This patch enables reader optimistic spinning for inodes that are under a DAX-based mount point.
On a 4-socket Haswell machine running on a 4.7-rc1 tip-based kernel, the fio test with multithreaded randrw and randwrite tests on the same file on a XFS partition on top of a NVDIMM with DAX were run, the aggregated bandwidths before and after the patch were as follows: Test BW before patch BW after patch % change ---- --------------- -------------- -------- randrw 1352 MB/s 2164 MB/s +60% randwrite 1710 MB/s 2550 MB/s +49% Signed-off-by: Waiman Long <[email protected]> --- fs/xfs/xfs_icache.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c index 99ee6ee..09f284f 100644 --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -71,6 +71,15 @@ xfs_inode_alloc( mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino); + /* + * Enable reader spinning for DAX nount point + */ + if (mp->m_flags & XFS_MOUNT_DAX) { + rwsem_set_rspin_threshold(&ip->i_iolock.mr_lock); + rwsem_set_rspin_threshold(&ip->i_mmaplock.mr_lock); + rwsem_set_rspin_threshold(&ip->i_lock.mr_lock); + } + /* initialise the xfs inode */ ip->i_ino = ino; ip->i_mount = mp; -- 1.7.1
