_blocks;
		i += mp->m_dirblkfsbs) {
		@@ -1287,6 +1289,7 @@ xfs_dir2_leaf_readbuf(
		}
		}
		}
		blk_finish_plug(&plug);

		out:
		*bpp = bp;