xfs: increase inode cluster size for v5 filesystems

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=8f80587bacb6eb893df0ee4e35fefa0dfcfdf9f4
Commit:     8f80587bacb6eb893df0ee4e35fefa0dfcfdf9f4
Parent:     9e3908e342eba6684621e616529669c17e271e7e
Author:     Dave Chinner <dchinner at redhat.com>
AuthorDate: Fri Nov 1 15:27:20 2013 +1100
Committer:  Ben Myers <bpm at sgi.com>
CommitDate: Mon Nov 18 09:29:36 2013 -0600

    xfs: increase inode cluster size for v5 filesystems
    
    v5 filesystems use 512 byte inodes as a minimum, so read inodes in
    clusters that are effectively half the size of a v4 filesystem with
    256 byte inodes. For v5 fielsystems, scale the inode cluster size
    with the size of the inode so that we keep a constant 32 inodes per
    cluster ratio for all inode IO.
    
    This only works if mkfs.xfs sets the inode alignment appropriately
    for larger inode clusters, so this functionality is made conditional
    on mkfs doing the right thing. xfs_repair needs to know about
    the inode alignment changes, too.
    
    Wall time:
    	create	bulkstat	find+stat	ls -R	unlink
    v4	237s	161s		173s		201s	299s
    v5	235s	163s		205s		 31s	356s
    patched	234s	160s		182s		 29s	317s
    
    System time:
    	create	bulkstat	find+stat	ls -R	unlink
    v4	2601s	2490s		1653s		1656s	2960s
    v5	2637s	2497s		1681s		  20s	3216s
    patched	2613s	2451s		1658s		  20s	3007s
    
    So, wall time same or down across the board, system time same or
    down across the board, and cache hit rates all improve except for
    the ls -R case which is a pure cold cache directory read workload
    on v5 filesystems...
    
    So, this patch removes most of the performance and CPU usage
    differential between v4 and v5 filesystems on traversal related
    workloads.
    
    Note: while this patch is currently for v5 filesystems only, there
    is no reason it can't be ported back to v4 filesystems.  This hasn't
    been done here because bringing the code back to v4 requires
    forwards and backwards kernel compatibility testing.  i.e. to
    deterine if older kernels(*) do the right thing with larger inode
    alignments but still only using 8k inode cluster sizes. None of this
    testing and validation on v4 filesystems has been done, so for the
    moment larger inode clusters is limited to v5 superblocks.
    
    (*) a current default config v4 filesystem should mount just fine on
    2.6.23 (when lazy-count support was introduced), and so if we change
    the alignment emitted by mkfs without a feature bit then we have to
    make sure it works properly on all kernels since 2.6.23. And if we
    allow it to be changed when the lazy-count bit is not set, then it's
    all kernels since v2 logs were introduced that need to be tested for
    compatibility...
    
    Signed-off-by: Dave Chinner <dchinner at redhat.com>
    Reviewed-by: Christoph Hellwig <hch at lst.de>
    Reviewed-by: Eric Sandeen <sandeen at redhat.com>
    Signed-off-by: Ben Myers <bpm at sgi.com>
---
 fs/xfs/xfs_mount.c      | 15 +++++++++++++++
 fs/xfs/xfs_mount.h      |  2 +-
 fs/xfs/xfs_trans_resv.c |  3 +--
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index da88f16..02df7b4 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -41,6 +41,7 @@
 #include "xfs_fsops.h"
 #include "xfs_trace.h"
 #include "xfs_icache.h"
+#include "xfs_dinode.h"
 
 
 #ifdef HAVE_PERCPU_SB
@@ -718,8 +719,22 @@ xfs_mountfs(
 	 * Set the inode cluster size.
 	 * This may still be overridden by the file system
 	 * block size if it is larger than the chosen cluster size.
+	 *
+	 * For v5 filesystems, scale the cluster size with the inode size to
+	 * keep a constant ratio of inode per cluster buffer, but only if mkfs
+	 * has set the inode alignment value appropriately for larger cluster
+	 * sizes.
 	 */
 	mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		int	new_size = mp->m_inode_cluster_size;
+
+		new_size *= mp->m_sb.sb_inodesize / XFS_DINODE_MIN_SIZE;
+		if (mp->m_sb.sb_inoalignmt >= XFS_B_TO_FSBT(mp, new_size))
+			mp->m_inode_cluster_size = new_size;
+		xfs_info(mp, "Using inode cluster size of %d bytes",
+			 mp->m_inode_cluster_size);
+	}
 
 	/*
 	 * Set inode alignment fields
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 1d8101a..a466c5e 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -112,7 +112,7 @@ typedef struct xfs_mount {
 	__uint8_t		m_blkbb_log;	/* blocklog - BBSHIFT */
 	__uint8_t		m_agno_log;	/* log #ag's */
 	__uint8_t		m_agino_log;	/* #bits for agino in inum */
-	__uint16_t		m_inode_cluster_size;/* min inode buf size */
+	uint			m_inode_cluster_size;/* min inode buf size */
 	uint			m_blockmask;	/* sb_blocksize-1 */
 	uint			m_blockwsize;	/* sb_blocksize in words */
 	uint			m_blockwmask;	/* blockwsize-1 */
diff --git a/fs/xfs/xfs_trans_resv.c b/fs/xfs/xfs_trans_resv.c
index d53d9f0..2fd59c0 100644
--- a/fs/xfs/xfs_trans_resv.c
+++ b/fs/xfs/xfs_trans_resv.c
@@ -385,8 +385,7 @@ xfs_calc_ifree_reservation(
 		xfs_calc_inode_res(mp, 1) +
 		xfs_calc_buf_res(2, mp->m_sb.sb_sectsize) +
 		xfs_calc_buf_res(1, XFS_FSB_TO_B(mp, 1)) +
-		MAX((__uint16_t)XFS_FSB_TO_B(mp, 1),
-		    XFS_INODE_CLUSTER_SIZE(mp)) +
+		max_t(uint, XFS_FSB_TO_B(mp, 1), XFS_INODE_CLUSTER_SIZE(mp)) +
 		xfs_calc_buf_res(1, 0) +
 		xfs_calc_buf_res(2 + XFS_IALLOC_BLOCKS(mp) +
 				 mp->m_in_maxlevels, 0) +